Re: [PATCH v2] drm/bridge: nwl-dsi: Get MIPI DSI controller and PHY ready in ->mode_set()

[Liu Ying <victor.liu@nxp.com>]

Hi Neil,

On Thu, 2021-04-22 at 14:07 +0200, Neil Armstrong wrote:
> Hi,
> 
> On 22/04/2021 11:31, Liu Ying wrote:
> > Hi Neil,
> > 
> > On Thu, 2021-04-22 at 10:48 +0200, Neil Armstrong wrote:
> > > Hi,
> > > 
> > > On 22/04/2021 07:14, Liu Ying wrote:
> > > > Some MIPI DSI panel drivers like 'raydium,rm68200' send
> > > > MIPI_DCS_SET_DISPLAY_ON commands in panel_funcs->prepare(), which
> > > > requires the MIPI DSI controller and PHY to be ready beforehand.
> > > > Without this patch, the nwl-dsi driver gets the MIPI DSI controller
> > > > and PHY ready in bridge_funcs->pre_enable(), which happens after
> > > > the panel_funcs->prepare(). So, this patch shifts the bridge operation
> > > > ealier from bridge_funcs->pre_enable() to bridge_funcs->mode_set().
> > > 
> > > This makes sense, this is how we do on the synopsys dw mipi dsi driver.
> > > 
> > > > This way, more MIPI DSI panels can connect to this nwl-dsi bridge.
> > > > Care is taken to make sure bridge_funcs->mode_set()/atomic_disable()
> > > > are called in pairs, which includes removing a check on unchanged HS
> > > > clock rate and forcing a full modeset when only connector's DPMS is
> > > > brought out of "Off" status.
> > > 
> > > I would split the changes in multiple patches to clarify the changes.
> > 
> > Maybe, I can split this into the below 3 patches:
> > 1) Remove a check on unchanged HS clock rate from ->mode_set().
> > 2) Force a full modeset when only connector's DPMS is brought out of
> > "Off" status. This will be done in ->atomic_check() together with the
> > fixup for H/VSYNC polarities.
> > 3) Shift the bridge operation as the last step.
> > 
> > I'll mention that 1) & 2) are needed by 3) in their commit message.
> 
> Sure, you can also put this split explanation in the cover letter.
> 
> > Does this split-up sound reasonable?
> 
> Yes makes sense, thanks

I've sent v3 to do the split-up.
I actually swap 1) and 2), which is trivial I assume.

