Hello Frieder, Am Mittwoch, 3. Mai 2023, 18:33:06 CEST schrieb Frieder Schrempf: > From: Frieder Schrempf <frieder.schre...@kontron.de> > > According to the documentation [1] the proper enable flow is: > > 1. Enable DSI link and keep data lanes in LP-11 (stop state) > 2. Disable stop state to bring data lanes into HS mode > > Currently we do this all at once within enable(), which doesn't > allow to meet the requirements of some downstream bridges. > > To fix this we now enable the DSI in pre_enable() and force it > into stop state using the FORCE_STOP_STATE bit in the ESCMODE > register until enable() is called where we reset the bit. > > We currently do this only for i.MX8M as Exynos uses a different > init flow where samsung_dsim_init() is called from > samsung_dsim_host_transfer(). > > [1] > https://docs.kernel.org/gpu/drm-kms-helpers.html#mipi-dsi-bridge-operation > > Signed-off-by: Frieder Schrempf <frieder.schre...@kontron.de> > --- > Changes for v2: > * Drop RFC > --- > drivers/gpu/drm/bridge/samsung-dsim.c | 25 +++++++++++++++++++++++-- > 1 file changed, 23 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c > b/drivers/gpu/drm/bridge/samsung-dsim.c index e0a402a85787..9775779721d9 > 100644 > --- a/drivers/gpu/drm/bridge/samsung-dsim.c > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c > @@ -859,6 +859,10 @@ static int samsung_dsim_init_link(struct samsung_dsim > *dsi) reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG); > reg &= ~DSIM_STOP_STATE_CNT_MASK; > reg |= DSIM_STOP_STATE_CNT(driver_data->reg_values[STOP_STATE_CNT]); > + > + if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) > + reg |= DSIM_FORCE_STOP_STATE; > + > samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg); > > reg = DSIM_BTA_TIMEOUT(0xff) | DSIM_LPDR_TIMEOUT(0xffff); > @@ -1340,6 +1344,9 @@ static void samsung_dsim_atomic_pre_enable(struct > drm_bridge *bridge, ret = samsung_dsim_init(dsi); > if (ret) > return; > + > + samsung_dsim_set_display_mode(dsi); > + samsung_dsim_set_display_enable(dsi, true); > } > } > > @@ -1347,9 +1354,16 @@ 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; > > - samsung_dsim_set_display_mode(dsi); > - samsung_dsim_set_display_enable(dsi, true); > + 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); > + } > > dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE; > } > @@ -1358,10 +1372,17 @@ 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); > + } > + > dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE; > }
I know that this is necessary right now, but I don't like that 'samsung_dsim_hw_is_exynos()' checks all over the place. Despite that: Tested-by: Alexander Stein <alexander.st...@ew.tq-group.com> #TQMa8MxML/MBa8Mx -- TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany Amtsgericht München, HRB 105018 Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider http://www.tq-group.com/
