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linux/drivers/iio/adc/at91-sama5d2_adc.c
Eugen Hristev 1a19879445 iio: adc: at91-sama5d2_adc: fix DMA conversion crash 
After the move of the postenable code to preenable, the DMA start was
done before the DMA init, which is not correct.
The DMA is initialized in set_watermark. Because of this, we need to call
the DMA start functions in set_watermark, after the DMA init, instead of
preenable hook, when the DMA is not properly setup yet.

Fixes: f3c034f617 ("iio: at91-sama5d2_adc: adjust iio_triggered_buffer_{predisable,postenable} positions")
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Link: https://lore.kernel.org/r/20200923121748.49384-1-eugen.hristev@microchip.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2020-09-29 17:50:35 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Atmel ADC driver for SAMA5D2 devices and compatible.
*
* Copyright (C) 2015 Atmel,
* 2015 Ludovic Desroches <ludovic.desroches@atmel.com>
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/pinctrl/consumer.h>
#include <linux/regulator/consumer.h>
/* Control Register */
#define AT91_SAMA5D2_CR 0x00
/* Software Reset */
#define AT91_SAMA5D2_CR_SWRST BIT(0)
/* Start Conversion */
#define AT91_SAMA5D2_CR_START BIT(1)
/* Touchscreen Calibration */
#define AT91_SAMA5D2_CR_TSCALIB BIT(2)
/* Comparison Restart */
#define AT91_SAMA5D2_CR_CMPRST BIT(4)
/* Mode Register */
#define AT91_SAMA5D2_MR 0x04
/* Trigger Selection */
#define AT91_SAMA5D2_MR_TRGSEL(v) ((v) << 1)
/* ADTRG */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG0 0
/* TIOA0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG1 1
/* TIOA1 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG2 2
/* TIOA2 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG3 3
/* PWM event line 0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG4 4
/* PWM event line 1 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG5 5
/* TIOA3 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG6 6
/* RTCOUT0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG7 7
/* Sleep Mode */
#define AT91_SAMA5D2_MR_SLEEP BIT(5)
/* Fast Wake Up */
#define AT91_SAMA5D2_MR_FWUP BIT(6)
/* Prescaler Rate Selection */
#define AT91_SAMA5D2_MR_PRESCAL(v) ((v) << AT91_SAMA5D2_MR_PRESCAL_OFFSET)
#define AT91_SAMA5D2_MR_PRESCAL_OFFSET 8
#define AT91_SAMA5D2_MR_PRESCAL_MAX 0xff
#define AT91_SAMA5D2_MR_PRESCAL_MASK GENMASK(15, 8)
/* Startup Time */
#define AT91_SAMA5D2_MR_STARTUP(v) ((v) << 16)
#define AT91_SAMA5D2_MR_STARTUP_MASK GENMASK(19, 16)
/* Analog Change */
#define AT91_SAMA5D2_MR_ANACH BIT(23)
/* Tracking Time */
#define AT91_SAMA5D2_MR_TRACKTIM(v) ((v) << 24)
#define AT91_SAMA5D2_MR_TRACKTIM_MAX 0xff
/* Transfer Time */
#define AT91_SAMA5D2_MR_TRANSFER(v) ((v) << 28)
#define AT91_SAMA5D2_MR_TRANSFER_MAX 0x3
/* Use Sequence Enable */
#define AT91_SAMA5D2_MR_USEQ BIT(31)
/* Channel Sequence Register 1 */
#define AT91_SAMA5D2_SEQR1 0x08
/* Channel Sequence Register 2 */
#define AT91_SAMA5D2_SEQR2 0x0c
/* Channel Enable Register */
#define AT91_SAMA5D2_CHER 0x10
/* Channel Disable Register */
#define AT91_SAMA5D2_CHDR 0x14
/* Channel Status Register */
#define AT91_SAMA5D2_CHSR 0x18
/* Last Converted Data Register */
#define AT91_SAMA5D2_LCDR 0x20
/* Interrupt Enable Register */
#define AT91_SAMA5D2_IER 0x24
/* Interrupt Enable Register - TS X measurement ready */
#define AT91_SAMA5D2_IER_XRDY BIT(20)
/* Interrupt Enable Register - TS Y measurement ready */
#define AT91_SAMA5D2_IER_YRDY BIT(21)
/* Interrupt Enable Register - TS pressure measurement ready */
#define AT91_SAMA5D2_IER_PRDY BIT(22)
/* Interrupt Enable Register - Data ready */
#define AT91_SAMA5D2_IER_DRDY BIT(24)
/* Interrupt Enable Register - general overrun error */
#define AT91_SAMA5D2_IER_GOVRE BIT(25)
/* Interrupt Enable Register - Pen detect */
#define AT91_SAMA5D2_IER_PEN BIT(29)
/* Interrupt Enable Register - No pen detect */
#define AT91_SAMA5D2_IER_NOPEN BIT(30)
/* Interrupt Disable Register */
#define AT91_SAMA5D2_IDR 0x28
/* Interrupt Mask Register */
#define AT91_SAMA5D2_IMR 0x2c
/* Interrupt Status Register */
#define AT91_SAMA5D2_ISR 0x30
/* Interrupt Status Register - Pen touching sense status */
#define AT91_SAMA5D2_ISR_PENS BIT(31)
/* Last Channel Trigger Mode Register */
#define AT91_SAMA5D2_LCTMR 0x34
/* Last Channel Compare Window Register */
#define AT91_SAMA5D2_LCCWR 0x38
/* Overrun Status Register */
#define AT91_SAMA5D2_OVER 0x3c
/* Extended Mode Register */
#define AT91_SAMA5D2_EMR 0x40
/* Extended Mode Register - Oversampling rate */
#define AT91_SAMA5D2_EMR_OSR(V) ((V) << 16)
#define AT91_SAMA5D2_EMR_OSR_MASK GENMASK(17, 16)
#define AT91_SAMA5D2_EMR_OSR_1SAMPLES 0
#define AT91_SAMA5D2_EMR_OSR_4SAMPLES 1
#define AT91_SAMA5D2_EMR_OSR_16SAMPLES 2
/* Extended Mode Register - Averaging on single trigger event */
#define AT91_SAMA5D2_EMR_ASTE(V) ((V) << 20)
/* Compare Window Register */
#define AT91_SAMA5D2_CWR 0x44
/* Channel Gain Register */
#define AT91_SAMA5D2_CGR 0x48
/* Channel Offset Register */
#define AT91_SAMA5D2_COR 0x4c
#define AT91_SAMA5D2_COR_DIFF_OFFSET 16
/* Channel Data Register 0 */
#define AT91_SAMA5D2_CDR0 0x50
/* Analog Control Register */
#define AT91_SAMA5D2_ACR 0x94
/* Analog Control Register - Pen detect sensitivity mask */
#define AT91_SAMA5D2_ACR_PENDETSENS_MASK GENMASK(1, 0)
/* Touchscreen Mode Register */
#define AT91_SAMA5D2_TSMR 0xb0
/* Touchscreen Mode Register - No touch mode */
#define AT91_SAMA5D2_TSMR_TSMODE_NONE 0
/* Touchscreen Mode Register - 4 wire screen, no pressure measurement */
#define AT91_SAMA5D2_TSMR_TSMODE_4WIRE_NO_PRESS 1
/* Touchscreen Mode Register - 4 wire screen, pressure measurement */
#define AT91_SAMA5D2_TSMR_TSMODE_4WIRE_PRESS 2
/* Touchscreen Mode Register - 5 wire screen */
#define AT91_SAMA5D2_TSMR_TSMODE_5WIRE 3
/* Touchscreen Mode Register - Average samples mask */
#define AT91_SAMA5D2_TSMR_TSAV_MASK GENMASK(5, 4)
/* Touchscreen Mode Register - Average samples */
#define AT91_SAMA5D2_TSMR_TSAV(x) ((x) << 4)
/* Touchscreen Mode Register - Touch/trigger frequency ratio mask */
#define AT91_SAMA5D2_TSMR_TSFREQ_MASK GENMASK(11, 8)
/* Touchscreen Mode Register - Touch/trigger frequency ratio */
#define AT91_SAMA5D2_TSMR_TSFREQ(x) ((x) << 8)
/* Touchscreen Mode Register - Pen Debounce Time mask */
#define AT91_SAMA5D2_TSMR_PENDBC_MASK GENMASK(31, 28)
/* Touchscreen Mode Register - Pen Debounce Time */
#define AT91_SAMA5D2_TSMR_PENDBC(x) ((x) << 28)
/* Touchscreen Mode Register - No DMA for touch measurements */
#define AT91_SAMA5D2_TSMR_NOTSDMA BIT(22)
