On Wed, May 3, 2023 at 9:33 AM Frieder Schrempf <frieder@xxxxxxx> wrote: > > From: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx> > > 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.schrempf@xxxxxxxxxx> > --- > 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; > } > > -- > 2.40.0 > Hi Frieder, I found this patch to break mipi-dsi display on my board which has: - FocalTech FT5406 10pt touch controller (with no interrupt) - Powertip PH800480T013-IDF02 compatible panel - Toshiba TC358762 compatible DSI to DBI bridge - ATTINY based regulator used for backlight controller and panel enable I enable this via a dt overlay in a pending patch imx8mm-venice-gw72xx-0x-rpidsi.dtso [1] which works on 6.4 but not 6.5-rc1 which has this patch. The issue appears as: [ 6.110585] samsung-dsim 32e60000.dsi: xfer timed out: 29 06 00 00 64 01 05 00 00 00 [ 6.326588] tc358762 32e60000.dsi.0: error initializing bridge (-110) Instead of [ 1.011729] samsung-dsim 32e10000.dsi: supply vddcore not found, using dummy regulator [ 1.019829] samsung-dsim 32e10000.dsi: supply vddio not found, using dummy regulator [ 5.649928] samsung-dsim 32e10000.dsi: [drm:samsung_dsim_host_attach] Attached tc358762 device I'm curious what board/panel were you needing this for and do you have any ideas why it broke my setup? I'm also curious what board/panel Alexander tested this with and if Adam or Jagan (or others) have tested this with their hardware? best regards, Tim [1] https://patchwork.kernel.org/project/linux-arm-kernel/patch/20230711221124.2127186-1-tharvey@xxxxxxxxxxxxx/
