pwm: ftm: Add Power Management support for FTM PWM

Add PM support for FTM PWM driver using callback function suspend
and resume in .driver.pm of platform_driver.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 48 insertions, 1 deletions

diff --git a/drivers/pwm/pwm-fsl-ftm.c b/drivers/pwm/pwm-fsl-ftm.c
index 9bfbea5dbf2f..f9dfc8b6407a 100644
--- a/drivers/pwm/pwm-fsl-ftm.c
+++ b/drivers/pwm/pwm-fsl-ftm.c
@@ -17,6 +17,7 @@
 #include <linux/mutex.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
+#include <linux/pm.h>
 #include <linux/pwm.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
@@ -436,7 +437,7 @@ static int fsl_pwm_probe(struct platform_device *pdev)
         if (IS_ERR(base))
                 return PTR_ERR(base);
 
-        fpc->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
+        fpc->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "ftm_sys", base,
                                                 &fsl_pwm_regmap_config);
         if (IS_ERR(fpc->regmap)) {
                 dev_err(&pdev->dev, "regmap init failed\n");
@@ -487,6 +488,51 @@ static int fsl_pwm_remove(struct platform_device *pdev)
         return pwmchip_remove(&fpc->chip);
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int fsl_pwm_suspend(struct device *dev)
+{
+        struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
+        u32 val;
+
+        regcache_cache_only(fpc->regmap, true);
+        regcache_mark_dirty(fpc->regmap);
+
+        /* read from cache */
+        regmap_read(fpc->regmap, FTM_OUTMASK, &val);
+        if ((val & 0xFF) != 0xFF) {
+                clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
+                clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
+                clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]);
+        }
+
+        return 0;
+}
+
+static int fsl_pwm_resume(struct device *dev)
+{
+        struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
+        u32 val;
+
+        /* read from cache */
+        regmap_read(fpc->regmap, FTM_OUTMASK, &val);
+        if ((val & 0xFF) != 0xFF) {
+                clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]);
+                clk_prepare_enable(fpc->clk[fpc->cnt_select]);
+                clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
+        }
+
+        /* restore all registers from cache */
+        regcache_cache_only(fpc->regmap, false);
+        regcache_sync(fpc->regmap);
+
+        return 0;
+}
+#endif
+
+static const struct dev_pm_ops fsl_pwm_pm_ops = {
+        SET_SYSTEM_SLEEP_PM_OPS(fsl_pwm_suspend, fsl_pwm_resume)
+};
+
 static const struct of_device_id fsl_pwm_dt_ids[] = {
         { .compatible = "fsl,vf610-ftm-pwm", },
         { /* sentinel */ }
@@ -497,6 +543,7 @@ static struct platform_driver fsl_pwm_driver = {
         .driver = {
                 .name = "fsl-ftm-pwm",
                 .of_match_table = fsl_pwm_dt_ids,
+                .pm = &fsl_pwm_pm_ops,
         },
         .probe = fsl_pwm_probe,
         .remove = fsl_pwm_remove,