[PATCH v2 2/2] hwmon: (sht15) Add device tree support

[PATCH v2 2/2] hwmon: (sht15) Add device tree support

[Marco Franchi]

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 v1:
- reworked to not require int returns in the sht15_probe_dt function;
- add a clear preference for dt or platform data
- Use 'device tree' instead of 'dts' in the Subject
 
 Documentation/devicetree/bindings/hwmon/sht15.txt | 25 +++++++++
 drivers/hwmon/sht15.c                             | 66 +++++++++++++++++++++--
 2 files changed, 87 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..6415f52
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/sht15.txt
@@ -0,0 +1,25 @@
+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.
+
+Optional properties:
+
+ - "checksum": boolean property that when present enables the CRC validation of the readings.
+ - "no-otp-reload": boolean property that when present indicates not to reload from OTP.
+ - "low-resolution": boolean property that when present indicates that the device operates in
+		low-resolution mode.
+Example:
+
+	temp_humid_sensor: sht15 {
+		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..70906f1 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 +912,56 @@ 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 the data if it could successfully get all information
+ * from dt or a negative error number.
+ */
+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) {
+		dev_err(dev, "data-gpios not found\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	pdata->gpio_sck = of_get_named_gpio(np, "clk-gpios", 0);
+	if (pdata->gpio_sck < 0) {
+		dev_err(dev, "clk-gpios not found\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	pdata->checksum = of_property_read_bool(np, "checksum");
+	pdata->no_otp_reload = of_property_read_bool(np, "no-otp-reload");
+	pdata->low_resolution = of_property_read_bool(np, "low-resolution");
+
+	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 +979,17 @@ 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 +1132,7 @@ 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,
-- 
2.7.4

[PATCH v2 1/2] dt: Add vendor prefix for Sensirion

[Marco Franchi]

Sensirion is a sensor manufacturer, providing relative humidity sensors,
temperature sensor and flow sensor solutions.

Signed-off-by: Marco Franchi <marco.franchi@nxp.com>
---
Changes since v1:
- none
 Documentation/devicetree/bindings/vendor-prefixes.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 7a98c33..43e1799 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -263,6 +263,7 @@ sbs	Smart Battery System
 schindler	Schindler
 seagate	Seagate Technology PLC
 semtech	Semtech Corporation
+sensirion	Sensirion AG
 sgx	SGX Sensortech
 sharp	Sharp Corporation
 si-en	Si-En Technology Ltd.
-- 
2.7.4

Re: [PATCH v2 2/2] hwmon: (sht15) Add device tree support

[Guenter Roeck]

On 02/14/2017 05:23 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 v1:
> - reworked to not require int returns in the sht15_probe_dt function;
> - add a clear preference for dt or platform data
> - Use 'device tree' instead of 'dts' in the Subject
>
>  Documentation/devicetree/bindings/hwmon/sht15.txt | 25 +++++++++
>  drivers/hwmon/sht15.c                             | 66 +++++++++++++++++++++--
>  2 files changed, 87 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..6415f52
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/sht15.txt
> @@ -0,0 +1,25 @@
> +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.
> +
> +Optional properties:
> +
> + - "checksum": boolean property that when present enables the CRC validation of the readings.
> + - "no-otp-reload": boolean property that when present indicates not to reload from OTP.
> + - "low-resolution": boolean property that when present indicates that the device operates in
> +		low-resolution mode.
> +Example:
> +
> +	temp_humid_sensor: sht15 {
> +		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..70906f1 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 +912,56 @@ 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 the data if it could successfully get all information
> + * from dt or a negative error number.
> + */
> +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) {
> +		dev_err(dev, "data-gpios not found\n");
> +		return ERR_PTR(-EINVAL);

Never replace an error return value with a different one. The called function
could return -EPROBE_DEFER, which you would want to have returned to the caller.
In that case, you would also not want to see an error message.

> +	}
> +
> +	pdata->gpio_sck = of_get_named_gpio(np, "clk-gpios", 0);
> +	if (pdata->gpio_sck < 0) {
> +		dev_err(dev, "clk-gpios not found\n");
> +		return ERR_PTR(-EINVAL);

Same here.

> +	}
> +
> +	pdata->checksum = of_property_read_bool(np, "checksum");
> +	pdata->no_otp_reload = of_property_read_bool(np, "no-otp-reload");
> +	pdata->low_resolution = of_property_read_bool(np, "low-resolution");
> +
> +	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 +979,17 @@ 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 +1132,7 @@ 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,
>