mfd: Support LP3974 RTC

The first releases of LP3974 have a large delay in RTC registers,
which requires 2 seconds of delay after writing to a rtc register
(recommended by National Semiconductor's engineers)
before reading it.

If "rtc_delay" field of the platform data is true, the rtc driver
assumes that such delays are required. Although we have not seen
LP3974s without requiring such delays, we assume that such LP3974s
will be released soon (or they have done so already) and they are
supported by "lp3974" without setting "rtc_delay" at the platform
data.

This patch adds delays with msleep when writing values to RTC registers
if the platform data has rtc_delay set.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/regulator/max8998.c b/drivers/regulator/max8998.c
index 7568df6122ab..af52ebfc4927 100644
--- a/drivers/regulator/max8998.c
+++ b/drivers/regulator/max8998.c
@@ -835,6 +835,12 @@ static int __devexit max8998_pmic_remove(struct platform_device *pdev)
         return 0;
 }
 
+static const struct platform_device_id max8998_pmic_id[] = {
+        { "max8998-pmic", TYPE_MAX8998 },
+        { "lp3974-pmic", TYPE_LP3974 },
+        { }
+};
+
 static struct platform_driver max8998_pmic_driver = {
         .driver = {
                 .name = "max8998-pmic",
@@ -842,6 +848,7 @@ static struct platform_driver max8998_pmic_driver = {
         },
         .probe = max8998_pmic_probe,
         .remove = __devexit_p(max8998_pmic_remove),
+        .id_table = max8998_pmic_id,
 };
 
 static int __init max8998_pmic_init(void)