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, 37 insertions, 9 deletions

diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
index b656d25a9767..23cc8297ec4c 100644
--- a/drivers/clk/at91/clk-generated.c
+++ b/drivers/clk/at91/clk-generated.c
@@ -27,6 +27,7 @@ struct clk_generated {
 	u32 id;
 	u32 gckdiv;
 	const struct clk_pcr_layout *layout;
+	struct at91_clk_pms pms;
 	u8 parent_id;
 	int chg_pid;
 };
@@ -34,25 +35,35 @@ struct clk_generated {
 #define to_clk_generated(hw) \
 	container_of(hw, struct clk_generated, hw)
 
-static int clk_generated_enable(struct clk_hw *hw)
+static int clk_generated_set(struct clk_generated *gck, int status)
 {
-	struct clk_generated *gck = to_clk_generated(hw);
 	unsigned long flags;
-
-	pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
-		 __func__, gck->gckdiv, gck->parent_id);
+	unsigned int enable = status ? AT91_PMC_PCR_GCKEN : 0;
 
 	spin_lock_irqsave(gck->lock, flags);
 	regmap_write(gck->regmap, gck->layout->offset,
 		     (gck->id & gck->layout->pid_mask));
 	regmap_update_bits(gck->regmap, gck->layout->offset,
 			   AT91_PMC_PCR_GCKDIV_MASK | gck->layout->gckcss_mask |
-			   gck->layout->cmd | AT91_PMC_PCR_GCKEN,
+			   gck->layout->cmd | enable,
 			   field_prep(gck->layout->gckcss_mask, gck->parent_id) |
 			   gck->layout->cmd |
 			   FIELD_PREP(AT91_PMC_PCR_GCKDIV_MASK, gck->gckdiv) |
-			   AT91_PMC_PCR_GCKEN);
+			   enable);
 	spin_unlock_irqrestore(gck->lock, flags);
+
+	return 0;
+}
+
+static int clk_generated_enable(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
+		 __func__, gck->gckdiv, gck->parent_id);
+
+	clk_generated_set(gck, 1);
+
 	return 0;
 }
 
@@ -245,6 +256,23 @@ static int clk_generated_set_rate(struct clk_hw *hw,
 	return 0;
 }
 
+static int clk_generated_save_context(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	gck->pms.status = clk_generated_is_enabled(&gck->hw);
+
+	return 0;
+}
+
+static void clk_generated_restore_context(struct clk_hw *hw)
+{
+	struct clk_generated *gck = to_clk_generated(hw);
+
+	if (gck->pms.status)
+		clk_generated_set(gck, gck->pms.status);
+}
+
 static const struct clk_ops generated_ops = {
 	.enable = clk_generated_enable,
 	.disable = clk_generated_disable,
@@ -254,6 +282,8 @@ static const struct clk_ops generated_ops = {
 	.get_parent = clk_generated_get_parent,
 	.set_parent = clk_generated_set_parent,
 	.set_rate = clk_generated_set_rate,
+	.save_context = clk_generated_save_context,
+	.restore_context = clk_generated_restore_context,
 };
 
 /**
@@ -320,8 +350,6 @@ at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
 	if (ret) {
 		kfree(gck);
 		hw = ERR_PTR(ret);
-	} else {
-		pmc_register_id(id);
 	}
 
 	return hw;