linux/drivers/iio/adc/sun4i-gpadc-iio.c

614 lines
17 KiB
C
Raw Normal View History

/* ADC driver for sunxi platforms' (A10, A13 and A31) GPADC
*
* Copyright (c) 2016 Quentin Schulz <quentin.schulz@free-electrons.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.
*
* The Allwinner SoCs all have an ADC that can also act as a touchscreen
* controller and a thermal sensor.
* The thermal sensor works only when the ADC acts as a touchscreen controller
* and is configured to throw an interrupt every fixed periods of time (let say
* every X seconds).
* One would be tempted to disable the IP on the hardware side rather than
* disabling interrupts to save some power but that resets the internal clock of
* the IP, resulting in having to wait X seconds every time we want to read the
* value of the thermal sensor.
* This is also the reason of using autosuspend in pm_runtime. If there was no
* autosuspend, the thermal sensor would need X seconds after every
* pm_runtime_get_sync to get a value from the ADC. The autosuspend allows the
* thermal sensor to be requested again in a certain time span before it gets
* shutdown for not being used.
*/
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/thermal.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/iio/machine.h>
#include <linux/mfd/sun4i-gpadc.h>
static unsigned int sun4i_gpadc_chan_select(unsigned int chan)
{
return SUN4I_GPADC_CTRL1_ADC_CHAN_SELECT(chan);
}
static unsigned int sun6i_gpadc_chan_select(unsigned int chan)
{
return SUN6I_GPADC_CTRL1_ADC_CHAN_SELECT(chan);
}
struct gpadc_data {
int temp_offset;
int temp_scale;
unsigned int tp_mode_en;
unsigned int tp_adc_select;
unsigned int (*adc_chan_select)(unsigned int chan);
unsigned int adc_chan_mask;
};
static const struct gpadc_data sun4i_gpadc_data = {
.temp_offset = -1932,
.temp_scale = 133,
.tp_mode_en = SUN4I_GPADC_CTRL1_TP_MODE_EN,
.tp_adc_select = SUN4I_GPADC_CTRL1_TP_ADC_SELECT,
.adc_chan_select = &sun4i_gpadc_chan_select,
.adc_chan_mask = SUN4I_GPADC_CTRL1_ADC_CHAN_MASK,
};
static const struct gpadc_data sun5i_gpadc_data = {
.temp_offset = -1447,
.temp_scale = 100,
.tp_mode_en = SUN4I_GPADC_CTRL1_TP_MODE_EN,
.tp_adc_select = SUN4I_GPADC_CTRL1_TP_ADC_SELECT,
.adc_chan_select = &sun4i_gpadc_chan_select,
.adc_chan_mask = SUN4I_GPADC_CTRL1_ADC_CHAN_MASK,
};
static const struct gpadc_data sun6i_gpadc_data = {
.temp_offset = -1623,
.temp_scale = 167,
.tp_mode_en = SUN6I_GPADC_CTRL1_TP_MODE_EN,
.tp_adc_select = SUN6I_GPADC_CTRL1_TP_ADC_SELECT,
.adc_chan_select = &sun6i_gpadc_chan_select,
.adc_chan_mask = SUN6I_GPADC_CTRL1_ADC_CHAN_MASK,
};
struct sun4i_gpadc_iio {
struct iio_dev *indio_dev;
struct completion completion;
int temp_data;
u32 adc_data;
struct regmap *regmap;
unsigned int fifo_data_irq;
atomic_t ignore_fifo_data_irq;
unsigned int temp_data_irq;
