ARM: OMAP: omap_device: Add omap_device_get_by_hwmod_name

An API which translates a standard hwmod name to corresponding
platform_device is useful for drivers when they need to look up the
device associated with a hwmod name to map back into the device
structure pointers. These ideally should be used by drivers in
mach directory. Using a generic hwmod name like "gpu" instead of
the actual device name which could change in the future, allows
us to:
a) Could in effect help replace apis such as omap2_get_mpuss_device,
omap2_get_iva_device, omap2_get_l3_device, omap4_get_dsp_device,
etc..
b) Scale to more devices rather than be restricted to named functions
c) Simplify driver's platform_data from passing additional fields
all doing the same thing with different function pointer names
just for accessing a different device name.

Signed-off-by: Nishanth Menon <nm@ti.com>
[b-cousson@ti.com: Adapt it to the new pdev pointer inside od,
remove the unneeded helpers, and fold the next patch here]
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/plat-omap/include/plat/omap_device.h

@@ -101,6 +101,7 @@ struct platform_device *omap_device_build_ss(const char *pdev_name, int pdev_id,
 					 int pm_lats_cnt, int is_early_device);
 
 void __iomem *omap_device_get_rt_va(struct omap_device *od);
+struct device *omap_device_get_by_hwmod_name(const char *oh_name);
 
 /* OMAP PM interface */
 int omap_device_align_pm_lat(struct platform_device *pdev,

arch/arm/plat-omap/omap_device.c

@@ -844,6 +844,42 @@ void __iomem *omap_device_get_rt_va(struct omap_device *od)
 	return omap_hwmod_get_mpu_rt_va(od->hwmods[0]);
 }
 
+/**
+ * omap_device_get_by_hwmod_name() - convert a hwmod name to
+ * device pointer.
+ * @oh_name: name of the hwmod device
+ *
+ * Returns back a struct device * pointer associated with a hwmod
+ * device represented by a hwmod_name
+ */
+struct device *omap_device_get_by_hwmod_name(const char *oh_name)
+{
+	struct omap_hwmod *oh;
+
+	if (!oh_name) {
+		WARN(1, "%s: no hwmod name!\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	oh = omap_hwmod_lookup(oh_name);
+	if (IS_ERR_OR_NULL(oh)) {
+		WARN(1, "%s: no hwmod for %s\n", __func__,
+			oh_name);
+		return ERR_PTR(oh ? PTR_ERR(oh) : -ENODEV);
+	}
+	if (IS_ERR_OR_NULL(oh->od)) {
+		WARN(1, "%s: no omap_device for %s\n", __func__,
+			oh_name);
+		return ERR_PTR(oh->od ? PTR_ERR(oh->od) : -ENODEV);
+	}
+
+	if (IS_ERR_OR_NULL(oh->od->pdev))
+		return ERR_PTR(oh->od->pdev ? PTR_ERR(oh->od->pdev) : -ENODEV);
+
+	return &oh->od->pdev->dev;
+}
+EXPORT_SYMBOL(omap_device_get_by_hwmod_name);
+
 /*
  * Public functions intended for use in omap_device_pm_latency
  * .activate_func and .deactivate_func function pointers