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Date: Tue, 21 Mar 2017 17:12:05 -0400
From: Sean Paul <seanpaul@chromium.org>
To: Brian Norris <briannorris@chromium.org>
Cc: Sean Paul <seanpaul@chromium.org>, Chris Zhong <zyw@rock-chips.com>,
        linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org,
        Thierry Reding <thierry.reding@gmail.com>
Subject: Re: [PATCH v2 2/2] drm/panel: add innolux,p079zca panel driver
Message-ID: <20170321211205.GM19389@art_vandelay>
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On Tue, Mar 21, 2017 at 01:38:31PM -0700, Brian Norris wrote:
> + Thierry for real
> 
> On Tue, Mar 21, 2017 at 03:26:35PM -0400, Sean Paul wrote:
> > 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");
> 
> And maybe include the error code in that message still?
> 
> 	ret = regulator_disable(innolux->supply);
> 	if (ret)
> 		DRM_DEV_ERROR(panel->dev, "failed to disable regulator after error (%d)\n",
> 			      ret);

Sure, but let's not have ret beside err, each function should have one or the
other. So, perhaps s/ret/regulator_err/ or similar.

Sean

> 
> Brian
> 
> > > +
> > > +	gpiod_set_value_cansleep(innolux->enable_gpio, 0);
> > > +	return err;
> > > +}
> > 
> > <snip>
> > 
> > > -- 
> > > 2.6.3

-- 
Sean Paul, Software Engineer, Google / Chromium OS