Hi, Jitao:
Jitao Shi <jitao.shi@xxxxxxxxxxxx> 於 2021年4月20日 週二 下午9:26寫道：
>
> Reset dsi HW to default when power on. Prevent the setting differet
> between bootloader and kernel.
>
> Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/mediatek/mtk_dsi.c | 36 +++++++++++++++++++++++++++++-
> 1 file changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 455fe582c6b5..113438ddd4cc 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -7,10 +7,12 @@
> #include <linux/component.h>
> #include <linux/iopoll.h>
> #include <linux/irq.h>
> +#include <linux/mfd/syscon.h>
> #include <linux/of.h>
> #include <linux/of_platform.h>
> #include <linux/phy/phy.h>
> #include <linux/platform_device.h>
> +#include <linux/regmap.h>
>
> #include <video/mipi_display.h>
> #include <video/videomode.h>
> @@ -143,6 +145,8 @@
> #define DATA_0 (0xff << 16)
> #define DATA_1 (0xff << 24)
>
> +#define MMSYS_SW_RST_DSI_B BIT(25)
> +
> #define NS_TO_CYCLE(n, c) ((n) / (c) + (((n) % (c)) ? 1 : 0))
>
> #define MTK_DSI_HOST_IS_READ(type) \
> @@ -186,7 +190,8 @@ struct mtk_dsi {
> struct drm_bridge *next_bridge;
> struct drm_connector *connector;
> struct phy *phy;
> -
> + struct regmap *mmsys_sw_rst_b;
> + u32 sw_rst_b;
> void __iomem *regs;
>
> struct clk *engine_clk;
> @@ -272,6 +277,16 @@ static void mtk_dsi_disable(struct mtk_dsi *dsi)
> mtk_dsi_mask(dsi, DSI_CON_CTRL, DSI_EN, 0);
> }
>
> +static void mtk_dsi_reset_all(struct mtk_dsi *dsi)
> +{
> + regmap_update_bits(dsi->mmsys_sw_rst_b, dsi->sw_rst_b,
> + MMSYS_SW_RST_DSI_B, 0);
> + usleep_range(1000, 1100);
> +
> + regmap_update_bits(dsi->mmsys_sw_rst_b, dsi->sw_rst_b,
> + MMSYS_SW_RST_DSI_B, MMSYS_SW_RST_DSI_B);
> +}
> +
> static void mtk_dsi_reset_engine(struct mtk_dsi *dsi)
> {
> mtk_dsi_mask(dsi, DSI_CON_CTRL, DSI_RESET, DSI_RESET);
> @@ -985,6 +1000,8 @@ static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
>
> ret = mtk_dsi_encoder_init(drm, dsi);
>
> + mtk_dsi_reset_all(dsi);
> +
> return ret;
> }
>
> @@ -1007,6 +1024,7 @@ static int mtk_dsi_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> struct drm_panel *panel;
> struct resource *regs;
> + struct regmap *regmap;
> int irq_num;
> int ret;
>
> @@ -1022,6 +1040,22 @@ static int mtk_dsi_probe(struct platform_device *pdev)
> return ret;
> }
>
> + regmap = syscon_regmap_lookup_by_phandle(dev->of_node,
> + "mediatek,syscon-dsi");
> + ret = of_property_read_u32_index(dev->of_node, "mediatek,syscon-dsi", 1,
> + &dsi->sw_rst_b);
> +
> + if (IS_ERR(regmap))
> + ret = PTR_ERR(regmap);
> +
> + if (ret) {
> + ret = PTR_ERR(regmap);
> + dev_err(dev, "Failed to get mmsys registers: %d\n", ret);
> + return ret;
> + }
> +
> + dsi->mmsys_sw_rst_b = regmap;
> +
It looks like that mtk-mmsys is the reset controller and mtk-dsi is
reset consumer. Please refer to [1], [2] to implement.
[1] https://www.kernel.org/doc/html/latest/driver-api/reset.html
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/reset/reset.txt?h=v5.12-rc8
Regards,
Chun-Kuang.
> ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> &panel, &dsi->next_bridge);
> if (ret)
> --
> 2.25.1
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