linux-kernel - Re: [PATCH] serial: 8250_dw: Fix assignment error of data in dw8250

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Message-ID: <7ff795d4-fb67-4c5d-04be-4eff7f9b70fa@huawei.com>
Date:   Fri, 4 Aug 2023 20:41:14 +0800
From:   Xia Fukun <xiafukun@...wei.com>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
CC:     <andy.shevchenko@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        <heikki.krogerus@...ux.intel.com>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-serial <linux-serial@...r.kernel.org>
Subject: Re: [PATCH] serial: 8250_dw: Fix assignment error of data in
 dw8250_probe()


On 2023/8/4 20:24, Ilpo Järvinen wrote:
> On Fri, 4 Aug 2023, Xia Fukun wrote:
> 
>> When the "ri-override" property is present in the device,
>> data->msr_mask_on and UART_MSR_RI should be used for
>> OR-assignment. Fix the errors in it.
>>  
>>  	if (device_property_read_bool(dev, "ri-override")) {
>>  		/* Always report Ring indicator as inactive */
>> -		data->msr_mask_off |= UART_MSR_RI;
>> +		data->msr_mask_on |= UART_MSR_RI;
>>  		data->msr_mask_off |= UART_MSR_TERI;
> 
> The comment and also documentation says RI signal is always kept inactive 
> when ri-override is present.
> 
> In Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml:
> 
>   ri-override:
>     description: Override the RI modem status signal. This signal will always
>       be reported as inactive instead of being obtained from the modem status
>       register. Define this if your serial port does not use this pin.
> 
> ...So why you think this patch is correct? (Please explain it in the v2
> changelog clearly if you think your patch is still correct thing to do, 
> thank you).
> 

Thank you very much for your reply. My understanding of this property is
indeed flawed. That is to say, in the "ri-override" property,
data->msr_mask_on will not be used, there will be no signal transmission?
In that case, you are right. My patch may be redundant.