Regards,
Liu Ying

> 
> Neil
> 
> > Thanks,
> > Liu Ying
> > 
> > > Neil
> > > 
> > > > Cc: Andrzej Hajda <a.hajda@samsung.com>
> > > > Cc: Neil Armstrong <narmstrong@baylibre.com>
> > > > Cc: Robert Foss <robert.foss@linaro.org>
> > > > Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
> > > > Cc: Jonas Karlman <jonas@kwiboo.se>
> > > > Cc: Jernej Skrabec <jernej.skrabec@siol.net>
> > > > Cc: David Airlie <airlied@linux.ie>
> > > > Cc: Daniel Vetter <daniel@ffwll.ch>
> > > > Cc: Guido Günther <agx@sigxcpu.org>
> > > > Cc: Robert Chiras <robert.chiras@nxp.com>
> > > > Cc: NXP Linux Team <linux-imx@nxp.com>
> > > > Signed-off-by: Liu Ying <victor.liu@nxp.com>
> > > > ---
> > > > v1->v2:
> > > > * Fix commit message typo - s/unchange/unchanged/
> > > > 
> > > >  drivers/gpu/drm/bridge/nwl-dsi.c | 86 +++++++++++++++++++++-------------------
> > > >  1 file changed, 46 insertions(+), 40 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
> > > > index be6bfc5..229f0b1 100644
> > > > --- a/drivers/gpu/drm/bridge/nwl-dsi.c
> > > > +++ b/drivers/gpu/drm/bridge/nwl-dsi.c
> > > > @@ -21,6 +21,7 @@
> > > >  #include <linux/sys_soc.h>
> > > >  #include <linux/time64.h>
> > > >  
> > > > +#include <drm/drm_atomic_state_helper.h>
> > > >  #include <drm/drm_bridge.h>
> > > >  #include <drm/drm_mipi_dsi.h>
> > > >  #include <drm/drm_of.h>
> > > > @@ -661,7 +662,7 @@ static irqreturn_t nwl_dsi_irq_handler(int irq, void *data)
> > > >  	return IRQ_HANDLED;
> > > >  }
> > > >  
> > > > -static int nwl_dsi_enable(struct nwl_dsi *dsi)
> > > > +static int nwl_dsi_mode_set(struct nwl_dsi *dsi)
> > > >  {
> > > >  	struct device *dev = dsi->dev;
> > > >  	union phy_configure_opts *phy_cfg = &dsi->phy_cfg;
> > > > @@ -748,7 +749,9 @@ static int nwl_dsi_disable(struct nwl_dsi *dsi)
> > > >  	return 0;
> > > >  }
> > > >  
> > > > -static void nwl_dsi_bridge_disable(struct drm_bridge *bridge)
> > > > +static void
> > > > +nwl_dsi_bridge_atomic_disable(struct drm_bridge *bridge,
> > > > +			      struct drm_bridge_state *old_bridge_state)
> > > >  {
> > > >  	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
> > > >  	int ret;
> > > > @@ -809,17 +812,6 @@ static int nwl_dsi_get_dphy_params(struct nwl_dsi *dsi,
> > > >  	return 0;
> > > >  }
> > > >  
> > > > -static bool nwl_dsi_bridge_mode_fixup(struct drm_bridge *bridge,
> > > > -				      const struct drm_display_mode *mode,
> > > > -				      struct drm_display_mode *adjusted_mode)
> > > > -{
> > > > -	/* At least LCDIF + NWL needs active high sync */
> > > > -	adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
> > > > -	adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
> > > > -
> > > > -	return true;
> > > > -}
> > > > -
> > > >  static enum drm_mode_status
> > > >  nwl_dsi_bridge_mode_valid(struct drm_bridge *bridge,
> > > >  			  const struct drm_display_info *info,
> > > > @@ -837,6 +829,29 @@ nwl_dsi_bridge_mode_valid(struct drm_bridge *bridge,
> > > >  	return MODE_OK;
> > > >  }
> > > >  
> > > > +static int nwl_dsi_bridge_atomic_check(struct drm_bridge *bridge,
> > > > +				       struct drm_bridge_state *bridge_state,
> > > > +				       struct drm_crtc_state *crtc_state,
> > > > +				       struct drm_connector_state *conn_state)
> > > > +{
> > > > +	struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
> > > > +
> > > > +	/* At least LCDIF + NWL needs active high sync */
> > > > +	adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
> > > > +	adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
> > > > +
> > > > +	/*
> > > > +	 * Do a full modeset if crtc_state->active is changed to be true.
> > > > +	 * This ensures our ->mode_set() is called to get the DSI controller
> > > > +	 * and the PHY ready to send DCS commands, when only the connector's
> > > > +	 * DPMS is brought out of "Off" status.
> > > > +	 */
> > > > +	if (crtc_state->active_changed && crtc_state->active)
> > > > +		crtc_state->mode_changed = true;
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > >  static void
