linux-kernel - Re: [PATCH v3 2/4] tty: serial: atmel: use devm_clk

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Message-ID: <b08857ab-ce3d-d597-b229-1a61b849118d@gmail.com>
Date:   Fri, 17 Jun 2022 15:06:24 +0200
From:   Richard Genoud <richard.genoud@...il.com>
To:     Claudiu Beznea <claudiu.beznea@...rochip.com>,
        richard.genoud@...il.com, gregkh@...uxfoundation.org,
        jirislaby@...nel.org, nicolas.ferre@...rochip.com,
        alexandre.belloni@...tlin.com, patrice.chotard@...s.st.com
Cc:     linux-serial@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/4] tty: serial: atmel: use devm_clk_get()


Le 16/06/2022 à 16:00, Claudiu Beznea a écrit :
> Use devm_clk_get() for serial clock instead of clk_get()/clk_put().
> With this move the clk_get in driver's probe function.
> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
Acked-by: Richard Genoud <richard.genoud@...il.com>

> ---
>   drivers/tty/serial/atmel_serial.c | 50 ++++++++++---------------------
>   1 file changed, 15 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index c618d7e93058..4cec97fd7241 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -2508,24 +2508,7 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
>   	if (ret)
>   		return ret;
>   
> -	/* for console, the clock could already be configured */
> -	if (!atmel_port->clk) {
> -		atmel_port->clk = clk_get(&mpdev->dev, "usart");
> -		if (IS_ERR(atmel_port->clk)) {
> -			ret = PTR_ERR(atmel_port->clk);
> -			atmel_port->clk = NULL;
> -			return ret;
> -		}
> -		ret = clk_prepare_enable(atmel_port->clk);
> -		if (ret) {
> -			clk_put(atmel_port->clk);
> -			atmel_port->clk = NULL;
> -			return ret;
> -		}
> -		port->uartclk = clk_get_rate(atmel_port->clk);
> -		clk_disable_unprepare(atmel_port->clk);
> -		/* only enable clock when USART is in use */
> -	}
> +	port->uartclk = clk_get_rate(atmel_port->clk);
>   
>   	/*
>   	 * Use TXEMPTY for interrupt when rs485 or ISO7816 else TXRDY or
> @@ -2896,14 +2879,23 @@ static int atmel_serial_probe(struct platform_device *pdev)
>   	atomic_set(&atmel_port->tasklet_shutdown, 0);
>   	spin_lock_init(&atmel_port->lock_suspended);
>   
> +	atmel_port->clk = devm_clk_get(&pdev->dev, "usart");
> +	if (IS_ERR(atmel_port->clk)) {
> +		ret = PTR_ERR(atmel_port->clk);
> +		goto err;
> +	}
> +	ret = clk_prepare_enable(atmel_port->clk);
> +	if (ret)
> +		goto err;
> +
>   	ret = atmel_init_port(atmel_port, pdev);
>   	if (ret)
> -		goto err_clear_bit;
> +		goto err_clk_disable_unprepare;
>   
>   	atmel_port->gpios = mctrl_gpio_init(&atmel_port->uart, 0);
>   	if (IS_ERR(atmel_port->gpios)) {
>   		ret = PTR_ERR(atmel_port->gpios);
> -		goto err_clear_bit;
> +		goto err_clk_disable_unprepare;
>   	}
>   
>   	if (!atmel_use_pdc_rx(&atmel_port->uart)) {
> @@ -2912,7 +2904,7 @@ static int atmel_serial_probe(struct platform_device *pdev)
>   				     sizeof(struct atmel_uart_char),
>   				     GFP_KERNEL);
>   		if (!data)
> -			goto err_alloc_ring;
> +			goto err_clk_disable_unprepare;
>   		atmel_port->rx_ring.buf = data;
>   	}
>   
> @@ -2936,12 +2928,6 @@ static int atmel_serial_probe(struct platform_device *pdev)
>   	device_init_wakeup(&pdev->dev, 1);
>   	platform_set_drvdata(pdev, atmel_port);
>   
> -	/*
> -	 * The peripheral clock has been disabled by atmel_init_port():
> -	 * enable it before accessing I/O registers
> -	 */
> -	clk_prepare_enable(atmel_port->clk);
> -
>   	if (rs485_enabled) {
>   		atmel_uart_writel(&atmel_port->uart, ATMEL_US_MR,
>   				  ATMEL_US_USMODE_NORMAL);
> @@ -2965,12 +2951,8 @@ static int atmel_serial_probe(struct platform_device *pdev)
>   err_add_port:
>   	kfree(atmel_port->rx_ring.buf);
>   	atmel_port->rx_ring.buf = NULL;
> -err_alloc_ring:
> -	if (!uart_console(&atmel_port->uart)) {
> -		clk_put(atmel_port->clk);
> -		atmel_port->clk = NULL;
> -	}
> -err_clear_bit:
> +err_clk_disable_unprepare:
> +	clk_disable_unprepare(atmel_port->clk);
>   	clear_bit(atmel_port->uart.line, atmel_ports_in_use);
>   err:
>   	return ret;
> @@ -3004,8 +2986,6 @@ static int atmel_serial_remove(struct platform_device *pdev)
>   
>   	clear_bit(port->line, atmel_ports_in_use);
>   
> -	clk_put(atmel_port->clk);
> -	atmel_port->clk = NULL;
>   	pdev->dev.of_node = NULL;
>   
>   	return ret;

Thanks !