linux-kernel - Re: [PATCH 1/2] backlight: hx8357: switch to using gpiod API

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Message-ID: <Y+DmBGiq9kvRBHLY@aspen.lan>
Date:   Mon, 6 Feb 2023 11:35:32 +0000
From:   Daniel Thompson <daniel.thompson@...aro.org>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     Lee Jones <lee@...nel.org>, Jingoo Han <jingoohan1@...il.com>,
        Helge Deller <deller@....de>, dri-devel@...ts.freedesktop.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] backlight: hx8357: switch to using gpiod API

On Tue, Jan 31, 2023 at 02:57:06PM -0800, Dmitry Torokhov wrote:
> Switch the driver from legacy gpio API that is deprecated to the newer
> gpiod API that respects line polarities described in ACPI/DT.
>
> This makes driver use standard property name for the reset gpio
> ("reset-gpios" vs "gpios-reset"), however there is a quirk in gpiolib
> to also recognize the legacy name and keep compatibility with older
> DTSes.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> ---
>
> All preparation gpiolib work to handle legacy names and polarity quirks
> has landed in mainline...
>
>  drivers/video/backlight/hx8357.c | 82 ++++++++++++++------------------
>  1 file changed, 37 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/video/backlight/hx8357.c b/drivers/video/backlight/hx8357.c
> index 9b50bc96e00f..a93e14adb846 100644
> --- a/drivers/video/backlight/hx8357.c
> +++ b/drivers/video/backlight/hx8357.c
> [snip]
> -	if (of_find_property(spi->dev.of_node, "im-gpios", NULL)) {
> -		lcd->use_im_pins = 1;
> -
> -		for (i = 0; i < HX8357_NUM_IM_PINS; i++) {
> -			lcd->im_pins[i] = of_get_named_gpio(spi->dev.of_node,
> -							    "im-gpios", i);
> -			if (lcd->im_pins[i] == -EPROBE_DEFER) {
> -				dev_info(&spi->dev, "GPIO requested is not here yet, deferring the probe\n");
> -				return -EPROBE_DEFER;
> -			}
> -			if (!gpio_is_valid(lcd->im_pins[i])) {
> -				dev_err(&spi->dev, "Missing dt property: im-gpios\n");
> -				return -EINVAL;
> +	gpiod_set_consumer_name(lcd->reset, "hx8357-reset");
> +
> +	for (i = 0; i < HX8357_NUM_IM_PINS; i++) {
> +		lcd->im_pins[i] = devm_gpiod_get_index(&spi->dev,
> +						       "im", i, GPIOD_OUT_LOW);
> +		ret = PTR_ERR_OR_ZERO(lcd->im_pins[i]);
> +		if (ret) {
> +			if (ret == -ENOENT) {
> +				if (i == 0)
> +					break;
> +				dev_err(&spi->dev, "Missing im gpios[%d]\n", i);
> +				ret = -EINVAL;
> +			} if (ret == -EPROBE_DEFER) {
> +				dev_info(&spi->dev, "im gpio[%d] is not here yet, deferring the probe\n",
> +					 i);
> +			} else {
> +				dev_err(&spi->dev, "failed to request im gpio[%d]: %d\n",
> +					i, ret);
>  			}

These last two clauses should be updated to return dev_err_probe(...)
instead.

With that change:
Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>


Daniel.