On 07/28/2014 04:00 AM, Inki Dae wrote:
> This patch adds LPM transfer support for video or command data.
>
> With this patch, Exynos MIPI DSI controller can transfer command or
> video data with HS or LP mode in accordance with mode_flags set
> by LCD Panel driver.
>
> Changelog v2: Enable High Speed clock only in case of stand by request.
>
> Signed-off-by: Inki Dae <inki.dae at samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park at samsung.com>
> ---
> drivers/gpu/drm/exynos/exynos_drm_dsi.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> index 5e78d45..1bed105 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> @@ -493,8 +493,11 @@ 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);
> +
> + if (!(dsi->mode_flags & MIPI_DSI_MODE_CMD_LPM))
> + reg |= DSIM_TX_REQUEST_HSCLK;
> +
> writel(reg, dsi->reg_base + DSIM_CLKCTRL_REG);
>
> return 0;
> @@ -553,6 +556,18 @@ static void exynos_dsi_set_phy_ctrl(struct exynos_dsi
> *dsi)
> writel(reg, dsi->reg_base + DSIM_PHYTIMING2_REG);
> }
>
> +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);
> +}
> +
I have tested DSIM_TX_REQUEST_HSCLK bit on trats device(video mode HS) -
it works with and without the bit set.
So I start to suspect this bit is not just for simply enable/disable HS
clock as function name suggests, do you know what is its
exact meaning? The specs are quite succinct on it.
On the other side I have found DSIM_TX_LPDT_LP and DSIM_CMD_LPDT_LP bits
in DSIM_ESCMODE register
which seems to be related to flags you have introduced:
- DSIM_CMD_LPDT_LP - transmit commands in LP mode,
- DSIM_TX_LPDT_LP - transmit data in LP mode.
The former is already triggered by MIPI_DSI_MSG_USE_LPM flag. Why do not
you use the latter?
Regards
Andrzej
> static void exynos_dsi_disable_clock(struct exynos_dsi *dsi)
> {
> u32 reg;
> @@ -705,6 +720,9 @@ static void exynos_dsi_set_display_enable(struct
> exynos_dsi *dsi, bool enable)
> {
> u32 reg;
>
> + if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_LPM) && enable)
> + exynos_dsi_enable_hs_clock(dsi, true);
> +
> reg = readl(dsi->reg_base + DSIM_MDRESOL_REG);
> if (enable)
> reg |= DSIM_MAIN_STAND_BY;
