[PATCH v2 06/14] OMAP: Voltage layer changes to support DVFS.

[Thara Gopinath <thara@ti.com>]

This patch introduces an API to take in the voltage domain and the
new voltage as parameter and to scale all the scalable devices
associated with the the voltage domain to the rate corresponding to the
new voltage and scale the voltage domain to the new voltage.

Signed-off-by: Thara Gopinath <thara@ti.com>
---
 arch/arm/mach-omap2/voltage.c             |   72 +++++++++++++++++++++++++++++
 arch/arm/plat-omap/include/plat/voltage.h |    7 +++
 2 files changed, 79 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/voltage.c b/arch/arm/mach-omap2/voltage.c
index 6c2e4ef..458f8c1 100644
--- a/arch/arm/mach-omap2/voltage.c
+++ b/arch/arm/mach-omap2/voltage.c
@@ -27,9 +27,11 @@
 #include <linux/spinlock.h>
 #include <linux/plist.h>
 #include <linux/slab.h>
+#include <linux/opp.h>
 
 #include <plat/common.h>
 #include <plat/voltage.h>
+#include <plat/omap_device.h>
 
 #include "prm-regbits-34xx.h"
 #include "prm44xx.h"
@@ -1678,6 +1680,76 @@ struct voltagedomain *omap_voltage_domain_lookup(char *name)
 }
 
 /**
+ * omap_voltage_scale : API to scale the devices associated with a
+ *			voltage domain vdd voltage.
+ * @volt_domain : the voltage domain to be scaled
+ * @volt : the new voltage for the voltage domain
+ *
+ * This API runs through the list of devices associated with the
+ * voltage domain and scales the device rates to those corresponding
+ * to the new voltage of the voltage domain. This API also scales
+ * the voltage domain voltage to the new value. Returns 0 on success
+ * else the error value.
+ */
+int omap_voltage_scale(struct voltagedomain *voltdm, unsigned long volt)
+{
+	unsigned long curr_volt;
+	int is_volt_scaled = 0;
+	struct omap_vdd_info *vdd;
+	struct omap_vdd_dev_list *temp_dev;
+
+	if (!voltdm || IS_ERR(voltdm)) {
+		pr_warning("%s: VDD specified does not exist!\n", __func__);
+		return -EINVAL;
+	}
+
+	vdd = container_of(voltdm, struct omap_vdd_info, voltdm);
+
+	mutex_lock(&vdd->scaling_mutex);
+
+	curr_volt = omap_voltage_get_nom_volt(voltdm);
+
+	if (curr_volt == volt) {
+		is_volt_scaled = 1;
+	} else if (curr_volt < volt) {
+		omap_voltage_scale_vdd(voltdm, volt);
+		is_volt_scaled = 1;
+	}
+
+	list_for_each_entry(temp_dev, &vdd->dev_list, node) {
+		struct device *dev;
+		struct opp *opp;
+		unsigned long freq;
+
+		dev = temp_dev->dev;
+
+		opp = opp_find_voltage(dev, volt);
+		if (IS_ERR(opp)) {
+			dev_err(dev, "%s: Unable to find OPP for"
+				"volt%ld\n", __func__, volt);
+			continue;
+		}
+
+		freq = opp_get_freq(opp);
+
+		if (freq == omap_device_get_rate(dev)) {
+			dev_warn(dev, "%s: Already at the requested"
+				"rate %ld\n", __func__, freq);
+			continue;
+		}
+
+		omap_device_set_rate(dev, freq);
+	}
+
+	if (!is_volt_scaled)
+		omap_voltage_scale_vdd(voltdm, volt);
+
+	mutex_unlock(&vdd->scaling_mutex);
+
+	return 0;
+}
+
+/**
  * omap_voltage_init : Volatage init API which does VP and VC init.
  */
 static int __init omap_voltage_init(void)
diff --git a/arch/arm/plat-omap/include/plat/voltage.h b/arch/arm/plat-omap/include/plat/voltage.h
index dc64a9a..54d50e2 100644
--- a/arch/arm/plat-omap/include/plat/voltage.h
+++ b/arch/arm/plat-omap/include/plat/voltage.h
@@ -153,6 +153,7 @@ void omap_change_voltscale_method(int voltscale_method);
 int omap_voltage_add_request(struct voltagedomain *voltdm, struct device *dev,
 		unsigned long *volt);
 int omap_voltage_add_dev(struct voltagedomain *voltdm, struct device *dev);
+int omap_voltage_scale(struct voltagedomain *voltdm, unsigned long volt);
 #else
 static inline void omap_voltage_register_pmic
 			(struct omap_volt_pmic_info *pmic_info) {}
@@ -169,6 +170,12 @@ static inline int omap_voltage_add_dev(struct voltagedomain *voltdm,
 {
 	return -EINVAL;
 }
+
+static inline int omap_voltage_scale(struct voltagedomain *voltdm,
+		unsigned long volt)
+{
+	return -EINVAL;
+}
 #endif
 
 #endif
-- 
1.7.0.4