mfd: twl6040: Optional clk32k clock handling

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>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

3 files changed, 14 insertions, 0 deletions

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 cb37bb8f8e41..574774d7f826 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];