[PATCH 06/16] serial: mvebu-uart: add soft reset at probe

From: gregory.clement@free-electrons•com (Gregory CLEMENT)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 06/16] serial: mvebu-uart: add soft reset at probe
Date: Fri, 06 Oct 2017 14:33:03 +0200	[thread overview]
Message-ID: <87h8vcfocg.fsf@free-electrons.com> (raw)
In-Reply-To: <20171006101344.15590-7-miquel.raynal@free-electrons.com> (Miquel Raynal's message of "Fri, 6 Oct 2017 12:13:34 +0200")

Hi Miquel,

 On ven., oct. 06 2017, Miquel Raynal <miquel.raynal@free-electrons•com> wrote:

> From: Allen Yan <yanwei@marvell•com>
>
> The existing UART driver relies on the bootloader to initialize the
> port(s). However, the secondary uart port may not be initialized
> properly in early boot stage. This patch adds the UART soft reset when
> probing, for all ports.
>
> Signed-off-by: Allen Yan <yanwei@marvell•com>
> Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons•com>

Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons•com>

Thanks,

Gregory

> ---
>  drivers/tty/serial/mvebu-uart.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
> index 82438884af1e..da756cfec0bb 100644
> --- a/drivers/tty/serial/mvebu-uart.c
> +++ b/drivers/tty/serial/mvebu-uart.c
> @@ -653,6 +653,11 @@ static int mvebu_uart_probe(struct platform_device *pdev)
>  	port->private_data = mvuart;
>  	platform_set_drvdata(pdev, mvuart);
>  
> +	/* UART Soft Reset*/
> +	writel(CTRL_SOFT_RST, port->membase + UART_CTRL(port));
> +	udelay(1);
> +	writel(0, port->membase + UART_CTRL(port));
> +
>  	ret = uart_add_one_port(&mvebu_uart_driver, port);
>  	if (ret)
>  		return ret;
> -- 
> 2.11.0
>
>
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-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com