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authorGerhard Sittig <gsi@denx.de>2013-08-23 18:01:44 +0200
committerWolfram Sang <wsa@the-dreams.de>2013-08-28 10:48:44 +0200
commitb3bfce2bc205ff4fdb4ec0b048513557cef459cf (patch)
tree5b006b07d78f10705e78e14911f3791de42cf0c6 /drivers/i2c
parent498c0146213aa5fbca3b63a6525e91c606c20c5e (diff)
i2c: mpc: cleanup clock API use
make the MPC I2C driver get, prepare and enable the gated clock item for register access during probe; disable and unprepare the clock upon remove(), put is done by the devm approach; hold a reference to the clock over the period of use clock lookup is non-fatal in this implementation as not all platforms may provide clock specs in their device tree, but failure to enable a clock when specified is considered fatal Signed-off-by: Gerhard Sittig <gsi@denx.de> Signed-off-by: Anatolij Gustschin <agust@denx.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-mpc.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index f4060939e959..b80c76888cab 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -20,6 +20,7 @@
#include <linux/of_platform.h>
#include <linux/slab.h>
+#include <linux/clk.h>
#include <linux/io.h>
#include <linux/fsl_devices.h>
#include <linux/i2c.h>
@@ -66,6 +67,7 @@ struct mpc_i2c {
#ifdef CONFIG_PM_SLEEP
u8 fdr, dfsrr;
#endif
+ struct clk *clk_per;
};
struct mpc_i2c_divider {
@@ -622,6 +624,8 @@ static int fsl_i2c_probe(struct platform_device *op)
int result = 0;
int plen;
struct resource res;
+ struct clk *clk;
+ int err;
match = of_match_device(mpc_i2c_of_match, &op->dev);
if (!match)
@@ -652,6 +656,21 @@ static int fsl_i2c_probe(struct platform_device *op)
}
}
+ /*
+ * enable clock for the I2C peripheral (non fatal),
+ * keep a reference upon successful allocation
+ */
+ clk = devm_clk_get(&op->dev, NULL);
+ if (!IS_ERR(clk)) {
+ err = clk_prepare_enable(clk);
+ if (err) {
+ dev_err(&op->dev, "failed to enable clock\n");
+ goto fail_request;
+ } else {
+ i2c->clk_per = clk;
+ }
+ }
+
if (of_get_property(op->dev.of_node, "fsl,preserve-clocking", NULL)) {
clock = MPC_I2C_CLOCK_PRESERVE;
} else {
@@ -697,6 +716,8 @@ static int fsl_i2c_probe(struct platform_device *op)
return result;
fail_add:
+ if (i2c->clk_per)
+ clk_disable_unprepare(i2c->clk_per);
free_irq(i2c->irq, i2c);
fail_request:
irq_dispose_mapping(i2c->irq);
@@ -712,6 +733,9 @@ static int fsl_i2c_remove(struct platform_device *op)
i2c_del_adapter(&i2c->adap);
+ if (i2c->clk_per)
+ clk_disable_unprepare(i2c->clk_per);
+
if (i2c->irq)
free_irq(i2c->irq, i2c);