Re: [PATCH 14/15] rtc/cmos: add OF bindings

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

On Fri, Dec 17, 2010 at 04:33:52PM +0100, Sebastian Andrzej Siewior wrote:
> This allows to load the OF driver based informations from the device
> tree. Systems without BIOS may need to perform some initialization.
> PowerPC creates a PNP device from the OF information and performs this
> kind of initialization in their private PCI quirk. This looks more
> generic.
> 
> Cc: rtc-linux@googlegroups.com
> Cc: Alessandro Zummo <a.zummo@towertech.it>
> Cc: devicetree-discuss@lists.ozlabs.org
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
> ---
>  Documentation/powerpc/dts-bindings/rtc-cmos.txt |   28 ++++++++++++++++
>  drivers/rtc/rtc-cmos.c                          |   40 +++++++++++++++++++++++
>  2 files changed, 68 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/powerpc/dts-bindings/rtc-cmos.txt
> 
> diff --git a/Documentation/powerpc/dts-bindings/rtc-cmos.txt b/Documentation/powerpc/dts-bindings/rtc-cmos.txt
> new file mode 100644
> index 0000000..7382989
> --- /dev/null
> +++ b/Documentation/powerpc/dts-bindings/rtc-cmos.txt
> @@ -0,0 +1,28 @@
> + Motorola mc146818 compatible RTC
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +Required properties:
> +  - compatible : "motorola,mc146818"
> +  - reg : should contain registers location and length.
> +
> +Optional properties:
> +  - interrupts : should contain interrupt.
> +  - interrupt-parent : interrupt source phandle.
> +  - ctrl-reg : Contains the initial value of the control register also
> +    called "Register B".
> +  - freq-reg : Contains the initial value of the frequency register also
> +    called "Regsiter A".
> +
> +"Register A" and "B" are usually initialized by the firmware (BIOS for
> +instance). If this is not done, it can be performed by the driver.
> +
> +ISA Example:
> +
> +	rtc@70 {
> +	         compatible = "motorola,mc146818";
> +	         interrupts = <8 3>;
> +	         interrupt-parent = <&ioapic1>;
> +	         ctrl-reg = <2>;
> +	         freq-reg = <0x26>;
> +	         reg = <1 0x70 2>;
> +	 };
> diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
> index 5856167..8cf0049 100644
> --- a/drivers/rtc/rtc-cmos.c
> +++ b/drivers/rtc/rtc-cmos.c
> @@ -36,6 +36,8 @@
>  #include <linux/platform_device.h>
>  #include <linux/mod_devicetable.h>
>  #include <linux/log2.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
>  
>  /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
>  #include <asm-generic/rtc.h>
> @@ -1121,6 +1123,15 @@ static struct pnp_driver cmos_pnp_driver = {
>  
>  #endif	/* CONFIG_PNP */
>  
> +#ifdef CONFIG_OF
> +static const struct of_device_id of_cmos_match[] = {
> +	{
> +		.compatible = "motorola,mc146818",
> +	},
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, of_cmos_match);
> +#endif
>  /*----------------------------------------------------------------*/
>  
>  /* Platform setup should have set up an RTC device, when PNP is
> @@ -1129,6 +1140,32 @@ static struct pnp_driver cmos_pnp_driver = {
>  
>  static int __init cmos_platform_probe(struct platform_device *pdev)
>  {
> +#ifdef CONFIG_OF
> +	if (pdev->dev.of_node) {
> +		struct device_node *node = pdev->dev.of_node;
> +		struct rtc_time time;
> +		int ret;
> +		const __be32 *val;
> +
> +		val = of_get_property(node, "ctrl-reg", NULL);
> +		if (val)
> +			CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
> +
> +		val = of_get_property(node, "freq-reg", NULL);
> +		if (val)
> +			CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
> +
> +		get_rtc_time(&time);
> +		ret = rtc_valid_tm(&time);
> +		if (ret) {
> +			struct rtc_time def_time = {
> +				.tm_year = 1,
> +				.tm_mday = 1,
> +			};
> +			set_rtc_time(&def_time);
> +		}
> +	}
> +#endif

It's usually cleaner to break the of-specific probe stuff into a
separate function that can be #ifdef'ed out as a whole instead of
having #ifdef blocks inside the probe functions.  Aside from that this
patch looks good to me.

>  	cmos_wake_setup(&pdev->dev);
>  	return cmos_do_probe(&pdev->dev,
>  			platform_get_resource(pdev, IORESOURCE_IO, 0),
> @@ -1157,6 +1194,9 @@ static struct platform_driver cmos_platform_driver = {
>  	.shutdown	= cmos_platform_shutdown,
>  	.driver = {
>  		.name		= (char *) driver_name,
> +#if defined(CONFIG_OF)
> +		.of_match_table = of_cmos_match,
> +#endif
>  		.suspend	= cmos_suspend,
>  		.resume		= cmos_resume,
>  	}
> -- 
> 1.7.3.2
> 
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