USB force fast charging

-Use base from Chad Froebel <chadfroebel@gmail.com> so we continue to
use the same generic sysfs mechanism

-Referenced franco's git for drivers/usb/otg/msm_otg.c changes
https://github.com/franciscofranco/mako/commit/5a8a4c8e23c7e1df39c740b9ce1d5dda20b0ede3

Off by default

Turn on:
echo 1 > /sys/kernel/fast_charge/force_fast_charge

Turn off:
echo 0 > /sys/kernel/fast_charge/force_fast_charge

Initial Port to Cancro:

Change-Id: Id8862493cb4afeb73d200dc605f557668ec4eb5c
Signed-off-by: Jean Francis Dominique S. Mabalot <jmabalot@google.com>

5 files changed, 139 insertions, 1 deletions

diff --git a/arch/arm/mach-msm/Kconfig b/arch/arm/mach-msm/Kconfig
index 50dab3c303f..5444b9cbb2c 100644
--- a/arch/arm/mach-msm/Kconfig
+++ b/arch/arm/mach-msm/Kconfig
@@ -3057,6 +3057,13 @@ config HAS_MACH_MEMUTILS
 	help
 	Faster memcpy performance for Krait
 
+config FORCE_FAST_CHARGE
+	bool "Force AC charge mode at will"
+	default y
+	help
+		A simple sysfs interface to force adapters that
+		are detected as USB to charge as AC.
+
 endif
 
 config KERNEL_TEXT_MPU_PROT
diff --git a/arch/arm/mach-msm/Makefile b/arch/arm/mach-msm/Makefile
index 2b6cfe4fa47..7b253e6df4c 100644
--- a/arch/arm/mach-msm/Makefile
+++ b/arch/arm/mach-msm/Makefile
@@ -419,3 +419,4 @@ obj-$(CONFIG_WALL_CLK_SYSFS) += wallclk_sysfs.o
 obj-$(CONFIG_HAS_MACH_MEMUTILS) += memutils/
 obj-$(CONFIG_ARCH_RANDOM) += early_random.o
 obj-$(CONFIG_PERFMAP) += perfmap.o
+obj-$(CONFIG_FORCE_FAST_CHARGE) += fastchg.o
diff --git a/arch/arm/mach-msm/fastchg.c b/arch/arm/mach-msm/fastchg.c
new file mode 100644
index 00000000000..9da2cabd581
--- /dev/null
+++ b/arch/arm/mach-msm/fastchg.c
@@ -0,0 +1,95 @@
+/*
+ * Author: Chad Froebel <chadfroebel@gmail.com>
+ *
+ * Simple port to Nexus 4 : motley <motley.slate@gmail.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/*
+ * Possible values for "force_fast_charge" are :
+ *
+ *   0 - disabled (default)
+ *   1 - substitute AC to USB unconditional
+*/
+
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+#include <linux/fastchg.h>
+
+int force_fast_charge;
+
+/* sysfs interface for "force_fast_charge" */
+static ssize_t force_fast_charge_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+return sprintf(buf, "%d\n", force_fast_charge);
+}
+
+static ssize_t force_fast_charge_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count)
+{
+
+int new_force_fast_charge;
+
+sscanf(buf, "%du", &new_force_fast_charge);
+
+if (new_force_fast_charge >= FAST_CHARGE_DISABLED && new_force_fast_charge <= FAST_CHARGE_FORCE_AC) {
+	/* update only if valid value provided */
+	force_fast_charge = new_force_fast_charge;
+}
+
+return count;
+}
+
+static struct kobj_attribute force_fast_charge_attribute =
+__ATTR(force_fast_charge, 0666, force_fast_charge_show, force_fast_charge_store);
+
+static struct attribute *force_fast_charge_attrs[] = {
+&force_fast_charge_attribute.attr,
+NULL,
+};
+
+static struct attribute_group force_fast_charge_attr_group = {
+.attrs = force_fast_charge_attrs,
+};
+
+/* Initialize fast charge sysfs folder */
+static struct kobject *force_fast_charge_kobj;
+
+int force_fast_charge_init(void)
+{
+	int force_fast_charge_retval;
+
+	force_fast_charge = FAST_CHARGE_DISABLED; /* Forced fast charge disabled by default */
+
+	force_fast_charge_kobj = kobject_create_and_add("fast_charge", kernel_kobj);
+	if (!force_fast_charge_kobj) {
+			return -ENOMEM;
+	}
+
+	force_fast_charge_retval = sysfs_create_group(force_fast_charge_kobj, &force_fast_charge_attr_group);
+
+	if (force_fast_charge_retval)
+		kobject_put(force_fast_charge_kobj);
+
+	if (force_fast_charge_retval)
+		kobject_put(force_fast_charge_kobj);
+
+	return (force_fast_charge_retval);
+}
+
+void force_fast_charge_exit(void)
+{
+	kobject_put(force_fast_charge_kobj);
+}
+
+module_init(force_fast_charge_init);
+module_exit(force_fast_charge_exit);
+
diff --git a/drivers/usb/otg/msm_otg.c b/drivers/usb/otg/msm_otg.c
index f4e7ea44df5..b953e8c1963 100644
--- a/drivers/usb/otg/msm_otg.c
+++ b/drivers/usb/otg/msm_otg.c
@@ -50,6 +50,11 @@
 #include <mach/msm_bus.h>
 #include <mach/rpm-regulator.h>
 
+#ifdef CONFIG_FORCE_FAST_CHARGE
+#include <linux/fastchg.h>
+#define USB_FASTCHG_LOAD 1000 /* uA */
+#endif
+
 #define MSM_USB_BASE	(motg->regs)
 #define DRIVER_NAME	"msm_otg"
 
@@ -1421,7 +1426,14 @@ static void msm_otg_notify_charger(struct msm_otg *motg, unsigned mA)
 
 	if (motg->cur_power == mA)
 		return;
-
+#ifdef CONFIG_FORCE_FAST_CHARGE
+	if (force_fast_charge == 1) {
+			mA = USB_FASTCHG_LOAD;
+			pr_info("USB fast charging is ON - 1000mA.\n");
+	} else {
+		pr_info("USB fast charging is OFF.\n");
+	}
+#endif
 	dev_info(motg->phy.dev, "Avail curr from USB = %u\n", mA);
 
 	/*
diff --git a/include/linux/fastchg.h b/include/linux/fastchg.h
new file mode 100644
index 00000000000..0570e039e22
--- /dev/null
+++ b/include/linux/fastchg.h
@@ -0,0 +1,23 @@
+/*
+ * Author: Chad Froebel <chadfroebel@gmail.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _LINUX_FASTCHG_H
+#define _LINUX_FASTCHG_H
+
+extern int force_fast_charge;
+
+#define FAST_CHARGE_DISABLED 0	/* default */
+#define FAST_CHARGE_FORCE_AC 1
+
+#endif