linux-kernel - Re: [PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs w/wo dynamic update

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Date:   Tue, 23 Aug 2016 23:26:13 -0700
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     Rajendra Nayak <rnayak@...eaurora.org>
Cc:     mturquette@...libre.com, linux-clk@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        tdas@...eaurora.org
Subject: Re: [PATCH v2 10/10] clk: qcom: Fix .set_rate to handle alpha PLLs
 w/wo dynamic update

On 08/11, Rajendra Nayak wrote:
> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
> index 2184dc1..68c90f3 100644
> --- a/drivers/clk/qcom/clk-alpha-pll.c
> +++ b/drivers/clk/qcom/clk-alpha-pll.c
> @@ -113,6 +113,11 @@ static int wait_for_pll_offline(struct clk_alpha_pll *pll, u32 mask)
>  #define PLL_OFFLINE_ACK		BIT(28)
>  #define PLL_ACTIVE_FLAG		BIT(30)
>  
> +/* alpha pll with dynamic update support */
> +#define PLL_UPDATE		BIT(22)
> +#define PLL_HW_LOGIC_BYPASS	BIT(23)
> +#define PLL_ACK_LATCH		BIT(29)

These need to move next to associated registers.

> +
>  void clk_alpha_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
>  			     const struct alpha_pll_config *config)
>  {
> @@ -366,6 +402,7 @@ clk_alpha_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
>  static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  				  unsigned long prate)
>  {
> +	int enabled;

bool

>  	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
>  	const struct pll_vco *vco;
>  	u32 l, off = pll->offset;
> @@ -378,6 +415,11 @@ static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  		return -EINVAL;
>  	}
>  
> +	enabled = hw->init->ops->is_enabled(hw);

We have clk_hw_is_enabled() for this.

> +
> +	if (!(pll->flags & SUPPORTS_DYNAMIC_UPDATE) && enabled)
> +		hw->init->ops->disable(hw);

Please call the function directly instead of going through the
init structure to get the clk ops.

> +
>  	a <<= (ALPHA_REG_BITWIDTH - ALPHA_BITWIDTH);
>  
>  	regmap_write(pll->clkr.regmap, off + PLL_L_VAL, l);
> @@ -391,6 +433,12 @@ static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>  	regmap_update_bits(pll->clkr.regmap, off + PLL_USER_CTL, PLL_ALPHA_EN,
>  			   PLL_ALPHA_EN);
>  
> +	if (!(pll->flags & SUPPORTS_DYNAMIC_UPDATE) && enabled)
> +		hw->init->ops->enable(hw);
> +
> +	if (pll->flags & SUPPORTS_DYNAMIC_UPDATE)
> +		clk_alpha_pll_dynamic_update(pll);
> +

Perhaps write it as

	if (pll->flags & SUPPORTS_DYNAMIC_UPDATE)
		clk_alpha_pll_dynamic_update()
	else if (enabled)
		toggle the enable bit...

-- 
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