atomic_t ignore_temp_data_irq;
const struct gpadc_data *data;
/* prevents concurrent reads of temperature and ADC */
struct mutex mutex;
};
#define SUN4I_GPADC_ADC_CHANNEL(_channel, _name) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = _channel, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.datasheet_name = _name, \
}
static struct iio_map sun4i_gpadc_hwmon_maps[] = {
{
.adc_channel_label = "temp_adc",
.consumer_dev_name = "iio_hwmon.0",
},
{ /* sentinel */ },
};
static const struct iio_chan_spec sun4i_gpadc_channels[] = {
SUN4I_GPADC_ADC_CHANNEL(0, "adc_chan0"),
SUN4I_GPADC_ADC_CHANNEL(1, "adc_chan1"),
SUN4I_GPADC_ADC_CHANNEL(2, "adc_chan2"),
SUN4I_GPADC_ADC_CHANNEL(3, "adc_chan3"),
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OFFSET),
.datasheet_name = "temp_adc",
},
};
static const struct iio_chan_spec sun4i_gpadc_channels_no_temp[] = {
SUN4I_GPADC_ADC_CHANNEL(0, "adc_chan0"),
SUN4I_GPADC_ADC_CHANNEL(1, "adc_chan1"),
SUN4I_GPADC_ADC_CHANNEL(2, "adc_chan2"),
SUN4I_GPADC_ADC_CHANNEL(3, "adc_chan3"),
};
static int sun4i_prepare_for_irq(struct iio_dev *indio_dev, int channel,
unsigned int irq)
{
struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
int ret;
u32 reg;
pm_runtime_get_sync(indio_dev->dev.parent);
reinit_completion(&info->completion);
ret = regmap_write(info->regmap, SUN4I_GPADC_INT_FIFOC,
SUN4I_GPADC_INT_FIFOC_TP_FIFO_TRIG_LEVEL(1) |
SUN4I_GPADC_INT_FIFOC_TP_FIFO_FLUSH);
if (ret)
return ret;
ret = regmap_read(info->regmap, SUN4I_GPADC_CTRL1, &reg);
if (ret)
return ret;
if (irq == info->fifo_data_irq) {
ret = regmap_write(info->regmap, SUN4I_GPADC_CTRL1,
info->data->tp_mode_en |
info->data->tp_adc_select |
info->data->adc_chan_select(channel));
/*
* When the IP changes channel, it needs a bit of time to get
* correct values.
*/
if ((reg & info->data->adc_chan_mask) !=
info->data->adc_chan_select(channel))
mdelay(10);
} else {
/*
* The temperature sensor returns valid data only when the ADC
* operates in touchscreen mode.
*/
ret = regmap_write(info->regmap, SUN4I_GPADC_CTRL1,
info->data->tp_mode_en);
}
if (ret)
return ret;
/*
* When the IP changes mode between ADC or touchscreen, it
* needs a bit of time to get correct values.
*/
if ((reg & info->data->tp_adc_select) != info->data->tp_adc_select)
mdelay(100);
return 0;
}
static int sun4i_gpadc_read(struct iio_dev *indio_dev, int channel, int *val,
unsigned int irq)
{
struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
int ret;
mutex_lock(&info->mutex);
ret = sun4i_prepare_for_irq(indio_dev, channel, irq);
if (ret)
goto err;
enable_irq(irq);
/*
* The temperature sensor throws an interruption periodically (currently
* set at periods of ~0.6s in sun4i_gpadc_runtime_resume). A 1s delay
* makes sure an interruption occurs in normal conditions. If it doesn't
* occur, then there is a timeout.