/* Touchscreen Mode Register - Disable pen detection */
#define AT91_SAMA5D2_TSMR_PENDET_DIS (0 << 24)
/* Touchscreen Mode Register - Enable pen detection */
#define AT91_SAMA5D2_TSMR_PENDET_ENA BIT(24)
/* Touchscreen X Position Register */
#define AT91_SAMA5D2_XPOSR 0xb4
/* Touchscreen Y Position Register */
#define AT91_SAMA5D2_YPOSR 0xb8
/* Touchscreen Pressure Register */
#define AT91_SAMA5D2_PRESSR 0xbc
/* Trigger Register */
#define AT91_SAMA5D2_TRGR 0xc0
/* Mask for TRGMOD field of TRGR register */
#define AT91_SAMA5D2_TRGR_TRGMOD_MASK GENMASK(2, 0)
/* No trigger, only software trigger can start conversions */
#define AT91_SAMA5D2_TRGR_TRGMOD_NO_TRIGGER 0
/* Trigger Mode external trigger rising edge */
#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_RISE 1
/* Trigger Mode external trigger falling edge */
#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_FALL 2
/* Trigger Mode external trigger any edge */
#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_ANY 3
/* Trigger Mode internal periodic */
#define AT91_SAMA5D2_TRGR_TRGMOD_PERIODIC 5
/* Trigger Mode - trigger period mask */
#define AT91_SAMA5D2_TRGR_TRGPER_MASK GENMASK(31, 16)
/* Trigger Mode - trigger period */
#define AT91_SAMA5D2_TRGR_TRGPER(x) ((x) << 16)
/* Correction Select Register */
#define AT91_SAMA5D2_COSR 0xd0
/* Correction Value Register */
#define AT91_SAMA5D2_CVR 0xd4
/* Channel Error Correction Register */
#define AT91_SAMA5D2_CECR 0xd8
/* Write Protection Mode Register */
#define AT91_SAMA5D2_WPMR 0xe4
/* Write Protection Status Register */
#define AT91_SAMA5D2_WPSR 0xe8
/* Version Register */
#define AT91_SAMA5D2_VERSION 0xfc
#define AT91_SAMA5D2_HW_TRIG_CNT 3
#define AT91_SAMA5D2_SINGLE_CHAN_CNT 12
#define AT91_SAMA5D2_DIFF_CHAN_CNT 6
#define AT91_SAMA5D2_TIMESTAMP_CHAN_IDX (AT91_SAMA5D2_SINGLE_CHAN_CNT + \
AT91_SAMA5D2_DIFF_CHAN_CNT + 1)
#define AT91_SAMA5D2_TOUCH_X_CHAN_IDX (AT91_SAMA5D2_SINGLE_CHAN_CNT + \
AT91_SAMA5D2_DIFF_CHAN_CNT * 2)
#define AT91_SAMA5D2_TOUCH_Y_CHAN_IDX (AT91_SAMA5D2_TOUCH_X_CHAN_IDX + 1)
#define AT91_SAMA5D2_TOUCH_P_CHAN_IDX (AT91_SAMA5D2_TOUCH_Y_CHAN_IDX + 1)
#define AT91_SAMA5D2_MAX_CHAN_IDX AT91_SAMA5D2_TOUCH_P_CHAN_IDX
#define AT91_SAMA5D2_TOUCH_SAMPLE_PERIOD_US 2000 /* 2ms */
#define AT91_SAMA5D2_TOUCH_PEN_DETECT_DEBOUNCE_US 200
#define AT91_SAMA5D2_XYZ_MASK GENMASK(11, 0)
#define AT91_SAMA5D2_MAX_POS_BITS 12
/*
* Maximum number of bytes to hold conversion from all channels
* without the timestamp.
*/
#define AT91_BUFFER_MAX_CONVERSION_BYTES ((AT91_SAMA5D2_SINGLE_CHAN_CNT + \
AT91_SAMA5D2_DIFF_CHAN_CNT) * 2)
/* This total must also include the timestamp */
#define AT91_BUFFER_MAX_BYTES (AT91_BUFFER_MAX_CONVERSION_BYTES + 8)
#define AT91_BUFFER_MAX_HWORDS (AT91_BUFFER_MAX_BYTES / 2)
#define AT91_HWFIFO_MAX_SIZE_STR "128"
#define AT91_HWFIFO_MAX_SIZE 128
/* Possible values for oversampling ratio */
#define AT91_OSR_1SAMPLES 1
#define AT91_OSR_4SAMPLES 4
#define AT91_OSR_16SAMPLES 16
#define AT91_SAMA5D2_CHAN_SINGLE(num, addr) \
{ \
.type = IIO_VOLTAGE, \
.channel = num, \
.address = addr, \
.scan_index = num, \
.scan_type = { \
.sign = 'u', \
.realbits = 14, \
.storagebits = 16, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ)|\
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
.datasheet_name = "CH"#num, \
.indexed = 1, \
}
#define AT91_SAMA5D2_CHAN_DIFF(num, num2, addr) \
{ \
.type = IIO_VOLTAGE, \
.differential = 1, \
.channel = num, \
.channel2 = num2, \
.address = addr, \
.scan_index = num + AT91_SAMA5D2_SINGLE_CHAN_CNT, \
.scan_type = { \
.sign = 's', \
.realbits = 14, \
.storagebits = 16, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ)|\
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
.datasheet_name = "CH"#num"-CH"#num2, \
.indexed = 1, \
}
#define AT91_SAMA5D2_CHAN_TOUCH(num, name, mod) \
{ \
.type = IIO_POSITIONRELATIVE, \
.modified = 1, \
.channel = num, \
.channel2 = mod, \
.scan_index = num, \
.scan_type = { \
.sign = 'u', \
.realbits = 12, \
.storagebits = 16, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ)|\
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
.datasheet_name = name, \
}
#define AT91_SAMA5D2_CHAN_PRESSURE(num, name) \
{ \
.type = IIO_PRESSURE, \
.channel = num, \
.scan_index = num, \
.scan_type = { \
.sign = 'u', \
.realbits = 12, \
.storagebits = 16, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ)|\
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
.datasheet_name = name, \
}
#define at91_adc_readl(st, reg) readl_relaxed(st->base + reg)
#define at91_adc_writel(st, reg, val) writel_relaxed(val, st->base + reg)
struct at91_adc_soc_info {
unsigned startup_time;
unsigned min_sample_rate;
unsigned max_sample_rate;
};
struct at91_adc_trigger {
char *name;
unsigned int trgmod_value;
unsigned int edge_type;
bool hw_trig;
};
/**
* struct at91_adc_dma - at91-sama5d2 dma information struct
* @dma_chan: the dma channel acquired
* @rx_buf: dma coherent allocated area
* @rx_dma_buf: dma handler for the buffer
* @phys_addr: physical address of the ADC base register
* @buf_idx: index inside the dma buffer where reading was last done
* @rx_buf_sz: size of buffer used by DMA operation
* @watermark: number of conversions to copy before DMA triggers irq
* @dma_ts: hold the start timestamp of dma operation
*/
struct at91_adc_dma {
struct dma_chan *dma_chan;
u8 *rx_buf;
dma_addr_t rx_dma_buf;
phys_addr_t phys_addr;
int buf_idx;
int rx_buf_sz;
int watermark;
s64 dma_ts;
};
/**
* struct at91_adc_touch - at91-sama5d2 touchscreen information struct
* @sample_period_val: the value for periodic trigger interval
* @touching: is the pen touching the screen or not
* @x_pos: temporary placeholder for pressure computation
* @channels_bitmask: bitmask with the touchscreen channels enabled
* @workq: workqueue for buffer data pushing
*/
struct at91_adc_touch {
u16 sample_period_val;
bool touching;
u16 x_pos;
unsigned long channels_bitmask;
struct work_struct workq;
};
struct at91_adc_state {
void __iomem *base;
int irq;
struct clk *per_clk;
struct regulator *reg;
struct regulator *vref;
int vref_uv;
unsigned int current_sample_rate;
struct iio_trigger *trig;
const struct at91_adc_trigger *selected_trig;
const struct iio_chan_spec *chan;
bool conversion_done;
u32 conversion_value;
unsigned int oversampling_ratio;
struct at91_adc_soc_info soc_info;
wait_queue_head_t wq_data_available;
struct at91_adc_dma dma_st;
struct at91_adc_touch touch_st;
struct iio_dev *indio_dev;
u16 buffer[AT91_BUFFER_MAX_HWORDS];
/*
* lock to prevent concurrent 'single conversion' requests through
* sysfs.
