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drm: bridge: samsung-dsim: Fix init during host transfer

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In case the downstream bridge or panel uses DSI transfers before the
DSI host was actually initialized through samsung_dsim_atomic_enable()
which clears the stop state (LP11) mode, all transfers will fail.

This happens with downstream bridges that are controlled by DSI
commands such as the tc358762.

As documented in [1] DSI hosts are expected to allow transfers
outside the normal bridge enable/disable flow.

To fix this make sure that stop state is cleared in
samsung_dsim_host_transfer() which restores the previous
behavior.

We also factor out the common code to enable/disable stop state
to samsung_dsim_set_stop_state().

[1] https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operation

Fixes: 0c14d31306 ("drm: bridge: samsung-dsim: Fix i.MX8M enable flow to meet spec")
Reported-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230724151640.555490-1-frieder@fris.de
This commit is contained in:
Frieder Schrempf 2023-07-24 17:16:32 +02:00 committed by Neil Armstrong
parent 50b6f2c829
commit 20c827683d
1 changed files with 17 additions and 10 deletions
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27
drivers/gpu/drm/bridge/samsung-dsim.c
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@ -1386,6 +1386,18 @@ static void samsung_dsim_disable_irq(struct samsung_dsim *dsi)
disable_irq(dsi->irq);
}
static void samsung_dsim_set_stop_state(struct samsung_dsim *dsi, bool enable)
{
u32 reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
if (enable)
reg |= DSIM_FORCE_STOP_STATE;
else
reg &= ~DSIM_FORCE_STOP_STATE;
samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
}
static int samsung_dsim_init(struct samsung_dsim *dsi)
{
const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
@ -1445,15 +1457,12 @@ static void samsung_dsim_atomic_enable(struct drm_bridge *bridge,
struct drm_bridge_state *old_bridge_state)
{
struct samsung_dsim *dsi = bridge_to_dsi(bridge);
u32 reg;
if (samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
samsung_dsim_set_display_mode(dsi);
samsung_dsim_set_display_enable(dsi, true);
} else {
reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
reg &= ~DSIM_FORCE_STOP_STATE;
samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
samsung_dsim_set_stop_state(dsi, false);
}
dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE;
@ -1463,16 +1472,12 @@ static void samsung_dsim_atomic_disable(struct drm_bridge *bridge,
struct drm_bridge_state *old_bridge_state)
{
struct samsung_dsim *dsi = bridge_to_dsi(bridge);
u32 reg;
if (!(dsi->state & DSIM_STATE_ENABLED))
return;
if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
reg |= DSIM_FORCE_STOP_STATE;
samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
}
if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type))
samsung_dsim_set_stop_state(dsi, true);
dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
}
@ -1775,6 +1780,8 @@ static ssize_t samsung_dsim_host_transfer(struct mipi_dsi_host *host,
if (ret)
return ret;
samsung_dsim_set_stop_state(dsi, false);
ret = mipi_dsi_create_packet(&xfer.packet, msg);
if (ret < 0)
return ret;