Subject: [PATCH 2/3] omap-serial: Add minimal device tree support

From: [email-masked] (Rob Herring)
Date: Wed, 16 Nov 2011 08:59:38 -0600

On 11/16/2011 05:02 AM, Rajendra Nayak wrote:
> Adapt the driver to device tree and pass minimal platform
> data from device tree needed for console boot.
> No power management features will be suppported for now
> since it requires more tweaks around OCP settings
> to toggle forceidle/noidle/smaridle bits and handling
> remote wakeup and dynamic muxing.
> 
> Signed-off-by: Rajendra Nayak <[email-masked]>
> ---
>  .../devicetree/bindings/serial/omap_serial.txt     |    9 +++++
>  drivers/tty/serial/omap-serial.c                   |   37 +++++++++++++++++++-
>  2 files changed, 45 insertions(+), 1 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/serial/omap_serial.txt
> 
> diff --git a/Documentation/devicetree/bindings/serial/omap_serial.txt b/Documentation/devicetree/bindings/serial/omap_serial.txt
> new file mode 100644
> index 0000000..bf6d631
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/omap_serial.txt
> @@ -0,0 +1,9 @@
> +OMAP UART controller
> +
> +Required properties:
> +- compatible : should be "ti,omap-uart"

This seems too generic. There are no h/w differences in the uart since
the 1st OMAP1 device?

> +- ti,hwmods : Must be "uart<n>", n being the instance number (1-based)
> +
> +Optional properties:
> +- clock-frequency : frequency of the clock input to the UART
> +- ti,console_hwmod : boolean, UART used as debug console
> diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
> index e1c8527..e3419c6 100644
> --- a/drivers/tty/serial/omap-serial.c
> +++ b/drivers/tty/serial/omap-serial.c
> @@ -38,6 +38,7 @@
>  #include <linux/serial_core.h>
>  #include <linux/irq.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/of.h>
>  
>  #include <plat/dma.h>
>  #include <plat/dmtimer.h>
> @@ -1322,6 +1323,22 @@ static void uart_tx_dma_callback(int lch, u16 ch_status, void *data)
>  	return;
>  }
>  
> +static struct omap_uart_port_info *of_get_uart_port_info(struct device *dev)
> +{
> +	struct omap_uart_port_info *omap_up_info;
> +
> +	omap_up_info = devm_kzalloc(dev, sizeof(*omap_up_info), GFP_KERNEL);
> +	if (!omap_up_info)
> +		return NULL; /* out of memory */
> +
> +	of_property_read_u32(dev->of_node, "clock-frequency",
> +					 &(*omap_up_info).uartclk);

&omap_up_info->uartclk

You want 0 to be the default freq?

> +
> +	return omap_up_info;
> +}
> +
> +static atomic_t omap_uart_next_id = ATOMIC_INIT(0);
> +
>  static int serial_omap_probe(struct platform_device *pdev)
>  {
>  	struct uart_omap_port	*up;
> @@ -1329,6 +1346,11 @@ static int serial_omap_probe(struct platform_device *pdev)
>  	struct omap_uart_port_info *omap_up_info = pdev->dev.platform_data;
>  	int ret = -ENOSPC;
>  
> +	if (pdev->dev.of_node) {
> +		omap_up_info = of_get_uart_port_info(&pdev->dev);
> +		pdev->id = atomic_inc_return(&omap_uart_next_id) - 1;

I don't think a driver changing this value is a good idea. Look at other
serial drivers like iMX for how they use aliases.

> +	}
> +
>  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	if (!mem) {
>  		dev_err(&pdev->dev, "no mem resource?\n");
> @@ -1523,7 +1545,7 @@ static int serial_omap_runtime_suspend(struct device *dev)
>  	if (!up)
>  		return -EINVAL;
>  
> -	if (!pdata->enable_wakeup)
> +	if (!pdata || !pdata->enable_wakeup)
>  		return 0;
>  
>  	if (pdata->get_context_loss_count)
> @@ -1582,12 +1604,25 @@ static const struct dev_pm_ops serial_omap_dev_pm_ops = {
>  				serial_omap_runtime_resume, NULL)
>  };
>  
> +#if defined(CONFIG_OF)
> +static const struct of_device_id omap_serial_of_match[] = {
> +	{
> +		.compatible = "ti,omap-uart",
> +	},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, omap_serial_of_match);
> +#else
> +#define omap_serial_of_match NULL
> +#endif
> +
>  static struct platform_driver serial_omap_driver = {
>  	.probe          = serial_omap_probe,
>  	.remove         = serial_omap_remove,
>  	.driver		= {
>  		.name	= DRIVER_NAME,
>  		.pm	= &serial_omap_dev_pm_ops,
> +		.of_match_table = omap_serial_of_match,

Use of_match_ptr and get rid of the #else

Rob