Re: [PATCH V4] clk: qcom: clk-alpha-pll: Add support for Stromer PLLs

[Stephen Boyd <sboyd@kernel.org>]

Quoting Kathiravan T (2022-12-27 05:25:07)
> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
> index f9e4cfd7261c..29866100df08 100644
> --- a/drivers/clk/qcom/clk-alpha-pll.c
> +++ b/drivers/clk/qcom/clk-alpha-pll.c
> @@ -204,9 +204,24 @@ const u8 clk_alpha_pll_regs[][PLL_OFF_MAX_REGS] = {
>                 [PLL_OFF_CONFIG_CTL] = 0x1C,
>                 [PLL_OFF_STATUS] = 0x20,
>         },
> +       [CLK_ALPHA_PLL_TYPE_STROMER] = {
> +               [PLL_OFF_L_VAL] = 0x08,
> +               [PLL_OFF_ALPHA_VAL] = 0x10,
> +               [PLL_OFF_ALPHA_VAL_U] = 0x14,
> +               [PLL_OFF_USER_CTL] = 0x18,
> +               [PLL_OFF_USER_CTL_U] = 0x1c,
> +               [PLL_OFF_CONFIG_CTL] = 0x20,
> +               [PLL_OFF_CONFIG_CTL_U] = 0xff,
> +               [PLL_OFF_TEST_CTL] = 0x30,
> +               [PLL_OFF_TEST_CTL_U] = 0x34,
> +               [PLL_OFF_STATUS] = 0x28,
> +       },
>  };
>  EXPORT_SYMBOL_GPL(clk_alpha_pll_regs);
>  
> +static unsigned long
> +alpha_pll_round_rate(unsigned long rate, unsigned long prate, u32 *l, u64 *a,

Is this necessary?

> +                    u32 alpha_width);
>  /*
>   * Even though 40 bits are present, use only 32 for ease of calculation.
>   */
> @@ -215,6 +230,8 @@ EXPORT_SYMBOL_GPL(clk_alpha_pll_regs);
>  #define ALPHA_BITWIDTH         32U
>  #define ALPHA_SHIFT(w)         min(w, ALPHA_BITWIDTH)
>  
> +#define        ALPHA_PLL_STATUS_REG_SHIFT      8
> +
>  #define PLL_HUAYRA_M_WIDTH             8
>  #define PLL_HUAYRA_M_SHIFT             8
>  #define PLL_HUAYRA_M_MASK              0xff
> @@ -325,7 +342,7 @@ static void clk_alpha_pll_write_config(struct regmap *regmap, unsigned int reg,
>  void clk_alpha_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
>                              const struct alpha_pll_config *config)
>  {
> -       u32 val, mask;
> +       u32 val, val_u, mask, mask_u;
>  
>         regmap_write(regmap, PLL_L_VAL(pll), config->l);
>         regmap_write(regmap, PLL_ALPHA_VAL(pll), config->alpha);
> @@ -355,14 +372,85 @@ void clk_alpha_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
>         mask |= config->pre_div_mask;
>         mask |= config->post_div_mask;
>         mask |= config->vco_mask;
> +       mask |= config->alpha_en_mask;
> +       mask |= config->alpha_mode_mask;
>  
>         regmap_update_bits(regmap, PLL_USER_CTL(pll), mask, val);
>  
> +       /* Stromer APSS PLL does not enable LOCK_DET by default, so enable it */

Instead of adding these things to clk_alpha_pll_configure() can you
introduce another api like clk_stromer_pll_configure() that sets these
values unconditionally? That way we don't have to think or worry about
the other alpha PLLs (of which there are many).

