2023년 8월 29일 (화) 오전 12:59, Michael Tretter <m.tret...@pengutronix.de>님이 작성:
> The PLL reference clock may change at runtime. Thus, reading the clock
> rate during probe is not sufficient to correctly configure the PLL for
> the expected hs clock.
>
> Read the actual rate of the reference clock before calculating the PLL
> configuration parameters.
>
> Signed-off-by: Michael Tretter <m.tret...@pengutronix.de>
>
Reviewed-by: Inki Dae <inki....@samsung.com>
Acked-by: Inki Dae <inki....@samsung.com>
Thanks,
Inki Dae
---
> drivers/gpu/drm/bridge/samsung-dsim.c | 16 +++++++++-------
> include/drm/bridge/samsung-dsim.h | 1 +
> 2 files changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 6778f1751faa..da90c2038042 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -611,7 +611,12 @@ static unsigned long samsung_dsim_set_pll(struct
> samsung_dsim *dsi,
> u16 m;
> u32 reg;
>
> - fin = dsi->pll_clk_rate;
> + if (dsi->pll_clk)
> + fin = clk_get_rate(dsi->pll_clk);
> + else
> + fin = dsi->pll_clk_rate;
> + dev_dbg(dsi->dev, "PLL ref clock freq %lu\n", fin);
> +
> fout = samsung_dsim_pll_find_pms(dsi, fin, freq, &p, &m, &s);
> if (!fout) {
> dev_err(dsi->dev,
> @@ -1821,18 +1826,15 @@ static int samsung_dsim_parse_dt(struct
> samsung_dsim *dsi)
> u32 lane_polarities[5] = { 0 };
> struct device_node *endpoint;
> int i, nr_lanes, ret;
> - struct clk *pll_clk;
>
> ret = samsung_dsim_of_read_u32(node, "samsung,pll-clock-frequency",
> &dsi->pll_clk_rate, 1);
> /* If it doesn't exist, read it from the clock instead of failing
> */
> if (ret < 0) {
> dev_dbg(dev, "Using sclk_mipi for pll clock frequency\n");
> - pll_clk = devm_clk_get(dev, "sclk_mipi");
> - if (!IS_ERR(pll_clk))
> - dsi->pll_clk_rate = clk_get_rate(pll_clk);
> - else
> - return PTR_ERR(pll_clk);
> + dsi->pll_clk = devm_clk_get(dev, "sclk_mipi");
> + if (IS_ERR(dsi->pll_clk))
> + return PTR_ERR(dsi->pll_clk);
> }
>
> /* If it doesn't exist, use pixel clock instead of failing */
> diff --git a/include/drm/bridge/samsung-dsim.h
> b/include/drm/bridge/samsung-dsim.h
> index 05100e91ecb9..31ff88f152fb 100644
> --- a/include/drm/bridge/samsung-dsim.h
> +++ b/include/drm/bridge/samsung-dsim.h
> @@ -87,6 +87,7 @@ struct samsung_dsim {
> void __iomem *reg_base;
> struct phy *phy;
> struct clk **clks;
> + struct clk *pll_clk;
> struct regulator_bulk_data supplies[2];
> int irq;
> struct gpio_desc *te_gpio;
>
> --
> 2.39.2
>
>