*/
if (!wait_for_completion_timeout(&info->completion,
msecs_to_jiffies(1000))) {
ret = -ETIMEDOUT;
goto err;
}
if (irq == info->fifo_data_irq)
*val = info->adc_data;
else
*val = info->temp_data;
ret = 0;
pm_runtime_mark_last_busy(indio_dev->dev.parent);
err:
pm_runtime_put_autosuspend(indio_dev->dev.parent);
mutex_unlock(&info->mutex);
return ret;
}
static int sun4i_gpadc_adc_read(struct iio_dev *indio_dev, int channel,
int *val)
{
struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
return sun4i_gpadc_read(indio_dev, channel, val, info->fifo_data_irq);
}
static int sun4i_gpadc_temp_read(struct iio_dev *indio_dev, int *val)
{
struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
return sun4i_gpadc_read(indio_dev, 0, val, info->temp_data_irq);
}
static int sun4i_gpadc_temp_offset(struct iio_dev *indio_dev, int *val)
{
struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
*val = info->data->temp_offset;
return 0;
}
static int sun4i_gpadc_temp_scale(struct iio_dev *indio_dev, int *val)
{
struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
*val = info->data->temp_scale;
return 0;
}
static int sun4i_gpadc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
int ret;
switch (mask) {
case IIO_CHAN_INFO_OFFSET:
ret = sun4i_gpadc_temp_offset(indio_dev, val);
if (ret)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_RAW:
if (chan->type == IIO_VOLTAGE)
ret = sun4i_gpadc_adc_read(indio_dev, chan->channel,
val);
else
ret = sun4i_gpadc_temp_read(indio_dev, val);
if (ret)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
if (chan->type == IIO_VOLTAGE) {
/* 3000mV / 4096 * raw */
*val = 0;
*val2 = 732421875;
return IIO_VAL_INT_PLUS_NANO;
}
ret = sun4i_gpadc_temp_scale(indio_dev, val);
if (ret)
return ret;
return IIO_VAL_INT;
default:
return -EINVAL;
}
return -EINVAL;
}
static const struct iio_info sun4i_gpadc_iio_info = {
.read_raw = sun4i_gpadc_read_raw,
.driver_module = THIS_MODULE,
};
static irqreturn_t sun4i_gpadc_temp_data_irq_handler(int irq, void *dev_id)
{
struct sun4i_gpadc_iio *info = dev_id;
if (atomic_read(&info->ignore_temp_data_irq))
goto out;
if (!regmap_read(info->regmap, SUN4I_GPADC_TEMP_DATA, &info->temp_data))
complete(&info->completion);
out:
disable_irq_nosync(info->temp_data_irq);
return IRQ_HANDLED;
}
static irqreturn_t sun4i_gpadc_fifo_data_irq_handler(int irq, void *dev_id)
{
struct sun4i_gpadc_iio *info = dev_id;
if (atomic_read(&info->ignore_fifo_data_irq))
goto out;
if (!regmap_read(info->regmap, SUN4I_GPADC_DATA, &info->adc_data))
complete(&info->completion);
out:
disable_irq_nosync(info->fifo_data_irq);
return IRQ_HANDLED;
}
static int sun4i_gpadc_runtime_suspend(struct device *dev)
{
struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
/* Disable the ADC on IP */
regmap_write(info->regmap, SUN4I_GPADC_CTRL1, 0);
/* Disable temperature sensor on IP */
regmap_write(info->regmap, SUN4I_GPADC_TPR, 0);
return 0;
}
static int sun4i_gpadc_runtime_resume(struct device *dev)
{
struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
/* clkin = 6MHz */
regmap_write(info->regmap, SUN4I_GPADC_CTRL0,
SUN4I_GPADC_CTRL0_ADC_CLK_DIVIDER(2) |
SUN4I_GPADC_CTRL0_FS_DIV(7) |
SUN4I_GPADC_CTRL0_T_ACQ(63));
regmap_write(info->regmap, SUN4I_GPADC_CTRL1, info->data->tp_mode_en);
regmap_write(info->regmap, SUN4I_GPADC_CTRL3,
SUN4I_GPADC_CTRL3_FILTER_EN |
SUN4I_GPADC_CTRL3_FILTER_TYPE(1));
/* period = SUN4I_GPADC_TPR_TEMP_PERIOD * 256 * 16 / clkin; ~0.6s */
regmap_write(info->regmap, SUN4I_GPADC_TPR,
