Re: [PATCH] iio: light: Add support for TXC PA12 als and proximity sensor

From: Sergei Zviagintsev
Date: Thu Jun 25 2015 - 13:40:15 EST

Hi,

I just was walking around and decided to look inside this driver :)
I left some comments below.

On Fri, Jun 26, 2015 at 01:29:22PM +0300, Adriana Reus wrote:
^^^
Your message came from future.

> Add support for TXC PA12203001 als and proximity sensor.
> Support for raw illuminance and proximity readings.
>
> Signed-off-by: Adriana Reus <adriana.reus@xxxxxxxxx>
> ---
> drivers/iio/light/Kconfig | 11 +
> drivers/iio/light/Makefile | 1 +
> drivers/iio/light/pa12203001.c | 501 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 513 insertions(+)
> create mode 100644 drivers/iio/light/pa12203001.c
>
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index e6198b7..30fd835 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -198,6 +198,17 @@ config LTR501
> This driver can also be built as a module. If so, the module
> will be called ltr501.
>
> +config PA12203001
> + tristate "TXC PA12203001 light and proximity sensor"
> + depends on I2C
> + select REGMAP_I2C
> + help
> + If you say yes here you get support for the TXC PA12203001
> + ambient light and proximity sensor.
> +
> + This driver can also be built as a module. If so, the module
> + will be called pa12203001.
> +
> config STK3310
> tristate "STK3310 ALS and proximity sensor"
> depends on I2C
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index e2d50fd..257fabd 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_ISL29125) += isl29125.o
> obj-$(CONFIG_JSA1212) += jsa1212.o
> obj-$(CONFIG_SENSORS_LM3533) += lm3533-als.o
> obj-$(CONFIG_LTR501) += ltr501.o
> +obj-$(CONFIG_PA12203001) += pa12203001.o
> obj-$(CONFIG_SENSORS_TSL2563) += tsl2563.o
> obj-$(CONFIG_STK3310) += stk3310.o
> obj-$(CONFIG_TCS3414) += tcs3414.o
> diff --git a/drivers/iio/light/pa12203001.c b/drivers/iio/light/pa12203001.c
> new file mode 100644
> index 0000000..03bee4c
> --- /dev/null
> +++ b/drivers/iio/light/pa12203001.c
> @@ -0,0 +1,501 @@
> +/*
> + * Copyright (c) 2015 Intel Corporation
> + *
> + * Driver for TXC PA12203001 Proximity and Ambient Light Sensor.
> + *
> + * 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.
> + * To do: Interrupt support.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/acpi.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/mutex.h>
> +#include <linux/pm.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +
> +#define PA12203001_DRIVER_NAME "pa12203001"
> +
> +#define PA12203001_REG_CFG0 0x00
> +#define PA12203001_REG_CFG1 0x01
> +#define PA12203001_REG_CFG2 0x02
> +#define PA12203001_REG_CFG3 0x03
> +
> +#define PA12203001_REG_ADL 0x0b
> +#define PA12203001_REG_PDH 0x0e
> +
> +#define PA12203001_REG_POFS 0x10
> +#define PA12203001_REG_PSET 0x11
> +
> +#define PA12203001_ALS_EN_MASK BIT(0)
> +#define PA12203001_PX_EN_MASK BIT(1)
> +#define PA12203001_PX_NORMAL_MODE_MASK (BIT(7) | BIT(6))
> +#define PA12203001_AFSR_MASK (BIT(5) | BIT(4))
> +
> +#define PA12203001_PSCAN 0x03
> +
> +/* als range 31000, ps, als disabled */
> +#define PA12203001_REG_CFG0_DEFAULT 0x30
> +
> +/* led current: 100 mA */
> +#define PA12203001_REG_CFG1_DEFAULT 0x10
> +
> +/* ps mode: normal, interrupts not active */
> +#define PA12203001_REG_CFG2_DEFAULT 0xcc
> +
> +#define PA12203001_REG_CFG3_DEFAULT 0x00
> +
> +#define PA12203001_SLEEP_DELAY_MS 3000
> +
> +/* available scales: corresponding to [500, 4000, 7000, 31000] lux */
> +static const int pa12203001_scales[] = { 7629, 61036, 106813, 473029};
> +
> +struct pa12203001_data {
> + struct i2c_client *client;
> +
> + /* protect device states */
> + struct mutex lock;
> +
> + bool als_enabled;
> + bool px_enabled;
> + bool als_needs_enable;
> + bool px_needs_enable;
> +
> + struct regmap *map;
> +};
> +
> +static IIO_CONST_ATTR(in_illuminance_scale_available,
> + "0.007629 0.061036 0.106813 0.473029");
> +
> +static struct attribute *pa12203001_attrs[] = {
> + &iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
> + NULL
> +};
> +
> +static const struct attribute_group pa12203001_attr_group = {
> + .attrs = pa12203001_attrs,
> +};
> +
> +static const struct iio_chan_spec pa12203001_channels[] = {
> + {
> + .type = IIO_LIGHT,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + },
> + {
> + .type = IIO_PROXIMITY,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> + }
> +};
> +
> +static const struct regmap_range pa12203001_volatile_regs_ranges[] = {
> + regmap_reg_range(PA12203001_REG_ADL, PA12203001_REG_ADL + 1),
> + regmap_reg_range(PA12203001_REG_PDH, PA12203001_REG_PDH),
> +};
> +
> +static const struct regmap_access_table pa12203001_volatile_regs = {
> + .yes_ranges = pa12203001_volatile_regs_ranges,
> + .n_yes_ranges = ARRAY_SIZE(pa12203001_volatile_regs_ranges),
> +};
> +
> +static const struct regmap_config pa12203001_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> + .max_register = PA12203001_REG_PSET,
> + .cache_type = REGCACHE_RBTREE,
> + .volatile_table = &pa12203001_volatile_regs,
> +};
> +
> +static inline int pa12203001_als_enable(struct pa12203001_data *data, u8 enable)
> +{
> + int ret;
> +
> + ret = regmap_update_bits(data->map, PA12203001_REG_CFG0,
> + PA12203001_ALS_EN_MASK, enable);
> + if (ret < 0)
> + return ret;
> +
> + data->als_enabled = !!enable;
> + return 0;
> +}
> +
> +static inline int pa12203001_px_enable(struct pa12203001_data *data, u8 enable)
> +{
> + int ret;
> +
> + ret = regmap_update_bits(data->map, PA12203001_REG_CFG0,
> + PA12203001_PX_EN_MASK, enable);
> + if (ret < 0)
> + return ret;
> +
> + data->px_enabled = !!enable;
> + return 0;
> +}
> +
> +static int pa12203001_set_power_state(struct pa12203001_data *data, bool on,
> + u8 mask)
> +{
> +#ifdef CONFIG_PM
> + int ret;
> +
> + mutex_lock(&data->lock);

