From: Gerhard Sittig <[email protected]> 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 Cc: Wolfram Sang <[email protected]> Signed-off-by: Gerhard Sittig <[email protected]> Signed-off-by: Anatolij Gustschin <[email protected]> --- drivers/i2c/busses/i2c-mpc.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c index ffac214..50da3b2 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_SLEEP 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) 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) @@ -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, 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 { @@ -699,6 +718,8 @@ 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); @@ -714,6 +735,9 @@ 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); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
