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

From: Liu Ying
Date: Fri Apr 16 2021 - 05:38:56 EST


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 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 unchange HS
clock rate and forcing a full modeset when only connector's DPMS is
brought out of "Off" status.

Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Cc: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
Cc: Robert Foss <robert.foss@xxxxxxxxxx>
Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Jonas Karlman <jonas@xxxxxxxxx>
Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Guido Günther <agx@xxxxxxxxxxx>
Cc: Robert Chiras <robert.chiras@xxxxxxx>
Cc: NXP Linux Team <linux-imx@xxxxxxx>
Signed-off-by: Liu Ying <victor.liu@xxxxxxx>
---
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 66b67402f1ac..873995f0a741 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;
@@ -742,7 +743,9 @@ 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;
@@ -803,17 +806,6 @@ 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,
@@ -831,6 +823,29 @@ 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,
@@ -846,13 +861,6 @@ 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 */
@@ -860,14 +868,8 @@ 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;
@@ -877,27 +879,29 @@ 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;
@@ -942,14 +946,16 @@ 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)
--
2.25.1