clk: at91: re-factor clocks suspend/resume

SAMA5D2 and SAMA7G5 have a special power saving mode (backup mode) where
most of the SoC's components are powered off (including PMC). Resuming
from this mode is done with the help of bootloader. Peripherals are not
aware of the power saving mode thus most of them are disabling clocks in
proper suspend API and re-enable them in resume API without taking into
account the previously setup rate. Moreover some of the peripherals are
acting as wakeup sources and are not disabling the clocks in this
scenario, when suspending. Since backup mode cuts the power for
peripherals, in resume part these clocks needs to be re-configured.

The initial PMC suspend/resume code was designed only for SAMA5D2's PMC
(as it was the only one supporting backup mode). SAMA7G supports also
backup mode and its PMC is different (few new functionalities, different
registers offsets, different offsets in registers for each
functionalities). To address both SAMA5D2 and SAMA7G5 PMC add
.save_context()/.resume_context() support to each clocks driver and call
this from PMC driver.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211011112719.3951784-2-claudiu.beznea@microchip.com
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 66 insertions, 0 deletions

diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c
index cfae2f59df66..8601b27c1ae0 100644
--- a/drivers/clk/at91/clk-main.c
+++ b/drivers/clk/at91/clk-main.c
@@ -28,6 +28,7 @@
 struct clk_main_osc {
 	struct clk_hw hw;
 	struct regmap *regmap;
+	struct at91_clk_pms pms;
 };
 
 #define to_clk_main_osc(hw) container_of(hw, struct clk_main_osc, hw)
@@ -37,6 +38,7 @@ struct clk_main_rc_osc {
 	struct regmap *regmap;
 	unsigned long frequency;
 	unsigned long accuracy;
+	struct at91_clk_pms pms;
 };
 
 #define to_clk_main_rc_osc(hw) container_of(hw, struct clk_main_rc_osc, hw)
@@ -51,6 +53,7 @@ struct clk_rm9200_main {
 struct clk_sam9x5_main {
 	struct clk_hw hw;
 	struct regmap *regmap;
+	struct at91_clk_pms pms;
 	u8 parent;
 };
 
@@ -120,10 +123,29 @@ static int clk_main_osc_is_prepared(struct clk_hw *hw)
 	return (status & AT91_PMC_MOSCS) && clk_main_parent_select(tmp);
 }
 
+static int clk_main_osc_save_context(struct clk_hw *hw)
+{
+	struct clk_main_osc *osc = to_clk_main_osc(hw);
+
+	osc->pms.status = clk_main_osc_is_prepared(hw);
+
+	return 0;
+}
+
+static void clk_main_osc_restore_context(struct clk_hw *hw)
+{
+	struct clk_main_osc *osc = to_clk_main_osc(hw);
+
+	if (osc->pms.status)
+		clk_main_osc_prepare(hw);
+}
+
 static const struct clk_ops main_osc_ops = {
 	.prepare = clk_main_osc_prepare,
 	.unprepare = clk_main_osc_unprepare,
 	.is_prepared = clk_main_osc_is_prepared,
+	.save_context = clk_main_osc_save_context,
+	.restore_context = clk_main_osc_restore_context,
 };
 
 struct clk_hw * __init
@@ -240,12 +262,31 @@ static unsigned long clk_main_rc_osc_recalc_accuracy(struct clk_hw *hw,
 	return osc->accuracy;
 }
 
+static int clk_main_rc_osc_save_context(struct clk_hw *hw)
+{
+	struct clk_main_rc_osc *osc = to_clk_main_rc_osc(hw);
+
+	osc->pms.status = clk_main_rc_osc_is_prepared(hw);
+
+	return 0;
+}
+
+static void clk_main_rc_osc_restore_context(struct clk_hw *hw)
+{
+	struct clk_main_rc_osc *osc = to_clk_main_rc_osc(hw);
+
+	if (osc->pms.status)
+		clk_main_rc_osc_prepare(hw);
+}
+
 static const struct clk_ops main_rc_osc_ops = {
 	.prepare = clk_main_rc_osc_prepare,
 	.unprepare = clk_main_rc_osc_unprepare,
 	.is_prepared = clk_main_rc_osc_is_prepared,
 	.recalc_rate = clk_main_rc_osc_recalc_rate,
 	.recalc_accuracy = clk_main_rc_osc_recalc_accuracy,
+	.save_context = clk_main_rc_osc_save_context,
+	.restore_context = clk_main_rc_osc_restore_context,
 };
 
 struct clk_hw * __init
@@ -465,12 +506,37 @@ static u8 clk_sam9x5_main_get_parent(struct clk_hw *hw)
 	return clk_main_parent_select(status);
 }
 
+static int clk_sam9x5_main_save_context(struct clk_hw *hw)
+{
+	struct clk_sam9x5_main *clkmain = to_clk_sam9x5_main(hw);
+
+	clkmain->pms.status = clk_main_rc_osc_is_prepared(&clkmain->hw);
+	clkmain->pms.parent = clk_sam9x5_main_get_parent(&clkmain->hw);
+
+	return 0;
+}
+
+static void clk_sam9x5_main_restore_context(struct clk_hw *hw)
+{
+	struct clk_sam9x5_main *clkmain = to_clk_sam9x5_main(hw);
+	int ret;
+
+	ret = clk_sam9x5_main_set_parent(hw, clkmain->pms.parent);
+	if (ret)
+		return;
+
+	if (clkmain->pms.status)
+		clk_sam9x5_main_prepare(hw);
+}
+
 static const struct clk_ops sam9x5_main_ops = {
 	.prepare = clk_sam9x5_main_prepare,
 	.is_prepared = clk_sam9x5_main_is_prepared,
 	.recalc_rate = clk_sam9x5_main_recalc_rate,
 	.set_parent = clk_sam9x5_main_set_parent,
 	.get_parent = clk_sam9x5_main_get_parent,
+	.save_context = clk_sam9x5_main_save_context,
+	.restore_context = clk_sam9x5_main_restore_context,
 };
 
 struct clk_hw * __init