Re: [PATCH 2/2] Input: zinitix - Handle proper supply names

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Linus,

On Fri, Jun 25, 2021 at 01:34:35PM +0200, Linus Walleij wrote:
> The supply names of the Zinitix touchscreen were a bit confused, the new
> bindings rectifies this.
> 
> To deal with old and new devicetrees, first check if we have "vddo" and in
> case that exists assume the old supply names. Else go and look for the new
> ones.
> 
> We cannot just get the regulators since we would get an OK and a dummy
> regulator: we need to check explicitly for the old supply name.
> 
> Use struct device *dev as a local variable instead of the I2C client since
> the device is what we are actually obtaining the resources from.
> 
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Michael Srba <Michael.Srba@seznam.cz>
> Cc: phone-devel@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> Mark: please check that I'm doing this check the right way, I assume
> that since we get regulator dummies this is the way I need to check
> for the old regulator name but maybe there are better ways.
> ---
>  drivers/input/touchscreen/zinitix.c | 22 +++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/zinitix.c b/drivers/input/touchscreen/zinitix.c
> index b8d901099378..7001307382f0 100644
> --- a/drivers/input/touchscreen/zinitix.c
> +++ b/drivers/input/touchscreen/zinitix.c
> @@ -252,16 +252,28 @@ static int zinitix_init_touch(struct bt541_ts_data *bt541)
>  
>  static int zinitix_init_regulators(struct bt541_ts_data *bt541)
>  {
> -	struct i2c_client *client = bt541->client;
> +	struct device *dev = &bt541->client->dev;
>  	int error;
>  
> -	bt541->supplies[0].supply = "vdd";
> -	bt541->supplies[1].supply = "vddo";
> -	error = devm_regulator_bulk_get(&client->dev,
> +	/*
> +	 * Some older device trees have erroneous names for the regulators,
> +	 * so check if "vddo" is present and in that case use these names
> +	 * and warn. Else use the proper supply names on the component.
> +	 */
> +	if (IS_ENABLED(CONFIG_OF) &&

Why is this check needed? The of_property_*() are stubbed out properly I
believe. We might need to check that dev->of_node is not NULL, although
I think of_* API handles this properly.

> +	    of_property_read_bool(dev->of_node, "vddo-supply")) {

If we go with this I do not like using of_property_read_bool() as this
is not a boolean property, but rather of_find_property().

However maybe we should use regulator_get_optional() which will not give
a dummy regulator? Still quite awkward, a dedicated API to see if a
regulator is defined would be nice.

> +		bt541->supplies[0].supply = "vdd";
> +		bt541->supplies[1].supply = "vddo";
> +	} else {
> +		/* Else use the proper supply names */
> +		bt541->supplies[0].supply = "vcca";
> +		bt541->supplies[1].supply = "vdd";
> +	}
> +	error = devm_regulator_bulk_get(dev,
>  					ARRAY_SIZE(bt541->supplies),
>  					bt541->supplies);
>  	if (error < 0) {
> -		dev_err(&client->dev, "Failed to get regulators: %d\n", error);
> +		dev_err(dev, "Failed to get regulators: %d\n", error);
>  		return error;
>  	}
>  
> -- 
> 2.31.1
> 

Thanks.

-- 
Dmitry