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linux/drivers/iio/adc/meson_saradc.c
Martin Blumenstingl 103a07d427 iio: adc: meson-saradc: fix potential crash in meson_sar_adc_clear_fifo 
meson_sar_adc_clear_fifo passes a 0 as value-pointer to regmap_read().
In case of the meson-saradc driver this ends up in regmap_mmio_read(),
where the value-pointer is de-referenced unconditionally to assign the
value which was read.
Fix this by passing an actual pointer, even though all we want to do is
to discard the value.

As a side-effect this fixes a sparse warning ("Using plain integer as
NULL pointer") as reported by Paolo Cretaro.

Fixes: 3adbf34273 ("iio: adc: add a driver for the SAR ADC found in Amlogic Meson SoCs")
Reported-by: Paolo Cretaro <paolocretaro@gmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2017-06-11 15:00:13 +01:00

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/*
* Amlogic Meson Successive Approximation Register (SAR) A/D Converter
*
* Copyright (C) 2017 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#define MESON_SAR_ADC_REG0 0x00
#define MESON_SAR_ADC_REG0_PANEL_DETECT BIT(31)
#define MESON_SAR_ADC_REG0_BUSY_MASK GENMASK(30, 28)
#define MESON_SAR_ADC_REG0_DELTA_BUSY BIT(30)
#define MESON_SAR_ADC_REG0_AVG_BUSY BIT(29)
#define MESON_SAR_ADC_REG0_SAMPLE_BUSY BIT(28)
#define MESON_SAR_ADC_REG0_FIFO_FULL BIT(27)
#define MESON_SAR_ADC_REG0_FIFO_EMPTY BIT(26)
#define MESON_SAR_ADC_REG0_FIFO_COUNT_MASK GENMASK(25, 21)
#define MESON_SAR_ADC_REG0_ADC_BIAS_CTRL_MASK GENMASK(20, 19)
#define MESON_SAR_ADC_REG0_CURR_CHAN_ID_MASK GENMASK(18, 16)
#define MESON_SAR_ADC_REG0_ADC_TEMP_SEN_SEL BIT(15)
#define MESON_SAR_ADC_REG0_SAMPLING_STOP BIT(14)
#define MESON_SAR_ADC_REG0_CHAN_DELTA_EN_MASK GENMASK(13, 12)
#define MESON_SAR_ADC_REG0_DETECT_IRQ_POL BIT(10)
#define MESON_SAR_ADC_REG0_DETECT_IRQ_EN BIT(9)
#define MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK GENMASK(8, 4)
#define MESON_SAR_ADC_REG0_FIFO_IRQ_EN BIT(3)
#define MESON_SAR_ADC_REG0_SAMPLING_START BIT(2)
#define MESON_SAR_ADC_REG0_CONTINUOUS_EN BIT(1)
#define MESON_SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE BIT(0)
#define MESON_SAR_ADC_CHAN_LIST 0x04
#define MESON_SAR_ADC_CHAN_LIST_MAX_INDEX_MASK GENMASK(26, 24)
#define MESON_SAR_ADC_CHAN_LIST_ENTRY_MASK(_chan) \
(GENMASK(2, 0) << ((_chan) * 3))
#define MESON_SAR_ADC_AVG_CNTL 0x08
#define MESON_SAR_ADC_AVG_CNTL_AVG_MODE_SHIFT(_chan) \
(16 + ((_chan) * 2))
#define MESON_SAR_ADC_AVG_CNTL_AVG_MODE_MASK(_chan) \
(GENMASK(17, 16) << ((_chan) * 2))
#define MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_SHIFT(_chan) \
(0 + ((_chan) * 2))
#define MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_MASK(_chan) \
(GENMASK(1, 0) << ((_chan) * 2))
#define MESON_SAR_ADC_REG3 0x0c
#define MESON_SAR_ADC_REG3_CNTL_USE_SC_DLY BIT(31)
#define MESON_SAR_ADC_REG3_CLK_EN BIT(30)
#define MESON_SAR_ADC_REG3_BL30_INITIALIZED BIT(28)
#define MESON_SAR_ADC_REG3_CTRL_CONT_RING_COUNTER_EN BIT(27)
#define MESON_SAR_ADC_REG3_CTRL_SAMPLING_CLOCK_PHASE BIT(26)
#define MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK GENMASK(25, 23)
#define MESON_SAR_ADC_REG3_DETECT_EN BIT(22)
#define MESON_SAR_ADC_REG3_ADC_EN BIT(21)
#define MESON_SAR_ADC_REG3_PANEL_DETECT_COUNT_MASK GENMASK(20, 18)
#define MESON_SAR_ADC_REG3_PANEL_DETECT_FILTER_TB_MASK GENMASK(17, 16)
#define MESON_SAR_ADC_REG3_ADC_CLK_DIV_SHIFT 10
#define MESON_SAR_ADC_REG3_ADC_CLK_DIV_WIDTH 5
#define MESON_SAR_ADC_REG3_BLOCK_DLY_SEL_MASK GENMASK(9, 8)
#define MESON_SAR_ADC_REG3_BLOCK_DLY_MASK GENMASK(7, 0)
#define MESON_SAR_ADC_DELAY 0x10
