Re: [PATCH 2/2] serial/imx: add device tree probe support

[Grant Likely <grant.likely@secretlab.ca>]

On Sun, Jul 03, 2011 at 03:56:00PM +0800, Shawn Guo wrote:
> It adds device tree probe support for imx tty/serial driver.
> 
> Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
> Signed-off-by: Jason Liu <jason.hui@linaro.org>
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> Cc: Sascha Hauer <s.hauer@pengutronix.de>
> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
> Cc: Grant Likely <grant.likely@secretlab.ca>

Minor comments below, but otherwise looks okay to me.  Feel free to
add the following when you respin with the first patch:

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

I don't see any reason preventing this from being ready to be queued
up for v3.1

g.

> ---
>  .../bindings/tty/serial/fsl-imx-uart.txt           |   19 +++++
>  drivers/tty/serial/imx.c                           |   82 +++++++++++++++++---
>  2 files changed, 91 insertions(+), 10 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
> 
> diff --git a/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt b/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
> new file mode 100644
> index 0000000..a9c0406
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
> @@ -0,0 +1,19 @@
> +* Freescale i.MX Universal Asynchronous Receiver/Transmitter (UART)
> +
> +Required properties:
> +- compatible : Should be "fsl,<soc>-uart"
> +- reg : Address and length of the register set for the device
> +- interrupts : Should contain uart interrupt
> +
> +Optional properties:
> +- fsl,uart-has-rtscts : Indicate the uart has rts and cts
> +- fsl,irda-mode : Indicate the uart supports irda mode
> +
> +Example:
> +
> +uart@73fbc000 {
> +	compatible = "fsl,imx51-uart", "fsl,imx21-uart";
> +	reg = <0x73fbc000 0x4000>;
> +	interrupts = <31>;
> +	fsl,uart-has-rtscts;
> +};
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 983f3bd..483c447 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -45,6 +45,8 @@
>  #include <linux/delay.h>
>  #include <linux/rational.h>
>  #include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>  
>  #include <asm/io.h>
>  #include <asm/irq.h>
> @@ -239,6 +241,12 @@ static struct platform_device_id imx_uart_devtype[] = {
>  	}
>  };
>  
> +static struct of_device_id imx_uart_dt_ids[] = {
> +	{ .compatible = "fsl,imx1-uart", .data = &imx_uart_devdata[IMX1_UART], },
> +	{ .compatible = "fsl,imx21-uart", .data = &imx_uart_devdata[IMX2_UART], },
> +	{ /* sentinel */ },

Nit: drop the ',' from the last entry so that nobody inadvertently
adds another entry to the list.

> +};
> +
>  /*
>   * Handle any change of modem status signal since we were last called.
>   */
> @@ -1261,6 +1269,58 @@ static int serial_imx_resume(struct platform_device *dev)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_OF
> +static int serial_imx_probe_dt(struct imx_port *sport,
> +		struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	const struct of_device_id *of_id =
> +			of_match_device(imx_uart_dt_ids, &pdev->dev);
> +
> +	if (!np)
> +		return -ENODEV;
> +
> +	pdev->id = of_alias_get_id(np, "serial");
> +	if (pdev->id < 0)
> +		return -ENODEV;

If you're bailing here, it would be friendly to spit out a klog
message saying why the driver has bailed.

> +	if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
> +		sport->have_rtscts = 1;
> +
> +	if (of_get_property(np, "fsl,irda-mode", NULL))
> +		sport->use_irda = 1;
> +
> +	sport->devdata = of_id->data;
> +
> +	return 0;
> +}
> +#else
> +static inline int serial_imx_probe_dt(struct imx_port *sport,
> +		struct platform_device *pdev)
> +{
> +	return -ENODEV;
> +}
> +#endif
> +
> +static int serial_imx_probe_pdata(struct imx_port *sport,
> +		struct platform_device *pdev)
> +{
> +	struct imxuart_platform_data *pdata = pdev->dev.platform_data;
> +
> +	if (!pdata)
> +		return 0;
> +
> +	if (pdata->flags & IMXUART_HAVE_RTSCTS)
> +		sport->have_rtscts = 1;
> +
> +	if (pdata->flags & IMXUART_IRDA)
> +		sport->use_irda = 1;
> +
> +	sport->devdata = &imx_uart_devdata[pdev->id_entry->driver_data];
> +
> +	return 0;
> +}
> +
>  static int serial_imx_probe(struct platform_device *pdev)
>  {
>  	struct imx_port *sport;
> @@ -1273,6 +1333,12 @@ static int serial_imx_probe(struct platform_device *pdev)
>  	if (!sport)
>  		return -ENOMEM;
>  
> +	ret = serial_imx_probe_dt(sport, pdev);
> +	if (ret == -ENODEV)
> +		ret = serial_imx_probe_pdata(sport, pdev);
> +	if (ret)
> +		goto free;
> +
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	if (!res) {
>  		ret = -ENODEV;
> @@ -1301,7 +1367,6 @@ static int serial_imx_probe(struct platform_device *pdev)
>  	init_timer(&sport->timer);
>  	sport->timer.function = imx_timeout;
>  	sport->timer.data     = (unsigned long)sport;
> -	sport->devdata = &imx_uart_devdata[pdev->id_entry->driver_data];
>  
>  	sport->clk = clk_get(&pdev->dev, "uart");
>  	if (IS_ERR(sport->clk)) {
> @@ -1312,17 +1377,13 @@ static int serial_imx_probe(struct platform_device *pdev)
>  
>  	sport->port.uartclk = clk_get_rate(sport->clk);
>  
> -	imx_ports[pdev->id] = sport;
> +	if (imx_ports[sport->port.line]) {
> +		ret = -EBUSY;
> +		goto clkput;
> +	}
> +	imx_ports[sport->port.line] = sport;
>  
>  	pdata = pdev->dev.platform_data;
> -	if (pdata && (pdata->flags & IMXUART_HAVE_RTSCTS))
> -		sport->have_rtscts = 1;
> -
> -#ifdef CONFIG_IRDA
> -	if (pdata && (pdata->flags & IMXUART_IRDA))
> -		sport->use_irda = 1;
> -#endif
> -
>  	if (pdata && pdata->init) {
>  		ret = pdata->init(pdev);
>  		if (ret)
> @@ -1384,6 +1445,7 @@ static struct platform_driver serial_imx_driver = {
>  	.driver		= {
>  		.name	= "imx-uart",
>  		.owner	= THIS_MODULE,
> +		.of_match_table = imx_uart_dt_ids,
>  	},
>  };
>  
> -- 
> 1.7.4.1
>