*/
struct mutex lock;
};
static const struct at91_adc_trigger at91_adc_trigger_list[] = {
{
.name = "external_rising",
.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_RISE,
.edge_type = IRQ_TYPE_EDGE_RISING,
.hw_trig = true,
},
{
.name = "external_falling",
.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_FALL,
.edge_type = IRQ_TYPE_EDGE_FALLING,
.hw_trig = true,
},
{
.name = "external_any",
.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_ANY,
.edge_type = IRQ_TYPE_EDGE_BOTH,
.hw_trig = true,
},
{
.name = "software",
.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_NO_TRIGGER,
.edge_type = IRQ_TYPE_NONE,
.hw_trig = false,
},
};
static const struct iio_chan_spec at91_adc_channels[] = {
AT91_SAMA5D2_CHAN_SINGLE(0, 0x50),
AT91_SAMA5D2_CHAN_SINGLE(1, 0x54),
AT91_SAMA5D2_CHAN_SINGLE(2, 0x58),
AT91_SAMA5D2_CHAN_SINGLE(3, 0x5c),
AT91_SAMA5D2_CHAN_SINGLE(4, 0x60),
AT91_SAMA5D2_CHAN_SINGLE(5, 0x64),
AT91_SAMA5D2_CHAN_SINGLE(6, 0x68),
AT91_SAMA5D2_CHAN_SINGLE(7, 0x6c),
AT91_SAMA5D2_CHAN_SINGLE(8, 0x70),
AT91_SAMA5D2_CHAN_SINGLE(9, 0x74),
AT91_SAMA5D2_CHAN_SINGLE(10, 0x78),
AT91_SAMA5D2_CHAN_SINGLE(11, 0x7c),
AT91_SAMA5D2_CHAN_DIFF(0, 1, 0x50),
AT91_SAMA5D2_CHAN_DIFF(2, 3, 0x58),
AT91_SAMA5D2_CHAN_DIFF(4, 5, 0x60),
AT91_SAMA5D2_CHAN_DIFF(6, 7, 0x68),
AT91_SAMA5D2_CHAN_DIFF(8, 9, 0x70),
AT91_SAMA5D2_CHAN_DIFF(10, 11, 0x78),
IIO_CHAN_SOFT_TIMESTAMP(AT91_SAMA5D2_TIMESTAMP_CHAN_IDX),
AT91_SAMA5D2_CHAN_TOUCH(AT91_SAMA5D2_TOUCH_X_CHAN_IDX, "x", IIO_MOD_X),
AT91_SAMA5D2_CHAN_TOUCH(AT91_SAMA5D2_TOUCH_Y_CHAN_IDX, "y", IIO_MOD_Y),
AT91_SAMA5D2_CHAN_PRESSURE(AT91_SAMA5D2_TOUCH_P_CHAN_IDX, "pressure"),
};
static int at91_adc_chan_xlate(struct iio_dev *indio_dev, int chan)
{
int i;
for (i = 0; i < indio_dev->num_channels; i++) {
if (indio_dev->channels[i].scan_index == chan)
return i;
}
return -EINVAL;
}
static inline struct iio_chan_spec const *
at91_adc_chan_get(struct iio_dev *indio_dev, int chan)
{
int index = at91_adc_chan_xlate(indio_dev, chan);
if (index < 0)
return NULL;
return indio_dev->channels + index;
}
static inline int at91_adc_of_xlate(struct iio_dev *indio_dev,
const struct of_phandle_args *iiospec)
{
return at91_adc_chan_xlate(indio_dev, iiospec->args[0]);
}
static unsigned int at91_adc_active_scan_mask_to_reg(struct iio_dev *indio_dev)
{
u32 mask = 0;
u8 bit;
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->num_channels) {
struct iio_chan_spec const *chan =
at91_adc_chan_get(indio_dev, bit);
mask |= BIT(chan->channel);
}
return mask & GENMASK(11, 0);
}
static void at91_adc_config_emr(struct at91_adc_state *st)
{
/* configure the extended mode register */
unsigned int emr = at91_adc_readl(st, AT91_SAMA5D2_EMR);
/* select oversampling per single trigger event */
emr |= AT91_SAMA5D2_EMR_ASTE(1);
/* delete leftover content if it's the case */
emr &= ~AT91_SAMA5D2_EMR_OSR_MASK;
/* select oversampling ratio from configuration */
switch (st->oversampling_ratio) {
case AT91_OSR_1SAMPLES:
emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_1SAMPLES) &
AT91_SAMA5D2_EMR_OSR_MASK;
break;
case AT91_OSR_4SAMPLES:
emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_4SAMPLES) &
AT91_SAMA5D2_EMR_OSR_MASK;
break;
case AT91_OSR_16SAMPLES:
emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_16SAMPLES) &
AT91_SAMA5D2_EMR_OSR_MASK;
break;
}
at91_adc_writel(st, AT91_SAMA5D2_EMR, emr);
}
static int at91_adc_adjust_val_osr(struct at91_adc_state *st, int *val)
{
if (st->oversampling_ratio == AT91_OSR_1SAMPLES) {
/*
* in this case we only have 12 bits of real data, but channel
* is registered as 14 bits, so shift left two bits
*/
*val <<= 2;
} else if (st->oversampling_ratio == AT91_OSR_4SAMPLES) {
/*
* in this case we have 13 bits of real data, but channel
* is registered as 14 bits, so left shift one bit
*/
*val <<= 1;
}
return IIO_VAL_INT;
}
static void at91_adc_adjust_val_osr_array(struct at91_adc_state *st, void *buf,
int len)
{
int i = 0, val;
u16 *buf_u16 = (u16 *) buf;
/*
* We are converting each two bytes (each sample).
* First convert the byte based array to u16, and convert each sample
* separately.
* Each value is two bytes in an array of chars, so to not shift
* more than we need, save the value separately.
* len is in bytes, so divide by two to get number of samples.
*/
while (i < len / 2) {
val = buf_u16[i];
at91_adc_adjust_val_osr(st, &val);
buf_u16[i] = val;
i++;
}
}
static int at91_adc_configure_touch(struct at91_adc_state *st, bool state)
{
u32 clk_khz = st->current_sample_rate / 1000;
int i = 0;
u16 pendbc;
u32 tsmr, acr;
if (!state) {
/* disabling touch IRQs and setting mode to no touch enabled */
at91_adc_writel(st, AT91_SAMA5D2_IDR,
AT91_SAMA5D2_IER_PEN | AT91_SAMA5D2_IER_NOPEN);
at91_adc_writel(st, AT91_SAMA5D2_TSMR, 0);
return 0;
}
/*
* debounce time is in microseconds, we need it in milliseconds to
* multiply with kilohertz, so, divide by 1000, but after the multiply.
