Hi Hans,
On Tue, Aug 16, 2016 at 09:35:24PM +0200, Hans de Goede wrote:
> On some tablets the touchscreen controller is powered by seperate
> regulators, add support for this.
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> .../bindings/input/touchscreen/silead_gsl1680.txt | 2 +
> drivers/input/touchscreen/silead.c | 51 ++++++++++++++++++++--
> 2 files changed, 49 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt b/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> index 37a9370..65eb4c7 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> @@ -22,6 +22,8 @@ Optional properties:
> - touchscreen-inverted-y : See touchscreen.txt
> - touchscreen-swapped-x-y : See touchscreen.txt
> - silead,max-fingers : maximum number of fingers the touchscreen can detect
> +- vddio-supply : regulator phandle for controller VDDIO
> +- avdd-supply : regulator phandle for controller AVDD
>
> Example:
>
> diff --git a/drivers/input/touchscreen/silead.c b/drivers/input/touchscreen/silead.c
> index 7379fe1..04992c5 100644
> --- a/drivers/input/touchscreen/silead.c
> +++ b/drivers/input/touchscreen/silead.c
> @@ -29,6 +29,7 @@
> #include <linux/input/touchscreen.h>
> #include <linux/pm.h>
> #include <linux/irq.h>
> +#include <linux/regulator/consumer.h>
>
> #include <asm/unaligned.h>
>
> @@ -72,6 +73,8 @@ enum silead_ts_power {
> struct silead_ts_data {
> struct i2c_client *client;
> struct gpio_desc *gpio_power;
> + struct regulator *vddio;
> + struct regulator *avdd;
> struct input_dev *input;
> char fw_name[64];
> struct touchscreen_properties prop;
> @@ -463,21 +466,52 @@ static int silead_ts_probe(struct i2c_client *client,
> if (client->irq <= 0)
> return -ENODEV;
>
> + data->vddio = devm_regulator_get_optional(dev, "vddio");
No need for devm_regulator_get_optional(), devm_regulator_get() will
give you dummy regulator that you can enable/disable.
regulator_get_optional() is only need if you have truly optional
functionality in controller and you need to adjust behavior depending on
presence of a regulator.
> + if (IS_ERR(data->vddio)) {
> + if (PTR_ERR(data->vddio) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + data->vddio = NULL;
> + }
> +
> + data->avdd = devm_regulator_get_optional(dev, "avdd");
> + if (IS_ERR(data->avdd)) {
> + if (PTR_ERR(data->avdd) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + data->avdd = NULL;
> + }
> +
> + /*
> + * Enable regulators at probe and disable them at remove, we need
> + * to keep the chip powered otherwise it forgets its firmware.
> + */
> + if (data->vddio) {
> + error = regulator_enable(data->vddio);
> + if (error)
> + return error;
> + }
> +
> + if (data->avdd) {
> + error = regulator_enable(data->avdd);
> + if (error)
> + goto disable_vddio;
> + }
Hmm, so you are enabling regulators and leave them on. That is not
great. I'd rather we powered the device up during probe(), but then shut
it off and waited for ->open() to be called. And power it down in
->close(). You also need to handle it in suspend and resume.
Thanks.
--
Dmitry
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