pwm: pwm-tiehrpwm: Low power sleep support

In low power modes of AM33XX platforms, peripherals power is cut off.
This patch supports low power sleep transition support for EHRPWM
driver.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

1 files changed, 83 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c
index 4fcafbfba60e..33e15c4fba02 100644
--- a/drivers/pwm/pwm-tiehrpwm.c
+++ b/drivers/pwm/pwm-tiehrpwm.c
@@ -113,6 +113,17 @@
 
 #define NUM_PWM_CHANNEL         2       /* EHRPWM channels */
 
+struct ehrpwm_context {
+        u16 tbctl;
+        u16 tbprd;
+        u16 cmpa;
+        u16 cmpb;
+        u16 aqctla;
+        u16 aqctlb;
+        u16 aqsfrc;
+        u16 aqcsfrc;
+};
+
 struct ehrpwm_pwm_chip {
         struct pwm_chip chip;
         unsigned int    clk_rate;
@@ -120,6 +131,7 @@ struct ehrpwm_pwm_chip {
         unsigned long period_cycles[NUM_PWM_CHANNEL];
         enum pwm_polarity polarity[NUM_PWM_CHANNEL];
         struct  clk     *tbclk;
+        struct ehrpwm_context ctx;
 };
 
 static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
@@ -127,6 +139,11 @@ static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
         return container_of(chip, struct ehrpwm_pwm_chip, chip);
 }
 
+static u16 ehrpwm_read(void *base, int offset)
+{
+        return readw(base + offset);
+}
+
 static void ehrpwm_write(void *base, int offset, unsigned int val)
 {
         writew(val & 0xFFFF, base + offset);
@@ -516,11 +533,77 @@ static int ehrpwm_pwm_remove(struct platform_device *pdev)
         return pwmchip_remove(&pc->chip);
 }
 
+void ehrpwm_pwm_save_context(struct ehrpwm_pwm_chip *pc)
+{
+        pm_runtime_get_sync(pc->chip.dev);
+        pc->ctx.tbctl = ehrpwm_read(pc->mmio_base, TBCTL);
+        pc->ctx.tbprd = ehrpwm_read(pc->mmio_base, TBPRD);
+        pc->ctx.cmpa = ehrpwm_read(pc->mmio_base, CMPA);
+        pc->ctx.cmpb = ehrpwm_read(pc->mmio_base, CMPB);
+        pc->ctx.aqctla = ehrpwm_read(pc->mmio_base, AQCTLA);
+        pc->ctx.aqctlb = ehrpwm_read(pc->mmio_base, AQCTLB);
+        pc->ctx.aqsfrc = ehrpwm_read(pc->mmio_base, AQSFRC);
+        pc->ctx.aqcsfrc = ehrpwm_read(pc->mmio_base, AQCSFRC);
+        pm_runtime_put_sync(pc->chip.dev);
+}
+
+void ehrpwm_pwm_restore_context(struct ehrpwm_pwm_chip *pc)
+{
+        ehrpwm_write(pc->mmio_base, TBPRD, pc->ctx.tbprd);
+        ehrpwm_write(pc->mmio_base, CMPA, pc->ctx.cmpa);
+        ehrpwm_write(pc->mmio_base, CMPB, pc->ctx.cmpb);
+        ehrpwm_write(pc->mmio_base, AQCTLA, pc->ctx.aqctla);
+        ehrpwm_write(pc->mmio_base, AQCTLB, pc->ctx.aqctlb);
+        ehrpwm_write(pc->mmio_base, AQSFRC, pc->ctx.aqsfrc);
+        ehrpwm_write(pc->mmio_base, AQCSFRC, pc->ctx.aqcsfrc);
+        ehrpwm_write(pc->mmio_base, TBCTL, pc->ctx.tbctl);
+}
+
+static int ehrpwm_pwm_suspend(struct device *dev)
+{
+        struct ehrpwm_pwm_chip *pc = dev_get_drvdata(dev);
+        int i;
+
+        ehrpwm_pwm_save_context(pc);
+        for (i = 0; i < pc->chip.npwm; i++) {
+                struct pwm_device *pwm = &pc->chip.pwms[i];
+
+                if (!test_bit(PWMF_ENABLED, &pwm->flags))
+                        continue;
+
+                /* Disable explicitly if PWM is running */
+                pm_runtime_put_sync(dev);
+        }
+        return 0;
+}
+
+static int ehrpwm_pwm_resume(struct device *dev)
+{
+        struct ehrpwm_pwm_chip *pc = dev_get_drvdata(dev);
+        int i;
+
+        for (i = 0; i < pc->chip.npwm; i++) {
+                struct pwm_device *pwm = &pc->chip.pwms[i];
+
+                if (!test_bit(PWMF_ENABLED, &pwm->flags))
+                        continue;
+
+                /* Enable explicitly if PWM was running */
+                pm_runtime_get_sync(dev);
+        }
+        ehrpwm_pwm_restore_context(pc);
+        return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(ehrpwm_pwm_pm_ops, ehrpwm_pwm_suspend,
+                ehrpwm_pwm_resume);
+
 static struct platform_driver ehrpwm_pwm_driver = {
         .driver = {
                 .name   = "ehrpwm",
                 .owner  = THIS_MODULE,
                 .of_match_table = ehrpwm_of_match,
+                .pm     = &ehrpwm_pwm_pm_ops,
         },
         .probe = ehrpwm_pwm_probe,
         .remove = ehrpwm_pwm_remove,