Re: [PATCH V6 07/21] clk: tegra: Support for OSC context save and restore

Dmitry Osipenko
2019-07-22T10:12:06Z

21.07.2019 22:40, Sowjanya Komatineni пишет:
> X-NVConfidentiality: public

What's that?

> This patch adds support for saving OSC clock frequency and the
> drive-strength during OSC clock init and creates an API to restore
> OSC control register value from the saved context.
>
> This API is invoked by Tegra210 clock driver during system resume
> to restore the OSC clock settings.
>
> Acked-by: Thierry Reding <treding@nvidia.com>
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
> drivers/clk/tegra/clk-tegra-fixed.c | 15 +++++++++++++++
> drivers/clk/tegra/clk.h | 1 +
> 2 files changed, 16 insertions(+)
>
> diff --git a/drivers/clk/tegra/clk-tegra-fixed.c b/drivers/clk/tegra/clk-tegra-fixed.c
> index 8d91b2b191cf..7c6c8abfcde6 100644
> --- a/drivers/clk/tegra/clk-tegra-fixed.c
> +++ b/drivers/clk/tegra/clk-tegra-fixed.c
> @@ -17,6 +17,10 @@
> #define OSC_CTRL 0x50
> #define OSC_CTRL_OSC_FREQ_SHIFT 28
> #define OSC_CTRL_PLL_REF_DIV_SHIFT 26
> +#define OSC_CTRL_MASK (0x3f2 | \
> + (0xf << OSC_CTRL_OSC_FREQ_SHIFT))
> +
> +static u32 osc_ctrl_ctx;
>
> int __init tegra_osc_clk_init(void __iomem *clk_base, struct tegra_clk *clks,
> unsigned long *input_freqs, unsigned int num,
> @@ -29,6 +33,7 @@ int __init tegra_osc_clk_init(void __iomem *clk_base, struct tegra_clk *clks,
> unsigned osc_idx;
>
> val = readl_relaxed(clk_base + OSC_CTRL);
> + osc_ctrl_ctx = val & OSC_CTRL_MASK;
> osc_idx = val >> OSC_CTRL_OSC_FREQ_SHIFT;
>
> if (osc_idx < num)
> @@ -96,3 +101,13 @@ void __init tegra_fixed_clk_init(struct tegra_clk *tegra_clks)
> *dt_clk = clk;
> }
> }
> +
> +void tegra_clk_osc_resume(void __iomem *clk_base)
> +{
> + u32 val;
> +
> + val = readl_relaxed(clk_base + OSC_CTRL) & ~OSC_CTRL_MASK;
> + val |= osc_ctrl_ctx;
> + writel_relaxed(val, clk_base + OSC_CTRL);
> + fence_udelay(2, clk_base);
> +}
> diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
> index 8532f5150091..3cd003b7512a 100644
> --- a/drivers/clk/tegra/clk.h
> +++ b/drivers/clk/tegra/clk.h
> @@ -849,6 +849,7 @@ int tegra_pll_p_div_to_hw(struct tegra_clk_pll *pll, u8 p_div);
> int div_frac_get(unsigned long rate, unsigned parent_rate, u8 width,
> u8 frac_width, u8 flags);
> void tegra_clk_sync_state_pll(struct clk_hw *hw);
> +void tegra_clk_osc_resume(void __iomem *clk_base);
>
> /* Combined read fence with delay */
> #define fence_udelay(delay, reg) \
>