On Fri, Feb 10, 2017 at 12:30:41PM -0200, Marco Franchi wrote:
> Allow the driver to work with dts 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 <[email protected]>
> ---
> Documentation/devicetree/bindings/hwmon/sht15.txt | 25 ++++++++
> drivers/hwmon/sht15.c | 69
> +++++++++++++++++++++--
> 2 files changed, 90 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 = <®_sht15>;
> + };
> diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c
> index f16687c..608ac9e 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 +912,59 @@ 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 1 if pdev isn't a device instatiated by dt, 0 if it
> + * could successfully get all information from dt or a negative error number.
> + */
Plese rework to not require negative/ 0 / 1 return. One possibility
would be to return NULL if no dt, PTR_ERR on error, and a pointer
to the data otherwise. More see below.
> +static int sht15_probe_dt(struct sht15_data *data, struct platform_device
> *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct sht15_platform_data *pdata;
> +
> + /* no device tree device */
> + if (!np)
> + return 1;
> +
> + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> + if (!pdata)
> + return -ENOMEM;
> +
> + data->pdata = pdata;
> +
> + data->pdata->gpio_data = of_get_named_gpio(np, "data-gpios", 0);
There is a local variable 'pdata'. Dereferencing data->pdata repeatedly
is not necessary.
> + if (data->pdata->gpio_data < 0) {
> + dev_err(&pdev->dev, "data-gpios not found\n");
> + return data->pdata->gpio_data;
> + }
> +
> + data->pdata->gpio_sck = of_get_named_gpio(np, "clk-gpios", 0);
> + if (data->pdata->gpio_sck < 0) {
> + dev_err(&pdev->dev, "clk-gpios not found\n");
> + return data->pdata->gpio_sck;
> + }
> +
> + data->pdata->checksum = of_property_read_bool(np, "checksum");
> + data->pdata->no_otp_reload = of_property_read_bool(np, "no-otp-reload");
> + data->pdata->low_resolution = of_property_read_bool(np,
> + "low-resolution");
> +
> + return 0;
> +}
> +#else
> +static inline int sht15_probe_dt(struct sht15_data *data,
> + struct platform_device *pdev)
> +{
> + return 1;
> +}
> +#endif
> +
> static int sht15_probe(struct platform_device *pdev)
> {
> int ret;
> @@ -928,11 +982,17 @@ 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;
> + ret = sht15_probe_dt(data, pdev);
I would rather see a clear preference for dt or platform data.
Also, passing 'data' to sht15_probe_dt() is really unnecessary,
and sht15_probe_dt() doesn't really need a pointer to the
platform device.
Example, if DT is preferred:
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;
}
}
Guenter
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