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, 7 insertions, 140 deletions

diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index b40035b011d0..b2806946a77a 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -3,6 +3,7 @@
  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
  */
 
+#include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/clkdev.h>
 #include <linux/clk/at91_pmc.h>
@@ -14,8 +15,6 @@
 
 #include <asm/proc-fns.h>
 
-#include <dt-bindings/clock/at91.h>
-
 #include "pmc.h"
 
 #define PMC_MAX_IDS 128
@@ -111,147 +110,19 @@ struct pmc_data *pmc_data_allocate(unsigned int ncore, unsigned int nsystem,
 }
 
 #ifdef CONFIG_PM
-static struct regmap *pmcreg;
-
-static u8 registered_ids[PMC_MAX_IDS];
-static u8 registered_pcks[PMC_MAX_PCKS];
-
-static struct
-{
-	u32 scsr;
-	u32 pcsr0;
-	u32 uckr;
-	u32 mor;
-	u32 mcfr;
-	u32 pllar;
-	u32 mckr;
-	u32 usb;
-	u32 imr;
-	u32 pcsr1;
-	u32 pcr[PMC_MAX_IDS];
-	u32 audio_pll0;
-	u32 audio_pll1;
-	u32 pckr[PMC_MAX_PCKS];
-} pmc_cache;
-
-/*
- * As Peripheral ID 0 is invalid on AT91 chips, the identifier is stored
- * without alteration in the table, and 0 is for unused clocks.
- */
-void pmc_register_id(u8 id)
-{
-	int i;
-
-	for (i = 0; i < PMC_MAX_IDS; i++) {
-		if (registered_ids[i] == 0) {
-			registered_ids[i] = id;
-			break;
-		}
-		if (registered_ids[i] == id)
-			break;
-	}
-}
-
-/*
- * As Programmable Clock 0 is valid on AT91 chips, there is an offset
- * of 1 between the stored value and the real clock ID.
- */
-void pmc_register_pck(u8 pck)
-{
-	int i;
-
-	for (i = 0; i < PMC_MAX_PCKS; i++) {
-		if (registered_pcks[i] == 0) {
-			registered_pcks[i] = pck + 1;
-			break;
-		}
-		if (registered_pcks[i] == (pck + 1))
-			break;
-	}
-}
-
-static int pmc_suspend(void)
+static int at91_pmc_suspend(void)
 {
-	int i;
-	u8 num;
-
-	regmap_read(pmcreg, AT91_PMC_SCSR, &pmc_cache.scsr);
-	regmap_read(pmcreg, AT91_PMC_PCSR, &pmc_cache.pcsr0);
-	regmap_read(pmcreg, AT91_CKGR_UCKR, &pmc_cache.uckr);
-	regmap_read(pmcreg, AT91_CKGR_MOR, &pmc_cache.mor);
-	regmap_read(pmcreg, AT91_CKGR_MCFR, &pmc_cache.mcfr);
-	regmap_read(pmcreg, AT91_CKGR_PLLAR, &pmc_cache.pllar);
-	regmap_read(pmcreg, AT91_PMC_MCKR, &pmc_cache.mckr);
-	regmap_read(pmcreg, AT91_PMC_USB, &pmc_cache.usb);
-	regmap_read(pmcreg, AT91_PMC_IMR, &pmc_cache.imr);
-	regmap_read(pmcreg, AT91_PMC_PCSR1, &pmc_cache.pcsr1);
-
-	for (i = 0; registered_ids[i]; i++) {
-		regmap_write(pmcreg, AT91_PMC_PCR,
-			     (registered_ids[i] & AT91_PMC_PCR_PID_MASK));
-		regmap_read(pmcreg, AT91_PMC_PCR,
-			    &pmc_cache.pcr[registered_ids[i]]);
-	}
-	for (i = 0; registered_pcks[i]; i++) {
-		num = registered_pcks[i] - 1;
-		regmap_read(pmcreg, AT91_PMC_PCKR(num), &pmc_cache.pckr[num]);
-	}
-
-	return 0;
+	return clk_save_context();
 }
 
-static bool pmc_ready(unsigned int mask)
+static void at91_pmc_resume(void)
 {
-	unsigned int status;
-
-	regmap_read(pmcreg, AT91_PMC_SR, &status);
-
-	return ((status & mask) == mask) ? 1 : 0;
-}
-
-static void pmc_resume(void)
-{
-	int i;
-	u8 num;
-	u32 tmp;
-	u32 mask = AT91_PMC_MCKRDY | AT91_PMC_LOCKA;
-
-	regmap_read(pmcreg, AT91_PMC_MCKR, &tmp);
-	if (pmc_cache.mckr != tmp)
-		pr_warn("MCKR was not configured properly by the firmware\n");
-	regmap_read(pmcreg, AT91_CKGR_PLLAR, &tmp);
-	if (pmc_cache.pllar != tmp)
-		pr_warn("PLLAR was not configured properly by the firmware\n");
-
-	regmap_write(pmcreg, AT91_PMC_SCER, pmc_cache.scsr);
-	regmap_write(pmcreg, AT91_PMC_PCER, pmc_cache.pcsr0);
-	regmap_write(pmcreg, AT91_CKGR_UCKR, pmc_cache.uckr);
-	regmap_write(pmcreg, AT91_CKGR_MOR, pmc_cache.mor);
-	regmap_write(pmcreg, AT91_CKGR_MCFR, pmc_cache.mcfr);
-	regmap_write(pmcreg, AT91_PMC_USB, pmc_cache.usb);
-	regmap_write(pmcreg, AT91_PMC_IMR, pmc_cache.imr);
-	regmap_write(pmcreg, AT91_PMC_PCER1, pmc_cache.pcsr1);
-
-	for (i = 0; registered_ids[i]; i++) {
-		regmap_write(pmcreg, AT91_PMC_PCR,
-			     pmc_cache.pcr[registered_ids[i]] |
-			     AT91_PMC_PCR_CMD);
-	}
-	for (i = 0; registered_pcks[i]; i++) {
-		num = registered_pcks[i] - 1;
-		regmap_write(pmcreg, AT91_PMC_PCKR(num), pmc_cache.pckr[num]);
-	}
-
-	if (pmc_cache.uckr & AT91_PMC_UPLLEN)
-		mask |= AT91_PMC_LOCKU;
-
-	while (!pmc_ready(mask))
-		cpu_relax();
+	clk_restore_context();
 }
 
 static struct syscore_ops pmc_syscore_ops = {
-	.suspend = pmc_suspend,
-	.resume = pmc_resume,
+	.suspend = at91_pmc_suspend,
+	.resume = at91_pmc_resume,
 };
 
 static const struct of_device_id sama5d2_pmc_dt_ids[] = {
@@ -271,11 +142,7 @@ static int __init pmc_register_ops(void)
 		of_node_put(np);
 		return -ENODEV;
 	}
-
-	pmcreg = device_node_to_regmap(np);
 	of_node_put(np);
-	if (IS_ERR(pmcreg))
-		return PTR_ERR(pmcreg);
 
 	register_syscore_ops(&pmc_syscore_ops);