Re: [PATCH v4 1/1] iio: ltr301: Add support for ltr301

[Jonathan Cameron <jic23@kernel.org>]

On 07/04/15 03:16, Kuppuswamy Sathyanarayanan wrote:
> Added support for Liteon 301 Ambient light sensor. Since
> LTR-301 and LTR-501 are register compatible(and even have same
> part id), LTR-501 driver has been extended to support both
> devices. LTR-501 is similar to LTR-301 in ALS sensing, But the
> only difference is, LTR-501 also supports proximity sensing.
> 
> LTR-501 - ALS + Proximity combo
> LTR-301 - ALS sensor.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Patch naming convention
iio:<name of driver>: Add support for ltr301
so here would be
iio:ltr501:Add support for ltr301.

Otherwise, looks good to me.  A comment inline that it might
make sense to introduced a ltr501_chip info structure and use
static const struct ltr501_chip_info[2] = {
[LTR301] = {
       .info = ...
       ....
       },
[LTR501] = {
}};

That way you make all the truely constant data apparently constant
and loose the switch statement. It makes for an easier to review / simpler
driver in the long run.

I haven't checked but this is probably what Daniel was suggesting in
his review for v1 of this patch.

Jonathan
> ---
>  drivers/iio/light/Kconfig  |  2 +-
>  drivers/iio/light/ltr501.c | 55 +++++++++++++++++++++++++++++++++++++++++++---
>  2 files changed, 53 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index a224afd..215e4a3 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -159,7 +159,7 @@ config LTR501
>  	select IIO_TRIGGERED_BUFFER
>  	help
>  	 If you say yes here you get support for the Lite-On LTR-501ALS-01
> -	 ambient light and proximity sensor.
> +	 ambient light and proximity sensor or LTR-301 ambient light sensor.
>  
>  	 This driver can also be built as a module.  If so, the module
>           will be called ltr501.
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index 62b7072..5cb0427 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/drivers/iio/light/ltr501.c
> @@ -45,10 +45,16 @@
>  
>  #define LTR501_PS_DATA_MASK 0x7ff
>  
> +enum ltr_chipset {
> +	LTR301,
> +	LTR501,
> +};
> +
>  struct ltr501_data {
>  	struct i2c_client *client;
>  	struct mutex lock_als, lock_ps;
>  	u8 als_contr, ps_contr;
> +	u8 chip_id;
>  };
>  
>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
> @@ -124,6 +130,13 @@ static const struct iio_chan_spec ltr501_channels[] = {
>  	IIO_CHAN_SOFT_TIMESTAMP(3),
>  };
>  
> +static const struct iio_chan_spec ltr301_channels[] = {
> +	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0),
> +	LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
> +		BIT(IIO_CHAN_INFO_SCALE)),
> +	IIO_CHAN_SOFT_TIMESTAMP(2),
> +};
> +
>  static const int ltr501_ps_gain[4][2] = {
>  	{1, 0}, {0, 250000}, {0, 125000}, {0, 62500}
>  };
> @@ -244,10 +257,19 @@ static struct attribute *ltr501_attributes[] = {
>  	NULL
>  };
>  
> +static struct attribute *ltr301_attributes[] = {
> +	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
> +	NULL
> +};
> +
>  static const struct attribute_group ltr501_attribute_group = {
>  	.attrs = ltr501_attributes,
>  };
>  
> +static const struct attribute_group ltr301_attribute_group = {
> +	.attrs = ltr301_attributes,
> +};
> +
>  static const struct iio_info ltr501_info = {
>  	.read_raw = ltr501_read_raw,
>  	.write_raw = ltr501_write_raw,
> @@ -255,6 +277,13 @@ static const struct iio_info ltr501_info = {
>  	.driver_module = THIS_MODULE,
>  };
>  
> +static const struct iio_info ltr301_info = {
> +	.read_raw = ltr501_read_raw,
> +	.write_raw = ltr501_write_raw,
> +	.attrs = &ltr301_attribute_group,
> +	.driver_module = THIS_MODULE,
> +};
> +
>  static int ltr501_write_contr(struct i2c_client *client, u8 als_val, u8 ps_val)
>  {
>  	int ret = i2c_smbus_write_byte_data(client, LTR501_ALS_CONTR, als_val);
> @@ -347,6 +376,13 @@ static int ltr501_probe(struct i2c_client *client,
>  	data = iio_priv(indio_dev);
>  	i2c_set_clientdata(client, indio_dev);
>  	data->client = client;
> +
> +	/* TODO: Add condition for ACPI */
> +	if (id)
> +		data->chip_id = id->driver_data;
> +	else
> +		return -ENODEV;
> +
>  	mutex_init(&data->lock_als);
>  	mutex_init(&data->lock_ps);
>  
> @@ -357,12 +393,24 @@ static int ltr501_probe(struct i2c_client *client,
>  		return -ENODEV;
>  
>  	indio_dev->dev.parent = &client->dev;
> -	indio_dev->info = &ltr501_info;
> -	indio_dev->channels = ltr501_channels;
>  	indio_dev->num_channels = ARRAY_SIZE(ltr501_channels);
>  	indio_dev->name = LTR501_DRV_NAME;
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  
> +	switch (data->chip_id) {
This could be factored out as a 'chip_info' static structure array thus
allowing this case statement to be a lookup.  Slightly neater as you
add more devices, but at this stage, dubious whether it's worth the
effort.
> +	case LTR301:
> +		indio_dev->info = &ltr301_info;
> +		indio_dev->channels = ltr301_channels;
> +		break;
> +	case LTR501:
> +		indio_dev->info = &ltr501_info;
> +		indio_dev->channels = ltr501_channels;
> +		break;
> +	default:
> +		dev_warn(&client->dev, "ltr chip invalid\n");
> +		return -ENODEV;
> +	}
> +
>  	ret = ltr501_init(data);
>  	if (ret < 0)
>  		return ret;
> @@ -422,7 +470,8 @@ static int ltr501_resume(struct device *dev)
>  static SIMPLE_DEV_PM_OPS(ltr501_pm_ops, ltr501_suspend, ltr501_resume);
>  
>  static const struct i2c_device_id ltr501_id[] = {
> -	{ "ltr501", 0 },
> +	{ "ltr301", LTR301 },
> +	{ "ltr501", LTR501 },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(i2c, ltr501_id);
>