[PATCH 1/2] mfd: twl6040: Fix deferred probe handling for clk32k

[Felipe Balbi]

On Fri, Sep 18, 2015 at 09:29:04AM -0700, Tony Lindgren wrote:
> Commit 68bab8662f49 ("mfd: twl6040: Optional clk32k clock handling")
> added clock handling for the 32k clock from palmas-clk. However, that
> patch did not consider a typical situation where twl6040 is built-in,
> and palmas-clk is a loadable module like we have in omap2plus_defconfig.
> 
> If palmas-clk is not loaded before twl6040 probes, we will get a
> "clk32k is not handled" warning during booting. This means that any
> drivers relying on this clock will mysteriously fail, including
> omap5-uevm WLAN and audio.
> 
> Note that for WLAN, we probably should also eventually get
> the clk32kgaudio for MMC3 directly as that's shared between
> audio and WLAN SDIO at least for omap5-uevm. It seems the
> WLAN chip cannot get it as otherwise MMC3 won't get properly
> probed.
> 
> Fixes: 68bab8662f49 ("mfd: twl6040: Optional clk32k clock handling")
> Cc: Benoit Cousson <bcousson at baylibre.com>
> Cc: Dr. H. Nikolaus Schaller <hns at goldelico.com>
> Cc: Grazvydas Ignotas <notasas at gmail.com>
> Cc: Lee Jones <lee.jones at linaro.org>
> Cc: Peter Ujfalusi <peter.ujfalusi at ti.com>
> Cc: Samuel Ortiz <sameo at linux.intel.com>
> Cc: Sourav Poddar <sourav.poddar at ti.com>
> Signed-off-by: Tony Lindgren <tony at atomide.com>

Reviewed-by: Felipe Balbi <balbi at ti.com>

> ---
>  drivers/mfd/twl6040.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> --- a/drivers/mfd/twl6040.c
> +++ b/drivers/mfd/twl6040.c
> @@ -647,6 +647,8 @@ static int twl6040_probe(struct i2c_client *client,
>  
>  	twl6040->clk32k = devm_clk_get(&client->dev, "clk32k");
>  	if (IS_ERR(twl6040->clk32k)) {
> +		if (PTR_ERR(twl6040->clk32k) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
>  		dev_info(&client->dev, "clk32k is not handled\n");
>  		twl6040->clk32k = NULL;
>  	}
> -- 
> 2.1.4
> 
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-- 
balbi
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