Re: [PATCH v10 12/13] drm/mediatek: update DSI sub driver flow for sending commands to panel

[YT Shen <yt.shen@mediatek.com>]

Hi CK,

On Wed, 2016-11-30 at 15:58 +0800, CK Hu wrote:
> Hi, YT:
> 
> some comments inline.
> 
> On Fri, 2016-11-25 at 18:34 +0800, YT Shen wrote:
> > This patch update enable/disable flow of DSI module.
> > Original flow works on there is a bridge chip: DSI -> bridge -> panel.
> > In this case: DSI -> panel, the DSI sub driver flow should be updated.
> > We need to initialize DSI first so that we can send commands to panel.
> > 
> > Signed-off-by: shaoming chen <shaoming.chen@mediatek.com>
> > Signed-off-by: YT Shen <yt.shen@mediatek.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dsi.c | 101 +++++++++++++++++++++++++++++--------
> >  1 file changed, 80 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index ded4202..0569f2e 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -126,6 +126,10 @@
> >  #define CLK_HS_POST			(0xff << 8)
> >  #define CLK_HS_EXIT			(0xff << 16)
> >  
> > +#define DSI_VM_CMD_CON		0x130
> > +#define VM_CMD_EN			BIT(0)
> > +#define TS_VFP_EN			BIT(5)
> > +
> >  #define DSI_CMDQ0		0x180
> >  #define CONFIG				(0xff << 0)
> >  #define SHORT_PACKET			0
> > @@ -249,7 +253,9 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
> >  	 * mipi_ratio is mipi clk coefficient for balance the pixel clk in mipi.
> >  	 * we set mipi_ratio is 1.05.
> >  	 */
> > -	dsi->data_rate = dsi->vm.pixelclock * 3 * 21 / (1 * 1000 * 10);
> > +	dsi->data_rate = dsi->vm.pixelclock * 12 * 21;
> > +	dsi->data_rate /= (dsi->lanes * 1000 * 10);
> 
> This looks like a bug fix that use lanes to calculate data rate.
This part add support when dsi->lanes != 4.

> 
> > +	DRM_DEBUG_DRIVER("set mipitx's data rate: %dMHz\n", dsi->data_rate);
> >  
> >  	ret = clk_set_rate(dsi->hs_clk, dsi->data_rate * 1000000);
> >  	if (ret < 0) {
> > @@ -333,16 +339,23 @@ static void mtk_dsi_set_mode(struct mtk_dsi *dsi)
> >  	u32 vid_mode = CMD_MODE;
> >  
> >  	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO) {
> > -		vid_mode = SYNC_PULSE_MODE;
> > -
> > -		if ((dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) &&
> > -		    !(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE))
> > +		if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
> >  			vid_mode = BURST_MODE;
> > +		else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> > +			vid_mode = SYNC_PULSE_MODE;
> > +		else
> > +			vid_mode = SYNC_EVENT_MODE;
> >  	}
> >  
> >  	writel(vid_mode, dsi->regs + DSI_MODE_CTRL);
> >  }
> >  
> > +static void mtk_dsi_set_vm_cmd(struct mtk_dsi *dsi)
> > +{
> > +	mtk_dsi_mask(dsi, DSI_VM_CMD_CON, VM_CMD_EN, VM_CMD_EN);
> > +	mtk_dsi_mask(dsi, DSI_VM_CMD_CON, TS_VFP_EN, TS_VFP_EN);
> > +}
> > +
> >  static void mtk_dsi_ps_control_vact(struct mtk_dsi *dsi)
> >  {
> >  	struct videomode *vm = &dsi->vm;
> > @@ -480,6 +493,16 @@ static void mtk_dsi_start(struct mtk_dsi *dsi)
> >  	writel(1, dsi->regs + DSI_START);
> >  }
> >  
> > +static void mtk_dsi_stop(struct mtk_dsi *dsi)
> > +{
> > +	writel(0, dsi->regs + DSI_START);
> > +}
> > +
> > +static void mtk_dsi_set_cmd_mode(struct mtk_dsi *dsi)
> > +{
> > +	writel(CMD_MODE, dsi->regs + DSI_MODE_CTRL);
> > +}
> > +
> >  static void mtk_dsi_set_interrupt_enable(struct mtk_dsi *dsi)
> >  {
> >  	u32 inten = LPRX_RD_RDY_INT_FLAG | CMD_DONE_INT_FLAG | VM_DONE_INT_FLAG;
> > @@ -538,6 +561,19 @@ static irqreturn_t mtk_dsi_irq(int irq, void *dev_id)
> >  	return IRQ_HANDLED;
> >  }
> >  
> > +static s32 mtk_dsi_switch_to_cmd_mode(struct mtk_dsi *dsi, u8 irq_flag, u32 t)
> > +{
> > +	mtk_dsi_irq_data_clear(dsi, irq_flag);
> > +	mtk_dsi_set_cmd_mode(dsi);
> > +
> > +	if (!mtk_dsi_wait_for_irq_done(dsi, irq_flag, t)) {
> > +		DRM_ERROR("failed to switch cmd mode\n");
> > +		return -ETIME;
> > +	} else {
> > +		return 0;
> > +	}
> > +}
> > +
> >  static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
> >  {
> >  	if (WARN_ON(dsi->refcount == 0))
> > @@ -546,11 +582,6 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
> >  	if (--dsi->refcount != 0)
> >  		return;
> >  
> > -	mtk_dsi_lane0_ulp_mode_enter(dsi);
> > -	mtk_dsi_clk_ulp_mode_enter(dsi);
> > -
> > -	mtk_dsi_disable(dsi);
> > -
> >  	clk_disable_unprepare(dsi->engine_clk);
> >  	clk_disable_unprepare(dsi->digital_clk);
> >  
> > @@ -564,13 +595,6 @@ static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
> >  	if (dsi->enabled)
> >  		return;
> >  
> > -	if (dsi->panel) {
> > -		if (drm_panel_prepare(dsi->panel)) {
> > -			DRM_ERROR("failed to setup the panel\n");
> > -			return;
> > -		}
> > -	}
> > -
> >  	ret = mtk_dsi_poweron(dsi);
> >  	if (ret < 0) {
> >  		DRM_ERROR("failed to power on dsi\n");
> > @@ -578,21 +602,43 @@ static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
> >  	}
> >  
> >  	mtk_dsi_rxtx_control(dsi);
> > +	mtk_dsi_ps_control_vact(dsi);
> > +	mtk_dsi_set_vm_cmd(dsi);
> 
> Even though dsi does not directly connect to panel, you newly set vm cmd
> here. This looks like a bug fix.
We will remove this if it is not necessary.