* round up to make sure pendbc is at least 1
*/
pendbc = round_up(AT91_SAMA5D2_TOUCH_PEN_DETECT_DEBOUNCE_US *
clk_khz / 1000, 1);
/* get the required exponent */
while (pendbc >> i++)
;
pendbc = i;
tsmr = AT91_SAMA5D2_TSMR_TSMODE_4WIRE_PRESS;
tsmr |= AT91_SAMA5D2_TSMR_TSAV(2) & AT91_SAMA5D2_TSMR_TSAV_MASK;
tsmr |= AT91_SAMA5D2_TSMR_PENDBC(pendbc) &
AT91_SAMA5D2_TSMR_PENDBC_MASK;
tsmr |= AT91_SAMA5D2_TSMR_NOTSDMA;
tsmr |= AT91_SAMA5D2_TSMR_PENDET_ENA;
tsmr |= AT91_SAMA5D2_TSMR_TSFREQ(2) & AT91_SAMA5D2_TSMR_TSFREQ_MASK;
at91_adc_writel(st, AT91_SAMA5D2_TSMR, tsmr);
acr = at91_adc_readl(st, AT91_SAMA5D2_ACR);
acr &= ~AT91_SAMA5D2_ACR_PENDETSENS_MASK;
acr |= 0x02 & AT91_SAMA5D2_ACR_PENDETSENS_MASK;
at91_adc_writel(st, AT91_SAMA5D2_ACR, acr);
/* Sample Period Time = (TRGPER + 1) / ADCClock */
st->touch_st.sample_period_val =
round_up((AT91_SAMA5D2_TOUCH_SAMPLE_PERIOD_US *
clk_khz / 1000) - 1, 1);
/* enable pen detect IRQ */
at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_PEN);
return 0;
}
static u16 at91_adc_touch_pos(struct at91_adc_state *st, int reg)
{
u32 val;
u32 scale, result, pos;
/*
* to obtain the actual position we must divide by scale
* and multiply with max, where
* max = 2^AT91_SAMA5D2_MAX_POS_BITS - 1
*/
/* first half of register is the x or y, second half is the scale */
val = at91_adc_readl(st, reg);
if (!val)
dev_dbg(&st->indio_dev->dev, "pos is 0\n");
pos = val & AT91_SAMA5D2_XYZ_MASK;
result = (pos << AT91_SAMA5D2_MAX_POS_BITS) - pos;
scale = (val >> 16) & AT91_SAMA5D2_XYZ_MASK;
if (scale == 0) {
dev_err(&st->indio_dev->dev, "scale is 0\n");
return 0;
}
result /= scale;
return result;
}
static u16 at91_adc_touch_x_pos(struct at91_adc_state *st)
{
st->touch_st.x_pos = at91_adc_touch_pos(st, AT91_SAMA5D2_XPOSR);
return st->touch_st.x_pos;
}
static u16 at91_adc_touch_y_pos(struct at91_adc_state *st)
{
return at91_adc_touch_pos(st, AT91_SAMA5D2_YPOSR);
}
static u16 at91_adc_touch_pressure(struct at91_adc_state *st)
{
u32 val;
u32 z1, z2;
u32 pres;
u32 rxp = 1;
u32 factor = 1000;
/* calculate the pressure */
val = at91_adc_readl(st, AT91_SAMA5D2_PRESSR);
z1 = val & AT91_SAMA5D2_XYZ_MASK;
z2 = (val >> 16) & AT91_SAMA5D2_XYZ_MASK;
if (z1 != 0)
pres = rxp * (st->touch_st.x_pos * factor / 1024) *
(z2 * factor / z1 - factor) /
factor;
else
pres = 0xFFFF; /* no pen contact */
/*
* The pressure from device grows down, minimum is 0xFFFF, maximum 0x0.
* We compute it this way, but let's return it in the expected way,
* growing from 0 to 0xFFFF.
*/
return 0xFFFF - pres;
}
static int at91_adc_read_position(struct at91_adc_state *st, int chan, u16 *val)
{
*val = 0;
if (!st->touch_st.touching)
return -ENODATA;
if (chan == AT91_SAMA5D2_TOUCH_X_CHAN_IDX)
*val = at91_adc_touch_x_pos(st);
else if (chan == AT91_SAMA5D2_TOUCH_Y_CHAN_IDX)
*val = at91_adc_touch_y_pos(st);
else
return -ENODATA;
return IIO_VAL_INT;
}
static int at91_adc_read_pressure(struct at91_adc_state *st, int chan, u16 *val)
{
*val = 0;
if (!st->touch_st.touching)
return -ENODATA;
if (chan == AT91_SAMA5D2_TOUCH_P_CHAN_IDX)
*val = at91_adc_touch_pressure(st);
else
return -ENODATA;
return IIO_VAL_INT;
}
static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
{
struct iio_dev *indio = iio_trigger_get_drvdata(trig);
struct at91_adc_state *st = iio_priv(indio);
u32 status = at91_adc_readl(st, AT91_SAMA5D2_TRGR);
/* clear TRGMOD */
status &= ~AT91_SAMA5D2_TRGR_TRGMOD_MASK;
if (state)
status |= st->selected_trig->trgmod_value;
/* set/unset hw trigger */
at91_adc_writel(st, AT91_SAMA5D2_TRGR, status);
return 0;
}
static int at91_adc_reenable_trigger(struct iio_trigger *trig)
{
struct iio_dev *indio = iio_trigger_get_drvdata(trig);
struct at91_adc_state *st = iio_priv(indio);
/* if we are using DMA, we must not reenable irq after each trigger */
if (st->dma_st.dma_chan)
return 0;
enable_irq(st->irq);
/* Needed to ACK the DRDY interruption */
at91_adc_readl(st, AT91_SAMA5D2_LCDR);
return 0;
}
static const struct iio_trigger_ops at91_adc_trigger_ops = {
.set_trigger_state = &at91_adc_configure_trigger,
.try_reenable = &at91_adc_reenable_trigger,
.validate_device = iio_trigger_validate_own_device,
};
static int at91_adc_dma_size_done(struct at91_adc_state *st)
{
struct dma_tx_state state;
enum dma_status status;
int i, size;
status = dmaengine_tx_status(st->dma_st.dma_chan,
st->dma_st.dma_chan->cookie,
&state);
if (status != DMA_IN_PROGRESS)
return 0;
/* Transferred length is size in bytes from end of buffer */
i = st->dma_st.rx_buf_sz - state.residue;
/* Return available bytes */
if (i >= st->dma_st.buf_idx)
size = i - st->dma_st.buf_idx;
else
size = st->dma_st.rx_buf_sz + i - st->dma_st.buf_idx;
return size;
}
static void at91_dma_buffer_done(void *data)
{
struct iio_dev *indio_dev = data;
iio_trigger_poll_chained(indio_dev->trig);
}
static int at91_adc_dma_start(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
struct dma_async_tx_descriptor *desc;
dma_cookie_t cookie;
int ret;
u8 bit;
if (!st->dma_st.dma_chan)
return 0;
/* we start a new DMA, so set buffer index to start */
st->dma_st.buf_idx = 0;
/*
* compute buffer size w.r.t. watermark and enabled channels.
