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

["Reus, Adriana" <adriana.reus@intel.com>]

Thank you for taking the time.
I'll upload a new patch-set in the following days with the requested tidy-ups.

Thanks,
Adriana
________________________________________
From: Sergei Zviagintsev [sergei@s15v.net]
Sent: Thursday, June 25, 2015 8:40 PM
To: Reus, Adriana
Cc: jic23@kernel.org; linux-iio@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iio: light: Add support for TXC PA12 als and proximity sensor

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.
That's because i am a time traveler.

> Add support for TXC PA12203001 als and proximity sensor.
> Support for raw illuminance and proximity readings.
>
> Signed-off-by: Adriana Reus <adriana.reus@intel.com>
> ---
>  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.
Yes, but only for the first if test. I can move it after to slightly optimize.
> +     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 :)
Will do

> +             } 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?
default should fall through, I'll add the statement for style reasons though.
> +     }
> +
> +     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?
I think so.

        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?
Will do 

> +
> +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@intel.com>");
> +MODULE_DESCRIPTION("Driver for TXC PA12203001 Proximity and Light Sensor");
> +MODULE_LICENSE("GPL v2");
> --
> 1.9.1
>
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