[PATCH] mfd: twl6040: Optional clk32k clock handling

[Peter Ujfalusi <peter.ujfalusi@ti.com>]

In certain boards the source for the clk32k clock can be gated. In these
boards the clk32k clock can be provided to the driver and it is going to be
enabled/disabled when it is needed.
If the clk32k clock is not provided the driver will assume that it is always
running.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 Documentation/devicetree/bindings/mfd/twl6040.txt |  2 ++
 drivers/mfd/twl6040.c                             | 10 ++++++++++
 include/linux/mfd/twl6040.h                       |  2 ++
 3 files changed, 14 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/twl6040.txt b/Documentation/devicetree/bindings/mfd/twl6040.txt
index 0f5dd709d752..a41157b5d930 100644
--- a/Documentation/devicetree/bindings/mfd/twl6040.txt
+++ b/Documentation/devicetree/bindings/mfd/twl6040.txt
@@ -19,6 +19,8 @@ Required properties:
 
 Optional properties, nodes:
 - enable-active-high: To power on the twl6040 during boot.
+- clocks: phandle to the clk32k clock provider
+- clock-names: Must be "clk32k"
 
 Vibra functionality
 Required properties:
diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
index 2e6504a8e1e3..12b314ea48dc 100644
--- a/drivers/mfd/twl6040.c
+++ b/drivers/mfd/twl6040.c
@@ -291,6 +291,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
 		if (twl6040->power_count++)
 			goto out;
 
+		clk_prepare_enable(twl6040->clk32k);
+
 		/* Allow writes to the chip */
 		regcache_cache_only(twl6040->regmap, false);
 
@@ -346,6 +348,8 @@ int twl6040_power(struct twl6040 *twl6040, int on)
 
 		twl6040->sysclk = 0;
 		twl6040->mclk = 0;
+
+		clk_disable_unprepare(twl6040->clk32k);
 	}
 
 out:
@@ -644,6 +648,12 @@ static int twl6040_probe(struct i2c_client *client,
 
 	i2c_set_clientdata(client, twl6040);
 
+	twl6040->clk32k = devm_clk_get(&client->dev, "clk32k");
+	if (IS_ERR(twl6040->clk32k)) {
+		dev_info(&client->dev, "clk32k is not handled\n");
+		twl6040->clk32k = NULL;
+	}
+
 	twl6040->supplies[0].supply = "vio";
 	twl6040->supplies[1].supply = "v2v1";
 	ret = devm_regulator_bulk_get(&client->dev, TWL6040_NUM_SUPPLIES,
diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
index a69d16b30c18..8f9fc3d26e6d 100644
--- a/include/linux/mfd/twl6040.h
+++ b/include/linux/mfd/twl6040.h
@@ -28,6 +28,7 @@
 #include <linux/interrupt.h>
 #include <linux/mfd/core.h>
 #include <linux/regulator/consumer.h>
+#include <linux/clk.h>
 
 #define TWL6040_REG_ASICID		0x01
 #define TWL6040_REG_ASICREV		0x02
@@ -223,6 +224,7 @@ struct twl6040 {
 	struct regmap *regmap;
 	struct regmap_irq_chip_data *irq_data;
 	struct regulator_bulk_data supplies[2]; /* supplies for vio, v2v1 */
+	struct clk *clk32k;
 	struct mutex mutex;
 	struct mutex irq_mutex;
 	struct mfd_cell cells[TWL6040_CELLS];
-- 
1.9.1