[PATCH] drm/bridge: dw-mipi-dsi: permit configuring the escape clock rate
Philippe CORNU
philippe.cornu at st.com
Fri Sep 11 04:29:27 EDT 2020
On 9/4/20 2:55 PM, Neil Armstrong wrote:
> The Amlogic D-PHY in the Amlogic AXG SoC Family does support a frequency
> higher than 10MHz for the TX Escape Clock, thus make the target rate
> configurable.
>
> Signed-off-by: Neil Armstrong <narmstrong at baylibre.com>
> ---
> drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 25 +++++++++++++++----
> include/drm/bridge/dw_mipi_dsi.h | 1 +
> 2 files changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index d580b2aa4ce9..31fc965c66fd 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -562,15 +562,30 @@ static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
>
> static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
> {
> + const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
> + unsigned int esc_rate; /* in MHz */
> + u32 esc_clk_division;
> + int ret;
> +
> /*
> * The maximum permitted escape clock is 20MHz and it is derived from
> - * lanebyteclk, which is running at "lane_mbps / 8". Thus we want:
> - *
> - * (lane_mbps >> 3) / esc_clk_division < 20
> + * lanebyteclk, which is running at "lane_mbps / 8".
> + */
> + if (phy_ops->get_esc_clk_rate) {
> + ret = phy_ops->get_esc_clk_rate(dsi->plat_data->priv_data,
> + &esc_rate);
> + if (ret)
> + DRM_DEBUG_DRIVER("Phy get_esc_clk_rate() failed\n");
> + } else
> + esc_rate = 20; /* Default to 20MHz */
> +
> + /*
> + * We want :
> + * (lane_mbps >> 3) / esc_clk_division < X
> * which is:
> - * (lane_mbps >> 3) / 20 > esc_clk_division
> + * (lane_mbps >> 3) / X > esc_clk_division
> */
> - u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
> + esc_clk_division = (dsi->lane_mbps >> 3) / esc_rate + 1;
>
> dsi_write(dsi, DSI_PWR_UP, RESET);
>
> diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h
> index b0e390b3288e..bda8aa7c2280 100644
> --- a/include/drm/bridge/dw_mipi_dsi.h
> +++ b/include/drm/bridge/dw_mipi_dsi.h
> @@ -36,6 +36,7 @@ struct dw_mipi_dsi_phy_ops {
> unsigned int *lane_mbps);
> int (*get_timing)(void *priv_data, unsigned int lane_mbps,
> struct dw_mipi_dsi_dphy_timing *timing);
> + int (*get_esc_clk_rate)(void *priv_data, unsigned int *esc_clk_rate);
> };
>
> struct dw_mipi_dsi_host_ops {
>
Hi Neil,
Thank you for the patch
Reviewed-by: Philippe Cornu <philippe.cornu at st.com>
Philippe :-)
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