linux-kernel - Re: [PATCH v2 2/6] clk: ingenic: Make PLL clock enable_bit and stable

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Date:   Thu, 27 Oct 2022 13:39:17 +0100
From:   Paul Cercueil <paul@...pouillou.net>
To:     Aidan MacDonald <aidanmacdonald.0x0@...il.com>
Cc:     mturquette@...libre.com, sboyd@...nel.org, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, zhouyu@...yeetech.com,
        linux-mips@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/6] clk: ingenic: Make PLL clock enable_bit and
 stable_bit optional

Hi Aidan,

Le mer. 26 oct. 2022 à 20:43:41 +0100, Aidan MacDonald 
<aidanmacdonald.0x0@...il.com> a écrit :
> When the enable bit is undefined, the clock is assumed to be always
> on and enable/disable is a no-op. When the stable bit is undefined,
> the PLL stable check is a no-op.
> 
> Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@...il.com>

Reviewed-by: Paul Cercueil <paul@...pouillou.net>

Cheers,
-Paul

> ---
>  drivers/clk/ingenic/cgu.c | 14 +++++++++++++-
>  drivers/clk/ingenic/cgu.h | 10 ++++++----
>  2 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/clk/ingenic/cgu.c b/drivers/clk/ingenic/cgu.c
> index 3481129114b1..aea01b6b2764 100644
> --- a/drivers/clk/ingenic/cgu.c
> +++ b/drivers/clk/ingenic/cgu.c
> @@ -189,6 +189,9 @@ static inline int ingenic_pll_check_stable(struct 
> ingenic_cgu *cgu,
>  {
>  	u32 ctl;
> 
> +	if (pll_info->stable_bit < 0)
> +		return 0;
> +
>  	return readl_poll_timeout(cgu->base + pll_info->reg, ctl,
>  				  ctl & BIT(pll_info->stable_bit),
>  				  0, 100 * USEC_PER_MSEC);
> @@ -230,7 +233,7 @@ ingenic_pll_set_rate(struct clk_hw *hw, unsigned 
> long req_rate,
>  	writel(ctl, cgu->base + pll_info->reg);
> 
>  	/* If the PLL is enabled, verify that it's stable */
> -	if (ctl & BIT(pll_info->enable_bit))
> +	if (pll_info->enable_bit >= 0 && (ctl & BIT(pll_info->enable_bit)))
>  		ret = ingenic_pll_check_stable(cgu, pll_info);
> 
>  	spin_unlock_irqrestore(&cgu->lock, flags);
> @@ -248,6 +251,9 @@ static int ingenic_pll_enable(struct clk_hw *hw)
>  	int ret;
>  	u32 ctl;
> 
> +	if (pll_info->enable_bit < 0)
> +		return 0;
> +
>  	spin_lock_irqsave(&cgu->lock, flags);
>  	if (pll_info->bypass_bit >= 0) {
>  		ctl = readl(cgu->base + pll_info->bypass_reg);
> @@ -278,6 +284,9 @@ static void ingenic_pll_disable(struct clk_hw *hw)
>  	unsigned long flags;
>  	u32 ctl;
> 
> +	if (pll_info->enable_bit < 0)
> +		return;
> +
>  	spin_lock_irqsave(&cgu->lock, flags);
>  	ctl = readl(cgu->base + pll_info->reg);
> 
> @@ -295,6 +304,9 @@ static int ingenic_pll_is_enabled(struct clk_hw 
> *hw)
>  	const struct ingenic_cgu_pll_info *pll_info = &clk_info->pll;
>  	u32 ctl;
> 
> +	if (pll_info->enable_bit < 0)
> +		return true;
> +
>  	ctl = readl(cgu->base + pll_info->reg);
> 
>  	return !!(ctl & BIT(pll_info->enable_bit));
> diff --git a/drivers/clk/ingenic/cgu.h b/drivers/clk/ingenic/cgu.h
> index 567142b584bb..a5e44ca7f969 100644
> --- a/drivers/clk/ingenic/cgu.h
> +++ b/drivers/clk/ingenic/cgu.h
> @@ -42,8 +42,10 @@
>   * @bypass_reg: the offset of the bypass control register within the 
> CGU
>   * @bypass_bit: the index of the bypass bit in the PLL control 
> register, or
>   *              -1 if there is no bypass bit
> - * @enable_bit: the index of the enable bit in the PLL control 
> register
> - * @stable_bit: the index of the stable bit in the PLL control 
> register
> + * @enable_bit: the index of the enable bit in the PLL control 
> register, or
> + *		-1 if there is no enable bit (ie, the PLL is always on)
> + * @stable_bit: the index of the stable bit in the PLL control 
> register, or
> + *		-1 if there is no stable bit
>   */
>  struct ingenic_cgu_pll_info {
>  	unsigned reg;
> @@ -54,8 +56,8 @@ struct ingenic_cgu_pll_info {
>  	u8 od_shift, od_bits, od_max;
>  	unsigned bypass_reg;
>  	s8 bypass_bit;
> -	u8 enable_bit;
> -	u8 stable_bit;
> +	s8 enable_bit;
> +	s8 stable_bit;
>  	void (*calc_m_n_od)(const struct ingenic_cgu_pll_info *pll_info,
>  			    unsigned long rate, unsigned long parent_rate,
>  			    unsigned int *m, unsigned int *n, unsigned int *od);
> --
> 2.38.1
>