On 7/31/19 4:11 AM, Dmitry Osipenko wrote:
31.07.2019 3:20, Sowjanya Komatineni пишет:
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@xxxxxxxxxx>
Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
---
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);
Why a full raw u32 OSC_CTRL value couldn't be simply saved and restored?
Storing and restoring only required fields to avoid accidental
misconfiguration.
OSC_CTRL register has other bits (PLL_REF_DIV) which are configured by
BR depending on OSC_FREQ and also setting PLL_REF_DIV while PLLS are in
use is not safe.
+ fence_udelay(2, clk_base);
+}
diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
index f1ef6ae8c979..abba6d8a04cd 100644
--- a/drivers/clk/tegra/clk.h
+++ b/drivers/clk/tegra/clk.h
@@ -842,6 +842,7 @@ 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 */