#define MESON_SAR_ADC_DELAY_INPUT_DLY_SEL_MASK GENMASK(25, 24)
#define MESON_SAR_ADC_DELAY_BL30_BUSY BIT(15)
#define MESON_SAR_ADC_DELAY_KERNEL_BUSY BIT(14)
#define MESON_SAR_ADC_DELAY_INPUT_DLY_CNT_MASK GENMASK(23, 16)
#define MESON_SAR_ADC_DELAY_SAMPLE_DLY_SEL_MASK GENMASK(9, 8)
#define MESON_SAR_ADC_DELAY_SAMPLE_DLY_CNT_MASK GENMASK(7, 0)
#define MESON_SAR_ADC_LAST_RD 0x14
#define MESON_SAR_ADC_LAST_RD_LAST_CHANNEL1_MASK GENMASK(23, 16)
#define MESON_SAR_ADC_LAST_RD_LAST_CHANNEL0_MASK GENMASK(9, 0)
#define MESON_SAR_ADC_FIFO_RD 0x18
#define MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK GENMASK(14, 12)
#define MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK GENMASK(11, 0)
#define MESON_SAR_ADC_AUX_SW 0x1c
#define MESON_SAR_ADC_AUX_SW_MUX_SEL_CHAN_MASK(_chan) \
(GENMASK(10, 8) << (((_chan) - 2) * 2))
#define MESON_SAR_ADC_AUX_SW_VREF_P_MUX BIT(6)
#define MESON_SAR_ADC_AUX_SW_VREF_N_MUX BIT(5)
#define MESON_SAR_ADC_AUX_SW_MODE_SEL BIT(4)
#define MESON_SAR_ADC_AUX_SW_YP_DRIVE_SW BIT(3)
#define MESON_SAR_ADC_AUX_SW_XP_DRIVE_SW BIT(2)
#define MESON_SAR_ADC_AUX_SW_YM_DRIVE_SW BIT(1)
#define MESON_SAR_ADC_AUX_SW_XM_DRIVE_SW BIT(0)
#define MESON_SAR_ADC_CHAN_10_SW 0x20
#define MESON_SAR_ADC_CHAN_10_SW_CHAN1_MUX_SEL_MASK GENMASK(25, 23)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN1_VREF_P_MUX BIT(22)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN1_VREF_N_MUX BIT(21)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN1_MODE_SEL BIT(20)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN1_YP_DRIVE_SW BIT(19)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN1_XP_DRIVE_SW BIT(18)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN1_YM_DRIVE_SW BIT(17)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN1_XM_DRIVE_SW BIT(16)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN0_MUX_SEL_MASK GENMASK(9, 7)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN0_VREF_P_MUX BIT(6)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN0_VREF_N_MUX BIT(5)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN0_MODE_SEL BIT(4)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN0_YP_DRIVE_SW BIT(3)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN0_XP_DRIVE_SW BIT(2)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN0_YM_DRIVE_SW BIT(1)
#define MESON_SAR_ADC_CHAN_10_SW_CHAN0_XM_DRIVE_SW BIT(0)
#define MESON_SAR_ADC_DETECT_IDLE_SW 0x24
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_SW_EN BIT(26)
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_MUX_MASK GENMASK(25, 23)
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_VREF_P_MUX BIT(22)
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_VREF_N_MUX BIT(21)
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_MODE_SEL BIT(20)
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_YP_DRIVE_SW BIT(19)
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_XP_DRIVE_SW BIT(18)
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_YM_DRIVE_SW BIT(17)
#define MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_XM_DRIVE_SW BIT(16)
#define MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_MUX_SEL_MASK GENMASK(9, 7)
#define MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_VREF_P_MUX BIT(6)
#define MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_VREF_N_MUX BIT(5)
#define MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_MODE_SEL BIT(4)
#define MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_YP_DRIVE_SW BIT(3)
#define MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_XP_DRIVE_SW BIT(2)
#define MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_YM_DRIVE_SW BIT(1)