> 
> > +	mtk_dsi_config_vdo_timing(dsi);
> > +	mtk_dsi_set_interrupt_enable(dsi);
> >  
> >  	mtk_dsi_clk_ulp_mode_leave(dsi);
> >  	mtk_dsi_lane0_ulp_mode_leave(dsi);
> >  	mtk_dsi_clk_hs_mode(dsi, 0);
> > -	mtk_dsi_set_mode(dsi);
> >  
> > -	mtk_dsi_ps_control_vact(dsi);
> > -	mtk_dsi_config_vdo_timing(dsi);
> > -	mtk_dsi_set_interrupt_enable(dsi);
> > +	if (dsi->panel) {
> > +		if (drm_panel_prepare(dsi->panel)) {
> > +			DRM_ERROR("failed to prepare the panel\n");
> > +
> > +			mtk_dsi_stop(dsi);
> 
> You never start dsi before here, why do you stop dsi here?
> 
> > +			mtk_dsi_poweroff(dsi);
> 
> Refer to next comment, you may goto undo item in bottom of this
> function.
> 
> > +			return;
> > +		}
> > +	}
> >  
> >  	mtk_dsi_set_mode(dsi);
> >  	mtk_dsi_clk_hs_mode(dsi, 1);
> >  
> >  	mtk_dsi_start(dsi);
> >  
> > +	if (dsi->panel) {
> > +		if (drm_panel_enable(dsi->panel)) {
> > +			DRM_ERROR("failed to enable the panel\n");
> > +
> > +			if (drm_panel_unprepare(dsi->panel))
> > +				DRM_ERROR("failed to unprepare the panel\n");
> > +
> > +			mtk_dsi_stop(dsi);
> 
> I think you should stop dsi before panel unprepare. Otherwise, why not
> move these undo item to the bottom of this function. For example:
> 
> 		if (drm_panel_enable(dsi->panel)) {
> 			DRM_ERROR("failed to enable the panel\n");
> 			goto stop_dsi;
> 
> ...
> 
> 	dsi->enabled = true;
> 	return;
> 
> stop_dsi:
> 	mtk_dsi_stop(dsi);
> 	if (drm_panel_unprepare(dsi->panel))
> 		DRM_ERROR("failed to unprepare the panel\n");
> poweroff_dsi:
> 	mtk_dsi_poweroff(dsi);
> 	return;
> 
We will move the error handling to the bottom of this function.

> > +			mtk_dsi_poweroff(dsi);
> > +			return;
> > +		}
> > +	}
> > +
> >  	dsi->enabled = true;
> >  }
> >  
> > @@ -608,6 +654,19 @@ static void mtk_output_dsi_disable(struct mtk_dsi *dsi)
> >  		}
> >  	}
> >  
> > +	mtk_dsi_stop(dsi);
> 
> Even though dsi does not directly connect to panel, you newly stop dsi
> here. This looks like a bug fix.
> 
> > +	if (!mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500)) {
> 
> ditto.
> 
> > +		if (dsi->panel) {
> > +			if (drm_panel_unprepare(dsi->panel))
> > +				DRM_ERROR("failed to unprepare the panel\n");
> > +		}
> > +	}
> > +
> > +	mtk_dsi_reset_engine(dsi);
> 
> ditto.
> 
> > +	mtk_dsi_lane0_ulp_mode_enter(dsi);
> > +	mtk_dsi_clk_ulp_mode_enter(dsi);
> > +	mtk_dsi_disable(dsi);
> > +
> >  	mtk_dsi_poweroff(dsi);
> >  
> >  	dsi->enabled = false;
> 
> Regards,
> CK
> 


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