Subject: [RFC PATCH 3/3] OMAP: omap_device: Add a method to build an omap_device from a DT node

From: [email-masked] (Kevin Hilman)
Date: Thu, 01 Sep 2011 16:40:39 -0700

Benoit Cousson <[email-masked]> writes:

> Add a notifier called during device_add phase. If a of_node is present,
> retrieve the hwmod entry in order to populate propely the omap_device
> structure.
> For the moment the resource from the device-tree are overloaded.
> DT does not support named resource yet, and thus, most driver
> will not work without that information.
>
> Signed-off-by: Benoit Cousson <[email-masked]>
> Cc: Kevin Hilman <[email-masked]>

Nice, minor comment below...

> ---
>  arch/arm/plat-omap/omap_device.c |  102 ++++++++++++++++++++++++++++++++++++++
>  1 files changed, 102 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
> index 70361f8..0ae9e7f 100644
> --- a/arch/arm/plat-omap/omap_device.c
> +++ b/arch/arm/plat-omap/omap_device.c
> @@ -85,6 +85,8 @@
>  #include <linux/clk.h>
>  #include <linux/clkdev.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/of_platform.h>
> +#include <linux/notifier.h>
>  
>  #include <plat/omap_device.h>
>  #include <plat/omap_hwmod.h>
> @@ -94,6 +96,8 @@
>  #define USE_WAKEUP_LAT			0
>  #define IGNORE_WAKEUP_LAT		1
>  
> +#define MAX_HWMOD_NAME_SIZE		32
> +
>  static int omap_device_register(struct platform_device *pdev);
>  static int omap_early_device_register(struct platform_device *pdev);
>  static struct omap_device *omap_device_alloc(struct platform_device *pdev,
> @@ -354,6 +358,100 @@ static int _dt_get_property(const char *prop, int len, int index, char *output,
>  	return -ENODEV;
>  }
>  
> +static struct dev_pm_domain omap_device_pm_domain;
> +
> +/**
> + * omap_device_build_from_dt - build an omap_device with multiple hwmods
> + * @pdev_name: name of the platform_device driver to use
> + * @pdev_id: this platform_device's connection ID
> + * @oh: ptr to the single omap_hwmod that backs this omap_device
> + * @pdata: platform_data ptr to associate with the platform_device
> + * @pdata_len: amount of memory pointed to by @pdata
> + * @pm_lats: pointer to a omap_device_pm_latency array for this device
> + * @pm_lats_cnt: ARRAY_SIZE() of @pm_lats
> + * @is_early_device: should the device be registered as an early device or not
> + *
> + * Function for building an omap_device already registered from device-tree
> + *
> + * Returns 0 or PTR_ERR() on error.
> + */
> +static int omap_device_build_from_dt(struct platform_device *pdev)
> +{
> +	struct omap_hwmod **hwmods;
> +	struct omap_device *od;
> +	struct omap_hwmod *oh;
> +	char oh_name[MAX_HWMOD_NAME_SIZE];
> +	const char *prop;
> +	int oh_cnt, i, prop_len;
> +	int ret = 0;
> +
> +	prop = of_get_property(pdev->dev.of_node, "hwmods", &prop_len);
> +	oh_cnt = _dt_count_property_string(prop, prop_len);
> +	if (!oh_cnt || IS_ERR_VALUE(oh_cnt)) {
> +		dev_warn(&pdev->dev, "No 'hwmods' to build omap_device\n");
> +		return -ENODEV;
> +	}
> +
> +	hwmods = kzalloc(sizeof(struct omap_hwmod *) * oh_cnt, GFP_KERNEL);
> +	if (!hwmods) {
> +		ret = -ENOMEM;
> +		goto odbfd_exit;
> +	}
> +
> +	for (i = 0; i < oh_cnt; i++) {
> +		_dt_get_property(prop, prop_len, i, oh_name,
> +				 MAX_HWMOD_NAME_SIZE);
> +
> +		oh = omap_hwmod_lookup(oh_name);
> +		if (!oh) {
> +			dev_err(&pdev->dev, "Cannot lookup hwmod '%s'\n",
> +				oh_name);
> +			ret = -EINVAL;
> +			goto odbfd_exit1;
> +		}
> +		hwmods[i] = oh;
> +	}
> +
> +	od = omap_device_alloc(pdev, hwmods, oh_cnt, NULL, 0);
> +	if (!od) {
> +		dev_err(&pdev->dev, "Cannot allocate omap_device for :%s\n",
> +			oh_name);
> +		ret = PTR_ERR(od);
> +		goto odbfd_exit1;
> +	}
> +
> +	if (of_get_property(pdev->dev.of_node, "no_idle_on_suspend", NULL))
> +		omap_device_disable_idle_on_suspend(pdev);
> +
> +	pdev->dev.pm_domain = &omap_device_pm_domain;
> +
> +odbfd_exit1:
> +	kfree(hwmods);
> +odbfd_exit:
> +	return ret;
> +}
> +
> +static int _omap_device_notifier_call(struct notifier_block *nb,
> +				      unsigned long event, void *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +
> +	switch (event) {
> +	case BUS_NOTIFY_ADD_DEVICE:
> +		if (pdev->dev.of_node) {
> +			dev_dbg(&pdev->dev, "add_device with DT bindings\n");
> +			omap_device_build_from_dt(pdev);
> +		}
> +		break;
> +
> +	case BUS_NOTIFY_DEL_DEVICE:
> +		dev_dbg(&pdev->dev, "del_device\n");

Need a delete/cleanup here.  

Looks like all all it needs to do is call omap_device_delete()?

Kevin

> +		break;
> +	}
> +
> +	return NOTIFY_DONE;
> +}
> +
>  
>  /* Public functions for use by core code */
>  
> @@ -1064,8 +1162,12 @@ struct device omap_device_parent = {
>  	.parent         = &platform_bus,
>  };
>  
> +static struct notifier_block platform_nb;
> +
>  static int __init omap_device_init(void)
>  {
> +	platform_nb.notifier_call = _omap_device_notifier_call;
> +	bus_register_notifier(&platform_bus_type, &platform_nb);
>  	return device_register(&omap_device_parent);
>  }
>  core_initcall(omap_device_init);