linux-kernel - Re: [PATCH v3 22/24] drm/rockchip: dw-mipi-dsi: support non-burst modes

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Message-ID: <20170216142222.2831e474.john@metanate.com>
Date:   Thu, 16 Feb 2017 14:22:22 +0000
From:   John Keeping <john@...anate.com>
To:     Chris Zhong <zyw@...k-chips.com>
Cc:     Sean Paul <seanpaul@...omium.org>,
        Mark Yao <mark.yao@...k-chips.com>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-rockchip@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 22/24] drm/rockchip: dw-mipi-dsi: support non-burst
 modes

On Thu, 16 Feb 2017 11:01:46 +0800, Chris Zhong wrote:

> On 02/01/2017 03:22 AM, Sean Paul wrote:
> > On Sun, Jan 29, 2017 at 01:24:42PM +0000, John Keeping wrote:
> >
> > Reviewed-by: Sean Paul <seanpaul@...omium.org>
> >  
> >> Signed-off-by: John Keeping <john@...anate.com>
> >> Reviewed-by: Chris Zhong <zyw@...k-chips.com>
> >> ---
> >> v3:
> >> - Add Chris' Reviewed-by
> >> Unchanged in v2
> >>
> >>   drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 16 +++++++++-------
> >>   1 file changed, 9 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> >> index 5bad92e2370e..58cb8ace2fe8 100644
> >> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> >> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> >> @@ -82,6 +82,7 @@
> >>   #define FRAME_BTA_ACK			BIT(14)
> >>   #define ENABLE_LOW_POWER		(0x3f << 8)
> >>   #define ENABLE_LOW_POWER_MASK		(0x3f << 8)
> >> +#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS	0x1
> >>   #define VID_MODE_TYPE_BURST_SYNC_PULSES		0x2  
> This field indicates the video mode transmission type as follows:
> 00: Non-burst with sync pulses
> 01: Non-burst with sync events
> 10 and 11: Burst mode
> 
> So, I think define the macro like this is better:
> 
> #define VID_MODE_TYPE_NON_BURST_SYNC_PULSES    0x0
> #define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS    0x1
> #define VID_MODE_TYPE_BURST            0x2
> 
> 
> >>   #define VID_MODE_TYPE_MASK			0x3
> >>   
> >> @@ -286,6 +287,7 @@ struct dw_mipi_dsi {
> >>   	u32 format;
> >>   	u16 input_div;
> >>   	u16 feedback_div;
> >> +	unsigned long mode_flags;
> >>   
> >>   	const struct dw_mipi_dsi_plat_data *pdata;
> >>   };
> >> @@ -551,15 +553,10 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
> >>   		return -EINVAL;
> >>   	}
> >>   
> >> -	if (!(device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) ||
> >> -	    !(device->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)) {
> >> -		dev_err(dsi->dev, "device mode is unsupported\n");
> >> -		return -EINVAL;
> >> -	}
> >> -
> >>   	dsi->lanes = device->lanes;
> >>   	dsi->channel = device->channel;
> >>   	dsi->format = device->format;
> >> +	dsi->mode_flags = device->mode_flags;
> >>   	dsi->panel = of_drm_find_panel(device->dev.of_node);
> >>   	if (dsi->panel)
> >>   		return drm_panel_attach(dsi->panel, &dsi->connector);
> >> @@ -716,7 +713,12 @@ static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
> >>   {
> >>   	u32 val;
> >>   
> >> -	val = VID_MODE_TYPE_BURST_SYNC_PULSES | ENABLE_LOW_POWER;
> >> +	val = ENABLE_LOW_POWER;
> >> +
> >> +	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
> >> +		val |= VID_MODE_TYPE_BURST_SYNC_PULSES;
> >> +	else if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE))
> >> +		val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;  
> 
> if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
> 	val |= VID_MODE_TYPE_BURST;
> else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> 	val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
> else
> 	val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;

OK, this is definitely clearer now that I've forgotten most of the
datasheet; without your definitions at the top it's not clear that
VID_MODE_TYPE_BURST_SYNC_PULSES is zero.