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

From: YT Shen
Date: Mon Dec 05 2016 - 07:43:22 EST

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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@xxxxxxxxxxxx>
> > Signed-off-by: YT Shen <yt.shen@xxxxxxxxxxxx>
> > ---
> > 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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