* scan_bytes is aligned so we need an exact size for DMA
*/
st->dma_st.rx_buf_sz = 0;
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->num_channels) {
struct iio_chan_spec const *chan =
at91_adc_chan_get(indio_dev, bit);
if (!chan)
continue;
st->dma_st.rx_buf_sz += chan->scan_type.storagebits / 8;
}
st->dma_st.rx_buf_sz *= st->dma_st.watermark;
/* Prepare a DMA cyclic transaction */
desc = dmaengine_prep_dma_cyclic(st->dma_st.dma_chan,
st->dma_st.rx_dma_buf,
st->dma_st.rx_buf_sz,
st->dma_st.rx_buf_sz / 2,
DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
if (!desc) {
dev_err(&indio_dev->dev, "cannot prepare DMA cyclic\n");
return -EBUSY;
}
desc->callback = at91_dma_buffer_done;
desc->callback_param = indio_dev;
cookie = dmaengine_submit(desc);
ret = dma_submit_error(cookie);
if (ret) {
dev_err(&indio_dev->dev, "cannot submit DMA cyclic\n");
dmaengine_terminate_async(st->dma_st.dma_chan);
return ret;
}
/* enable general overrun error signaling */
at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_GOVRE);
/* Issue pending DMA requests */
dma_async_issue_pending(st->dma_st.dma_chan);
/* consider current time as DMA start time for timestamps */
st->dma_st.dma_ts = iio_get_time_ns(indio_dev);
dev_dbg(&indio_dev->dev, "DMA cyclic started\n");
return 0;
}
static bool at91_adc_buffer_check_use_irq(struct iio_dev *indio,
struct at91_adc_state *st)
{
/* if using DMA, we do not use our own IRQ (we use DMA-controller) */
if (st->dma_st.dma_chan)
return false;
/* if the trigger is not ours, then it has its own IRQ */
if (iio_trigger_validate_own_device(indio->trig, indio))
return false;
return true;
}
static bool at91_adc_current_chan_is_touch(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
return !!bitmap_subset(indio_dev->active_scan_mask,
&st->touch_st.channels_bitmask,
AT91_SAMA5D2_MAX_CHAN_IDX + 1);
}
static int at91_adc_buffer_prepare(struct iio_dev *indio_dev)
{
int ret;
u8 bit;
struct at91_adc_state *st = iio_priv(indio_dev);
/* check if we are enabling triggered buffer or the touchscreen */
if (at91_adc_current_chan_is_touch(indio_dev))
return at91_adc_configure_touch(st, true);
/* if we are not in triggered mode, we cannot enable the buffer. */
if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
return -EINVAL;
/* we continue with the triggered buffer */
ret = at91_adc_dma_start(indio_dev);
if (ret) {
dev_err(&indio_dev->dev, "buffer prepare failed\n");
return ret;
}
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->num_channels) {
struct iio_chan_spec const *chan =
at91_adc_chan_get(indio_dev, bit);
u32 cor;
if (!chan)
continue;
/* these channel types cannot be handled by this trigger */
if (chan->type == IIO_POSITIONRELATIVE ||
chan->type == IIO_PRESSURE)
continue;
cor = at91_adc_readl(st, AT91_SAMA5D2_COR);
if (chan->differential)
cor |= (BIT(chan->channel) | BIT(chan->channel2)) <<
AT91_SAMA5D2_COR_DIFF_OFFSET;
else
cor &= ~(BIT(chan->channel) <<
AT91_SAMA5D2_COR_DIFF_OFFSET);
at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
}
if (at91_adc_buffer_check_use_irq(indio_dev, st))
at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_DRDY);
return 0;
}
static int at91_adc_buffer_postdisable(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
u8 bit;
/* check if we are disabling triggered buffer or the touchscreen */
if (at91_adc_current_chan_is_touch(indio_dev))
return at91_adc_configure_touch(st, false);
/* if we are not in triggered mode, nothing to do here */
if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
return -EINVAL;
/*
* For each enable channel we must disable it in hardware.
* In the case of DMA, we must read the last converted value
* to clear EOC status and not get a possible interrupt later.
* This value is being read by DMA from LCDR anyway, so it's not lost.
*/
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->num_channels) {
struct iio_chan_spec const *chan =
at91_adc_chan_get(indio_dev, bit);
if (!chan)
continue;
/* these channel types are virtual, no need to do anything */
if (chan->type == IIO_POSITIONRELATIVE ||
chan->type == IIO_PRESSURE)
continue;
at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
if (st->dma_st.dma_chan)
at91_adc_readl(st, chan->address);
}
if (at91_adc_buffer_check_use_irq(indio_dev, st))
at91_adc_writel(st, AT91_SAMA5D2_IDR, AT91_SAMA5D2_IER_DRDY);
/* read overflow register to clear possible overflow status */
at91_adc_readl(st, AT91_SAMA5D2_OVER);
/* if we are using DMA we must clear registers and end DMA */
if (st->dma_st.dma_chan)
dmaengine_terminate_sync(st->dma_st.dma_chan);
return 0;
}
static const struct iio_buffer_setup_ops at91_buffer_setup_ops = {
.postdisable = &at91_adc_buffer_postdisable,
};
static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *indio,
char *trigger_name)
{
struct iio_trigger *trig;
int ret;
trig = devm_iio_trigger_alloc(&indio->dev, "%s-dev%d-%s", indio->name,
indio->id, trigger_name);
if (!trig)
return NULL;
trig->dev.parent = indio->dev.parent;
iio_trigger_set_drvdata(trig, indio);
trig->ops = &at91_adc_trigger_ops;
ret = devm_iio_trigger_register(&indio->dev, trig);
if (ret)
return ERR_PTR(ret);
return trig;
}
static int at91_adc_trigger_init(struct iio_dev *indio)
{
struct at91_adc_state *st = iio_priv(indio);
st->trig = at91_adc_allocate_trigger(indio, st->selected_trig->name);
if (IS_ERR(st->trig)) {
dev_err(&indio->dev,
"could not allocate trigger\n");
return PTR_ERR(st->trig);
}
return 0;
}
static void at91_adc_trigger_handler_nodma(struct iio_dev *indio_dev,
struct iio_poll_func *pf)
{
struct at91_adc_state *st = iio_priv(indio_dev);
int i = 0;
int val;
u8 bit;
u32 mask = at91_adc_active_scan_mask_to_reg(indio_dev);
unsigned int timeout = 50;
/*
* Check if the conversion is ready. If not, wait a little bit, and
* in case of timeout exit with an error.
*/
while ((at91_adc_readl(st, AT91_SAMA5D2_ISR) & mask) != mask &&
timeout) {
usleep_range(50, 100);
timeout--;
}
/* Cannot read data, not ready. Continue without reporting data */
if (!timeout)
return;
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->num_channels) {
struct iio_chan_spec const *chan =
at91_adc_chan_get(indio_dev, bit);
if (!chan)
continue;
/*
* Our external trigger only supports the voltage channels.
* In case someone requested a different type of channel
* just put zeroes to buffer.
* This should not happen because we check the scan mode
* and scan mask when we enable the buffer, and we don't allow
* the buffer to start with a mixed mask (voltage and something
* else).
* Thus, emit a warning.
*/
if (chan->type == IIO_VOLTAGE) {
val = at91_adc_readl(st, chan->address);
at91_adc_adjust_val_osr(st, &val);
st->buffer[i] = val;
} else {
st->buffer[i] = 0;
WARN(true, "This trigger cannot handle this type of channel");
}
i++;
}
iio_push_to_buffers_with_timestamp(indio_dev, st->buffer,
pf->timestamp);
}
static void at91_adc_trigger_handler_dma(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
int transferred_len = at91_adc_dma_size_done(st);
s64 ns = iio_get_time_ns(indio_dev);
s64 interval;
int sample_index = 0, sample_count, sample_size;
u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
/* if we reached this point, we cannot sample faster */
if (status & AT91_SAMA5D2_IER_GOVRE)
pr_info_ratelimited("%s: conversion overrun detected\n",
indio_dev->name);
sample_size = div_s64(st->dma_st.rx_buf_sz, st->dma_st.watermark);
sample_count = div_s64(transferred_len, sample_size);
/*
* interval between samples is total time since last transfer handling
* divided by the number of samples (total size divided by sample size)
*/
interval = div_s64((ns - st->dma_st.dma_ts), sample_count);
while (transferred_len >= sample_size) {
/*
* for all the values in the current sample,
* adjust the values inside the buffer for oversampling
*/
at91_adc_adjust_val_osr_array(st,
&st->dma_st.rx_buf[st->dma_st.buf_idx],
sample_size);
iio_push_to_buffers_with_timestamp(indio_dev,
(st->dma_st.rx_buf + st->dma_st.buf_idx),
(st->dma_st.dma_ts + interval * sample_index));
/* adjust remaining length */
transferred_len -= sample_size;
/* adjust buffer index */
st->dma_st.buf_idx += sample_size;
/* in case of reaching end of buffer, reset index */
if (st->dma_st.buf_idx >= st->dma_st.rx_buf_sz)
st->dma_st.buf_idx = 0;
sample_index++;
}
/* adjust saved time for next transfer handling */
st->dma_st.dma_ts = iio_get_time_ns(indio_dev);
}
static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct at91_adc_state *st = iio_priv(indio_dev);
/*
* If it's not our trigger, start a conversion now, as we are
* actually polling the trigger now.