If tests below are false, then we are holding the lock with no reason.

> + if (on && (mask & PA12203001_ALS_EN_MASK)) {
> + if (data->px_enabled) {
> + ret = pa12203001_als_enable(data,
> + PA12203001_ALS_EN_MASK);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + return ret;
> + }

Use of `goto' would save two lines per exit point :)

> + } else {
> + data->als_needs_enable = true;
> + }
> + }
> +
> + if (on && (mask & PA12203001_PX_EN_MASK)) {
> + if (data->als_enabled) {
> + ret = pa12203001_px_enable(data, PA12203001_PX_EN_MASK);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> + } else {
> + data->px_needs_enable = true;
> + }
> + }
> + mutex_unlock(&data->lock);
> +
> + if (on) {
> + /* Get reference and resume */
> + ret = pm_runtime_get_sync(&data->client->dev);
> + if (ret < 0)
> + pm_runtime_put_noidle(&data->client->dev);
> +
> + } else {
> + /*
> + * Turning off - restart timer, drop reference
> + * and setup autosuspend
> + */
> + pm_runtime_mark_last_busy(&data->client->dev);
> + ret = pm_runtime_put_autosuspend(&data->client->dev);
> + }
> + return ret;
> +
> +#endif
> + return 0;
> +}
> +
> +static int pa12203001_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val,
> + int *val2, long mask)
> +{
> + struct pa12203001_data *data = iio_priv(indio_dev);
> + int ret;
> + u8 dev_mask;
> + unsigned int reg_byte;
> + __le16 reg_word;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + switch (chan->type) {
> + case IIO_LIGHT:
> + dev_mask = PA12203001_ALS_EN_MASK;
> + ret = pa12203001_set_power_state(data, true, dev_mask);
> + if (ret < 0)
> + return ret;
> + /*
> + * ALS ADC value is stored in registers
> + * PA12203001_REG_ADL and in PA12203001_REG_ADL + 1.
> + */
> + ret = regmap_bulk_read(data->map, PA12203001_REG_ADL,
> + &reg_word, 2);
> + if (ret < 0)
> + return ret;
> + *val = le16_to_cpu(reg_word);
> + ret = pa12203001_set_power_state(data, false, dev_mask);
> + if (ret < 0)
> + return ret;
> + break;
> + case IIO_PROXIMITY:
> + dev_mask = PA12203001_PX_EN_MASK;
> + ret = pa12203001_set_power_state(data, true, dev_mask);
> + if (ret < 0)
> + return ret;
> + ret = regmap_read(data->map, PA12203001_REG_PDH,
> + &reg_byte);
> + if (ret < 0)
> + return ret;
> + *val = reg_byte;
> + ret = pa12203001_set_power_state(data, false, dev_mask);
> + if (ret < 0)
> + return ret;
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> +
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + ret = regmap_read(data->map, PA12203001_REG_CFG0, &reg_byte);
> + if (ret < 0)
> + return ret;
> + *val = 0;
> + reg_byte = (reg_byte & PA12203001_AFSR_MASK);
> + *val2 = pa12203001_scales[reg_byte >> 4];
> + return IIO_VAL_INT_PLUS_MICRO;
> + default:
> + break;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int pa12203001_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int val,
> + int val2, long mask)
> +{
> + struct pa12203001_data *data = iio_priv(indio_dev);
> + int i, ret;
> + unsigned int reg_byte;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_SCALE:
> + ret = regmap_read(data->map, PA12203001_REG_CFG0, &reg_byte);
> + if (val != 0 || ret < 0)
> + return -EINVAL;
> + for (i = 0; i < ARRAY_SIZE(pa12203001_scales); i++) {
> + if (val2 == pa12203001_scales[i])
> + return regmap_update_bits(data->map,
> + PA12203001_REG_CFG0,
> + PA12203001_AFSR_MASK,
> + (i << 4));
> + }
> + break;

