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 <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-mv64xxx.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 43207f5..4c6282a 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);
--
2.6.4
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