drivers/rtc/rtc-isl12057.c: add proper handling of oscillator failure bit
authorArnaud Ebalard <arno@natisbad.org>
Wed, 10 Dec 2014 23:54:08 +0000 (15:54 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 11 Dec 2014 01:41:16 +0000 (17:41 -0800)
As suggested by Uwe, instead of clearing oscillator failure bit
unconditionally at driver load, this patch adds proper handling of the
flag.  The driver now returns -ENODATA when reading time from the device
and oscillator failure bit is set.  The flag is now cleared only when the
a new time value is pushed to the device.

Signed-off-by: Arnaud Ebalard <arno@natisbad.org>
Reported-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Acked-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Peter Huewe <peter.huewe@infineon.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rtc/rtc-isl12057.c

index b538fabfcfd3d9048dc5d87132f60d692305424a..fe562820a54a047f615aa5351b1a9d5986d12b84 100644 (file)
@@ -164,17 +164,32 @@ static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
        struct isl12057_rtc_data *data = dev_get_drvdata(dev);
        u8 regs[ISL12057_RTC_SEC_LEN];
+       unsigned int sr;
        int ret;
 
        mutex_lock(&data->lock);
+       ret = regmap_read(data->regmap, ISL12057_REG_SR, &sr);
+       if (ret) {
+               dev_err(dev, "%s: unable to read oscillator status flag\n",
+                       __func__);
+               goto out;
+       } else {
+               if (sr & ISL12057_REG_SR_OSF) {
+                       ret = -ENODATA;
+                       goto out;
+               }
+       }
+
        ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs,
                               ISL12057_RTC_SEC_LEN);
+       if (ret)
+               dev_err(dev, "%s: unable to read RTC time\n", __func__);
+
+out:
        mutex_unlock(&data->lock);
 
-       if (ret) {
-               dev_err(dev, "%s: RTC read failed\n", __func__);
+       if (ret)
                return ret;
-       }
 
        isl12057_rtc_regs_to_tm(tm, regs);
 
@@ -194,10 +209,22 @@ static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm)
        mutex_lock(&data->lock);
        ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs,
                                ISL12057_RTC_SEC_LEN);
-       mutex_unlock(&data->lock);
+       if (ret) {
+               dev_err(dev, "%s: writing RTC time failed\n", __func__);
+               goto out;
+       }
 
-       if (ret)
-               dev_err(dev, "%s: RTC write failed\n", __func__);
+       /*
+        * Now that RTC time has been updated, let's clear oscillator
+        * failure flag, if needed.
+        */
+       ret = regmap_update_bits(data->regmap, ISL12057_REG_SR,
+                                ISL12057_REG_SR_OSF, 0);
+       if (ret < 0)
+               dev_err(dev, "Unable to clear oscillator failure bit\n");
+
+out:
+       mutex_unlock(&data->lock);
 
        return ret;
 }
@@ -219,14 +246,6 @@ static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap)
                return ret;
        }
 
-       /* Clear oscillator failure bit if needed */
-       ret = regmap_update_bits(regmap, ISL12057_REG_SR,
-                                ISL12057_REG_SR_OSF, 0);
-       if (ret < 0) {
-               dev_err(dev, "Unable to clear oscillator failure bit\n");
-               return ret;
-       }
-
        /* Clear alarm bit if needed */
        ret = regmap_update_bits(regmap, ISL12057_REG_SR,
                                 ISL12057_REG_SR_A1F, 0);