SUN4I_GPADC_TPR_TEMP_ENABLE |
SUN4I_GPADC_TPR_TEMP_PERIOD(800));
return 0;
}
static int sun4i_gpadc_get_temp(void *data, int *temp)
{
struct sun4i_gpadc_iio *info = (struct sun4i_gpadc_iio *)data;
int val, scale, offset;
if (sun4i_gpadc_temp_read(info->indio_dev, &val))
return -ETIMEDOUT;
sun4i_gpadc_temp_scale(info->indio_dev, &scale);
sun4i_gpadc_temp_offset(info->indio_dev, &offset);
*temp = (val + offset) * scale;
return 0;
}
static const struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
.get_temp = &sun4i_gpadc_get_temp,
};
static const struct dev_pm_ops sun4i_gpadc_pm_ops = {
.runtime_suspend = &sun4i_gpadc_runtime_suspend,
.runtime_resume = &sun4i_gpadc_runtime_resume,
};
static int sun4i_irq_init(struct platform_device *pdev, const char *name,
irq_handler_t handler, const char *devname,
unsigned int *irq, atomic_t *atomic)
{
int ret;
struct sun4i_gpadc_dev *mfd_dev = dev_get_drvdata(pdev->dev.parent);
struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(&pdev->dev));
/*
* Once the interrupt is activated, the IP continuously performs
* conversions thus throws interrupts. The interrupt is activated right
* after being requested but we want to control when these interrupts
* occur thus we disable it right after being requested. However, an
* interrupt might occur between these two instructions and we have to
* make sure that does not happen, by using atomic flags. We set the
* flag before requesting the interrupt and unset it right after
* disabling the interrupt. When an interrupt occurs between these two
* instructions, reading the atomic flag will tell us to ignore the
* interrupt.
*/
atomic_set(atomic, 1);
ret = platform_get_irq_byname(pdev, name);
if (ret < 0) {
dev_err(&pdev->dev, "no %s interrupt registered\n", name);
return ret;
}
ret = regmap_irq_get_virq(mfd_dev->regmap_irqc, ret);
if (ret < 0) {
dev_err(&pdev->dev, "failed to get virq for irq %s\n", name);
return ret;
}
*irq = ret;
ret = devm_request_any_context_irq(&pdev->dev, *irq, handler, 0,
devname, info);
if (ret < 0) {
dev_err(&pdev->dev, "could not request %s interrupt: %d\n",
name, ret);
return ret;
}
disable_irq(*irq);
atomic_set(atomic, 0);
return 0;
}
static int sun4i_gpadc_probe(struct platform_device *pdev)
{
struct sun4i_gpadc_iio *info;
struct iio_dev *indio_dev;
int ret;
struct sun4i_gpadc_dev *sun4i_gpadc_dev;
sun4i_gpadc_dev = dev_get_drvdata(pdev->dev.parent);
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
if (!indio_dev)
return -ENOMEM;
info = iio_priv(indio_dev);
platform_set_drvdata(pdev, indio_dev);
mutex_init(&info->mutex);
info->regmap = sun4i_gpadc_dev->regmap;
info->indio_dev = indio_dev;
init_completion(&info->completion);
indio_dev->name = dev_name(&pdev->dev);
indio_dev->dev.parent = &pdev->dev;
indio_dev->dev.of_node = pdev->dev.of_node;
indio_dev->info = &sun4i_gpadc_iio_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->num_channels = ARRAY_SIZE(sun4i_gpadc_channels);
indio_dev->channels = sun4i_gpadc_channels;
info->data = (struct gpadc_data *)platform_get_device_id(pdev)->driver_data;
/*
* Since the controller needs to be in touchscreen mode for its thermal
* sensor to operate properly, and that switching between the two modes
* needs a delay, always registering in the thermal framework will
* significantly slow down the conversion rate of the ADCs.
*
* Therefore, instead of depending on THERMAL_OF in Kconfig, we only
* register the sensor if that option is enabled, eventually leaving
* that choice to the user.