#define MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_XM_DRIVE_SW BIT(0)
#define MESON_SAR_ADC_DELTA_10 0x28
#define MESON_SAR_ADC_DELTA_10_TEMP_SEL BIT(27)
#define MESON_SAR_ADC_DELTA_10_TS_REVE1 BIT(26)
#define MESON_SAR_ADC_DELTA_10_CHAN1_DELTA_VALUE_MASK GENMASK(25, 16)
#define MESON_SAR_ADC_DELTA_10_TS_REVE0 BIT(15)
#define MESON_SAR_ADC_DELTA_10_TS_C_SHIFT 11
#define MESON_SAR_ADC_DELTA_10_TS_C_MASK GENMASK(14, 11)
#define MESON_SAR_ADC_DELTA_10_TS_VBG_EN BIT(10)
#define MESON_SAR_ADC_DELTA_10_CHAN0_DELTA_VALUE_MASK GENMASK(9, 0)
/*
* NOTE: registers from here are undocumented (the vendor Linux kernel driver
* and u-boot source served as reference). These only seem to be relevant on
* GXBB and newer.
*/
#define MESON_SAR_ADC_REG11 0x2c
#define MESON_SAR_ADC_REG11_BANDGAP_EN BIT(13)
#define MESON_SAR_ADC_REG13 0x34
#define MESON_SAR_ADC_REG13_12BIT_CALIBRATION_MASK GENMASK(13, 8)
#define MESON_SAR_ADC_MAX_FIFO_SIZE 32
#define MESON_SAR_ADC_TIMEOUT 100 /* ms */
/* for use with IIO_VAL_INT_PLUS_MICRO */
#define MILLION 1000000
#define MESON_SAR_ADC_CHAN(_chan) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = _chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_AVERAGE_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
BIT(IIO_CHAN_INFO_CALIBBIAS) | \
BIT(IIO_CHAN_INFO_CALIBSCALE), \
.datasheet_name = "SAR_ADC_CH"#_chan, \
}
/*
* TODO: the hardware supports IIO_TEMP for channel 6 as well which is
* currently not supported by this driver.
*/
static const struct iio_chan_spec meson_sar_adc_iio_channels[] = {
MESON_SAR_ADC_CHAN(0),
MESON_SAR_ADC_CHAN(1),
MESON_SAR_ADC_CHAN(2),
MESON_SAR_ADC_CHAN(3),
MESON_SAR_ADC_CHAN(4),
MESON_SAR_ADC_CHAN(5),
MESON_SAR_ADC_CHAN(6),
MESON_SAR_ADC_CHAN(7),
IIO_CHAN_SOFT_TIMESTAMP(8),
};
enum meson_sar_adc_avg_mode {
NO_AVERAGING = 0x0,
MEAN_AVERAGING = 0x1,
MEDIAN_AVERAGING = 0x2,
};
enum meson_sar_adc_num_samples {
ONE_SAMPLE = 0x0,
TWO_SAMPLES = 0x1,
FOUR_SAMPLES = 0x2,
EIGHT_SAMPLES = 0x3,
};
enum meson_sar_adc_chan7_mux_sel {
CHAN7_MUX_VSS = 0x0,
CHAN7_MUX_VDD_DIV4 = 0x1,
CHAN7_MUX_VDD_DIV2 = 0x2,
CHAN7_MUX_VDD_MUL3_DIV4 = 0x3,
CHAN7_MUX_VDD = 0x4,
CHAN7_MUX_CH7_INPUT = 0x7,
};
struct meson_sar_adc_data {
unsigned int resolution;
const char *name;
};
struct meson_sar_adc_priv {
struct regmap *regmap;
struct regulator *vref;
const struct meson_sar_adc_data *data;
struct clk *clkin;
struct clk *core_clk;
struct clk *sana_clk;
struct clk *adc_sel_clk;
struct clk *adc_clk;
struct clk_gate clk_gate;
struct clk *adc_div_clk;
struct clk_divider clk_div;
struct completion done;
int calibbias;
int calibscale;
};
static const struct regmap_config meson_sar_adc_regmap_config = {
.reg_bits = 8,
.val_bits = 32,
.reg_stride = 4,
.max_register = MESON_SAR_ADC_REG13,
};
static unsigned int meson_sar_adc_get_fifo_count(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
u32 regval;
regmap_read(priv->regmap, MESON_SAR_ADC_REG0, &regval);
return FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval);
}
static int meson_sar_adc_calib_val(struct iio_dev *indio_dev, int val)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int tmp;
/* use val_calib = scale * val_raw + offset calibration function */
tmp = div_s64((s64)val * priv->calibscale, MILLION) + priv->calibbias;
return clamp(tmp, 0, (1 << priv->data->resolution) - 1);
}
static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int regval, timeout = 10000;
/*
* NOTE: we need a small delay before reading the status, otherwise
* the sample engine may not have started internally (which would
* seem to us that sampling is already finished).
