From: Thomas Petazzoni Date: Fri, 22 Apr 2016 13:19:52 +0000 (+0200) Subject: i2c: mv64xxx: handle probe deferral for the clock X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9f4d6f164229d4221272186597d9393f654adbb9;p=linux-beck.git i2c: mv64xxx: handle probe deferral for the clock If a clock is registered by a platform driver and not by the OF_CLK_DECLARE() mechanism, it might show up after the first attempt to probe i2c-mv64xxx. In order to solve this, we need to handle -EPROBE_PREFER as a special return value of devm_clk_get(), and return the same error code from probe(). This gives us three situations: - There is no reference to a clock in the DT. In this case, devm_clk_get() returns an error that is not -EPROBE_DEFER (something like -ENODEV), and we continue the probing without enabling the clock. - There is a reference to the clock in the DT, and the clock is ready. devm_clk_get() returns a valid reference to the clock, and we prepare/enable it. - There is a reference to the clock in the DT, but the clock is not ready. devm_clk_get() returns -EPROBE_DEFER, and we exit from probe() with the same error code so that probe() is tried again later. This is needed for Marvell Armada 7K/8K, where the clock driver is a platform driver. Signed-off-by: Thomas Petazzoni Signed-off-by: Wolfram Sang --- diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index 43207f52e5a3..4c6282a78109 100644 --- a/drivers/i2c/busses/i2c-mv64xxx.c +++ b/drivers/i2c/busses/i2c-mv64xxx.c @@ -910,6 +910,8 @@ mv64xxx_i2c_probe(struct platform_device *pd) #if defined(CONFIG_HAVE_CLK) /* Not all platforms have a clk */ drv_data->clk = devm_clk_get(&pd->dev, NULL); + if (IS_ERR(drv_data->clk) && PTR_ERR(drv_data->clk) == -EPROBE_DEFER) + return -EPROBE_DEFER; if (!IS_ERR(drv_data->clk)) { clk_prepare(drv_data->clk); clk_enable(drv_data->clk);