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Message-ID: <178556dc-a011-e1e6-4147-dbf584672d32@baylibre.com>
Date: Thu, 22 Apr 2021 14:07:04 +0200
From: Neil Armstrong <narmstrong@...libre.com>
To: Liu Ying <victor.liu@....com>, dri-devel@...ts.freedesktop.org
Cc: linux-kernel@...r.kernel.org, Andrzej Hajda <a.hajda@...sung.com>,
Robert Foss <robert.foss@...aro.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>,
Jernej Skrabec <jernej.skrabec@...l.net>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Guido Günther <agx@...xcpu.org>,
Robert Chiras <robert.chiras@....com>,
NXP Linux Team <linux-imx@....com>
Subject: Re: [PATCH v2] drm/bridge: nwl-dsi: Get MIPI DSI controller and PHY
ready in ->mode_set()
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.hajda@...sung.com>
>>> Cc: Neil Armstrong <narmstrong@...libre.com>
>>> Cc: Robert Foss <robert.foss@...aro.org>
>>> Cc: Laurent Pinchart <Laurent.pinchart@...asonboard.com>
>>> Cc: Jonas Karlman <jonas@...boo.se>
>>> Cc: Jernej Skrabec <jernej.skrabec@...l.net>
>>> Cc: David Airlie <airlied@...ux.ie>
>>> Cc: Daniel Vetter <daniel@...ll.ch>
>>> Cc: Guido Günther <agx@...xcpu.org>
>>> Cc: Robert Chiras <robert.chiras@....com>
>>> Cc: NXP Linux Team <linux-imx@....com>
>>> Signed-off-by: Liu Ying <victor.liu@....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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