Re: [PATCH 2/3] clk: qcom: clk-alpha-pll: Add Pongo PLL

[Stephen Boyd <sboyd@kernel.org>]

Quoting Krzysztof Kozlowski (2024-11-28 07:08:00)
> @@ -360,13 +384,14 @@ static int wait_for_pll(struct clk_alpha_pll *pll, u32 mask, bool inverse,
>         u32 val;
>         int count;
>         int ret;
> -       const char *name = clk_hw_get_name(&pll->clkr.hw);
> +       const char *name;
>  
>         ret = regmap_read(pll->clkr.regmap, PLL_MODE(pll), &val);
>         if (ret)
>                 return ret;
>  
> -       for (count = 200; count > 0; count--) {
> +       /* Pongo PLLs using a 32KHz reference can take upwards of 1500us to lock. */
> +       for (count = 1500; count > 0; count--) {
>                 ret = regmap_read(pll->clkr.regmap, PLL_MODE(pll), &val);
>                 if (ret)
>                         return ret;
> @@ -378,6 +403,13 @@ static int wait_for_pll(struct clk_alpha_pll *pll, u32 mask, bool inverse,
>                 udelay(1);
>         }
>  
> +       /* Called with clocks already registered ... */
> +       if (pll->clkr.hw.core)
> +               name = clk_hw_get_name(&pll->clkr.hw);
> +       else
> +               /* or before registering, when init data is present */
> +               name = pll->clkr.hw.init->name;

This is sad. Why can't we enable the PLL from the clk prepare/enable
path? PLLs are typically calibrated during clk_prepare().

> +
>         WARN(1, "%s failed to %s!\n", name, action);
>         return -ETIMEDOUT;
>  }
> @@ -2524,6 +2556,129 @@ const struct clk_ops clk_alpha_pll_reset_lucid_evo_ops = {
>  };
>  EXPORT_SYMBOL_GPL(clk_alpha_pll_reset_lucid_evo_ops);
>  
> +static int alpha_pll_pongo_elu_enable(struct clk_hw *hw)
> +{
> +       struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
> +       struct regmap *regmap = pll->clkr.regmap;
> +       int ret;
> +
> +       /* Check if PLL is already enabled */
> +       if (trion_pll_is_enabled(pll, regmap))
> +               return 0;
> +
> +       ret = regmap_update_bits(regmap, PLL_MODE(pll), PLL_RESET_N, PLL_RESET_N);
> +       if (ret)
> +               return ret;
> +
> +       /* Set operation mode to RUN */
> +       regmap_write(regmap, PLL_OPMODE(pll), PLL_RUN);
> +
> +       ret = wait_for_pll_enable_lock(pll);
> +       if (ret)
> +               return ret;
> +
> +       /* Enable the global PLL outputs */
> +       ret = regmap_update_bits(regmap, PLL_MODE(pll), PLL_OUTCTRL, PLL_OUTCTRL);
> +       if (ret)
> +               return ret;
> +
> +       /* Ensure that the write above goes through before returning. */
> +       mb();
> +
> +       return ret;
> +}
> +
> +static void alpha_pll_pongo_elu_disable(struct clk_hw *hw)
> +{
> +       struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
> +       struct regmap *regmap = pll->clkr.regmap;
> +       int ret;
> +
> +       /* Disable the global PLL output */
> +       ret = regmap_update_bits(regmap, PLL_MODE(pll), PLL_OUTCTRL, 0);
> +       if (ret)
> +               return;
> +
> +       /* Place the PLL mode in STANDBY */
> +       regmap_write(regmap, PLL_OPMODE(pll), PLL_STANDBY);
> +}
> +
> +static unsigned long alpha_pll_pongo_elu_recalc_rate(struct clk_hw *hw,
> +                                                    unsigned long parent_rate)
> +{
> +       struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
> +       struct regmap *regmap = pll->clkr.regmap;
> +       u32 l;
> +
> +       if (regmap_read(regmap, PLL_L_VAL(pll), &l))
> +               return 0;
> +
> +       l &= PONGO_PLL_L_VAL_MASK;
> +
> +       return alpha_pll_calc_rate(parent_rate, l, 0, pll_alpha_width(pll));
> +}
> +
> +const struct clk_ops clk_alpha_pll_pongo_elu_ops = {
> +       .enable = alpha_pll_pongo_elu_enable,
> +       .disable = alpha_pll_pongo_elu_disable,
> +       .recalc_rate = alpha_pll_pongo_elu_recalc_rate,
> +};
> +EXPORT_SYMBOL(clk_alpha_pll_pongo_elu_ops);

GPL please.

