linux-kernel - Re: [PATCH] tpm_tis_spi: set default probe function if device id not match

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Date:   Wed, 12 May 2021 04:19:16 +0300
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     乱石 <zhangliguang@...ux.alibaba.com>
Cc:     Peter Huewe <peterhuewe@....de>, Jason Gunthorpe <jgg@...pe.ca>,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tpm_tis_spi: set default probe function if device id not
 match

On Wed, May 12, 2021 at 09:07:56AM +0800, 乱石 wrote:
> 在 2021/5/10 4:39, Jarkko Sakkinen 写道:
> > On Sat, May 08, 2021 at 10:46:57AM +0800, 乱石 wrote:
> > > Hi,
> > > 
> > > 在 2021/5/8 10:01, Jarkko Sakkinen 写道:
> > > > On Fri, May 07, 2021 at 10:52:55PM +0800, Liguang Zhang wrote:
> > > > > In DSDT table, TPM _CID was SMO0768, and no _HID definition. After a
> > > > > kernel upgrade from 4.19 to 5.10, TPM probe function was changed which
> > > > > causes device probe fails. In order to make newer kernel to be
> > > > > compatible with the older acpi definition, it would be best set default
> > > > > probe function.
> > > > > 
> > > > > Signed-off-by: Liguang Zhang <zhangliguang@...ux.alibaba.com>
> > > > > ---
> > > > >    drivers/char/tpm/tpm_tis_spi_main.c | 12 ++++++++----
> > > > >    1 file changed, 8 insertions(+), 4 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/char/tpm/tpm_tis_spi_main.c b/drivers/char/tpm/tpm_tis_spi_main.c
> > > > > index 3856f6ebcb34..da632a582621 100644
> > > > > --- a/drivers/char/tpm/tpm_tis_spi_main.c
> > > > > +++ b/drivers/char/tpm/tpm_tis_spi_main.c
> > > > > @@ -240,10 +240,14 @@ static int tpm_tis_spi_driver_probe(struct spi_device *spi)
> > > > >    	tpm_tis_spi_probe_func probe_func;
> > > > >    	probe_func = of_device_get_match_data(&spi->dev);
> > > > > -	if (!probe_func && spi_dev_id)
> > > > > -		probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
> > > > > -	if (!probe_func)
> > > > > -		return -ENODEV;
> > > > > +	if (!probe_func) {
> > > > > +		if (spi_dev_id) {
> > > > > +			probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
> > > > > +			if (!probe_func)
> > > > > +				return -ENODEV;
> > > > Perhaps also hear fallback to tpm_tis_spi_probe?
> > > 
> > > Yes, I do not think of a good way. Do you have any suggestions?
> > So, I just think that when you have this part:
> > 
> > 
> > if (!probe_func) {
> > 	if (spi_dev_id) {
> >                  probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
> >                  if (!probe_func)
> >                          return -ENODEV;
> > 
> > Why in here would not you also want to fallback to tpm_tis_spi_probe?
> 
> Sorry to trouble you, do you have a good way to resolve the compatible
> problem caused by kernel update (4.19 -> 5.10) ?

I think I'll take this as it is.

I'll apply it to my tree and take it as part of next pr.

Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>

/Jarkko