[RFC 5/7] OMAP: Introduce set_rate and get_rate API in omap device layer

[Thara Gopinath <thara@ti.com>]

This patch adds omap_device_set_rate and omap_device_get_rate
API's which can be used to generic device rate scaling.

Signed-off-by: Thara Gopinath <thara@ti.com>
---
 arch/arm/plat-omap/include/plat/omap_device.h |    2 +
 arch/arm/plat-omap/omap_device.c              |   87 +++++++++++++++++++++++++
 2 files changed, 89 insertions(+), 0 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h
index 3694b62..e0d06bb 100644
--- a/arch/arm/plat-omap/include/plat/omap_device.h
+++ b/arch/arm/plat-omap/include/plat/omap_device.h
@@ -114,6 +114,8 @@ int omap_device_enable_hwmods(struct omap_device *od);
 int omap_device_disable_clocks(struct omap_device *od);
 int omap_device_enable_clocks(struct omap_device *od);
 
+int omap_device_set_rate(struct device *dev, unsigned long rate);
+unsigned long omap_device_get_rate(struct device *dev);
 
 /*
  * Entries should be kept in latency order ascending
diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
index 6614cba..900bb5d 100644
--- a/arch/arm/plat-omap/omap_device.c
+++ b/arch/arm/plat-omap/omap_device.c
@@ -85,6 +85,8 @@
 
 #include <plat/omap_device.h>
 #include <plat/omap_hwmod.h>
+#include <plat/opp.h>
+#include <plat/voltage.h>
 
 /* These parameters are passed to _omap_device_{de,}activate() */
 #define USE_WAKEUP_LAT			0
@@ -734,3 +736,88 @@ int omap_device_enable_clocks(struct omap_device *od)
 	/* XXX pass along return value here? */
 	return 0;
 }
+
+/**
+ * omap_device_set_rate - Set a new rate at which the device is to operate
+ * @dev : the device pointer
+ * @rate : the rnew rate for the device.
+ *
+ * This API gets the device opp table associated with this device and
+ * tries putting the device to the requested rate and the voltage domain
+ * associated with the device to the voltage corresponding to the
+ * requested rate. Since multiple devices can be assocciated with a
+ * voltage domain this API finds out the possible voltage the
+ * voltage domain can enter and then decides on the final device
+ * rate. Return 0 on success else the error value
+ */
+int omap_device_set_rate(struct device *dev, unsigned long rate)
+{
+	struct device_opp *dev_opp;
+	struct omap_opp *opp;
+	unsigned long volt, freq;
+	int ret;
+
+	dev_opp = opp_find_dev_opp(dev);
+	if (IS_ERR(dev_opp)) {
+		dev_warn(dev, "%s: Unable to find device opp table\n",
+			__func__);
+		return -ENODEV;
+	}
+
+	/* Get the possible rate from the opp layer */
+	freq = rate;
+	opp = opp_find_freq_ceil(dev, &freq);
+	if (IS_ERR(opp)) {
+		dev_err(dev, "%s: Unable to find OPP for freq%ld\n",
+			__func__, rate);
+		return -ENODEV;
+	}
+	if (unlikely(freq != rate))
+		dev_warn(dev, "%s: Available freq %ld != dpll freq %ld.\n",
+			__func__, freq, rate);
+
+	/* Get the voltage corresponding to the requested frequency */
+	volt = opp_get_voltage(opp);
+
+	/*
+	 * Call into the voltage layer to get the final voltage possible
+	 * for the voltage domain associated with the device.
+	 */
+
+	ret = omap_volt_get_final(dev_opp->volt_domain, dev, &volt);
+	if (ret) {
+		dev_err(dev, "%s: Unable to get the final volt for scaling\n",
+			__func__);
+		return ret;
+	}
+
+	/* Do the actual scaling */
+	return omap_voltage_scale(dev_opp->volt_domain, volt);
+}
+
+/**
+ * omap_device_get_rate - Gets the current operating rate of the device
+ * @dev - the device pointer
+ *
+ * This API returns the current operating rate of the device on success.
+ * Else returns the error value.
+ */
+unsigned long omap_device_get_rate(struct device *dev)
+{
+	struct device_opp *dev_opp;
+
+	dev_opp = opp_find_dev_opp(dev);
+
+	if (IS_ERR(dev_opp)) {
+		dev_warn(dev, "%s: Unable to find device opp table\n",
+			__func__);
+		return -ENODEV;
+	}
+
+	if (!dev_opp->get_rate) {
+		dev_warn(dev, "%s: No get_rate API\n", __func__);
+		return -EINVAL;
+	}
+
+	return dev_opp->get_rate(dev);
+}
-- 
1.7.0.rc1.33.g07cf0f