From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Thompson <daniel.thompson@linaro.org>
Date: Wed, 11 Sep 2019 10:25:33 +0000
Subject: Re: [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin
Message-Id: <20190911102533.not4ta3xwgm6bhjo@holly.lan>
List-Id: <linux-fbdev.vger.kernel.org>
References: <20190910212909.18095-1-andreas@kemnade.info>
 <20190910212909.18095-3-andreas@kemnade.info>
In-Reply-To: <20190910212909.18095-3-andreas@kemnade.info>
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To: Andreas Kemnade <andreas@kemnade.info>
Cc: lee.jones@linaro.org, jingoohan1@gmail.com, jacek.anaszewski@gmail.com, pavel@ucw.cz, dmurphy@ti.com, robh+dt@kernel.org, mark.rutland@arm.com, b.zolnierkie@samsung.com, dri-devel@lists.freedesktop.org, linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org, "H. Nikolaus Schaller" <hns@goldelico.com>

On Tue, Sep 10, 2019 at 11:29:09PM +0200, Andreas Kemnade wrote:
> For now just enable it in the probe function to allow i2c
> access. Disabling also means resetting the register values
> to default and according to the datasheet does not give
> power savings
> 
> Tested on Kobo Clara HD.
> 
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> ---
> changes in v2:
> - simplification
> - correct gpio direction initialisation
> 
>  drivers/video/backlight/lm3630a_bl.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
> index 8f84f3684f04..9d0639d4202d 100644
> --- a/drivers/video/backlight/lm3630a_bl.c
> +++ b/drivers/video/backlight/lm3630a_bl.c
> @@ -12,6 +12,8 @@
>  #include <linux/uaccess.h>
>  #include <linux/interrupt.h>
>  #include <linux/regmap.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/gpio.h>

Nitpicking... but I don't think linux/gpio.h is used anymore.


>  #include <linux/pwm.h>
>  #include <linux/platform_data/lm3630a_bl.h>
>  
> @@ -48,6 +50,7 @@ struct lm3630a_chip {
>  	struct lm3630a_platform_data *pdata;
>  	struct backlight_device *bleda;
>  	struct backlight_device *bledb;
> +	struct gpio_desc *enable_gpio;
>  	struct regmap *regmap;
>  	struct pwm_device *pwmd;
>  };
> @@ -535,6 +538,13 @@ static int lm3630a_probe(struct i2c_client *client,
>  	}
>  	pchip->pdata = pdata;
>  
> +	pchip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable",
> +						GPIOD_OUT_HIGH);
> +	if (IS_ERR(pchip->enable_gpio)) {
> +		rval = PTR_ERR(pchip->enable_gpio);
> +		return rval;
> +	}
> +
>  	/* chip initialize */
>  	rval = lm3630a_chip_init(pchip);
>  	if (rval < 0) {
> -- 
> 2.20.1
>