This patch adds non-continuous clock mode support.
Clock mode on Clock Lane is continuous clock by default.
So if we want to transmit data in non-continuous clock mode
to reduce power consumption, then host driver should clear
DSIM_TX_REQUEST_HSCLK.
For this, this patch makes the host driver set DSIM_TX_REQUEST_HSCLK
only in case that dsi->mode_flags has no MIPI_DSI_CLOCK_NON_CONTINUOUS
flag.
Signed-off-by: Inki Dae <inki.dae at samsung.com>
---
drivers/gpu/drm/exynos/exynos_drm_dsi.c | 32 +++++++++++++++++++++++++++++--
1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index 86aebd8..8c43c96 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -493,8 +493,17 @@ static int exynos_dsi_enable_clock(struct exynos_dsi *dsi)
| DSIM_ESC_PRESCALER(esc_div)
| DSIM_LANE_ESC_CLK_EN_CLK
| DSIM_LANE_ESC_CLK_EN_DATA(BIT(dsi->lanes) - 1)
- | DSIM_BYTE_CLK_SRC(0)
- | DSIM_TX_REQUEST_HSCLK;
+ | DSIM_BYTE_CLK_SRC(0);
+
+ /*
+ * Set DSIM_TX_REQUEST_HSCLK only in case of not requesting
+ * non-continous clock mode. So if MIPI_DSI_CLOCK_NON_CONTINUOUS,
+ * then host controller will turn off the HS clock between high-speed
+ * transmissions.
+ */
+ if (!(dsi->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
+ reg |= DSIM_TX_REQUEST_HSCLK;
+
writel(reg, dsi->reg_base + DSIM_CLKCTRL_REG);
return 0;
@@ -701,10 +710,29 @@ static void exynos_dsi_set_display_mode(struct exynos_dsi
*dsi)
dev_dbg(dsi->dev, "LCD size = %dx%d\n", vm->hactive, vm->vactive);
}
+static void exynos_dsi_enable_hs_clock(struct exynos_dsi *dsi,
+ bool enable)
+{
+ u32 reg = readl(dsi->reg_base + DSIM_CLKCTRL_REG);
+
+ reg &= ~DSIM_TX_REQUEST_HSCLK;
+ if (enable)
+ reg |= DSIM_TX_REQUEST_HSCLK;
+
+ writel(reg, dsi->reg_base + DSIM_CLKCTRL_REG);
+}
+
static void exynos_dsi_set_display_enable(struct exynos_dsi *dsi, bool enable)
{
u32 reg;
+ /*
+ * Set DSIM_TX_REQUEST_HSCLK. In case of video data, host controller
+ * will transmit the data in HS mode always.
+ */
+ if (enable)
+ exynos_dsi_enable_hs_clock(dsi, true);
+
reg = readl(dsi->reg_base + DSIM_MDRESOL_REG);
if (enable)
reg |= DSIM_MAIN_STAND_BY;
--
1.7.9.5