> +       val_u = config->status_reg_val << ALPHA_PLL_STATUS_REG_SHIFT;
> +       val_u |= config->lock_det;
> +
> +       mask_u = config->status_reg_mask;
> +       mask_u |= config->lock_det;
> +
> +       if (val_u)
> +               regmap_update_bits(regmap, PLL_USER_CTL_U(pll), mask_u, val_u);
> +
> +       if (config->test_ctl_val)
> +               regmap_write(regmap, PLL_TEST_CTL(pll), config->test_ctl_val);
> +
> +       if (config->test_ctl_hi_val)
> +               regmap_write(regmap, PLL_TEST_CTL_U(pll), config->test_ctl_hi_val);
> +
>         if (pll->flags & SUPPORTS_FSM_MODE)
>                 qcom_pll_set_fsm_mode(regmap, PLL_MODE(pll), 6, 0);
>  }
>  EXPORT_SYMBOL_GPL(clk_alpha_pll_configure);
>  
> +static int clk_alpha_pll_stromer_determine_rate(struct clk_hw *hw,
> +                                               struct clk_rate_request *req)
> +{
> +       u32 l;
> +       u64 a;
> +
> +       req->rate = alpha_pll_round_rate(req->rate, req->best_parent_rate,
> +                                        &l, &a, ALPHA_REG_BITWIDTH);
> +
> +       return 0;
> +}
> +
> +static int clk_alpha_pll_stromer_set_rate(struct clk_hw *hw, unsigned long rate,
> +                                         unsigned long prate)
> +{
> +       struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
> +       u32 l;
> +       int ret;
> +       u64 a;
> +
> +       rate = alpha_pll_round_rate(rate, prate, &l, &a, ALPHA_REG_BITWIDTH);
> +
> +       regmap_write(pll->clkr.regmap, PLL_L_VAL(pll), l);
> +       regmap_write(pll->clkr.regmap, PLL_ALPHA_VAL(pll), a);
> +       regmap_write(pll->clkr.regmap, PLL_ALPHA_VAL_U(pll),
> +                    a >> ALPHA_BITWIDTH);
> +
> +       regmap_update_bits(pll->clkr.regmap, PLL_USER_CTL(pll),
> +                          PLL_ALPHA_EN, PLL_ALPHA_EN);
> +
> +       if (!clk_hw_is_enabled(hw))
> +               return 0;
> +
> +       /*
> +        * Stromer PLL supports Dynamic programming.
> +        * It allows the PLL frequency to be changed on-the-fly without first
> +        * execution of a shutdown procedure followed by a bring up procedure.
> +        */
> +

Drop newline above please.

> +       regmap_update_bits(pll->clkr.regmap, PLL_MODE(pll), PLL_UPDATE,
> +                          PLL_UPDATE);
> +
> +       ret = wait_for_pll_update(pll);
> +       if (ret)
> +               return ret;
> +
> +       ret = wait_for_pll_enable_lock(pll);
> +       if (ret)
> +               return ret;
> +
> +       return 0;

Just use

	return wait_for_pll_enable_lock(pll);

> +}
> +
>  static int clk_alpha_pll_hwfsm_enable(struct clk_hw *hw)
>  {
>         int ret;
> @@ -1013,6 +1101,16 @@ const struct clk_ops clk_alpha_pll_hwfsm_ops = {
>  };
>  EXPORT_SYMBOL_GPL(clk_alpha_pll_hwfsm_ops);
>  
> +const struct clk_ops clk_alpha_pll_stromer_ops = {
> +       .enable = clk_alpha_pll_enable,
> +       .disable = clk_alpha_pll_disable,
> +       .is_enabled = clk_alpha_pll_is_enabled,
> +       .recalc_rate = clk_alpha_pll_recalc_rate,
> +       .determine_rate = clk_alpha_pll_stromer_determine_rate,
> +       .set_rate = clk_alpha_pll_stromer_set_rate,
> +};
> +EXPORT_SYMBOL_GPL(clk_alpha_pll_stromer_ops);
> +
>  const struct clk_ops clk_alpha_pll_fixed_trion_ops = {
>         .enable = clk_trion_pll_enable,
>         .disable = clk_trion_pll_disable,
> diff --git a/drivers/clk/qcom/clk-alpha-pll.h b/drivers/clk/qcom/clk-alpha-pll.h
> index 2bdae362c827..1d122919e275 100644
> --- a/drivers/clk/qcom/clk-alpha-pll.h
> +++ b/drivers/clk/qcom/clk-alpha-pll.h
> @@ -1,5 +1,5 @@
>  /* SPDX-License-Identifier: GPL-2.0 */
> -/* Copyright (c) 2015, 2018, The Linux Foundation. All rights reserved. */
> +/* Copyright (c) 2015, 2018, 2021 The Linux Foundation. All rights reserved. */

2022 or 2023?