linux-kernel - Re: [PATCH] mfd: ab8500-sysctrl: Handle probe deferral

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Date:   Fri, 13 Jan 2017 16:06:20 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mfd: ab8500-sysctrl: Handle probe deferral

On Fri, 13 Jan 2017, Linus Walleij wrote:

> In the current boot, clients making use of the AB8500 sysctrl
> may be probed before the ab8500-sysctrl driver. This gives them
> -EINVAL, but should rather give -EPROBE_DEFER.
> 
> Before this, the abx500 clock driver didn't probe properly,
> and as a result the codec driver in turn using the clocks did
> not probe properly. After this patch, everything probes
> properly.
> 
> Also add OF compatible-string probing. This driver is all
> device tree, so let's just make a drive-by-fix of that as
> well.

Sneaky!  I usually ask for separate patches for this kind of stuff.

But hey, it's (just after) Christmas.

Applied, thanks.

> Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
> ---
>  drivers/mfd/ab8500-sysctrl.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mfd/ab8500-sysctrl.c b/drivers/mfd/ab8500-sysctrl.c
> index 80c0efa66ac1..5b0a0850ef69 100644
> --- a/drivers/mfd/ab8500-sysctrl.c
> +++ b/drivers/mfd/ab8500-sysctrl.c
> @@ -101,7 +101,7 @@ int ab8500_sysctrl_read(u16 reg, u8 *value)
>  	u8 bank;
>  
>  	if (sysctrl_dev == NULL)
> -		return -EINVAL;
> +		return -EPROBE_DEFER;
>  
>  	bank = (reg >> 8);
>  	if (!valid_bank(bank))
> @@ -117,11 +117,13 @@ int ab8500_sysctrl_write(u16 reg, u8 mask, u8 value)
>  	u8 bank;
>  
>  	if (sysctrl_dev == NULL)
> -		return -EINVAL;
> +		return -EPROBE_DEFER;
>  
>  	bank = (reg >> 8);
> -	if (!valid_bank(bank))
> +	if (!valid_bank(bank)) {
> +		pr_err("invalid bank\n");
>  		return -EINVAL;
> +	}
>  
>  	return abx500_mask_and_set_register_interruptible(sysctrl_dev, bank,
>  		(u8)(reg & 0xFF), mask, value);
> @@ -148,9 +150,15 @@ static int ab8500_sysctrl_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static const struct of_device_id ab8500_sysctrl_match[] = {
> +	{ .compatible = "stericsson,ab8500-sysctrl", },
> +	{}
> +};
> +
>  static struct platform_driver ab8500_sysctrl_driver = {
>  	.driver = {
>  		.name = "ab8500-sysctrl",
> +		.of_match_table = ab8500_sysctrl_match,
>  	},
>  	.probe = ab8500_sysctrl_probe,
>  	.remove = ab8500_sysctrl_remove,

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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