Re: [PATCH] leds-pca963x: add bindings to invert polarity

[Jacek Anaszewski <j.anaszewski@samsung.com>]

Hi Anders,

Thanks for the patch.
Please note that there has already been an attempt to add
the support for inverted output polarity to this driver and related
discussion [1]. This thread remains quiet for around two weeks.

Cc Olliver and Ricardo.

[1] https://lkml.org/lkml/2016/4/19/95

Best regards,
Jacek Anaszewski

On 05/02/2016 11:41 AM, Anders Darander wrote:
> Add a new DT property, nxp,inverted, to invert the polarity of the output.
>
> Tested on PCA9634.
>
> Signed-off-by: Anders Darander <anders@chargestorm.se>
> ---
>   Documentation/devicetree/bindings/leds/pca963x.txt |  1 +
>   drivers/leds/leds-pca963x.c                        | 17 +++++++++++++++--
>   include/linux/platform_data/leds-pca963x.h         |  6 ++++++
>   3 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/leds/pca963x.txt b/Documentation/devicetree/bindings/leds/pca963x.txt
> index dafbe99..68579c5 100644
> --- a/Documentation/devicetree/bindings/leds/pca963x.txt
> +++ b/Documentation/devicetree/bindings/leds/pca963x.txt
> @@ -7,6 +7,7 @@ Optional properties:
>   - nxp,totem-pole : use totem pole (push-pull) instead of open-drain (pca9632 defaults
>     to open-drain, newer chips to totem pole)
>   - nxp,hw-blink : use hardware blinking instead of software blinking
> +- nxp,inverted: invert the polarity of the generated PWM
>
>   Each led is represented as a sub-node of the nxp,pca963x device.
>
> diff --git a/drivers/leds/leds-pca963x.c b/drivers/leds/leds-pca963x.c
> index 407eba1..41b7648 100644
> --- a/drivers/leds/leds-pca963x.c
> +++ b/drivers/leds/leds-pca963x.c
> @@ -294,6 +294,12 @@ pca963x_dt_init(struct i2c_client *client, struct pca963x_chipdef *chip)
>   	else
>   		pdata->blink_type = PCA963X_SW_BLINK;
>
> +	/* default to non-inverted output, unless inverted is specified */
> +	if (of_property_read_bool(np, "nxp,inverted"))
> +		pdata->dir = PCA963X_INVERTED;
> +	else
> +		pdata->dir = PCA963X_NORMAL;
> +
>   	return pdata;
>   }
>
> @@ -395,11 +401,18 @@ static int pca963x_probe(struct i2c_client *client,
>   	i2c_smbus_write_byte_data(client, PCA963X_MODE1, 0x00);
>
>   	if (pdata) {
> +		u8 mode2 = i2c_smbus_read_byte_data(pca963x->chip->client,
> +						    PCA963X_MODE2);
>   		/* Configure output: open-drain or totem pole (push-pull) */
>   		if (pdata->outdrv == PCA963X_OPEN_DRAIN)
> -			i2c_smbus_write_byte_data(client, PCA963X_MODE2, 0x01);
> +			mode2 |= 0x01;
>   		else
> -			i2c_smbus_write_byte_data(client, PCA963X_MODE2, 0x05);
> +			mode2 |= 0x05;
> +		/* Configure direction: normal or inverted */
> +		if (pdata->dir == PCA963X_INVERTED)
> +			mode2 |= 0x10;
> +		i2c_smbus_write_byte_data(pca963x->chip->client, PCA963X_MODE2,
> +					  mode2);
>   	}
>
>   	return 0;
> diff --git a/include/linux/platform_data/leds-pca963x.h b/include/linux/platform_data/leds-pca963x.h
> index e731f00..54e845f 100644
> --- a/include/linux/platform_data/leds-pca963x.h
> +++ b/include/linux/platform_data/leds-pca963x.h
> @@ -33,10 +33,16 @@ enum pca963x_blink_type {
>   	PCA963X_HW_BLINK,
>   };
>
> +enum pca963x_direction {
> +	PCA963X_NORMAL,
> +	PCA963X_INVERTED,
> +};
> +
>   struct pca963x_platform_data {
>   	struct led_platform_data leds;
>   	enum pca963x_outdrv outdrv;
>   	enum pca963x_blink_type blink_type;
> +	enum pca963x_direction dir;
>   };
>
>   #endif /* __LINUX_PCA963X_H*/
>