[PATCH v3 06/31] i2c: mpc: cleanup clock API use
From: Gerhard Sittig <hidden>
Date: 2013-07-22 12:14:33
Also in:
linux-devicetree, linuxppc-dev
Subsystem:
freescale mpc i2c driver, i2c subsystem, i2c subsystem host drivers, the rest · Maintainers:
Chris Packham, Wolfram Sang, Andi Shyti, Linus Torvalds
make the MPC I2C driver get, prepare and enable the peripheral clock
('per' for access to the peripheral's registers) during probe;
disable, unprepare and put the clock upon remove(); 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 enable errors for
specified clocks are considered fatal
Signed-off-by: Gerhard Sittig <redacted>
---
drivers/i2c/busses/i2c-mpc.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index 7607dc0..9e837be 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c@@ -21,6 +21,7 @@ #include <linux/of_i2c.h> #include <linux/slab.h> +#include <linux/clk.h> #include <linux/io.h> #include <linux/fsl_devices.h> #include <linux/i2c.h>
@@ -67,6 +68,7 @@ struct mpc_i2c { #ifdef CONFIG_PM u8 fdr, dfsrr; #endif + struct clk *clk_per; }; struct mpc_i2c_divider {
@@ -623,6 +625,8 @@ static int fsl_i2c_probe(struct platform_device *op) u32 clock = MPC_I2C_CLOCK_LEGACY; int result = 0; int plen; + struct clk *clk; + int err; match = of_match_device(mpc_i2c_of_match, &op->dev); if (!match)
@@ -653,6 +657,21 @@ 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, "per"); + if (!IS_ERR(clk)) { + err = clk_prepare_enable(clk); + if (err) { + dev_err(&op->dev, "failed to enable clock\n"); + devm_clk_put(&op->dev, clk); + } else { + i2c->clk_per = clk; + } + } + if (of_get_property(op->dev.of_node, "fsl,preserve-clocking", NULL)) { clock = MPC_I2C_CLOCK_PRESERVE; } else {
@@ -696,6 +715,10 @@ static int fsl_i2c_probe(struct platform_device *op) return result; fail_add: + if (i2c->clk_per) { + clk_disable_unprepare(i2c->clk_per); + devm_clk_put(&op->dev, i2c->clk_per); + } free_irq(i2c->irq, i2c); fail_request: irq_dispose_mapping(i2c->irq);
@@ -711,6 +734,11 @@ static int fsl_i2c_remove(struct platform_device *op) i2c_del_adapter(&i2c->adap); + if (i2c->clk_per) { + clk_disable_unprepare(i2c->clk_per); + devm_clk_put(&op->dev, i2c->clk_per); + } + if (i2c->irq) free_irq(i2c->irq, i2c);
--
1.7.10.4