linux-kernel - Re: [PATCH v8 04/21] clk: tegra: pllout: Save and restore pllout context

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Date:   Sun, 11 Aug 2019 21:04:24 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Sowjanya Komatineni <skomatineni@...dia.com>,
        thierry.reding@...il.com, jonathanh@...dia.com, tglx@...utronix.de,
        jason@...edaemon.net, marc.zyngier@....com,
        linus.walleij@...aro.org, stefan@...er.ch, mark.rutland@....com
Cc:     pdeschrijver@...dia.com, pgaikwad@...dia.com, sboyd@...nel.org,
        linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
        jckuo@...dia.com, josephl@...dia.com, talho@...dia.com,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
        mperttunen@...dia.com, spatra@...dia.com, robh+dt@...nel.org,
        devicetree@...r.kernel.org, rjw@...ysocki.net,
        viresh.kumar@...aro.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v8 04/21] clk: tegra: pllout: Save and restore pllout
 context

09.08.2019 2:46, Sowjanya Komatineni пишет:
> This patch implements save and restore of pllout context.
> 
> During system suspend, core power goes off and looses the settings
> of the Tegra CAR controller registers.
> 
> So during suspend entry the state of pllout is saved and on resume
> it is restored back to have pllout in same state as before suspend.
> 
> pllout rate is saved and restore in clock divider so it will be at
> same rate as before suspend when pllout state is restored.
> 
> Acked-by: Thierry Reding <treding@...dia.com>
> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
> ---
>  drivers/clk/tegra/clk-pll-out.c  | 9 +++++++++
>  drivers/clk/tegra/clk-tegra210.c | 3 ++-
>  drivers/clk/tegra/clk.h          | 6 ++++++
>  3 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/tegra/clk-pll-out.c b/drivers/clk/tegra/clk-pll-out.c
> index 35f2bf00e1e6..d8bf89a81e6d 100644
> --- a/drivers/clk/tegra/clk-pll-out.c
> +++ b/drivers/clk/tegra/clk-pll-out.c
> @@ -69,10 +69,19 @@ static void clk_pll_out_disable(struct clk_hw *hw)
>  		spin_unlock_irqrestore(pll_out->lock, flags);
>  }
>  
> +static void tegra_clk_pll_out_restore_context(struct clk_hw *hw)
> +{
> +	if (!__clk_get_enable_count(hw->clk))
> +		clk_pll_out_disable(hw);
> +	else
> +		clk_pll_out_enable(hw);
> +}
> +
>  const struct clk_ops tegra_clk_pll_out_ops = {
>  	.is_enabled = clk_pll_out_is_enabled,
>  	.enable = clk_pll_out_enable,
>  	.disable = clk_pll_out_disable,
> +	.restore_context = tegra_clk_pll_out_restore_context,
>  };
>  
>  struct clk *tegra_clk_register_pll_out(const char *name,
> diff --git a/drivers/clk/tegra/clk-tegra210.c b/drivers/clk/tegra/clk-tegra210.c
> index df172d5772d7..4721ee030d1c 100644
> --- a/drivers/clk/tegra/clk-tegra210.c
> +++ b/drivers/clk/tegra/clk-tegra210.c
> @@ -3200,7 +3200,8 @@ static void __init tegra210_pll_init(void __iomem *clk_base,
>  					 8, 8, 1, NULL);
>  	clk = tegra_clk_register_pll_out("pll_re_out1", "pll_re_out1_div",
>  					 clk_base + PLLRE_OUT1, 1, 0,
> -					 CLK_SET_RATE_PARENT, 0, NULL);
> +					 CLK_SET_RATE_PARENT, TEGRA_PLLRE_OUT,
> +					 NULL);
>  	clks[TEGRA210_CLK_PLL_RE_OUT1] = clk;
>  
>  	/* PLLE */
> diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
> index 905bf1096558..a464524fbc90 100644
> --- a/drivers/clk/tegra/clk.h
> +++ b/drivers/clk/tegra/clk.h
> @@ -437,6 +437,10 @@ struct clk *tegra_clk_register_pllu_tegra210(const char *name,
>   * @rst_bit_idx:	bit to reset PLL divider
>   * @lock:		register lock
>   * @flags:		hardware-specific flags
> + *
> + * Flags:
> + * TEGRA_PLLRE_OUT - This flag indicates that it is PLLRE_OUT and is used to
> + *		     identify PLLRE_OUT during clk_pll_out save and restore.
>   */
>  struct tegra_clk_pll_out {
>  	struct clk_hw	hw;
> @@ -447,6 +451,8 @@ struct tegra_clk_pll_out {
>  	u8		flags;
>  };
>  
> +#define TEGRA_PLLRE_OUT BIT(0)
> +
>  #define to_clk_pll_out(_hw) container_of(_hw, struct tegra_clk_pll_out, hw)
>  
>  extern const struct clk_ops tegra_clk_pll_out_ops;
> 

Looks like the TEGRA_PLLRE_OUT flag is unused.