mfd: Add support for enabling tps65910 external 32-kHz oscillator

Add flag to platform data to enable external 32-kHz crystal oscillator
(or square wave) input.

The tps6591x can use either an internal 32-kHz RC oscillator or an
external crystal (or square wave) to generate the 32-kHz clock.

The default setting depends on the selected boot mode. In boot mode 00
the internal RC oscillator is used at power-on, but the external crystal
oscillator (or square wave) can be enabled by clearing the ck32k_ctrl
flag in the device control register.

Note that there is no way to switch from the external crystal oscillator
to the internal RC oscillator.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/drivers/mfd/tps65910.c b/drivers/mfd/tps65910.c
index be9e07b77325..b0526b7d6550 100644
--- a/drivers/mfd/tps65910.c
+++ b/drivers/mfd/tps65910.c
@@ -68,6 +68,25 @@ static const struct regmap_config tps65910_regmap_config = {
         .cache_type = REGCACHE_RBTREE,
 };
 
+static int __devinit tps65910_misc_init(struct tps65910 *tps65910,
+                                        struct tps65910_board *pmic_pdata)
+{
+        struct device *dev = tps65910->dev;
+        int ret;
+
+        if (pmic_pdata->en_ck32k_xtal) {
+                ret = tps65910_reg_clear_bits(tps65910,
+                                                TPS65910_DEVCTRL,
+                                                DEVCTRL_CK32K_CTRL_MASK);
+                if (ret < 0) {
+                        dev_err(dev, "clear ck32k_ctrl failed: %d\n", ret);
+                        return ret;
+                }
+        }
+
+        return 0;
+}
+
 static int __devinit tps65910_sleepinit(struct tps65910 *tps65910,
                 struct tps65910_board *pmic_pdata)
 {
@@ -243,7 +262,7 @@ static __devinit int tps65910_i2c_probe(struct i2c_client *i2c,
         init_data->irq_base = pmic_plat_data->irq_base;
 
         tps65910_irq_init(tps65910, init_data->irq, init_data);
-
+        tps65910_misc_init(tps65910, pmic_plat_data);
         tps65910_sleepinit(tps65910, pmic_plat_data);
 
         return ret;