*/
if (IS_ENABLED(CONFIG_THERMAL_OF)) {
/*
* This driver is a child of an MFD which has a node in the DT
* but not its children, because of DT backward compatibility
* for A10, A13 and A31 SoCs. Therefore, the resulting devices
* of this driver do not have an of_node variable.
* However, its parent (the MFD driver) has an of_node variable
* and since devm_thermal_zone_of_sensor_register uses its first
* argument to match the phandle defined in the node of the
* thermal driver with the of_node of the device passed as first
* argument and the third argument to call ops from
* thermal_zone_of_device_ops, the solution is to use the parent
* device as first argument to match the phandle with its
* of_node, and the device from this driver as third argument to
* return the temperature.
*/
struct thermal_zone_device *tzd;
tzd = devm_thermal_zone_of_sensor_register(pdev->dev.parent, 0,
info,
&sun4i_ts_tz_ops);
if (IS_ERR(tzd)) {
dev_err(&pdev->dev,
"could not register thermal sensor: %ld\n",
PTR_ERR(tzd));
ret = PTR_ERR(tzd);
goto err;
}
} else {
indio_dev->num_channels =
ARRAY_SIZE(sun4i_gpadc_channels_no_temp);
indio_dev->channels = sun4i_gpadc_channels_no_temp;
}
pm_runtime_set_autosuspend_delay(&pdev->dev,
SUN4I_GPADC_AUTOSUSPEND_DELAY);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_suspended(&pdev->dev);
pm_runtime_enable(&pdev->dev);
if (IS_ENABLED(CONFIG_THERMAL_OF)) {
ret = sun4i_irq_init(pdev, "TEMP_DATA_PENDING",
sun4i_gpadc_temp_data_irq_handler,
"temp_data", &info->temp_data_irq,
&info->ignore_temp_data_irq);
if (ret < 0)
goto err;
}
ret = sun4i_irq_init(pdev, "FIFO_DATA_PENDING",
sun4i_gpadc_fifo_data_irq_handler, "fifo_data",
&info->fifo_data_irq, &info->ignore_fifo_data_irq);
if (ret < 0)
goto err;
if (IS_ENABLED(CONFIG_THERMAL_OF)) {
ret = iio_map_array_register(indio_dev, sun4i_gpadc_hwmon_maps);
if (ret < 0) {
dev_err(&pdev->dev,
"failed to register iio map array\n");
goto err;
}
}
ret = devm_iio_device_register(&pdev->dev, indio_dev);
if (ret < 0) {
dev_err(&pdev->dev, "could not register the device\n");
goto err_map;
}
return 0;
err_map:
if (IS_ENABLED(CONFIG_THERMAL_OF))
iio_map_array_unregister(indio_dev);
err:
pm_runtime_put(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return ret;
}
static int sun4i_gpadc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
pm_runtime_put(&pdev->dev);
pm_runtime_disable(&pdev->dev);
if (IS_ENABLED(CONFIG_THERMAL_OF))
iio_map_array_unregister(indio_dev);
return 0;
}
static const struct platform_device_id sun4i_gpadc_id[] = {
{ "sun4i-a10-gpadc-iio", (kernel_ulong_t)&sun4i_gpadc_data },
{ "sun5i-a13-gpadc-iio", (kernel_ulong_t)&sun5i_gpadc_data },
{ "sun6i-a31-gpadc-iio", (kernel_ulong_t)&sun6i_gpadc_data },
{ /* sentinel */ },
};
static struct platform_driver sun4i_gpadc_driver = {
.driver = {
.name = "sun4i-gpadc-iio",
.pm = &sun4i_gpadc_pm_ops,
},
.id_table = sun4i_gpadc_id,
.probe = sun4i_gpadc_probe,
.remove = sun4i_gpadc_remove,
};
module_platform_driver(sun4i_gpadc_driver);
MODULE_DESCRIPTION("ADC driver for sunxi platforms");
MODULE_AUTHOR("Quentin Schulz <quentin.schulz@free-electrons.com>");
MODULE_LICENSE("GPL v2");