Re: [PATCH 1/2] hwmon: shtc1: add support for device tree bindings

[Chris Ruehl]

Hi Guenter,

On 3/7/2020 1:48 pm, Guenter Roeck wrote:
> On 7/2/20 8:48 PM, Chris Ruehl wrote:
> > Add support for DTS bindings to the shtc driver, use CONFIG_OF
> > to compile in the code if needed.
>
> Ah, here it is. The introducing patch should say something like "[PATCH 0/2]".
>
> > Signed-off-by: Chris Ruehl <chris.ruehl@xxxxxxxxxxxx>
> > ---
> >   drivers/hwmon/shtc1.c | 30 ++++++++++++++++++++++++++++++
> >   1 file changed, 30 insertions(+)
> >
> > diff --git a/drivers/hwmon/shtc1.c b/drivers/hwmon/shtc1.c
> > index a0078ccede03..3bcabc1cbce8 100644
> > --- a/drivers/hwmon/shtc1.c
> > +++ b/drivers/hwmon/shtc1.c
> > @@ -14,6 +14,9 @@
> >   #include <linux/err.h>
> >   #include <linux/delay.h>
> >   #include <linux/platform_data/shtc1.h>
> > +#ifdef CONFIG_OF
>
> No. Please no conditional includes.

OK, will be fixed and same for below.

> > +#include <linux/of.h>
> > +#endif
> >   
> >   /* commands (high precision mode) */
> >   static const unsigned char shtc1_cmd_measure_blocking_hpm[]    = { 0x7C, 0xA2 };
> > @@ -196,6 +199,10 @@ static int shtc1_probe(struct i2c_client *client,
> >   	enum shtcx_chips chip = id->driver_data;
> >   	struct i2c_adapter *adap = client->adapter;
> >   	struct device *dev = &client->dev;
> > +#ifdef CONFIG_OF
> > +	struct device_node *np = dev->of_node;
> > +	u8 value;
> > +#endif
> >   
> >   	if (!i2c_check_functionality(adap, I2C_FUNC_I2C)) {
> >   		dev_err(dev, "plain i2c transactions not supported\n");
> > @@ -235,6 +242,20 @@ static int shtc1_probe(struct i2c_client *client,
> >   
> >   	if (client->dev.platform_data)
> >   		data->setup = *(struct shtc1_platform_data *)dev->platform_data;
> > +
> > +#ifdef CONFIG_OF
>
> Unnecessary ifdef. Selection of devicetree data or not can be made
> based on np != NULL. Also, if devictree data is available, platform
> data should be ignored to avoid confusion.

Ok, I wasn't aware this rule. Will change it.

> > +	if (np) {
> > +		if (of_property_read_bool(np, "sensirion,blocking_io")) {
> > +			of_property_read_u8(np, "sensirion,blocking_io", &value);
> > +			data->setup.blocking_io = (value > 0) ? true : false;
> > +		}
> Why this complexity, and why not just make the property a boolean ?
>
> > +		if (of_property_read_bool(np, "sensicon,high_precision")) {
> > +			of_property_read_u8(np, "sensirion,high_precision", &value);
> > +			data->setup.high_precision = (value > 0) ? true : false;
>
> "sensicon,high_precision" should also be a boolean.
>
> > +		}
> > +	}
> > +#endif
> > +
> >   	shtc1_select_command(data);
> >   	mutex_init(&data->update_lock);
> >   
> > @@ -257,6 +278,15 @@ static const struct i2c_device_id shtc1_id[] = {
> >   };
> >   MODULE_DEVICE_TABLE(i2c, shtc1_id);
> >   
> > +#ifdef CONFIG_OF
> > +static const struct of_device_id shtc1_of_match[] = {
> > +	{ .compatible = "sensirion,shtc1" },
> > +	{ .compatible = "sensirion,shtw1" },
> > +	{ .compatible = "sensirion,shtc3" },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, shtc1_of_match);
> > +#endif
> >   static struct i2c_driver shtc1_i2c_driver = {
> >   	.driver.name  = "shtc1",
> >   	.probe        = shtc1_probe,
> Not sure how this works without setting of_match_table. I guess it just works
> accidentally because .id_table also provides a devicetree match. Still,
> of_match_table should be set.

Thanks, I will take care of this in the v2 version.

> Guenter