Re: [PATCH 3/4] drm/mediatek: fix the wrong pixel clock when resolution is 4K

From: Bibby Hsieh
Date: Mon Jul 25 2016 - 02:24:19 EST


Hi, CK,

Thanks for your comments.

On Wed, 2016-07-20 at 15:57 +0800, CK Hu wrote:
> Hi, Bibby:
>
> Some comments inline.
>
> On Wed, 2016-07-20 at 12:03 +0800, Bibby Hsieh wrote:
> > From: Junzhi Zhao <junzhi.zhao@xxxxxxxxxxxx>
> >
> > Pixel clock should be 297MHz when resolution is 4K.
> >
> > Signed-off-by: Junzhi Zhao <junzhi.zhao@xxxxxxxxxxxx>
> > Signed-off-by: Bibby Hsieh <bibby.hsieh@xxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/mediatek/mtk_dpi.c | 184 +++++++++++++++++++++++++-----------
> > 1 file changed, 131 insertions(+), 53 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index d05ca79..c0f04d2 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -60,14 +60,35 @@ enum mtk_dpi_out_color_format {
> > MTK_DPI_COLOR_FORMAT_YCBCR_422_FULL
> > };
> >
> > +enum mtk_dpi_clk_id {
> > + MTK_DPI_CLK_DPI_ENGINE,
> > + MTK_DPI_CLK_DPI_PIXEL,
> > + MTK_DPI_CLK_TVD_PLL,
> > + MTK_DPI_CLK_TVDPLL_MUX,
> > + MTK_DPI_CLK_TVDPLL_D2,
> > + MTK_DPI_CLK_TVDPLL_D4,
> > + MTK_DPI_CLK_TVDPLL_D8,
> > + MTK_DPI_CLK_TVDPLL_D16,
> > + MTK_DPI_CLK_COUNT,
> > +};
> > +
> > +static const char * const mtk_dpi_clk_names[MTK_DPI_CLK_COUNT] = {
> > + [MTK_DPI_CLK_DPI_ENGINE] = "engine",
> > + [MTK_DPI_CLK_DPI_PIXEL] = "pixel",
> > + [MTK_DPI_CLK_TVD_PLL] = "pll",
> > + [MTK_DPI_CLK_TVDPLL_MUX] = "tvdpll_mux",
> > + [MTK_DPI_CLK_TVDPLL_D2] = "tvdpll_d2",
> > + [MTK_DPI_CLK_TVDPLL_D4] = "tvdpll_d4",
> > + [MTK_DPI_CLK_TVDPLL_D8] = "tvdpll_d8",
> > + [MTK_DPI_CLK_TVDPLL_D16] = "tvdpll_d16",
> > +};
> > +
> > struct mtk_dpi {
> > struct mtk_ddp_comp ddp_comp;
> > struct drm_encoder encoder;
> > void __iomem *regs;
> > struct device *dev;
> > - struct clk *engine_clk;
> > - struct clk *pixel_clk;
> > - struct clk *tvd_clk;
> > + struct clk *clk[MTK_DPI_CLK_COUNT];
> > int irq;
> > struct drm_display_mode mode;
> > enum mtk_dpi_out_color_format color_format;
> > @@ -76,6 +97,7 @@ struct mtk_dpi {
> > enum mtk_dpi_out_channel_swap channel_swap;
> > bool power_sta;
> > u8 power_ctl;
> > + void *data;
> > };
> >
> > static inline struct mtk_dpi *mtk_dpi_from_encoder(struct drm_encoder *e)
> > @@ -114,6 +136,11 @@ struct mtk_dpi_yc_limit {
> > u16 c_bottom;
> > };
> >
> > +struct mtk_dpi_conf {
> > + int (*parse_clk_from_dt)(struct mtk_dpi *dpi, struct device_node *np);
> > + int (*clk_config)(struct mtk_dpi *dpi, struct drm_display_mode *mode);
> > +};
> > +
> > static void mtk_dpi_mask(struct mtk_dpi *dpi, u32 offset, u32 val, u32 mask)
> > {
> > u32 tmp = readl(dpi->regs + offset) & ~mask;
> > @@ -377,8 +404,8 @@ static void mtk_dpi_power_off(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl)
> > return;
> >
> > mtk_dpi_disable(dpi);
> > - clk_disable_unprepare(dpi->pixel_clk);
> > - clk_disable_unprepare(dpi->engine_clk);
> > + clk_disable_unprepare(dpi->clk[MTK_DPI_CLK_DPI_PIXEL]);
> > + clk_disable_unprepare(dpi->clk[MTK_DPI_CLK_DPI_ENGINE]);
> > dpi->power_sta = false;
> > }
> >
> > @@ -395,13 +422,13 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl)
> > if (dpi->power_sta)
> > return 0;
> >
> > - ret = clk_prepare_enable(dpi->engine_clk);
> > + ret = clk_prepare_enable(dpi->clk[MTK_DPI_CLK_DPI_ENGINE]);
> > if (ret) {
> > dev_err(dpi->dev, "Failed to enable engine clock: %d\n", ret);
> > goto err_eng;
> > }
> >
> > - ret = clk_prepare_enable(dpi->pixel_clk);