*/
if (iio_trigger_validate_own_device(indio_dev->trig, indio_dev))
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
if (st->dma_st.dma_chan)
at91_adc_trigger_handler_dma(indio_dev);
else
at91_adc_trigger_handler_nodma(indio_dev, pf);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int at91_adc_buffer_init(struct iio_dev *indio)
{
return devm_iio_triggered_buffer_setup(&indio->dev, indio,
&iio_pollfunc_store_time,
&at91_adc_trigger_handler, &at91_buffer_setup_ops);
}
static unsigned at91_adc_startup_time(unsigned startup_time_min,
unsigned adc_clk_khz)
{
static const unsigned int startup_lookup[] = {
0, 8, 16, 24,
64, 80, 96, 112,
512, 576, 640, 704,
768, 832, 896, 960
};
unsigned ticks_min, i;
/*
* Since the adc frequency is checked before, there is no reason
* to not meet the startup time constraint.
*/
ticks_min = startup_time_min * adc_clk_khz / 1000;
for (i = 0; i < ARRAY_SIZE(startup_lookup); i++)
if (startup_lookup[i] > ticks_min)
break;
return i;
}
static void at91_adc_setup_samp_freq(struct iio_dev *indio_dev, unsigned freq)
{
struct at91_adc_state *st = iio_priv(indio_dev);
unsigned f_per, prescal, startup, mr;
f_per = clk_get_rate(st->per_clk);
prescal = (f_per / (2 * freq)) - 1;
startup = at91_adc_startup_time(st->soc_info.startup_time,
freq / 1000);
mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
mr &= ~(AT91_SAMA5D2_MR_STARTUP_MASK | AT91_SAMA5D2_MR_PRESCAL_MASK);
mr |= AT91_SAMA5D2_MR_STARTUP(startup);
mr |= AT91_SAMA5D2_MR_PRESCAL(prescal);
at91_adc_writel(st, AT91_SAMA5D2_MR, mr);
dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
freq, startup, prescal);
st->current_sample_rate = freq;
}
static inline unsigned at91_adc_get_sample_freq(struct at91_adc_state *st)
{
return st->current_sample_rate;
}
static void at91_adc_touch_data_handler(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
u8 bit;
u16 val;
int i = 0;
for_each_set_bit(bit, indio_dev->active_scan_mask,
AT91_SAMA5D2_MAX_CHAN_IDX + 1) {
struct iio_chan_spec const *chan =
at91_adc_chan_get(indio_dev, bit);
if (chan->type == IIO_POSITIONRELATIVE)
at91_adc_read_position(st, chan->channel, &val);
else if (chan->type == IIO_PRESSURE)
at91_adc_read_pressure(st, chan->channel, &val);
else
continue;
st->buffer[i] = val;
i++;
}
/*
* Schedule work to push to buffers.
* This is intended to push to the callback buffer that another driver
* registered. We are still in a handler from our IRQ. If we push
* directly, it means the other driver has it's callback called
* from our IRQ context. Which is something we better avoid.
* Let's schedule it after our IRQ is completed.
*/
schedule_work(&st->touch_st.workq);
}
static void at91_adc_pen_detect_interrupt(struct at91_adc_state *st)
{
at91_adc_writel(st, AT91_SAMA5D2_IDR, AT91_SAMA5D2_IER_PEN);
at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_NOPEN |
AT91_SAMA5D2_IER_XRDY | AT91_SAMA5D2_IER_YRDY |
AT91_SAMA5D2_IER_PRDY);
at91_adc_writel(st, AT91_SAMA5D2_TRGR,
AT91_SAMA5D2_TRGR_TRGMOD_PERIODIC |
AT91_SAMA5D2_TRGR_TRGPER(st->touch_st.sample_period_val));
st->touch_st.touching = true;
}
static void at91_adc_no_pen_detect_interrupt(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
at91_adc_writel(st, AT91_SAMA5D2_TRGR,
AT91_SAMA5D2_TRGR_TRGMOD_NO_TRIGGER);
at91_adc_writel(st, AT91_SAMA5D2_IDR, AT91_SAMA5D2_IER_NOPEN |
AT91_SAMA5D2_IER_XRDY | AT91_SAMA5D2_IER_YRDY |
AT91_SAMA5D2_IER_PRDY);
st->touch_st.touching = false;
at91_adc_touch_data_handler(indio_dev);
at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_PEN);
}
static void at91_adc_workq_handler(struct work_struct *workq)
{
struct at91_adc_touch *touch_st = container_of(workq,
struct at91_adc_touch, workq);
struct at91_adc_state *st = container_of(touch_st,
struct at91_adc_state, touch_st);
struct iio_dev *indio_dev = st->indio_dev;
iio_push_to_buffers(indio_dev, st->buffer);
}
static irqreturn_t at91_adc_interrupt(int irq, void *private)
{
struct iio_dev *indio = private;
struct at91_adc_state *st = iio_priv(indio);
u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR);
u32 rdy_mask = AT91_SAMA5D2_IER_XRDY | AT91_SAMA5D2_IER_YRDY |
AT91_SAMA5D2_IER_PRDY;
if (!(status & imr))
return IRQ_NONE;
if (status & AT91_SAMA5D2_IER_PEN) {
/* pen detected IRQ */
at91_adc_pen_detect_interrupt(st);
} else if ((status & AT91_SAMA5D2_IER_NOPEN)) {
/* nopen detected IRQ */
at91_adc_no_pen_detect_interrupt(indio);
} else if ((status & AT91_SAMA5D2_ISR_PENS) &&
((status & rdy_mask) == rdy_mask)) {
/* periodic trigger IRQ - during pen sense */
at91_adc_touch_data_handler(indio);
} else if (status & AT91_SAMA5D2_ISR_PENS) {
/*
* touching, but the measurements are not ready yet.
* read and ignore.
*/
status = at91_adc_readl(st, AT91_SAMA5D2_XPOSR);
status = at91_adc_readl(st, AT91_SAMA5D2_YPOSR);
status = at91_adc_readl(st, AT91_SAMA5D2_PRESSR);
} else if (iio_buffer_enabled(indio) &&
(status & AT91_SAMA5D2_IER_DRDY)) {
/* triggered buffer without DMA */
disable_irq_nosync(irq);
iio_trigger_poll(indio->trig);
} else if (iio_buffer_enabled(indio) && st->dma_st.dma_chan) {
/* triggered buffer with DMA - should not happen */
disable_irq_nosync(irq);
WARN(true, "Unexpected irq occurred\n");
} else if (!iio_buffer_enabled(indio)) {
/* software requested conversion */
st->conversion_value = at91_adc_readl(st, st->chan->address);
st->conversion_done = true;
wake_up_interruptible(&st->wq_data_available);
}
return IRQ_HANDLED;
}
static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val)
{
struct at91_adc_state *st = iio_priv(indio_dev);
u32 cor = 0;
u16 tmp_val;
int ret;
/*
* Keep in mind that we cannot use software trigger or touchscreen
* if external trigger is enabled
*/
if (chan->type == IIO_POSITIONRELATIVE) {
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
mutex_lock(&st->lock);
ret = at91_adc_read_position(st, chan->channel,
&tmp_val);
*val = tmp_val;
mutex_unlock(&st->lock);
iio_device_release_direct_mode(indio_dev);
return at91_adc_adjust_val_osr(st, val);
}
if (chan->type == IIO_PRESSURE) {
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
mutex_lock(&st->lock);
ret = at91_adc_read_pressure(st, chan->channel,
&tmp_val);
*val = tmp_val;
mutex_unlock(&st->lock);
iio_device_release_direct_mode(indio_dev);
return at91_adc_adjust_val_osr(st, val);
}
/* in this case we have a voltage channel */
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
mutex_lock(&st->lock);
st->chan = chan;
if (chan->differential)
cor = (BIT(chan->channel) | BIT(chan->channel2)) <<
AT91_SAMA5D2_COR_DIFF_OFFSET;
at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
ret = wait_event_interruptible_timeout(st->wq_data_available,
st->conversion_done,
msecs_to_jiffies(1000));
if (ret == 0)
ret = -ETIMEDOUT;
if (ret > 0) {
*val = st->conversion_value;
ret = at91_adc_adjust_val_osr(st, val);
if (chan->scan_type.sign == 's')
*val = sign_extend32(*val, 11);
st->conversion_done = false;
}
at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
/* Needed to ACK the DRDY interruption */
at91_adc_readl(st, AT91_SAMA5D2_LCDR);
mutex_unlock(&st->lock);
iio_device_release_direct_mode(indio_dev);
return ret;
}
static int at91_adc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct at91_adc_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
return at91_adc_read_info_raw(indio_dev, chan, val);
case IIO_CHAN_INFO_SCALE:
*val = st->vref_uv / 1000;
if (chan->differential)
*val *= 2;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = at91_adc_get_sample_freq(st);
return IIO_VAL_INT;
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
*val = st->oversampling_ratio;
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int at91_adc_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct at91_adc_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
if ((val != AT91_OSR_1SAMPLES) && (val != AT91_OSR_4SAMPLES) &&
(val != AT91_OSR_16SAMPLES))
return -EINVAL;
/* if no change, optimize out */
if (val == st->oversampling_ratio)
return 0;
st->oversampling_ratio = val;
/* update ratio */
at91_adc_config_emr(st);
return 0;
case IIO_CHAN_INFO_SAMP_FREQ:
if (val < st->soc_info.min_sample_rate ||
val > st->soc_info.max_sample_rate)
return -EINVAL;
at91_adc_setup_samp_freq(indio_dev, val);
return 0;
default:
return -EINVAL;
};
}
static void at91_adc_dma_init(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct at91_adc_state *st = iio_priv(indio_dev);
struct dma_slave_config config = {0};
/*
* We make the buffer double the size of the fifo,
* such that DMA uses one half of the buffer (full fifo size)
* and the software uses the other half to read/write.