*/
do {
udelay(1);
regmap_read(priv->regmap, MESON_SAR_ADC_REG0, &regval);
} while (FIELD_GET(MESON_SAR_ADC_REG0_BUSY_MASK, regval) && timeout--);
if (timeout < 0)
return -ETIMEDOUT;
return 0;
}
static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
int *val)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int regval, fifo_chan, fifo_val, count;
if(!wait_for_completion_timeout(&priv->done,
msecs_to_jiffies(MESON_SAR_ADC_TIMEOUT)))
return -ETIMEDOUT;
count = meson_sar_adc_get_fifo_count(indio_dev);
if (count != 1) {
dev_err(&indio_dev->dev,
"ADC FIFO has %d element(s) instead of one\n", count);
return -EINVAL;
}
regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, &regval);
fifo_chan = FIELD_GET(MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK, regval);
if (fifo_chan != chan->channel) {
dev_err(&indio_dev->dev,
"ADC FIFO entry belongs to channel %d instead of %d\n",
fifo_chan, chan->channel);
return -EINVAL;
}
fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK, regval);
fifo_val &= GENMASK(priv->data->resolution - 1, 0);
*val = meson_sar_adc_calib_val(indio_dev, fifo_val);
return 0;
}
static void meson_sar_adc_set_averaging(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum meson_sar_adc_avg_mode mode,
enum meson_sar_adc_num_samples samples)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int val, channel = chan->channel;
val = samples << MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_SHIFT(channel);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_AVG_CNTL,
MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_MASK(channel),
val);
val = mode << MESON_SAR_ADC_AVG_CNTL_AVG_MODE_SHIFT(channel);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_AVG_CNTL,
MESON_SAR_ADC_AVG_CNTL_AVG_MODE_MASK(channel), val);
}
static void meson_sar_adc_enable_channel(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
u32 regval;
/*
* the SAR ADC engine allows sampling multiple channels at the same
* time. to keep it simple we're only working with one *internal*
* channel, which starts counting at index 0 (which means: count = 1).
*/
regval = FIELD_PREP(MESON_SAR_ADC_CHAN_LIST_MAX_INDEX_MASK, 0);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_CHAN_LIST,
MESON_SAR_ADC_CHAN_LIST_MAX_INDEX_MASK, regval);
/* map channel index 0 to the channel which we want to read */
regval = FIELD_PREP(MESON_SAR_ADC_CHAN_LIST_ENTRY_MASK(0),
chan->channel);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_CHAN_LIST,
MESON_SAR_ADC_CHAN_LIST_ENTRY_MASK(0), regval);
regval = FIELD_PREP(MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_MUX_MASK,
chan->channel);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DETECT_IDLE_SW,
MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_MUX_MASK,
regval);
regval = FIELD_PREP(MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_MUX_SEL_MASK,
chan->channel);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DETECT_IDLE_SW,
MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_MUX_SEL_MASK,
regval);
if (chan->channel == 6)
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELTA_10,
MESON_SAR_ADC_DELTA_10_TEMP_SEL, 0);
}
static void meson_sar_adc_set_chan7_mux(struct iio_dev *indio_dev,
enum meson_sar_adc_chan7_mux_sel sel)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
u32 regval;
regval = FIELD_PREP(MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, sel);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
MESON_SAR_ADC_REG3_CTRL_CHAN7_MUX_SEL_MASK, regval);
usleep_range(10, 20);
}
static void meson_sar_adc_start_sample_engine(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
reinit_completion(&priv->done);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_FIFO_IRQ_EN,
MESON_SAR_ADC_REG0_FIFO_IRQ_EN);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE,
MESON_SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_SAMPLING_START,
MESON_SAR_ADC_REG0_SAMPLING_START);
}
static void meson_sar_adc_stop_sample_engine(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_FIFO_IRQ_EN, 0);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_SAMPLING_STOP,
MESON_SAR_ADC_REG0_SAMPLING_STOP);
/* wait until all modules are stopped */
meson_sar_adc_wait_busy_clear(indio_dev);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE, 0);
}