default case?

> + }
> +
> + return -EINVAL;
> +}
> +
> +static const struct iio_info pa12203001_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = pa12203001_read_raw,
> + .write_raw = pa12203001_write_raw,
> + .attrs = &pa12203001_attr_group,
> +};
> +
> +static int pa12203001_init(struct iio_dev *indio_dev)
> +{
> + struct pa12203001_data *data = iio_priv(indio_dev);
> + int ret;
> +
> + ret = regmap_write(data->map, PA12203001_REG_CFG0,
> + PA12203001_REG_CFG0_DEFAULT);
> + if (ret < 0)
> + return ret;
> +
> + ret = regmap_write(data->map, PA12203001_REG_CFG1,
> + PA12203001_REG_CFG1_DEFAULT);
> + if (ret < 0)
> + return ret;
> +
> + ret = regmap_write(data->map, PA12203001_REG_CFG2,
> + PA12203001_REG_CFG2_DEFAULT);
> + if (ret < 0)
> + return ret;
> +
> + ret = regmap_write(data->map, PA12203001_REG_CFG3,
> + PA12203001_REG_CFG3_DEFAULT);
> + if (ret < 0)
> + return ret;
> +
> + return regmap_write(data->map, PA12203001_REG_PSET,
> + PA12203001_PSCAN);
> +}

Is the following acceptable?

struct {
u8 reg;
u8 val;
} regvals[] = { { PA12203001_REG_CFG, PA12203001_REG_CFG0_DEFAULT }, ... };

int i, ret;

for (i = 0; i < ARRAY_SIZE(regvals); i++) {
ret = regmap_write(data->map, regvals[i].reg, regvals[i].val);
if (ret < 0)
return ret;
}

return 0;

> +
> +static int pa12203001_power_on(struct iio_dev *indio_dev)
> +{
> + struct pa12203001_data *data = iio_priv(indio_dev);
> + int ret;
> + u8 enable = 0xff;
> +
> + mutex_lock(&data->lock);
> + ret = pa12203001_als_enable(data, enable);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + return ret;
> + }

goto is pretty conventional here (ch. 7 CodingStyle)

> +
> + ret = pa12203001_px_enable(data, enable);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> + mutex_unlock(&data->lock);
> + return 0;
> +}
> +
> +static int pa12203001_power_off(struct iio_dev *indio_dev)
> +{
> + struct pa12203001_data *data = iio_priv(indio_dev);
> + int ret;
> + u8 disable = 0x00;
> +
> + mutex_lock(&data->lock);
> + ret = pa12203001_als_enable(data, disable);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> +
> + ret = pa12203001_px_enable(data, disable);
> + if (ret < 0) {
> + mutex_unlock(&data->lock);
> + return ret;
> + }
> + mutex_unlock(&data->lock);
> + return 0;
> +}

If I see it correctly, the only difference between power_on and
power_off functions is in one byte which is submitted to
{als,px}_enable(). Isn't it better to merge them in the third function
to reduce code duplication?

