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Subject: Re: [PATCH V5 09/18] clk: tegra: Add save and restore context support
 for peripheral clocks
To:     Sowjanya Komatineni <skomatineni@nvidia.com>,
        thierry.reding@gmail.com, jonathanh@nvidia.com, tglx@linutronix.de,
        jason@lakedaemon.net, marc.zyngier@arm.com,
        linus.walleij@linaro.org, stefan@agner.ch, mark.rutland@arm.com
Cc:     pdeschrijver@nvidia.com, pgaikwad@nvidia.com, sboyd@kernel.org,
        linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org,
        jckuo@nvidia.com, josephl@nvidia.com, talho@nvidia.com,
        linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
        mperttunen@nvidia.com, spatra@nvidia.com, robh+dt@kernel.org,
        devicetree@vger.kernel.org
References: <1561687972-19319-1-git-send-email-skomatineni@nvidia.com>
 <1561687972-19319-10-git-send-email-skomatineni@nvidia.com>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <711a6e01-f3c2-9bbe-60af-4f8701102d6d@gmail.com>
Date:   Sat, 29 Jun 2019 16:17:59 +0300
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28.06.2019 5:12, Sowjanya Komatineni пишет:
> This patch implements save and restore context for peripheral fixed
> clock ops, peripheral gate clock ops, sdmmc mux clock ops, and
> peripheral clock ops.
> 
> During system suspend, core power goes off and looses the settings
> of the Tegra CAR controller registers.
> 
> So during suspend entry clock and reset state of peripherals is saved
> and on resume they are restored to have clocks back to same rate and
> state as before suspend.
> 
> Acked-by: Thierry Reding <treding@nvidia.com>
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
>  drivers/clk/tegra/clk-periph-fixed.c | 31 ++++++++++++++++++++++++++
>  drivers/clk/tegra/clk-periph-gate.c  | 34 ++++++++++++++++++++++++++++
>  drivers/clk/tegra/clk-periph.c       | 43 ++++++++++++++++++++++++++++++++++++
>  drivers/clk/tegra/clk-sdmmc-mux.c    | 30 +++++++++++++++++++++++++
>  drivers/clk/tegra/clk.h              |  8 +++++++
>  5 files changed, 146 insertions(+)
> 
> diff --git a/drivers/clk/tegra/clk-periph-fixed.c b/drivers/clk/tegra/clk-periph-fixed.c
> index c088e7a280df..981f68b0a937 100644
> --- a/drivers/clk/tegra/clk-periph-fixed.c
> +++ b/drivers/clk/tegra/clk-periph-fixed.c
> @@ -60,11 +60,42 @@ tegra_clk_periph_fixed_recalc_rate(struct clk_hw *hw,
>  	return (unsigned long)rate;
>  }
>  
> +static int tegra_clk_periph_fixed_save_context(struct clk_hw *hw)
> +{
> +	struct tegra_clk_periph_fixed *fixed = to_tegra_clk_periph_fixed(hw);
> +	u32 mask = 1 << (fixed->num % 32);
> +
> +	fixed->enb_ctx = readl(fixed->base + fixed->regs->enb_reg) & mask;
> +	fixed->rst_ctx = readl(fixed->base + fixed->regs->rst_reg) & mask;
> +

readl_relaxed() ?