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

Neil

> 
> Thanks,
> Liu Ying
> 
>>
>> Neil
>>
>>> Cc: Andrzej Hajda <a.ha...@samsung.com>
>>> Cc: Neil Armstrong <narmstr...@baylibre.com>
>>> Cc: Robert Foss <robert.f...@linaro.org>
>>> Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
>>> Cc: Jonas Karlman <jo...@kwiboo.se>
>>> Cc: Jernej Skrabec <jernej.skra...@siol.net>
>>> Cc: David Airlie <airl...@linux.ie>
>>> Cc: Daniel Vetter <dan...@ffwll.ch>
>>> Cc: Guido Günther <a...@sigxcpu.org>
>>> Cc: Robert Chiras <robert.chi...@nxp.com>
>>> Cc: NXP Linux Team <linux-...@nxp.com>
>>> Signed-off-by: Liu Ying <victor....@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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