static int meson_sar_adc_lock(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int val, timeout = 10000;
mutex_lock(&indio_dev->mlock);
/* prevent BL30 from using the SAR ADC while we are using it */
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
MESON_SAR_ADC_DELAY_KERNEL_BUSY,
MESON_SAR_ADC_DELAY_KERNEL_BUSY);
/* wait until BL30 releases it's lock (so we can use the SAR ADC) */
do {
udelay(1);
regmap_read(priv->regmap, MESON_SAR_ADC_DELAY, &val);
} while (val & MESON_SAR_ADC_DELAY_BL30_BUSY && timeout--);
if (timeout < 0)
return -ETIMEDOUT;
return 0;
}
static void meson_sar_adc_unlock(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
/* allow BL30 to use the SAR ADC again */
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
MESON_SAR_ADC_DELAY_KERNEL_BUSY, 0);
mutex_unlock(&indio_dev->mlock);
}
static void meson_sar_adc_clear_fifo(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
unsigned int count, tmp;
for (count = 0; count < MESON_SAR_ADC_MAX_FIFO_SIZE; count++) {
if (!meson_sar_adc_get_fifo_count(indio_dev))
break;
regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, &tmp);
}
}
static int meson_sar_adc_get_sample(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum meson_sar_adc_avg_mode avg_mode,
enum meson_sar_adc_num_samples avg_samples,
int *val)
{
int ret;
ret = meson_sar_adc_lock(indio_dev);
if (ret)
return ret;
/* clear the FIFO to make sure we're not reading old values */
meson_sar_adc_clear_fifo(indio_dev);
meson_sar_adc_set_averaging(indio_dev, chan, avg_mode, avg_samples);
meson_sar_adc_enable_channel(indio_dev, chan);
meson_sar_adc_start_sample_engine(indio_dev);
ret = meson_sar_adc_read_raw_sample(indio_dev, chan, val);
meson_sar_adc_stop_sample_engine(indio_dev);
meson_sar_adc_unlock(indio_dev);
if (ret) {
dev_warn(indio_dev->dev.parent,
"failed to read sample for channel %d: %d\n",
chan->channel, ret);
return ret;
}
return IIO_VAL_INT;
}
static int meson_sar_adc_iio_info_read_raw(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
int *val, int *val2, long mask)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
return meson_sar_adc_get_sample(indio_dev, chan, NO_AVERAGING,
ONE_SAMPLE, val);
break;
case IIO_CHAN_INFO_AVERAGE_RAW:
return meson_sar_adc_get_sample(indio_dev, chan,
MEAN_AVERAGING, EIGHT_SAMPLES,
val);
break;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(priv->vref);
if (ret < 0) {
dev_err(indio_dev->dev.parent,
"failed to get vref voltage: %d\n", ret);
return ret;
}
*val = ret / 1000;
*val2 = priv->data->resolution;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_CALIBBIAS:
*val = priv->calibbias;
return IIO_VAL_INT;
case IIO_CHAN_INFO_CALIBSCALE:
*val = priv->calibscale / MILLION;
*val2 = priv->calibscale % MILLION;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static int meson_sar_adc_clk_init(struct iio_dev *indio_dev,
void __iomem *base)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
struct clk_init_data init;
const char *clk_parents[1];
init.name = devm_kasprintf(&indio_dev->dev, GFP_KERNEL, "%s#adc_div",
of_node_full_name(indio_dev->dev.of_node));
init.flags = 0;
init.ops = &clk_divider_ops;
clk_parents[0] = __clk_get_name(priv->clkin);
init.parent_names = clk_parents;
init.num_parents = 1;
priv->clk_div.reg = base + MESON_SAR_ADC_REG3;
priv->clk_div.shift = MESON_SAR_ADC_REG3_ADC_CLK_DIV_SHIFT;
priv->clk_div.width = MESON_SAR_ADC_REG3_ADC_CLK_DIV_WIDTH;
priv->clk_div.hw.init = &init;
priv->clk_div.flags = 0;
priv->adc_div_clk = devm_clk_register(&indio_dev->dev,
&priv->clk_div.hw);
if (WARN_ON(IS_ERR(priv->adc_div_clk)))
return PTR_ERR(priv->adc_div_clk);
init.name = devm_kasprintf(&indio_dev->dev, GFP_KERNEL, "%s#adc_en",
of_node_full_name(indio_dev->dev.of_node));
init.flags = CLK_SET_RATE_PARENT;
init.ops = &clk_gate_ops;
clk_parents[0] = __clk_get_name(priv->adc_div_clk);
init.parent_names = clk_parents;
init.num_parents = 1;
priv->clk_gate.reg = base + MESON_SAR_ADC_REG3;
priv->clk_gate.bit_idx = fls(MESON_SAR_ADC_REG3_CLK_EN);
priv->clk_gate.hw.init = &init;
priv->adc_clk = devm_clk_register(&indio_dev->dev, &priv->clk_gate.hw);
if (WARN_ON(IS_ERR(priv->adc_clk)))
return PTR_ERR(priv->adc_clk);
return 0;
}
static int meson_sar_adc_init(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int regval, ret;
/*
* make sure we start at CH7 input since the other muxes are only used
* for internal calibration.
