linux-kernel - Re: [PATCH v3] spi: xilinx: use device property accessors.

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Message-ID: <ac0c9ceb-0c34-49f2-a486-1d87e488f607@amd.com>
Date: Fri, 23 Jan 2026 08:11:47 +0100
From: Michal Simek <michal.simek@....com>
To: Andrew Lunn <andrew@...n.ch>, abdurrahman@...thop.ai
Cc: Mark Brown <broonie@...nel.org>, linux-spi@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] spi: xilinx: use device property accessors.



On 1/22/26 17:18, Andrew Lunn wrote:
> On Thu, Jan 22, 2026 at 09:00:29AM +0000, Abdurrahman Hussain via B4 Relay wrote:
>> From: Abdurrahman Hussain <abdurrahman@...thop.ai>
>>
>> Switch to device property accessors.
>>
>> Signed-off-by: Abdurrahman Hussain <abdurrahman@...thop.ai>
>> ---
>> Switch to generic device property accessors.
>>
>> Changed from v3:
>>
>> Removed the patches to make irq optional from the series
>>
>> 2.52.0
>>
>> base-commit: 944aacb68baf7624ab8d277d0ebf07f025ca137c
>> ---
>>   drivers/spi/spi-xilinx.c | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
>> index c86dc56f38b4..c4b70e95b695 100644
>> --- a/drivers/spi/spi-xilinx.c
>> +++ b/drivers/spi/spi-xilinx.c
>> @@ -405,11 +405,11 @@ static int xilinx_spi_probe(struct platform_device *pdev)
>>   		bits_per_word = pdata->bits_per_word;
>>   		force_irq = pdata->force_irq;
>>   	} else {
>> -		of_property_read_u32(pdev->dev.of_node, "xlnx,num-ss-bits",
>> -					  &num_cs);
>> -		ret = of_property_read_u32(pdev->dev.of_node,
>> -					   "xlnx,num-transfer-bits",
>> -					   &bits_per_word);
>> +		device_property_read_u32(&pdev->dev, "xlnx,num-ss-bits",
>> +					 &num_cs);
>> +		ret = device_property_read_u32(&pdev->dev,
>> +					       "xlnx,num-transfer-bits",
>> +					       &bits_per_word);
> 
> It could be my grep foo is broken, but there does not appear to be any
> users of xlnx,num-transfer-bits and xlnx,num-ss-bits. So it would be
> better to just remove them. There is no point Maintaining an API
> nobody uses. And it would be silly to spread that API to ACPI if
> nobody it going to use it.
> 

"xlnx,num-transfer-bits"
bits_per_word is initializing bytes_per_word which is used in code for transfer 
sizes calculations.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/spi/spi-xilinx.c?h=v6.19-rc6#n470
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/spi/spi-xilinx.c?h=v6.19-rc6#n125

"xlnx,num-ss-bits"
num_cs is used in host->num_chipselect to declare amount of chip selects.

Both are also the part of DT bindings. The name of property exactly match the 
name used in design tool. That's why it is 1:1 mapping and driver is quite old 
before num-cs property has been created.

Thanks,
Michal