> > > >  nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
> > > >  			const struct drm_display_mode *mode,
> > > > @@ -852,13 +867,6 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
> > > >  	if (ret < 0)
> > > >  		return;
> > > >  
> > > > -	/*
> > > > -	 * If hs clock is unchanged, we're all good - all parameters are
> > > > -	 * derived from it atm.
> > > > -	 */
> > > > -	if (new_cfg.mipi_dphy.hs_clk_rate == dsi->phy_cfg.mipi_dphy.hs_clk_rate)
> > > > -		return;
> > > > -
> > > >  	phy_ref_rate = clk_get_rate(dsi->phy_ref_clk);
> > > >  	DRM_DEV_DEBUG_DRIVER(dev, "PHY at ref rate: %lu\n", phy_ref_rate);
> > > >  	/* Save the new desired phy config */
> > > > @@ -866,14 +874,8 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
> > > >  
> > > >  	memcpy(&dsi->mode, adjusted_mode, sizeof(dsi->mode));
> > > >  	drm_mode_debug_printmodeline(adjusted_mode);
> > > > -}
> > > >  
> > > > -static void nwl_dsi_bridge_pre_enable(struct drm_bridge *bridge)
> > > > -{
> > > > -	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
> > > > -	int ret;
> > > > -
> > > > -	pm_runtime_get_sync(dsi->dev);
> > > > +	pm_runtime_get_sync(dev);
> > > >  
> > > >  	if (clk_prepare_enable(dsi->lcdif_clk) < 0)
> > > >  		return;
> > > > @@ -883,27 +885,29 @@ static void nwl_dsi_bridge_pre_enable(struct drm_bridge *bridge)
> > > >  	/* Step 1 from DSI reset-out instructions */
> > > >  	ret = reset_control_deassert(dsi->rst_pclk);
> > > >  	if (ret < 0) {
> > > > -		DRM_DEV_ERROR(dsi->dev, "Failed to deassert PCLK: %d\n", ret);
> > > > +		DRM_DEV_ERROR(dev, "Failed to deassert PCLK: %d\n", ret);
> > > >  		return;
> > > >  	}
> > > >  
> > > >  	/* Step 2 from DSI reset-out instructions */
> > > > -	nwl_dsi_enable(dsi);
> > > > +	nwl_dsi_mode_set(dsi);
> > > >  
> > > >  	/* Step 3 from DSI reset-out instructions */
> > > >  	ret = reset_control_deassert(dsi->rst_esc);
> > > >  	if (ret < 0) {
> > > > -		DRM_DEV_ERROR(dsi->dev, "Failed to deassert ESC: %d\n", ret);
> > > > +		DRM_DEV_ERROR(dev, "Failed to deassert ESC: %d\n", ret);
> > > >  		return;
> > > >  	}
> > > >  	ret = reset_control_deassert(dsi->rst_byte);
> > > >  	if (ret < 0) {
> > > > -		DRM_DEV_ERROR(dsi->dev, "Failed to deassert BYTE: %d\n", ret);
> > > > +		DRM_DEV_ERROR(dev, "Failed to deassert BYTE: %d\n", ret);
> > > >  		return;
> > > >  	}
> > > >  }
> > > >  
> > > > -static void nwl_dsi_bridge_enable(struct drm_bridge *bridge)
> > > > +static void
> > > > +nwl_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
> > > > +			     struct drm_bridge_state *old_bridge_state)
> > > >  {
> > > >  	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
> > > >  	int ret;
> > > > @@ -948,14 +952,16 @@ static void nwl_dsi_bridge_detach(struct drm_bridge *bridge)
> > > >  }
> > > >  
> > > >  static const struct drm_bridge_funcs nwl_dsi_bridge_funcs = {
> > > > -	.pre_enable = nwl_dsi_bridge_pre_enable,
> > > > -	.enable     = nwl_dsi_bridge_enable,
> > > > -	.disable    = nwl_dsi_bridge_disable,
> > > > -	.mode_fixup = nwl_dsi_bridge_mode_fixup,
> > > > -	.mode_set   = nwl_dsi_bridge_mode_set,
> > > > -	.mode_valid = nwl_dsi_bridge_mode_valid,
> > > > -	.attach	    = nwl_dsi_bridge_attach,
> > > > -	.detach	    = nwl_dsi_bridge_detach,
> > > > +	.atomic_duplicate_state	= drm_atomic_helper_bridge_duplicate_state,
> > > > +	.atomic_destroy_state	= drm_atomic_helper_bridge_destroy_state,
> > > > +	.atomic_reset		= drm_atomic_helper_bridge_reset,
> > > > +	.atomic_check		= nwl_dsi_bridge_atomic_check,
> > > > +	.atomic_enable		= nwl_dsi_bridge_atomic_enable,
> > > > +	.atomic_disable		= nwl_dsi_bridge_atomic_disable,
> > > > +	.mode_set		= nwl_dsi_bridge_mode_set,
> > > > +	.mode_valid		= nwl_dsi_bridge_mode_valid,
> > > > +	.attach			= nwl_dsi_bridge_attach,
> > > > +	.detach			= nwl_dsi_bridge_detach,
> > > >  };
> > > >  
> > > >  static int nwl_dsi_parse_dt(struct nwl_dsi *dsi)
> > > > 

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