*/
meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT);
/*
* leave sampling delay and the input clocks as configured by BL30 to
* make sure BL30 gets the values it expects when reading the
* temperature sensor.
*/
regmap_read(priv->regmap, MESON_SAR_ADC_REG3, &regval);
if (regval & MESON_SAR_ADC_REG3_BL30_INITIALIZED)
return 0;
meson_sar_adc_stop_sample_engine(indio_dev);
/* update the channel 6 MUX to select the temperature sensor */
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_ADC_TEMP_SEN_SEL,
MESON_SAR_ADC_REG0_ADC_TEMP_SEN_SEL);
/* disable all channels by default */
regmap_write(priv->regmap, MESON_SAR_ADC_CHAN_LIST, 0x0);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
MESON_SAR_ADC_REG3_CTRL_SAMPLING_CLOCK_PHASE, 0);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
MESON_SAR_ADC_REG3_CNTL_USE_SC_DLY,
MESON_SAR_ADC_REG3_CNTL_USE_SC_DLY);
/* delay between two samples = (10+1) * 1uS */
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
MESON_SAR_ADC_DELAY_INPUT_DLY_CNT_MASK,
FIELD_PREP(MESON_SAR_ADC_DELAY_SAMPLE_DLY_CNT_MASK,
10));
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
MESON_SAR_ADC_DELAY_SAMPLE_DLY_SEL_MASK,
FIELD_PREP(MESON_SAR_ADC_DELAY_SAMPLE_DLY_SEL_MASK,
0));
/* delay between two samples = (10+1) * 1uS */
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
MESON_SAR_ADC_DELAY_INPUT_DLY_CNT_MASK,
FIELD_PREP(MESON_SAR_ADC_DELAY_INPUT_DLY_CNT_MASK,
10));
regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
MESON_SAR_ADC_DELAY_INPUT_DLY_SEL_MASK,
FIELD_PREP(MESON_SAR_ADC_DELAY_INPUT_DLY_SEL_MASK,
1));
ret = clk_set_parent(priv->adc_sel_clk, priv->clkin);
if (ret) {
dev_err(indio_dev->dev.parent,
"failed to set adc parent to clkin\n");
return ret;
}
ret = clk_set_rate(priv->adc_clk, 1200000);
if (ret) {
dev_err(indio_dev->dev.parent,
"failed to set adc clock rate\n");
return ret;
}
return 0;
}
static int meson_sar_adc_hw_enable(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int ret;
u32 regval;
ret = meson_sar_adc_lock(indio_dev);
if (ret)
goto err_lock;
ret = regulator_enable(priv->vref);
if (ret < 0) {
dev_err(indio_dev->dev.parent,
"failed to enable vref regulator\n");
goto err_vref;
}
ret = clk_prepare_enable(priv->core_clk);
if (ret) {
dev_err(indio_dev->dev.parent, "failed to enable core clk\n");
goto err_core_clk;
}
ret = clk_prepare_enable(priv->sana_clk);
if (ret) {
dev_err(indio_dev->dev.parent, "failed to enable sana clk\n");
goto err_sana_clk;
}
regval = FIELD_PREP(MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, 1);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, regval);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG11,
MESON_SAR_ADC_REG11_BANDGAP_EN,
MESON_SAR_ADC_REG11_BANDGAP_EN);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
MESON_SAR_ADC_REG3_ADC_EN,
MESON_SAR_ADC_REG3_ADC_EN);
udelay(5);
ret = clk_prepare_enable(priv->adc_clk);
if (ret) {
dev_err(indio_dev->dev.parent, "failed to enable adc clk\n");
goto err_adc_clk;
}
meson_sar_adc_unlock(indio_dev);
return 0;
err_adc_clk:
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
MESON_SAR_ADC_REG3_ADC_EN, 0);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG11,
MESON_SAR_ADC_REG11_BANDGAP_EN, 0);
clk_disable_unprepare(priv->sana_clk);
err_sana_clk:
clk_disable_unprepare(priv->core_clk);
err_core_clk:
regulator_disable(priv->vref);
err_vref:
meson_sar_adc_unlock(indio_dev);
err_lock:
return ret;
}
