Re: [PATCH 1/2] mtd: rawnand: gpmi: Fix suspend/resume problem

[Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>]

Hi Esben,

On Thu, Jan 02, 2020 at 02:08:25PM +0100, Esben Haabendal wrote:
> On system resume, the gpmi clock must be enabled before accessing gpmi
> block.  Without this, resume causes something like
> 
> [  661.348790] gpmi_reset_block(5cbb0f7e): module reset timeout
> [  661.348889] gpmi-nand 1806000.gpmi-nand: Error setting GPMI : -110
> [  661.348928] PM: dpm_run_callback(): platform_pm_resume+0x0/0x44 returns -110
> [  661.348961] PM: Device 1806000.gpmi-nand failed to resume: error -110
> 
> Signed-off-by: Esben Haabendal <esben@xxxxxxxxxx>
> ---
>  drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> index 334fe3130285..7ac8c8b95afc 100644
> --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> @@ -148,6 +148,10 @@ static int gpmi_init(struct gpmi_nand_data *this)
>  	struct resources *r = &this->resources;
>  	int ret;
>  
> +	ret = pm_runtime_get_sync(this->dev);
> +	if (ret < 0)
> +		return ret;

This increases the devices usage counter...

> +
>  	ret = gpmi_reset_block(r->gpmi_regs, false);
>  	if (ret)
>  		goto err_out;
> @@ -181,6 +185,8 @@ static int gpmi_init(struct gpmi_nand_data *this)
>  
>  	return 0;

... but doesn't decrease it in the success case. This means this patch
effectively disables runtime pm. You should fall through here as fixed
in Han Xus patch.

>  err_out:
> +	pm_runtime_mark_last_busy(this->dev);
> +	pm_runtime_put_autosuspend(this->dev);
>  	return ret;

Sascha

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