Re: [PATCH V6 3/5] tty: serial: meson: Describes the calculation of the UART baud rate clock using a clock frame

From: Jerome Brunet <jbrunet@baylibre.com>
To: Jiri Slaby <jirislaby@kernel.org>, Yu Tu <yu.tu@amlogic.com>,
	linux-serial@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Kevin Hilman <khilman@baylibre.com>,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Subject: Re: [PATCH V6 3/5] tty: serial: meson: Describes the calculation of the UART baud rate clock using a clock frame
Date: Thu, 20 Jan 2022 22:48:05 +0100	[thread overview]
Message-ID: <1jbl062i4o.fsf@starbuckisacylon.baylibre.com> (raw)
In-Reply-To: <7a8016ba-730b-f599-2032-31cf03990a55@kernel.org>

On Tue 18 Jan 2022 at 10:39, Jiri Slaby <jirislaby@kernel.org> wrote:

> On 18. 01. 22, 4:09, Yu Tu wrote:
>> Using the common Clock code to describe the UART baud rate clock
>> makes it easier for the UART driver to be compatible with the
>> baud rate requirements of the UART IP on different meson chips.
> ...
>> --- a/drivers/tty/serial/meson_uart.c
>> +++ b/drivers/tty/serial/meson_uart.c
> ...
>> @@ -629,57 +640,105 @@ static struct uart_driver meson_uart_driver = {
>>   	.cons		= MESON_SERIAL_CONSOLE,
>>   };
>>   -static inline struct clk *meson_uart_probe_clock(struct device *dev,
>> -						 const char *id)
>> -{
>> -	struct clk *clk = NULL;
>> -	int ret;
>> -
>> -	clk = devm_clk_get(dev, id);
>> -	if (IS_ERR(clk))
>> -		return clk;
>> -
>> -	ret = clk_prepare_enable(clk);
>> -	if (ret) {
>> -		dev_err(dev, "couldn't enable clk\n");
>> -		return ERR_PTR(ret);
>> -	}
>> -
>> -	devm_add_action_or_reset(dev,
>> -			(void(*)(void *))clk_disable_unprepare,
>> -			clk);
>> -
>> -	return clk;
>> -}
>> +static struct clk_div_table xtal_div_table[] = {
>
> This can be const, right?
>
>> +	{0, 3},
>> +	{1, 1},
>> +	{2, 2},
>> +	{3, 2},
>
> Not sure if you didn't remove too much whitespace. I think it should be
> like: "{ 0, 3 },". But I actually don't care, it's a minor thing.

Seconds
It worth fixing in the next version

>
> I cannot comment on the rest (clk and OF part) as my knowledge is pretty
> limited there. Leaving up to others.
>
> thanks,