linux-kernel - Re: [PATCH v2 4/5] tty/serial: atmel

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Date:	Wed, 12 Oct 2011 19:03:18 -0600
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Nicolas Ferre <nicolas.ferre@...el.com>
Cc:	linux-arm-kernel@...ts.infradead.org,
	devicetree-discuss@...ts.ozlabs.org, robherring2@...il.com,
	claudio@...dence.eu.com, jesper.nilsson@...s.com,
	alan@...rguk.ukuu.org.uk, linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org
Subject: Re: [PATCH v2 4/5] tty/serial: atmel_serial: auto-enumerate ports

On Wed, Oct 12, 2011 at 06:06:59PM +0200, Nicolas Ferre wrote:
> If no platform data provided to enumerate ports, use a bit field
> to choose port number and check if port is already initialized.
> Use this mechanism for both console and plain serial ports.
> 
> Signed-off-by: Nicolas Ferre <nicolas.ferre@...el.com>

Acked-by: Grant Likely <grant.likely@...retlab.ca>

> ---
>  drivers/tty/serial/atmel_serial.c |   44 ++++++++++++++++++++++++++++++------
>  1 files changed, 36 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index bb72354..1074329 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -157,6 +157,7 @@ struct atmel_uart_port {
>  };
>  
>  static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
> +static unsigned long atmel_ports_in_use;
>  
>  #ifdef SUPPORT_SYSRQ
>  static struct console atmel_console;
> @@ -1423,7 +1424,6 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
>  	port->flags		= UPF_BOOT_AUTOCONF;
>  	port->ops		= &atmel_pops;
>  	port->fifosize		= 1;
> -	port->line		= pdata->num;
>  	port->dev		= &pdev->dev;
>  	port->mapbase	= pdev->resource[0].start;
>  	port->irq	= pdev->resource[1].start;
> @@ -1613,10 +1613,15 @@ static struct console atmel_console = {
>  static int __init atmel_console_init(void)
>  {
>  	if (atmel_default_console_device) {
> -		add_preferred_console(ATMEL_DEVICENAME,
> -				      atmel_default_console_device->id, NULL);
> -		atmel_init_port(&atmel_ports[atmel_default_console_device->id],
> -				atmel_default_console_device);
> +		int id = atmel_default_console_device->id;
> +		struct atmel_uart_port *port = &atmel_ports[id];
> +
> +		set_bit(id, &atmel_ports_in_use);
> +		port->backup_imr = 0;
> +		port->uart.line = id;
> +
> +		add_preferred_console(ATMEL_DEVICENAME, id, NULL);
> +		atmel_init_port(port, atmel_default_console_device);
>  		register_console(&atmel_console);
>  	}
>  
> @@ -1715,12 +1720,33 @@ static int __devinit atmel_serial_probe(struct platform_device *pdev)
>  	struct atmel_uart_port *port;
>  	struct atmel_uart_data *pdata = pdev->dev.platform_data;
>  	void *data;
> -	int ret;
> +	int ret = -ENODEV;
>  
>  	BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1));
>  
> -	port = &atmel_ports[pdata->num];
> +	if (pdata)
> +		ret = pdata->num;
> +
> +	if (ret < 0)
> +		/* port id not found in platform data:
> +		 * auto-enumerate it */
> +		ret = find_first_zero_bit(&atmel_ports_in_use,
> +				sizeof(atmel_ports_in_use));
> +
> +	if (ret > ATMEL_MAX_UART) {
> +		ret = -ENODEV;
> +		goto err;
> +	}
> +
> +	if (test_and_set_bit(ret, &atmel_ports_in_use)) {
> +		/* port already in use */
> +		ret = -EBUSY;
> +		goto err;
> +	}
> +
> +	port = &atmel_ports[ret];
>  	port->backup_imr = 0;
> +	port->uart.line = ret;
>  
>  	atmel_init_port(port, pdev);
>  
> @@ -1766,7 +1792,7 @@ err_alloc_ring:
>  		clk_put(port->clk);
>  		port->clk = NULL;
>  	}
> -
> +err:
>  	return ret;
>  }
>  
> @@ -1786,6 +1812,8 @@ static int __devexit atmel_serial_remove(struct platform_device *pdev)
>  
>  	/* "port" is allocated statically, so we shouldn't free it */
>  
> +	clear_bit(port->line, &atmel_ports_in_use);
> +
>  	clk_put(atmel_port->clk);
>  
>  	return ret;
> -- 
> 1.7.5.4
> 
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