i2c: riic: Add Runtime PM support

- Replace explicit clock handling by Runtime PM calls,
  - Streamline Runtime PM handling in error paths,
  - Enable Runtime PM in .probe(),
  - Disable Runtime PM in .remove(),
  - Make sure the device is runtime-resumed when disabling interrupts in
    .remove().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
index b75ff14..f31413f 100644 (file)
--- a/drivers/i2c/busses/i2c-riic.c
+++ b/drivers/i2c/busses/i2c-riic.c
@@ -43,6 +43,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 
 #define RIIC_ICCR1     0x00
 #define RIIC_ICCR2     0x04
@@ -112,12 +113,10 @@ static int riic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 {
        struct riic_dev *riic = i2c_get_adapdata(adap);
        unsigned long time_left;
-       int i, ret;
+       int i;
        u8 start_bit;
 
-       ret = clk_prepare_enable(riic->clk);
-       if (ret)
-               return ret;
+       pm_runtime_get_sync(adap->dev.parent);
 
        if (readb(riic->base + RIIC_ICCR2) & ICCR2_BBSY) {
                riic->err = -EBUSY;
@@ -150,7 +149,7 @@ static int riic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
        }
 
  out:
-       clk_disable_unprepare(riic->clk);
+       pm_runtime_put(adap->dev.parent);
 
        return riic->err ?: num;
 }
@@ -281,20 +280,18 @@ static const struct i2c_algorithm riic_algo = {
 
 static int riic_init_hw(struct riic_dev *riic, struct i2c_timings *t)
 {
-       int ret;
+       int ret = 0;
        unsigned long rate;
        int total_ticks, cks, brl, brh;
 
-       ret = clk_prepare_enable(riic->clk);
-       if (ret)
-               return ret;
+       pm_runtime_get_sync(riic->adapter.dev.parent);
 
        if (t->bus_freq_hz > 400000) {
                dev_err(&riic->adapter.dev,
                        "unsupported bus speed (%dHz). 400000 max\n",
                        t->bus_freq_hz);
-               clk_disable_unprepare(riic->clk);
-               return -EINVAL;
+               ret = -EINVAL;
+               goto out;
        }
 
        rate = clk_get_rate(riic->clk);
@@ -332,8 +329,8 @@ static int riic_init_hw(struct riic_dev *riic, struct i2c_timings *t)
        if (brl > (0x1F + 3)) {
                dev_err(&riic->adapter.dev, "invalid speed (%lu). Too slow.\n",
                        (unsigned long)t->bus_freq_hz);
-               clk_disable_unprepare(riic->clk);
-               return -EINVAL;
+               ret = -EINVAL;
+               goto out;
        }
 
        brh = total_ticks - brl;
@@ -378,9 +375,9 @@ static int riic_init_hw(struct riic_dev *riic, struct i2c_timings *t)
 
        riic_clear_set_bit(riic, ICCR1_IICRST, 0, RIIC_ICCR1);
 
-       clk_disable_unprepare(riic->clk);
-
-       return 0;
+out:
+       pm_runtime_put(riic->adapter.dev.parent);
+       return ret;
 }
 
 static struct riic_irq_desc riic_irqs[] = {
@@ -439,28 +436,36 @@ static int riic_i2c_probe(struct platform_device *pdev)
 
        i2c_parse_fw_timings(&pdev->dev, &i2c_t, true);
 
+       pm_runtime_enable(&pdev->dev);
+
        ret = riic_init_hw(riic, &i2c_t);
        if (ret)
-               return ret;
-
+               goto out;
 
        ret = i2c_add_adapter(adap);
        if (ret)
-               return ret;
+               goto out;
 
        platform_set_drvdata(pdev, riic);
 
        dev_info(&pdev->dev, "registered with %dHz bus speed\n",
                 i2c_t.bus_freq_hz);
        return 0;
+
+out:
+       pm_runtime_disable(&pdev->dev);
+       return ret;
 }
 
 static int riic_i2c_remove(struct platform_device *pdev)
 {
        struct riic_dev *riic = platform_get_drvdata(pdev);
 
+       pm_runtime_get_sync(&pdev->dev);
        writeb(0, riic->base + RIIC_ICIER);
+       pm_runtime_put(&pdev->dev);
        i2c_del_adapter(&riic->adapter);
+       pm_runtime_disable(&pdev->dev);
 
        return 0;
 }