linux-kernel - Re: [PATCH 2/2 v4] tty/serial/8250: use mctrl

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Message-ID: <20190604165224.GP9224@smile.fi.intel.com>
Date:   Tue, 4 Jun 2019 19:52:24 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Stefan Roese <sr@...x.de>
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        Yegor Yefremov <yegorslists@...glemail.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Giulio Benetti <giulio.benetti@...ronovasrl.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Johan Hovold <johan@...nel.org>
Subject: Re: [PATCH 2/2 v4] tty/serial/8250: use mctrl_gpio helpers

On Mon, Jun 03, 2019 at 10:33:32AM +0200, Stefan Roese wrote:
> From: Yegor Yefremov <yegorslists@...glemail.com>
> 
> This patch permits the usage for GPIOs to control
> the CTS/RTS/DTR/DSR/DCD/RI signals.

> +	if (up->gpios) {

> +		mctrl_gpio_set(up->gpios, mctrl_gpio);
> +	}

...

> +	if (up->gpios) {

> +		mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio);

> +	}

...

> +			gpios = mctrl_gpio_init(&uart->port, 0);
> +			if (IS_ERR(gpios)) {
> +				if (PTR_ERR(gpios) != -ENOSYS)
> +					return PTR_ERR(gpios);
> +			}

...

> +	if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios,
> +						UART_GPIO_RTS))) {

> +	}

...

> -	if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {
> +	if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW
> +		&& IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios,
> +							UART_GPIO_RTS))) {

> }

...

> +	if (up->gpios)
> +		mctrl_gpio_disable_ms(up->gpios);

...

> +	if (up->gpios)
> +		mctrl_gpio_enable_ms(up->gpios);

...

> +	if (up->gpios)
> +		return mctrl_gpio_get(up->gpios, &ret);


Can we rather make this mimic the gpiod_get_optional() API?

So, if we get an error, it's an error, otherwise with NULL pointer the
operations goes to be no-op.

[IS_ERR_OR_NULL() -> IS_ERR(), if (up->gpios) -> /dev/null, etc]


-- 
With Best Regards,
Andy Shevchenko