*/
unsigned int pages = DIV_ROUND_UP(AT91_HWFIFO_MAX_SIZE *
AT91_BUFFER_MAX_CONVERSION_BYTES * 2,
PAGE_SIZE);
if (st->dma_st.dma_chan)
return;
st->dma_st.dma_chan = dma_request_chan(&pdev->dev, "rx");
if (IS_ERR(st->dma_st.dma_chan)) {
dev_info(&pdev->dev, "can't get DMA channel\n");
st->dma_st.dma_chan = NULL;
goto dma_exit;
}
st->dma_st.rx_buf = dma_alloc_coherent(st->dma_st.dma_chan->device->dev,
pages * PAGE_SIZE,
&st->dma_st.rx_dma_buf,
GFP_KERNEL);
if (!st->dma_st.rx_buf) {
dev_info(&pdev->dev, "can't allocate coherent DMA area\n");
goto dma_chan_disable;
}
/* Configure DMA channel to read data register */
config.direction = DMA_DEV_TO_MEM;
config.src_addr = (phys_addr_t)(st->dma_st.phys_addr
+ AT91_SAMA5D2_LCDR);
config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
config.src_maxburst = 1;
config.dst_maxburst = 1;
if (dmaengine_slave_config(st->dma_st.dma_chan, &config)) {
dev_info(&pdev->dev, "can't configure DMA slave\n");
goto dma_free_area;
}
dev_info(&pdev->dev, "using %s for rx DMA transfers\n",
dma_chan_name(st->dma_st.dma_chan));
return;
dma_free_area:
dma_free_coherent(st->dma_st.dma_chan->device->dev, pages * PAGE_SIZE,
st->dma_st.rx_buf, st->dma_st.rx_dma_buf);
dma_chan_disable:
dma_release_channel(st->dma_st.dma_chan);
st->dma_st.dma_chan = NULL;
dma_exit:
dev_info(&pdev->dev, "continuing without DMA support\n");
}
static void at91_adc_dma_disable(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct at91_adc_state *st = iio_priv(indio_dev);
unsigned int pages = DIV_ROUND_UP(AT91_HWFIFO_MAX_SIZE *
AT91_BUFFER_MAX_CONVERSION_BYTES * 2,
PAGE_SIZE);
/* if we are not using DMA, just return */
if (!st->dma_st.dma_chan)
return;
/* wait for all transactions to be terminated first*/
dmaengine_terminate_sync(st->dma_st.dma_chan);
dma_free_coherent(st->dma_st.dma_chan->device->dev, pages * PAGE_SIZE,
st->dma_st.rx_buf, st->dma_st.rx_dma_buf);
dma_release_channel(st->dma_st.dma_chan);
st->dma_st.dma_chan = NULL;
dev_info(&pdev->dev, "continuing without DMA support\n");
}
static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
{
struct at91_adc_state *st = iio_priv(indio_dev);
int ret;
if (val > AT91_HWFIFO_MAX_SIZE)
return -EINVAL;
if (!st->selected_trig->hw_trig) {
dev_dbg(&indio_dev->dev, "we need hw trigger for DMA\n");
return 0;
}
dev_dbg(&indio_dev->dev, "new watermark is %u\n", val);
st->dma_st.watermark = val;
/*
* The logic here is: if we have watermark 1, it means we do
* each conversion with it's own IRQ, thus we don't need DMA.
* If the watermark is higher, we do DMA to do all the transfers in bulk
*/
if (val == 1)
at91_adc_dma_disable(to_platform_device(&indio_dev->dev));
else if (val > 1)
at91_adc_dma_init(to_platform_device(&indio_dev->dev));
/*
* We can start the DMA only after setting the watermark and
* having the DMA initialization completed
*/
ret = at91_adc_buffer_prepare(indio_dev);
if (ret)
at91_adc_dma_disable(to_platform_device(&indio_dev->dev));
return ret;
}
static int at91_adc_update_scan_mode(struct iio_dev *indio_dev,
const unsigned long *scan_mask)
{
struct at91_adc_state *st = iio_priv(indio_dev);
if (bitmap_subset(scan_mask, &st->touch_st.channels_bitmask,
AT91_SAMA5D2_MAX_CHAN_IDX + 1))
return 0;
/*
* if the new bitmap is a combination of touchscreen and regular
* channels, then we are not fine
*/
if (bitmap_intersects(&st->touch_st.channels_bitmask, scan_mask,
AT91_SAMA5D2_MAX_CHAN_IDX + 1))
return -EINVAL;
return 0;
}
static void at91_adc_hw_init(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
/*
* Transfer field must be set to 2 according to the datasheet and
* allows different analog settings for each channel.
