Re: [PATCH v2] tty: ar933x_uart: add device tree support and binding documentation

[Kumar Gala <galak@codeaurora.org>]

On Aug 29, 2013, at 4:48 AM, Gabor Juhos wrote:

> Modify the probe routine to get the port line number
> from device tree if the 'of_node' is populated in the
> platform device. The driver can be built as module,
> thus add an OF specific module device table as well
> to support module auto loading.
> 
> This makes it possible to use the driver for AR9330
> UART devices specified in device tree.
> 
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
> ---
> Changes since v1:
>  - move the doc from bindings/tty/serial to bindings/serial
> 
> The patch is agains the 'tty-next' branch of the
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tree
> ---
> .../devicetree/bindings/serial/qca,ar9330-uart.txt |   34 ++++++++++++++++++++
> drivers/tty/serial/ar933x_uart.c                   |   28 ++++++++++++++--
> 2 files changed, 59 insertions(+), 3 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/serial/qca,ar9330-uart.txt
> 
> diff --git a/Documentation/devicetree/bindings/serial/qca,ar9330-uart.txt b/Documentation/devicetree/bindings/serial/qca,ar9330-uart.txt
> new file mode 100644
> index 0000000..c5e032c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/qca,ar9330-uart.txt
> @@ -0,0 +1,34 @@
> +* Qualcomm Atheros AR9330 High-Speed UART
> +
> +Required properties:
> +
> +- compatible: Must be "qca,ar9330-uart"

If the driver is called ar933x, is there a reason not to do so with the compatible and binding spec?

> +
> +- reg: Specifies the physical base address of the controller and
> +  the length of the memory mapped region.
> +
> +- interrupt-parent: The phandle for the interrupt controller that
> +  services interrupts for this device.
> +
> +- interrupts: Specifies the interrupt source of the parent interrupt
> +  controller. The format of the interrupt specifier depends on the
> +  parent interrupt controller.
> +
> +Additional requirements:
> +
> +  Each UART port must have an alias correctly numbered in "aliases"
> +  node.
> +
> +Example:
> +
> +	aliases {
> +		serial0 = &uart0;
> +	};
> +
> +	uart0: uart@18020000 {
> +		compatible = "qca,ar9330-uart";
> +		reg = <0x18020000 0x14>;
> +
> +		interrupt-parent = <&intc>;
> +		interrupts = <3>;
> +	};
> diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c
> index 0437a9e..acd03af 100644
> --- a/drivers/tty/serial/ar933x_uart.c
> +++ b/drivers/tty/serial/ar933x_uart.c
> @@ -17,6 +17,8 @@
> #include <linux/sysrq.h>
> #include <linux/delay.h>
> #include <linux/platform_device.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> #include <linux/tty.h>
> #include <linux/tty_flip.h>
> #include <linux/serial_core.h>
> @@ -623,13 +625,24 @@ static int ar933x_uart_probe(struct platform_device *pdev)
> 	struct uart_port *port;
> 	struct resource *mem_res;
> 	struct resource *irq_res;
> +	struct device_node *np;
> 	unsigned int baud;
> 	int id;
> 	int ret;
> 
> -	id = pdev->id;
> -	if (id == -1)
> -		id = 0;
> +	np = pdev->dev.of_node;
> +	if (config_enabled(CONFIG_OF) && np) {
> +		id = of_alias_get_id(np, "serial");
> +		if (id < 0) {
> +			dev_err(&pdev->dev, "unable to get alias id, err=%d\n",
> +				id);
> +			return id;
> +		}
> +	} else {
> +		id = pdev->id;
> +		if (id == -1)
> +			id = 0;
> +	}
> 
> 	if (id > CONFIG_SERIAL_AR933X_NR_UARTS)
> 		return -EINVAL;
> @@ -713,12 +726,21 @@ static int ar933x_uart_remove(struct platform_device *pdev)
> 	return 0;
> }
> 
> +#ifdef CONFIG_OF
> +static const struct of_device_id ar933x_uart_of_ids[] = {
> +	{ .compatible = "qca,ar9330-uart" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, ar933x_uart_of_ids);
> +#endif
> +
> static struct platform_driver ar933x_uart_platform_driver = {
> 	.probe		= ar933x_uart_probe,
> 	.remove		= ar933x_uart_remove,
> 	.driver		= {
> 		.name		= DRIVER_NAME,
> 		.owner		= THIS_MODULE,
> +		.of_match_table = of_match_ptr(ar933x_uart_of_ids),
> 	},
> };
> 
> -- 
> 1.7.10
> --
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-- 
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