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Date:   Sat, 8 May 2021 05:01:51 +0300
From:   Jarkko Sakkinen <jarkko@kernel.org>
To:     Liguang Zhang <zhangliguang@linux.alibaba.com>
Cc:     Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
        linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tpm_tis_spi: set default probe function if device id not
 match
Message-ID: <YJXxDzougt3ZC01q@kernel.org>
References: <20210507145255.44033-1-zhangliguang@linux.alibaba.com>
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In-Reply-To: <20210507145255.44033-1-zhangliguang@linux.alibaba.com>
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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@linux.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?

> +		} else
> +			probe_func = tpm_tis_spi_probe;
> +	}
>  
>  	return probe_func(spi);
>  }
> -- 
> 2.19.1.6.gb485710b
> 
> 

/Jarkko