static int meson_sar_adc_hw_disable(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int ret;
ret = meson_sar_adc_lock(indio_dev);
if (ret)
return ret;
clk_disable_unprepare(priv->adc_clk);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG3,
MESON_SAR_ADC_REG3_ADC_EN, 0);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG11,
MESON_SAR_ADC_REG11_BANDGAP_EN, 0);
clk_disable_unprepare(priv->sana_clk);
clk_disable_unprepare(priv->core_clk);
regulator_disable(priv->vref);
meson_sar_adc_unlock(indio_dev);
return 0;
}
static irqreturn_t meson_sar_adc_irq(int irq, void *data)
{
struct iio_dev *indio_dev = data;
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
unsigned int cnt, threshold;
u32 regval;
regmap_read(priv->regmap, MESON_SAR_ADC_REG0, &regval);
cnt = FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval);
threshold = FIELD_GET(MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, regval);
if (cnt < threshold)
return IRQ_NONE;
complete(&priv->done);
return IRQ_HANDLED;
}
static int meson_sar_adc_calib(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int ret, nominal0, nominal1, value0, value1;
/* use points 25% and 75% for calibration */
nominal0 = (1 << priv->data->resolution) / 4;
nominal1 = (1 << priv->data->resolution) * 3 / 4;
meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
usleep_range(10, 20);
ret = meson_sar_adc_get_sample(indio_dev,
&meson_sar_adc_iio_channels[7],
MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
if (ret < 0)
goto out;
meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
usleep_range(10, 20);
ret = meson_sar_adc_get_sample(indio_dev,
&meson_sar_adc_iio_channels[7],
MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
if (ret < 0)
goto out;
if (value1 <= value0) {
ret = -EINVAL;
goto out;
}
priv->calibscale = div_s64((nominal1 - nominal0) * (s64)MILLION,
value1 - value0);
priv->calibbias = nominal0 - div_s64((s64)value0 * priv->calibscale,
MILLION);
ret = 0;
out:
meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_CH7_INPUT);
return ret;
}
static const struct iio_info meson_sar_adc_iio_info = {
.read_raw = meson_sar_adc_iio_info_read_raw,
.driver_module = THIS_MODULE,
};
struct meson_sar_adc_data meson_sar_adc_gxbb_data = {
.resolution = 10,
.name = "meson-gxbb-saradc",
};
struct meson_sar_adc_data meson_sar_adc_gxl_data = {
.resolution = 12,
.name = "meson-gxl-saradc",
};
struct meson_sar_adc_data meson_sar_adc_gxm_data = {
.resolution = 12,
.name = "meson-gxm-saradc",
};
static const struct of_device_id meson_sar_adc_of_match[] = {
{
.compatible = "amlogic,meson-gxbb-saradc",
.data = &meson_sar_adc_gxbb_data,
}, {
.compatible = "amlogic,meson-gxl-saradc",
.data = &meson_sar_adc_gxl_data,
}, {
.compatible = "amlogic,meson-gxm-saradc",
.data = &meson_sar_adc_gxm_data,
},
{},
};
MODULE_DEVICE_TABLE(of, meson_sar_adc_of_match);
static int meson_sar_adc_probe(struct platform_device *pdev)
{
struct meson_sar_adc_priv *priv;
struct iio_dev *indio_dev;
struct resource *res;
void __iomem *base;
const struct of_device_id *match;
int irq, ret;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
if (!indio_dev) {
dev_err(&pdev->dev, "failed allocating iio device\n");
return -ENOMEM;
}
priv = iio_priv(indio_dev);
init_completion(&priv->done);
match = of_match_device(meson_sar_adc_of_match, &pdev->dev);
priv->data = match->data;
indio_dev->name = priv->data->name;
indio_dev->dev.parent = &pdev->dev;
