[PATCH v4 2/4] mfd: wm5110: Add register patch required for low power sleep

[Charles Keepax <ckeepax@opensource.wolfsonmicro.com>]

Some register settings must be applied before the first time low power
sleep mode is entered on the wm5110 to ensure optimium performance.
These settings require SYSCLK to be enabled whilst they are being
applied. This patch applies the settings using the recently factored out
boot time SYSCLK functionality.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/mfd/arizona-core.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
index 13428cf..534d946 100644
--- a/drivers/mfd/arizona-core.c
+++ b/drivers/mfd/arizona-core.c
@@ -364,6 +364,38 @@ err:
 	return ret ?: err;
 }
 
+/*
+ * Register patch to some of the CODECs internal write sequences
+ * to ensure a clean exit from the low power sleep state.
+ */
+static const struct reg_default wm5110_sleep_patch[] = {
+	{ 0x337A, 0xC100 },
+	{ 0x337B, 0x0041 },
+	{ 0x3300, 0xA210 },
+	{ 0x3301, 0x050C },
+};
+
+static inline int wm5110_apply_sleep_patch(struct arizona *arizona)
+{
+	struct arizona_sysclk_state state;
+	int err, ret;
+
+	ret = arizona_enable_freerun_sysclk(arizona, &state);
+	if (ret)
+		return ret;
+
+	ret = regmap_multi_reg_write_bypassed(arizona->regmap,
+					      wm5110_sleep_patch,
+					      ARRAY_SIZE(wm5110_sleep_patch));
+
+	err = arizona_disable_freerun_sysclk(arizona, &state);
+
+	if (ret)
+		return ret;
+	else
+		return err;
+}
+
 #ifdef CONFIG_PM
 static int arizona_runtime_resume(struct device *dev)
 {
@@ -933,6 +965,16 @@ int arizona_dev_init(struct arizona *arizona)
 				goto err_reset;
 			}
 			break;
+		case WM5110:
+		case WM8280:
+			ret = wm5110_apply_sleep_patch(arizona);
+			if (ret) {
+				dev_err(arizona->dev,
+					"Failed to apply sleep patch: %d\n",
+					ret);
+				goto err_reset;
+			}
+			break;
 		default:
 			break;
 		}
-- 
1.7.2.5