> > + ret = clk_prepare_enable(dpi->clk[MTK_DPI_CLK_DPI_PIXEL]);
> > if (ret) {
> > dev_err(dpi->dev, "Failed to enable pixel clock: %d\n", ret);
> > goto err_pixel;
> > @@ -412,7 +439,7 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl)
> > return 0;
> >
> > err_pixel:
> > - clk_disable_unprepare(dpi->engine_clk);
> > + clk_disable_unprepare(dpi->clk[MTK_DPI_CLK_DPI_ENGINE]);
> > err_eng:
> > dpi->power_ctl &= ~pctl;
> > return ret;
> > @@ -428,34 +455,16 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
> > struct mtk_dpi_sync_param vsync_leven = { 0 };
> > struct mtk_dpi_sync_param vsync_rodd = { 0 };
> > struct mtk_dpi_sync_param vsync_reven = { 0 };
> > - unsigned long pix_rate;
> > - unsigned long pll_rate;
> > - unsigned int factor;
> > + struct mtk_dpi_conf *conf;
> > + int ret;
> >
> > if (!dpi) {
> > dev_err(dpi->dev, "invalid argument\n");
> > return -EINVAL;
> > }
> >
> > - pix_rate = 1000UL * mode->clock;
> > - if (mode->clock <= 74000)
> > - factor = 8 * 3;
> > - else
> > - factor = 4 * 3;
> > - pll_rate = pix_rate * factor;
> > -
> > - dev_dbg(dpi->dev, "Want PLL %lu Hz, pixel clock %lu Hz\n",
> > - pll_rate, pix_rate);
> > -
> > - clk_set_rate(dpi->tvd_clk, pll_rate);
> > - pll_rate = clk_get_rate(dpi->tvd_clk);
> > -
> > - pix_rate = pll_rate / factor;
> > - clk_set_rate(dpi->pixel_clk, pix_rate);
> > - pix_rate = clk_get_rate(dpi->pixel_clk);
> > -
> > - dev_dbg(dpi->dev, "Got PLL %lu Hz, pixel clock %lu Hz\n",
> > - pll_rate, pix_rate);
> > + conf = (struct mtk_dpi_conf *)dpi->data;
> > + ret = conf->clk_config(dpi, mode);
>
> Nothing to do with return error?
>
Ok, I will fix that.
> >
> > limit.c_bottom = 0x0010;
> > limit.c_top = 0x0FE0;
> > @@ -656,20 +665,109 @@ static const struct component_ops mtk_dpi_component_ops = {
> > .unbind = mtk_dpi_unbind,
> > };
> >
> > +static int mt8173_parse_clk_from_dt(struct mtk_dpi *dpi, struct device_node *np)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(mtk_dpi_clk_names); i++) {
> > + dpi->clk[i] = of_clk_get_by_name(np,
> > + mtk_dpi_clk_names[i]);
> > + if (IS_ERR(dpi->clk[i]))
> > + return PTR_ERR(dpi->clk[i]);
> > + }
> > + return 0;
> > +}
>
> I think parsing device tree is a pure SW behavior. Would this vary for
> different MTK soc?
>
Yes
> > +
> > +static int mt8173_clk_config(struct mtk_dpi *dpi, struct drm_display_mode *mode)
> > +{
> > + unsigned long pix_rate;
> > + unsigned long pll_rate;
> > + unsigned int factor;
> > + struct clk *parent;
> > + int ret;
> > +
> > + if (mode->clock <= 27000) {
> > + factor = 16 * 3;
> > + parent = dpi->clk[MTK_DPI_CLK_TVDPLL_D16];
> > + } else if (mode->clock <= 74250) {
> > + factor = 8 * 3;
> > + parent = dpi->clk[MTK_DPI_CLK_TVDPLL_D8];
> > + } else if (mode->clock <= 167000) {
> > + factor = 4 * 3;
> > + parent = dpi->clk[MTK_DPI_CLK_TVDPLL_D4];
> > + } else {
> > + factor = 2 * 3;
> > + parent = dpi->clk[MTK_DPI_CLK_TVDPLL_D2];
> > + }
> > +
> > + pix_rate = 1000UL * mode->clock;
> > + pll_rate = pix_rate * factor;
> > +
> > + dev_dbg(dpi->dev, "Want PLL %lu Hz, pixel clock %lu Hz\n",
> > + pll_rate, pix_rate);
> > +
> > + ret = clk_prepare_enable(dpi->clk[MTK_DPI_CLK_TVDPLL_MUX]);
> > + if (ret) {
> > + dev_err(dpi->dev, "tvdpll_mux enable fail\n");
> > + return ret;
> > + }
> > +
> > + ret = clk_set_parent(dpi->clk[MTK_DPI_CLK_TVDPLL_MUX], parent);
> > + if (ret) {
> > + dev_err(dpi->dev, "tvdpll_mux set parent fail\n");
>
> Before return, you may undo something.