> +
> +static int pa12203001_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct pa12203001_data *data;
> + struct iio_dev *indio_dev;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&client->dev,
> + sizeof(struct pa12203001_data));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + data = iio_priv(indio_dev);
> + i2c_set_clientdata(client, indio_dev);
> + data->client = client;
> +
> + data->map = devm_regmap_init_i2c(client, &pa12203001_regmap_config);
> + if (IS_ERR(data->map))
> + return PTR_ERR(data->map);
> +
> + mutex_init(&data->lock);
> +
> + indio_dev->dev.parent = &client->dev;
> + indio_dev->info = &pa12203001_info;
> + indio_dev->name = PA12203001_DRIVER_NAME;
> + indio_dev->channels = pa12203001_channels;
> + indio_dev->num_channels = ARRAY_SIZE(pa12203001_channels);
> + indio_dev->modes = INDIO_DIRECT_MODE;
> +
> + ret = pa12203001_init(indio_dev);
> + if (ret < 0)
> + return ret;
> +
> + ret = pa12203001_power_on(indio_dev);
> + if (ret < 0)
> + return ret;
> +
> + ret = pm_runtime_set_active(&client->dev);
> + if (ret < 0) {
> + pa12203001_power_off(indio_dev);
> + return ret;
> + }
> +
> + pm_runtime_enable(&client->dev);
> + pm_runtime_set_autosuspend_delay(&client->dev,
> + PA12203001_SLEEP_DELAY_MS);
> + pm_runtime_use_autosuspend(&client->dev);
> +
> + return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static int pa12203001_remove(struct i2c_client *client)
> +{
> + struct iio_dev *indio_dev = i2c_get_clientdata(client);

We use additional var in this function to store device pointer, but do
not use it in suspend(), resume() etc where more complicated
constructions are used. Just for consistency :)

> +
> + pm_runtime_disable(&client->dev);
> + pm_runtime_set_suspended(&client->dev);
> +
> + return pa12203001_power_off(indio_dev);
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int pa12203001_suspend(struct device *dev)
> +{
> + return pa12203001_power_off(i2c_get_clientdata(to_i2c_client(dev)));
> +}
> +
> +static int pa12203001_resume(struct device *dev)
> +{
> + return pa12203001_power_on(i2c_get_clientdata(to_i2c_client(dev)));
> +}
> +#endif
> +
> +#ifdef CONFIG_PM
> +static int pa12203001_runtime_suspend(struct device *dev)
> +{
> + return pa12203001_power_off(i2c_get_clientdata(to_i2c_client(dev)));
> +}
> +
> +static int pa12203001_runtime_resume(struct device *dev)
> +{
> + struct pa12203001_data *data;
> +
> + data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
> +
> + mutex_lock(&data->lock);
> + if (data->als_needs_enable) {
> + pa12203001_als_enable(data, PA12203001_ALS_EN_MASK);
> + data->als_needs_enable = false;
> + }
> + if (data->px_needs_enable) {
> + pa12203001_px_enable(data, PA12203001_PX_EN_MASK);
> + data->px_needs_enable = false;
> + }
> + mutex_unlock(&data->lock);
> + return 0;
> +}
> +#endif
> +
> +static const struct dev_pm_ops pa12203001_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(pa12203001_suspend, pa12203001_resume)
> + SET_RUNTIME_PM_OPS(pa12203001_runtime_suspend,
> + pa12203001_runtime_resume, NULL)
> +};
> +
> +static const struct acpi_device_id pa12203001_acpi_match[] = {
> + { "TXCPA122", 0},
> + {}
> +};
> +
> +MODULE_DEVICE_TABLE(acpi, pa12203001_acpi_match);
> +
> +static const struct i2c_device_id pa12203001_id[] = {
> + {"txcpa122", 0},
> + {}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, pa12203001_id);
> +
> +static struct i2c_driver pa12203001_driver = {
> + .driver = {
> + .name = PA12203001_DRIVER_NAME,
> + .pm = &pa12203001_pm_ops,
> + .acpi_match_table = ACPI_PTR(pa12203001_acpi_match),
> + },
> + .probe = pa12203001_probe,
> + .remove = pa12203001_remove,
> + .id_table = pa12203001_id,
> +
> +};
> +module_i2c_driver(pa12203001_driver);
> +
> +MODULE_AUTHOR("Adriana Reus <adriana.reus@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Driver for TXC PA12203001 Proximity and Light Sensor");
> +MODULE_LICENSE("GPL v2");
> --
> 1.9.1
>
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