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Date: Tue, 21 Mar 2017 15:26:35 -0400
From: Sean Paul <seanpaul@chromium.org>
To: Chris Zhong <zyw@rock-chips.com>
Cc: linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2 2/2] drm/panel: add innolux,p079zca panel driver
Message-ID: <20170321192635.GA19389@art_vandelay>
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On Wed, Mar 15, 2017 at 03:19:13PM +0800, Chris Zhong wrote:
> Support Innolux P079ZCA 7.85" 768x1024 TFT LCD panel, it is a MIPI DSI
> panel.
> 
> Signed-off-by: Chris Zhong <zyw@rock-chips.com>
> ---
> 
> Changes in v2:
> - add some error check
> - always use Low power mode to send commend
> - add comments for all the sleep
> - use DRM_DEV_ERROR instead of dev_err
> 

Minor suggestion below. Once that's cleared up, you can add:
Reviewed-by: Sean Paul <seanpaul@chromium.org>

Also, please add Thierry directly to your patches so he sees them.


>  drivers/gpu/drm/panel/Kconfig                 |  11 +
>  drivers/gpu/drm/panel/Makefile                |   1 +
>  drivers/gpu/drm/panel/panel-innolux-p079zca.c | 344 ++++++++++++++++++++++++++
>  3 files changed, 356 insertions(+)
>  create mode 100644 drivers/gpu/drm/panel/panel-innolux-p079zca.c
> 

<snip>
> +static int innolux_panel_prepare(struct drm_panel *panel)
> +{
> +	struct innolux_panel *innolux = to_innolux_panel(panel);
> +	int err, ret;
> +
> +	if (innolux->prepared)
> +		return 0;
> +
> +	gpiod_set_value_cansleep(innolux->enable_gpio, 0);
> +
> +	err = regulator_enable(innolux->supply);
> +	if (err < 0)
> +		return err;
> +
> +	/* T2: 15ms - 1000ms */
> +	usleep_range(15000, 16000);
> +
> +	gpiod_set_value_cansleep(innolux->enable_gpio, 1);
> +
> +	/* T4: 15ms - 1000ms */
> +	usleep_range(15000, 16000);
> +
> +	err = mipi_dsi_dcs_exit_sleep_mode(innolux->link);
> +	if (err < 0) {
> +		DRM_DEV_ERROR(panel->dev, "failed to exit sleep mode: %d\n",
> +			      err);
> +		goto poweroff;
> +	}
> +
> +	/* T6: 120ms - 1000ms*/
> +	msleep(120);
> +
> +	err = mipi_dsi_dcs_set_display_on(innolux->link);
> +	if (err < 0) {
> +		DRM_DEV_ERROR(panel->dev, "failed to set display on: %d\n",
> +			      err);
> +		goto poweroff;
> +	}
> +
> +	/* T7: 5ms */
> +	usleep_range(5000, 6000);
> +
> +	innolux->prepared = true;
> +
> +	return 0;
> +
> +poweroff:
> +	ret = regulator_disable(innolux->supply);
> +	if (ret)
> +		return ret;

I don't think we should be returning this error code. If we're here, it's
because something else triggered err, and we should return that. Change this to:

if (regulator_disable(innolux->supply))
        DRM_DEV_ERROR(panel->dev, "failed to disable regulator after error\n");



Sean

> +
> +	gpiod_set_value_cansleep(innolux->enable_gpio, 0);
> +	return err;
> +}

<snip>

> -- 
> 2.6.3
> 
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