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Subject[PATCH v3] clk: at91: Add sama5d2 suspend/resume
Date
On sama5d2, VDD core maybe be cut while in suspend. This means registers
will be lost. Ensure they are saved and restored properly.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
Changes in v3:
- use regmap_read_poll_timeout to handle the USB PLL
- fix typo


drivers/clk/at91/pmc.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 104 insertions(+)

diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 526df5ba042d..7fe1dc8d1829 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -13,7 +13,9 @@
#include <linux/clk/at91_pmc.h>
#include <linux/of.h>
#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
#include <linux/regmap.h>
+#include <linux/syscore_ops.h>

#include <asm/proc-fns.h>

@@ -41,3 +43,105 @@ int of_at91_get_clk_range(struct device_node *np, const char *propname,
return 0;
}
EXPORT_SYMBOL_GPL(of_at91_get_clk_range);
+
+#ifdef CONFIG_PM
+static struct regmap *pmcreg;
+
+static struct
+{
+ u32 scsr;
+ u32 pcsr0;
+ u32 uckr;
+ u32 mor;
+ u32 mcfr;
+ u32 pllar;
+ u32 mckr;
+ u32 usb;
+ u32 imr;
+ u32 pcsr1;
+ u32 pcr[64];
+} pmc_cache;
+
+static int pmc_suspend(void)
+{
+ int i;
+
+ regmap_read(pmcreg, AT91_PMC_IMR, &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 = 2; i < 64; i++) {
+ regmap_write(pmcreg, AT91_PMC_PCR, (i & AT91_PMC_PCR_PID_MASK));
+ regmap_read(pmcreg, AT91_PMC_PCR, &pmc_cache.pcr[i]);
+ }
+
+ return 0;
+}
+
+static void pmc_resume(void)
+{
+ int i, ret = 0;
+ u32 tmp;
+
+ 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_IMR, 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 = 2; i < 64; i++) {
+ regmap_write(pmcreg, AT91_PMC_PCR, (i & AT91_PMC_PCR_PID_MASK));
+ regmap_write(pmcreg, AT91_PMC_PCR, pmc_cache.pcr[i]);
+ }
+
+ if (pmc_cache.uckr & AT91_PMC_UPLLEN) {
+ ret = regmap_read_poll_timeout(pmcreg, AT91_PMC_SR, tmp, !(tmp & AT91_PMC_LOCKU), 10, 5000);
+ if (ret)
+ pr_crit("USB PLL didn't lock when resuming\n");
+ }
+}
+
+static struct syscore_ops pmc_syscore_ops = {
+ .suspend = pmc_suspend,
+ .resume = pmc_resume,
+};
+
+static const struct of_device_id sama5d2_pmc_dt_ids[] = {
+ { .compatible = "atmel,sama5d2-pmc" },
+ { /* sentinel */ }
+};
+
+static int __init pmc_register_ops(void)
+{
+ struct device_node *np;
+
+ np = of_find_matching_node(NULL, sama5d2_pmc_dt_ids);
+
+ pmcreg = syscon_node_to_regmap(np);
+ if (IS_ERR(pmcreg))
+ return PTR_ERR(pmcreg);
+
+ register_syscore_ops(&pmc_syscore_ops);
+
+ return 0;
+}
+/* This has to happen before arch_initcall because of the tcb_clksrc driver */
+postcore_initcall(pmc_register_ops);
+#endif
--
2.11.0
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