Thread (41 messages) 41 messages, 5 authors, 2019-11-08
STALE2437d REVIEWED: 4 (3M)
Revisions (8)
  1. v3 [diff vs current]
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  3. v5 [diff vs current]
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  7. v8 [diff vs current]
  8. v9 current

[PATCH v9 03/22] clk: tegra: divider: Save and restore divider rate

From: Sowjanya Komatineni <skomatineni@nvidia.com>
Date: 2019-08-16 19:42:31
Also in: linux-clk, linux-gpio, linux-pm, linux-tegra, lkml
Subsystem: common clk framework, tegra clock driver, the rest · Maintainers: Michael Turquette, Stephen Boyd, Prashant Gaikwad, Linus Torvalds

This patch implements context restore for clock divider.

During system suspend, core power goes off and looses the settings
of the Tegra CAR controller registers.

So on resume, clock dividers are restored back for normal operation.

Acked-by: Thierry Reding <redacted>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
 drivers/clk/tegra/clk-divider.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
diff --git a/drivers/clk/tegra/clk-divider.c b/drivers/clk/tegra/clk-divider.c
index e76731fb7d69..ca0de5f11f84 100644
--- a/drivers/clk/tegra/clk-divider.c
+++ b/drivers/clk/tegra/clk-divider.c
@@ -109,10 +109,21 @@ static int clk_frac_div_set_rate(struct clk_hw *hw, unsigned long rate,
 	return 0;
 }
 
+static void clk_divider_restore_context(struct clk_hw *hw)
+{
+	struct clk_hw *parent = clk_hw_get_parent(hw);
+	unsigned long parent_rate = clk_hw_get_rate(parent);
+	unsigned long rate = clk_hw_get_rate(hw);
+
+	if (clk_frac_div_set_rate(hw, rate, parent_rate) < 0)
+		WARN_ON(1);
+}
+
 const struct clk_ops tegra_clk_frac_div_ops = {
 	.recalc_rate = clk_frac_div_recalc_rate,
 	.set_rate = clk_frac_div_set_rate,
 	.round_rate = clk_frac_div_round_rate,
+	.restore_context = clk_divider_restore_context,
 };
 
 struct clk *tegra_clk_register_divider(const char *name,
-- 
2.7.4
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