indio_dev->dev.of_node = pdev->dev.of_node;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &meson_sar_adc_iio_info;
indio_dev->channels = meson_sar_adc_iio_channels;
indio_dev->num_channels = ARRAY_SIZE(meson_sar_adc_iio_channels);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(base))
return PTR_ERR(base);
irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
if (!irq)
return -EINVAL;
ret = devm_request_irq(&pdev->dev, irq, meson_sar_adc_irq, IRQF_SHARED,
dev_name(&pdev->dev), indio_dev);
if (ret)
return ret;
priv->regmap = devm_regmap_init_mmio(&pdev->dev, base,
&meson_sar_adc_regmap_config);
if (IS_ERR(priv->regmap))
return PTR_ERR(priv->regmap);
priv->clkin = devm_clk_get(&pdev->dev, "clkin");
if (IS_ERR(priv->clkin)) {
dev_err(&pdev->dev, "failed to get clkin\n");
return PTR_ERR(priv->clkin);
}
priv->core_clk = devm_clk_get(&pdev->dev, "core");
if (IS_ERR(priv->core_clk)) {
dev_err(&pdev->dev, "failed to get core clk\n");
return PTR_ERR(priv->core_clk);
}
priv->sana_clk = devm_clk_get(&pdev->dev, "sana");
if (IS_ERR(priv->sana_clk)) {
if (PTR_ERR(priv->sana_clk) == -ENOENT) {
priv->sana_clk = NULL;
} else {
dev_err(&pdev->dev, "failed to get sana clk\n");
return PTR_ERR(priv->sana_clk);
}
}
priv->adc_clk = devm_clk_get(&pdev->dev, "adc_clk");
if (IS_ERR(priv->adc_clk)) {
if (PTR_ERR(priv->adc_clk) == -ENOENT) {
priv->adc_clk = NULL;
} else {
dev_err(&pdev->dev, "failed to get adc clk\n");
return PTR_ERR(priv->adc_clk);
}
}
priv->adc_sel_clk = devm_clk_get(&pdev->dev, "adc_sel");
if (IS_ERR(priv->adc_sel_clk)) {
if (PTR_ERR(priv->adc_sel_clk) == -ENOENT) {
priv->adc_sel_clk = NULL;
} else {
dev_err(&pdev->dev, "failed to get adc_sel clk\n");
return PTR_ERR(priv->adc_sel_clk);
}
}
/* on pre-GXBB SoCs the SAR ADC itself provides the ADC clock: */
if (!priv->adc_clk) {
ret = meson_sar_adc_clk_init(indio_dev, base);
if (ret)
return ret;
}
priv->vref = devm_regulator_get(&pdev->dev, "vref");
if (IS_ERR(priv->vref)) {
dev_err(&pdev->dev, "failed to get vref regulator\n");
return PTR_ERR(priv->vref);
}
priv->calibscale = MILLION;
ret = meson_sar_adc_init(indio_dev);
if (ret)
goto err;
ret = meson_sar_adc_hw_enable(indio_dev);
if (ret)
goto err;
ret = meson_sar_adc_calib(indio_dev);
if (ret)
dev_warn(&pdev->dev, "calibration failed\n");
platform_set_drvdata(pdev, indio_dev);
ret = iio_device_register(indio_dev);
if (ret)
goto err_hw;
return 0;
err_hw:
meson_sar_adc_hw_disable(indio_dev);
err:
return ret;
}
static int meson_sar_adc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
iio_device_unregister(indio_dev);
return meson_sar_adc_hw_disable(indio_dev);
}
static int __maybe_unused meson_sar_adc_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
return meson_sar_adc_hw_disable(indio_dev);
}
static int __maybe_unused meson_sar_adc_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
return meson_sar_adc_hw_enable(indio_dev);
}
static SIMPLE_DEV_PM_OPS(meson_sar_adc_pm_ops,
meson_sar_adc_suspend, meson_sar_adc_resume);
static struct platform_driver meson_sar_adc_driver = {
.probe = meson_sar_adc_probe,
.remove = meson_sar_adc_remove,
.driver = {
.name = "meson-saradc",
.of_match_table = meson_sar_adc_of_match,
.pm = &meson_sar_adc_pm_ops,
},
};
module_platform_driver(meson_sar_adc_driver);
MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
MODULE_DESCRIPTION("Amlogic Meson SAR ADC driver");
MODULE_LICENSE("GPL v2");
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