Re: [PATCH v4 2/2] hwmon: (sht15) Add device tree support

[Guenter Roeck <linux@roeck-us.net>]

On 02/16/2017 04:23 AM, Marco Franchi wrote:
> Allow the driver to work with device tree support.
>
> Based on initial patch submission from Peter Fox.
>
> Tested on a imx7d-sdb board connected to a SHT15 board via Mikro Bus.
>
> Signed-off-by: Marco Franchi <marco.franchi@nxp.com>
> ---
> Changes since v3:
> -Remove the optional properties because they are not hardware description

Yes but they are in platform data. I thought that kind of configuration data
is fair game nowadays for devicetree data, but on the other side I must admit
that I may not be up to date on what is permitted or not.

Either case, I'll queue this patch up for -next. Refinements can be made
later if/when needed.

Thanks,
Guenter

> -Change the sensor node name
>
>  Documentation/devicetree/bindings/hwmon/sht15.txt | 19 +++++++
>  drivers/hwmon/sht15.c                             | 64 +++++++++++++++++++++--
>  2 files changed, 79 insertions(+), 4 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/sht15.txt
>
> diff --git a/Documentation/devicetree/bindings/hwmon/sht15.txt b/Documentation/devicetree/bindings/hwmon/sht15.txt
> new file mode 100644
> index 0000000..6a80277
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/sht15.txt
> @@ -0,0 +1,19 @@
> +Sensirion SHT15 Humidity and Temperature Sensor
> +
> +Required properties:
> +
> + - "compatible": must be "sensirion,sht15".
> + - "data-gpios": GPIO connected to the data line.
> + - "clk-gpios": GPIO connected to the clock line.
> + - "vcc-supply": regulator that drives the VCC pin.
> +
> +Example:
> +
> +	sensor {
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&pinctrl_sensor>;
> +		compatible = "sensirion,sht15";
> +		clk-gpios = <&gpio4 12 0>;
> +		data-gpios = <&gpio4 13 0>;
> +		vcc-supply = <&reg_sht15>;
> +	};
> diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c
> index f16687c..69141b2 100644
> --- a/drivers/hwmon/sht15.c
> +++ b/drivers/hwmon/sht15.c
> @@ -34,6 +34,7 @@
>  #include <linux/slab.h>
>  #include <linux/atomic.h>
>  #include <linux/bitrev.h>
> +#include <linux/of_gpio.h>
>
>  /* Commands */
>  #define SHT15_MEASURE_TEMP		0x03
> @@ -911,6 +912,54 @@ static int sht15_invalidate_voltage(struct notifier_block *nb,
>  	return NOTIFY_OK;
>  }
>
> +#ifdef CONFIG_OF
> +static const struct of_device_id sht15_dt_match[] = {
> +	{ .compatible = "sensirion,sht15" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, sht15_dt_match);
> +
> +/*
> + * This function returns NULL if pdev isn't a device instatiated by dt,
> + * a pointer to pdata if it could successfully get all information
> + * from dt or a negative ERR_PTR() on error.
> + */
> +static struct sht15_platform_data *sht15_probe_dt(struct device *dev)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct sht15_platform_data *pdata;
> +
> +	/* no device tree device */
> +	if (!np)
> +		return NULL;
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return ERR_PTR(-ENOMEM);
> +
> +	pdata->gpio_data = of_get_named_gpio(np, "data-gpios", 0);
> +	if (pdata->gpio_data < 0) {
> +		if (pdata->gpio_data != -EPROBE_DEFER)
> +			dev_err(dev, "data-gpios not found\n");
> +		return ERR_PTR(pdata->gpio_data);
> +	}
> +
> +	pdata->gpio_sck = of_get_named_gpio(np, "clk-gpios", 0);
> +	if (pdata->gpio_sck < 0) {
> +		if (pdata->gpio_sck != -EPROBE_DEFER)
> +			dev_err(dev, "clk-gpios not found\n");
> +		return ERR_PTR(pdata->gpio_sck);
> +	}
> +
> +	return pdata;
> +}
> +#else
> +static inline struct sht15_platform_data *sht15_probe_dt(struct device *dev)
> +{
> +	return NULL;
> +}
> +#endif
> +
>  static int sht15_probe(struct platform_device *pdev)
>  {
>  	int ret;
> @@ -928,11 +977,17 @@ static int sht15_probe(struct platform_device *pdev)
>  	data->dev = &pdev->dev;
>  	init_waitqueue_head(&data->wait_queue);
>
> -	if (dev_get_platdata(&pdev->dev) == NULL) {
> -		dev_err(&pdev->dev, "no platform data supplied\n");
> -		return -EINVAL;
> +	data->pdata = sht15_probe_dt(&pdev->dev);
> +	if (IS_ERR(data->pdata))
> +		return PTR_ERR(data->pdata);
> +	if (data->pdata == NULL) {
> +		data->pdata = dev_get_platdata(&pdev->dev);
> +		if (data->pdata == NULL) {
> +			dev_err(&pdev->dev, "no platform data supplied\n");
> +			return -EINVAL;
> +		}
>  	}
> -	data->pdata = dev_get_platdata(&pdev->dev);
> +
>  	data->supply_uv = data->pdata->supply_mv * 1000;
>  	if (data->pdata->checksum)
>  		data->checksumming = true;
> @@ -1075,6 +1130,7 @@ MODULE_DEVICE_TABLE(platform, sht15_device_ids);
>  static struct platform_driver sht15_driver = {
>  	.driver = {
>  		.name = "sht15",
> +		.of_match_table = of_match_ptr(sht15_dt_match),
>  	},
>  	.probe = sht15_probe,
>  	.remove = sht15_remove,
>