*/
at91_adc_writel(st, AT91_SAMA5D2_MR,
AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
at91_adc_setup_samp_freq(indio_dev, st->soc_info.min_sample_rate);
/* configure extended mode register */
at91_adc_config_emr(st);
}
static ssize_t at91_adc_get_fifo_state(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct at91_adc_state *st = iio_priv(indio_dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", !!st->dma_st.dma_chan);
}
static ssize_t at91_adc_get_watermark(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct at91_adc_state *st = iio_priv(indio_dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", st->dma_st.watermark);
}
static IIO_DEVICE_ATTR(hwfifo_enabled, 0444,
at91_adc_get_fifo_state, NULL, 0);
static IIO_DEVICE_ATTR(hwfifo_watermark, 0444,
at91_adc_get_watermark, NULL, 0);
static IIO_CONST_ATTR(hwfifo_watermark_min, "2");
static IIO_CONST_ATTR(hwfifo_watermark_max, AT91_HWFIFO_MAX_SIZE_STR);
static IIO_CONST_ATTR(oversampling_ratio_available,
__stringify(AT91_OSR_1SAMPLES) " "
__stringify(AT91_OSR_4SAMPLES) " "
__stringify(AT91_OSR_16SAMPLES));
static struct attribute *at91_adc_attributes[] = {
&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
NULL,
};
static const struct attribute_group at91_adc_attribute_group = {
.attrs = at91_adc_attributes,
};
static const struct attribute *at91_adc_fifo_attributes[] = {
&iio_const_attr_hwfifo_watermark_min.dev_attr.attr,
&iio_const_attr_hwfifo_watermark_max.dev_attr.attr,
&iio_dev_attr_hwfifo_watermark.dev_attr.attr,
&iio_dev_attr_hwfifo_enabled.dev_attr.attr,
NULL,
};
static const struct iio_info at91_adc_info = {
.attrs = &at91_adc_attribute_group,
.read_raw = &at91_adc_read_raw,
.write_raw = &at91_adc_write_raw,
.update_scan_mode = &at91_adc_update_scan_mode,
.of_xlate = &at91_adc_of_xlate,
.hwfifo_set_watermark = &at91_adc_set_watermark,
};
static int at91_adc_probe(struct platform_device *pdev)
{
struct iio_dev *indio_dev;
struct at91_adc_state *st;
struct resource *res;
int ret, i;
u32 edge_type = IRQ_TYPE_NONE;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
indio_dev->name = dev_name(&pdev->dev);
indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
indio_dev->info = &at91_adc_info;
indio_dev->channels = at91_adc_channels;
indio_dev->num_channels = ARRAY_SIZE(at91_adc_channels);
st = iio_priv(indio_dev);
st->indio_dev = indio_dev;
bitmap_set(&st->touch_st.channels_bitmask,
AT91_SAMA5D2_TOUCH_X_CHAN_IDX, 1);
bitmap_set(&st->touch_st.channels_bitmask,
AT91_SAMA5D2_TOUCH_Y_CHAN_IDX, 1);
bitmap_set(&st->touch_st.channels_bitmask,
AT91_SAMA5D2_TOUCH_P_CHAN_IDX, 1);
st->oversampling_ratio = AT91_OSR_1SAMPLES;
ret = of_property_read_u32(pdev->dev.of_node,
"atmel,min-sample-rate-hz",
&st->soc_info.min_sample_rate);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,min-sample-rate-hz\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node,
"atmel,max-sample-rate-hz",
&st->soc_info.max_sample_rate);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,max-sample-rate-hz\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node, "atmel,startup-time-ms",
&st->soc_info.startup_time);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,startup-time-ms\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node,
"atmel,trigger-edge-type", &edge_type);
if (ret) {
dev_dbg(&pdev->dev,
"atmel,trigger-edge-type not specified, only software trigger available\n");
}
st->selected_trig = NULL;
/* find the right trigger, or no trigger at all */
for (i = 0; i < AT91_SAMA5D2_HW_TRIG_CNT + 1; i++)
if (at91_adc_trigger_list[i].edge_type == edge_type) {
st->selected_trig = &at91_adc_trigger_list[i];
break;
}
if (!st->selected_trig) {
dev_err(&pdev->dev, "invalid external trigger edge value\n");
return -EINVAL;
}
init_waitqueue_head(&st->wq_data_available);
mutex_init(&st->lock);
INIT_WORK(&st->touch_st.workq, at91_adc_workq_handler);
st->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
if (IS_ERR(st->base))
return PTR_ERR(st->base);
/* if we plan to use DMA, we need the physical address of the regs */
st->dma_st.phys_addr = res->start;
st->irq = platform_get_irq(pdev, 0);
if (st->irq <= 0) {
if (!st->irq)
st->irq = -ENXIO;
return st->irq;
}
st->per_clk = devm_clk_get(&pdev->dev, "adc_clk");
if (IS_ERR(st->per_clk))
return PTR_ERR(st->per_clk);
st->reg = devm_regulator_get(&pdev->dev, "vddana");
if (IS_ERR(st->reg))
return PTR_ERR(st->reg);
st->vref = devm_regulator_get(&pdev->dev, "vref");
if (IS_ERR(st->vref))
return PTR_ERR(st->vref);
ret = devm_request_irq(&pdev->dev, st->irq, at91_adc_interrupt, 0,
pdev->dev.driver->name, indio_dev);
if (ret)
return ret;
ret = regulator_enable(st->reg);
if (ret)
return ret;
ret = regulator_enable(st->vref);
if (ret)
goto reg_disable;
st->vref_uv = regulator_get_voltage(st->vref);
if (st->vref_uv <= 0) {
ret = -EINVAL;
goto vref_disable;
}
at91_adc_hw_init(indio_dev);
ret = clk_prepare_enable(st->per_clk);
if (ret)
goto vref_disable;
platform_set_drvdata(pdev, indio_dev);
ret = at91_adc_buffer_init(indio_dev);
if (ret < 0) {
dev_err(&pdev->dev, "couldn't initialize the buffer.\n");
goto per_clk_disable_unprepare;
}
if (st->selected_trig->hw_trig) {
ret = at91_adc_trigger_init(indio_dev);
if (ret < 0) {
dev_err(&pdev->dev, "couldn't setup the triggers.\n");
goto per_clk_disable_unprepare;
}
/*
* Initially the iio buffer has a length of 2 and
* a watermark of 1
*/
st->dma_st.watermark = 1;
iio_buffer_set_attrs(indio_dev->buffer,
at91_adc_fifo_attributes);
}
if (dma_coerce_mask_and_coherent(&indio_dev->dev, DMA_BIT_MASK(32)))
dev_info(&pdev->dev, "cannot set DMA mask to 32-bit\n");
ret = iio_device_register(indio_dev);
if (ret < 0)
goto dma_disable;
if (st->selected_trig->hw_trig)
dev_info(&pdev->dev, "setting up trigger as %s\n",
st->selected_trig->name);
dev_info(&pdev->dev, "version: %x\n",
readl_relaxed(st->base + AT91_SAMA5D2_VERSION));
return 0;
dma_disable:
at91_adc_dma_disable(pdev);
per_clk_disable_unprepare:
clk_disable_unprepare(st->per_clk);
vref_disable:
regulator_disable(st->vref);
reg_disable:
regulator_disable(st->reg);
return ret;
}
static int at91_adc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct at91_adc_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
at91_adc_dma_disable(pdev);
clk_disable_unprepare(st->per_clk);
regulator_disable(st->vref);
regulator_disable(st->reg);
return 0;
}
static __maybe_unused int at91_adc_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct at91_adc_state *st = iio_priv(indio_dev);
/*
* Do a sofware reset of the ADC before we go to suspend.
* this will ensure that all pins are free from being muxed by the ADC
* and can be used by for other devices.
* Otherwise, ADC will hog them and we can't go to suspend mode.
*/
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
clk_disable_unprepare(st->per_clk);
regulator_disable(st->vref);
regulator_disable(st->reg);
return pinctrl_pm_select_sleep_state(dev);
}
static __maybe_unused int at91_adc_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct at91_adc_state *st = iio_priv(indio_dev);
int ret;
ret = pinctrl_pm_select_default_state(dev);
if (ret)
goto resume_failed;
ret = regulator_enable(st->reg);
if (ret)
goto resume_failed;
ret = regulator_enable(st->vref);
if (ret)
goto reg_disable_resume;
ret = clk_prepare_enable(st->per_clk);
if (ret)
goto vref_disable_resume;
at91_adc_hw_init(indio_dev);
/* reconfiguring trigger hardware state */
if (!iio_buffer_enabled(indio_dev))
return 0;
/* check if we are enabling triggered buffer or the touchscreen */
if (at91_adc_current_chan_is_touch(indio_dev))
return at91_adc_configure_touch(st, true);
else
return at91_adc_configure_trigger(st->trig, true);
/* not needed but more explicit */
return 0;
vref_disable_resume:
regulator_disable(st->vref);
reg_disable_resume:
regulator_disable(st->reg);
resume_failed:
dev_err(&indio_dev->dev, "failed to resume\n");
return ret;
}
static SIMPLE_DEV_PM_OPS(at91_adc_pm_ops, at91_adc_suspend, at91_adc_resume);
static const struct of_device_id at91_adc_dt_match[] = {
{
.compatible = "atmel,sama5d2-adc",
}, {
/* sentinel */
}
};
MODULE_DEVICE_TABLE(of, at91_adc_dt_match);
static struct platform_driver at91_adc_driver = {
.probe = at91_adc_probe,
.remove = at91_adc_remove,
.driver = {
.name = "at91-sama5d2_adc",
.of_match_table = at91_adc_dt_match,
.pm = &at91_adc_pm_ops,
},
};
module_platform_driver(at91_adc_driver)
MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
MODULE_DESCRIPTION("Atmel AT91 SAMA5D2 ADC");
MODULE_LICENSE("GPL v2");
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