I think we can remove this function at the new version, because we make
some changes here according Philipp' comments.
>
> > + return ret;
> > + }
> > + clk_disable_unprepare(dpi->clk[MTK_DPI_CLK_TVDPLL_MUX]);
> > +
> > + ret = clk_set_rate(dpi->clk[MTK_DPI_CLK_TVD_PLL], pll_rate);
> > + if (ret) {
> > + dev_err(dpi->dev, "dpi pll_rate set rate fail\n");
> > + return ret;
> > + }
> > + pll_rate = clk_get_rate(dpi->clk[MTK_DPI_CLK_TVD_PLL]);
> > + pix_rate = clk_get_rate(dpi->clk[MTK_DPI_CLK_DPI_PIXEL]);
> > +
> > + dev_dbg(dpi->dev, "Got PLL %lu Hz, pixel clock %lu Hz\n",
> > + pll_rate, pix_rate);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct mtk_dpi_conf mt8173_conf = {
> > + .parse_clk_from_dt = mt8173_parse_clk_from_dt,
> > + .clk_config = mt8173_clk_config,
> > +};
> > +
> > +static const struct of_device_id mtk_dpi_of_ids[] = {
> > + { .compatible = "mediatek,mt8173-dpi",
> > + .data = &mt8173_conf,
> > + },
> > + {}
> > +};
> > +
> > static int mtk_dpi_probe(struct platform_device *pdev)
> > {
> > struct device *dev = &pdev->dev;
> > struct mtk_dpi *dpi;
> > struct resource *mem;
> > + struct device_node *np = dev->of_node;
> > struct device_node *ep, *bridge_node = NULL;
> > int comp_id;
> > + const struct of_device_id *match;
> > + struct mtk_dpi_conf *conf;
> > int ret;
> >
> > + match = of_match_node(mtk_dpi_of_ids, dev->of_node);
> > + if (!match)
> > + return -ENODEV;
> > +
> > dpi = devm_kzalloc(dev, sizeof(*dpi), GFP_KERNEL);
> > if (!dpi)
> > return -ENOMEM;
> >
> > dpi->dev = dev;
> > + dpi->data = (void *)match->data;
> > + conf = (struct mtk_dpi_conf *)match->data;
> >
> > mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > dpi->regs = devm_ioremap_resource(dev, mem);
> > @@ -679,24 +777,9 @@ static int mtk_dpi_probe(struct platform_device *pdev)
> > return ret;
> > }
> >
> > - dpi->engine_clk = devm_clk_get(dev, "engine");
> > - if (IS_ERR(dpi->engine_clk)) {
> > - ret = PTR_ERR(dpi->engine_clk);
> > - dev_err(dev, "Failed to get engine clock: %d\n", ret);
> > - return ret;
> > - }
> > -
> > - dpi->pixel_clk = devm_clk_get(dev, "pixel");
> > - if (IS_ERR(dpi->pixel_clk)) {
> > - ret = PTR_ERR(dpi->pixel_clk);
> > - dev_err(dev, "Failed to get pixel clock: %d\n", ret);
> > - return ret;
> > - }
> > -
> > - dpi->tvd_clk = devm_clk_get(dev, "pll");
> > - if (IS_ERR(dpi->tvd_clk)) {
> > - ret = PTR_ERR(dpi->tvd_clk);
> > - dev_err(dev, "Failed to get tvdpll clock: %d\n", ret);
> > + ret = conf->parse_clk_from_dt(dpi, np);
> > + if (ret) {
> > + dev_err(dev, "parse tvd div clk failed!");
> > return ret;
> > }
> >
> > @@ -754,11 +837,6 @@ static int mtk_dpi_remove(struct platform_device *pdev)
> > return 0;
> > }
> >
> > -static const struct of_device_id mtk_dpi_of_ids[] = {
> > - { .compatible = "mediatek,mt8173-dpi", },
> > - {}
> > -};
> > -
> > struct platform_driver mtk_dpi_driver = {
> > .probe = mtk_dpi_probe,
> > .remove = mtk_dpi_remove,
>
> Regards,
> CK
>