PWM: ehrpwm: Support for low power sleep

This pattch
1. Adds context save/restore functionality to support low power sleep
transitions.
2. Adds pm_runtime [get_sync/put_sync] in context save function to
handle unenabled clock situation.
3. Removes check for clock use count.

Signed-off-by: Philip, Avinash <avinashphilip@ti.com>

2 files changed, 59 insertions, 2 deletions

diff --git a/drivers/pwm/ehrpwm.c b/drivers/pwm/ehrpwm.c
index 8140ce7f1bbf..d37db5229dbe 100644
--- a/drivers/pwm/ehrpwm.c
+++ b/drivers/pwm/ehrpwm.c
@@ -1509,12 +1509,53 @@ err_mem_failure:
 }
 
 #ifdef CONFIG_PM
+
+void ehrpwm_context_save(struct ehrpwm_pwm *ehrpwm,
+                struct ehrpwm_context *ehrpwm_ctx)
+{
+        pm_runtime_get_sync(ehrpwm->dev);
+        ehrpwm_ctx->tbctl = ehrpwm_read(ehrpwm, TBCTL);
+        ehrpwm_ctx->tbprd = ehrpwm_read(ehrpwm, TBPRD);
+        if (ehrpwm->version == PWM_VERSION_1)
+                ehrpwm_ctx->hrcfg = ehrpwm_read(ehrpwm, AM335X_HRCNFG);
+        else
+                ehrpwm_ctx->hrcfg = ehrpwm_read(ehrpwm, HRCNFG);
+        ehrpwm_ctx->aqctla = ehrpwm_read(ehrpwm, AQCTLA);
+        ehrpwm_ctx->aqctlb = ehrpwm_read(ehrpwm, AQCTLB);
+        ehrpwm_ctx->cmpa = ehrpwm_read(ehrpwm, CMPA);
+        ehrpwm_ctx->cmpb = ehrpwm_read(ehrpwm, CMPB);
+        ehrpwm_ctx->tzctl = ehrpwm_read(ehrpwm, TZCTL);
+        ehrpwm_ctx->tzflg = ehrpwm_read(ehrpwm, TZFLG);
+        ehrpwm_ctx->tzclr = ehrpwm_read(ehrpwm, TZCLR);
+        ehrpwm_ctx->tzfrc = ehrpwm_read(ehrpwm, TZFRC);
+        pm_runtime_put_sync(ehrpwm->dev);
+}
+
+void ehrpwm_context_restore(struct ehrpwm_pwm *ehrpwm,
+                struct ehrpwm_context *ehrpwm_ctx)
+{
+        ehrpwm_write(ehrpwm, TBCTL, ehrpwm_ctx->tbctl);
+        ehrpwm_write(ehrpwm, TBPRD, ehrpwm_ctx->tbprd);
+        if (ehrpwm->version == PWM_VERSION_1)
+                ehrpwm_write(ehrpwm, AM335X_HRCNFG, ehrpwm_ctx->hrcfg);
+        else
+                ehrpwm_write(ehrpwm, HRCNFG, ehrpwm_ctx->hrcfg);
+        ehrpwm_write(ehrpwm, AQCTLA, ehrpwm_ctx->aqctla);
+        ehrpwm_write(ehrpwm, AQCTLB, ehrpwm_ctx->aqctlb);
+        ehrpwm_write(ehrpwm, CMPA, ehrpwm_ctx->cmpa);
+        ehrpwm_write(ehrpwm, CMPB, ehrpwm_ctx->cmpb);
+        ehrpwm_write(ehrpwm, TZCTL, ehrpwm_ctx->tzctl);
+        ehrpwm_write(ehrpwm, TZFLG, ehrpwm_ctx->tzflg);
+        ehrpwm_write(ehrpwm, TZCLR, ehrpwm_ctx->tzclr);
+        ehrpwm_write(ehrpwm, TZFRC, ehrpwm_ctx->tzfrc);
+}
+
 static int ehrpwm_suspend(struct platform_device *pdev, pm_message_t state)
 {
         struct ehrpwm_pwm *ehrpwm = platform_get_drvdata(pdev);
 
-        if (ehrpwm->clk->usecount > 0)
-                pm_runtime_put_sync(ehrpwm->dev);
+        ehrpwm_context_save(ehrpwm, &ehrpwm->ctx);
+        pm_runtime_put_sync(ehrpwm->dev);
 
         return 0;
 }
@@ -1524,6 +1565,7 @@ static int ehrpwm_resume(struct platform_device *pdev)
         struct ehrpwm_pwm *ehrpwm = platform_get_drvdata(pdev);
 
         pm_runtime_get_sync(ehrpwm->dev);
+        ehrpwm_context_restore(ehrpwm, &ehrpwm->ctx);
 
         return 0;
 }
diff --git a/include/linux/pwm/ehrpwm.h b/include/linux/pwm/ehrpwm.h
index 56f88068bf43..53a448143dcc 100644
--- a/include/linux/pwm/ehrpwm.h
+++ b/include/linux/pwm/ehrpwm.h
@@ -19,6 +19,20 @@ struct tz_int {
         p_fcallback pcallback;
 };
 
+struct ehrpwm_context {
+        u32 tbctl;
+        u32 tbprd;
+        u32 hrcfg;
+        u32 aqctla;
+        u32 aqctlb;
+        u32 cmpa;
+        u32 cmpb;
+        u32 tzctl;
+        u32 tzflg;
+        u32 tzclr;
+        u32 tzfrc;
+};
+
 struct ehrpwm_pwm {
         struct pwm_device pwm[NCHAN];
         struct pwm_device_ops ops;
@@ -32,6 +46,7 @@ struct ehrpwm_pwm {
         u8 version;
         void __iomem *config_mem_base;
         struct device *dev;
+        struct ehrpwm_context ctx;
 };
 
 enum tz_event {