> +
> +void clk_pongo_elu_pll_configure(struct clk_alpha_pll *pll,
> +                                struct regmap *regmap,
> +                                const struct alpha_pll_config *config)
> +{
> +       u32 val;
> +
> +       regmap_update_bits(regmap, PLL_USER_CTL(pll), PONGO_PLL_OUT_MASK,
> +                          PONGO_PLL_OUT_MASK);
> +
> +       if (trion_pll_is_enabled(pll, regmap))
> +               return;
> +
> +       if (regmap_read(regmap, PLL_L_VAL(pll), &val))
> +               return;
> +       val &= PONGO_PLL_L_VAL_MASK;
> +       if (val)
> +               return;
> +
> +       clk_alpha_pll_write_config(regmap, PLL_L_VAL(pll), config->l);
> +       clk_alpha_pll_write_config(regmap, PLL_ALPHA_VAL(pll), config->alpha);
> +       clk_alpha_pll_write_config(regmap, PLL_CONFIG_CTL(pll), config->config_ctl_val);
> +       clk_alpha_pll_write_config(regmap, PLL_CONFIG_CTL_U(pll), config->config_ctl_hi_val);
> +       clk_alpha_pll_write_config(regmap, PLL_CONFIG_CTL_U1(pll), config->config_ctl_hi1_val);
> +       clk_alpha_pll_write_config(regmap, PLL_CONFIG_CTL_U2(pll), config->config_ctl_hi2_val);
> +       clk_alpha_pll_write_config(regmap, PLL_USER_CTL(pll),
> +                                  config->user_ctl_val | PONGO_PLL_OUT_MASK);
> +       clk_alpha_pll_write_config(regmap, PLL_USER_CTL_U(pll), config->user_ctl_hi_val);
> +       clk_alpha_pll_write_config(regmap, PLL_TEST_CTL(pll), config->test_ctl_val);
> +       clk_alpha_pll_write_config(regmap, PLL_TEST_CTL_U(pll), config->test_ctl_hi_val);
> +       clk_alpha_pll_write_config(regmap, PLL_TEST_CTL_U1(pll), config->test_ctl_hi1_val);
> +       clk_alpha_pll_write_config(regmap, PLL_TEST_CTL_U2(pll), config->test_ctl_hi2_val);
> +       clk_alpha_pll_write_config(regmap, PLL_TEST_CTL_U3(pll), config->test_ctl_hi3_val);
> +
> +       /* Disable PLL output */
> +       regmap_update_bits(regmap, PLL_MODE(pll), PLL_OUTCTRL, 0);
> +
> +       /* Enable PLL intially to one-time calibrate against XO. */
> +       regmap_write(regmap, PLL_OPMODE(pll), PLL_RUN);
> +       regmap_update_bits(regmap, PLL_MODE(pll), PLL_RESET_N, PLL_RESET_N);
> +       regmap_update_bits(regmap, PLL_MODE(pll), PONGO_XO_PRESENT, PONGO_XO_PRESENT);
> +
> +       /* Set regmap for wait_for_pll() */
> +       pll->clkr.regmap = regmap;
> +       if (wait_for_pll_enable_lock(pll))
> +               return;
> +
> +       /* Disable PLL after one-time calibration. */
> +       regmap_write(regmap, PLL_OPMODE(pll), PLL_STANDBY);
> +
> +       /* Select internally generated clock. */
> +       regmap_update_bits(regmap, PLL_MODE(pll), PONGO_CLOCK_SELECT, PONGO_CLOCK_SELECT);
> +}
> +EXPORT_SYMBOL(clk_pongo_elu_pll_configure);

GPL please.