clk: tegra: Support for OSC context save and restore

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>
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/clk/tegra/clk-tegra-fixed.c b/drivers/clk/tegra/clk-tegra-fixed.c
index 8d91b2b191cf076e8d70c065475d6c859f660bfb..7c6c8abfcde655620815cea83200d7e39328d1ba 100644 (file)
--- 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 20b3ee123050aff401998a32b647809bf12af80f..7c956ce521d610cf2e28fef6b95955179e598ac3 100644 (file)
--- a/drivers/clk/tegra/clk.h
+++ b/drivers/clk/tegra/clk.h
@@ -829,6 +829,7 @@ u16 tegra_pll_get_fixed_mdiv(struct clk_hw *hw, unsigned long input_rate);
 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_osc_resume(void __iomem *clk_base);
 
 
 /* Combined read fence with delay */