drm/bridge/synopsys: dsi: add support for non-continuous HS clock

Current code enables the HS clock when video mode is started or to
send out a HS command, and disables the HS clock to send out a LP
command. This is not what DSI spec specify.

Enable HS clock either in command and in video mode.
Set automatic HS clock management for panels and devices that
support non-continuous HS clock.
Signed-off-by: Antonio Borneo <antonio.borneo@st.com>
Tested-by: Philippe Cornu <philippe.cornu@st.com>
Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200701194234.18123-1-yannick.fertre@st.com

drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c

@@ -375,7 +375,6 @@ static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
 	if (lpm)
 		val |= CMD_MODE_ALL_LP;
 
-	dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
 	dsi_write(dsi, DSI_CMD_MODE_CFG, val);
 
 	val = dsi_read(dsi, DSI_VID_MODE_CFG);
@@ -558,16 +557,22 @@ static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
 static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
 				 unsigned long mode_flags)
 {
+	u32 val;
+
 	dsi_write(dsi, DSI_PWR_UP, RESET);
 
 	if (mode_flags & MIPI_DSI_MODE_VIDEO) {
 		dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
 		dw_mipi_dsi_video_mode_config(dsi);
-		dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
 	} else {
 		dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
 	}
 
+	val = PHY_TXREQUESTCLKHS;
+	if (dsi->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS)
+		val |= AUTO_CLKLANE_CTRL;
+	dsi_write(dsi, DSI_LPCLK_CTRL, val);
+
 	dsi_write(dsi, DSI_PWR_UP, POWERUP);
 }