usb: gadget: android: Maxim 14675 driver support

add USB string to signal 12V max - 5V min charging

bug 1321188
bug 1456402

(cherry picked from commit 43c6f013e6a7cc09c83d66956715386d2ff659e7)
Change-Id: Ia13575a9da8f206b0b578c86854b9284b3a7f777
Reviewed-on: http://git-master/r/400492
Signed-off-by: Philip Rakity <prakity@nvidia.com>
Reviewed-on: http://git-master/r/417037
GVS: Gerrit_Virtual_Submit
Reviewed-by: Rakesh Babu Bodla <rbodla@nvidia.com>
Reviewed-by: Venkat Moganty <vmoganty@nvidia.com>

diff --git a/drivers/usb/gadget/android.c b/drivers/usb/gadget/android.c
index 980281ad767f470bf7637dcfc4dec9cdccd8b3f0..e33641c281532310df9eb1c1e907b980da62afc8 100644 (file)
--- a/drivers/usb/gadget/android.c
+++ b/drivers/usb/gadget/android.c
@@ -4,7 +4,7 @@
  * Copyright (C) 2008 Google, Inc.
  * Author: Mike Lockwood <lockwood@android.com>
  *         Benoit Goby <benoit@android.com>
- * Copyright (c) 2013, NVIDIA CORPORATION. All rights reserved.
+ * Copyright (c) 2013-2014, NVIDIA CORPORATION. All rights reserved.
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
@@ -28,6 +28,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/usb/composite.h>
 #include <linux/usb/gadget.h>
+#include <linux/of_platform.h>
 
 #include "gadget_chips.h"
 
@@ -114,6 +115,7 @@ static void android_unbind_config(struct usb_configuration *c);
 static char manufacturer_string[256];
 static char product_string[256];
 static char serial_string[256];
+static char maxim_string[256];
 
 /* String Table */
 static struct usb_string strings_dev[] = {
@@ -1289,6 +1291,26 @@ field ## _store(struct device *dev, struct device_attribute *attr,       \
 }                                                                      \
 static DEVICE_ATTR(field, S_IRUGO | S_IWUSR, field ## _show, field ## _store);
 
+#define DESCRIPTOR_STRING_ATTR_MANUFACTURER(field, buffer)             \
+static ssize_t                                                         \
+field ## _show(struct device *dev, struct device_attribute *attr,      \
+               char *buf)                                              \
+{                                                                      \
+       return sprintf(buf, "%s", buffer);                              \
+}                                                                      \
+static ssize_t                                                         \
+field ## _store(struct device *dev, struct device_attribute *attr,     \
+               const char *buf, size_t size)                           \
+{                                                                      \
+       int ret;                                                        \
+       if (size >= (sizeof(buffer) - strlen(maxim_string)))            \
+               return -EINVAL;                                         \
+       ret = strlcpy(buffer, buf, sizeof(buffer));                     \
+       strncat(buffer, maxim_string, strlen(maxim_string));            \
+       return ret;                                                     \
+}                                                                      \
+static DEVICE_ATTR(field, S_IRUGO | S_IWUSR, field ## _show, field ## _store);
+
 
 DESCRIPTOR_ATTR(idVendor, "%04x\n")
 DESCRIPTOR_ATTR(idProduct, "%04x\n")
@@ -1296,7 +1318,7 @@ DESCRIPTOR_ATTR(bcdDevice, "%04x\n")
 DESCRIPTOR_ATTR(bDeviceClass, "%d\n")
 DESCRIPTOR_ATTR(bDeviceSubClass, "%d\n")
 DESCRIPTOR_ATTR(bDeviceProtocol, "%d\n")
-DESCRIPTOR_STRING_ATTR(iManufacturer, manufacturer_string)
+DESCRIPTOR_STRING_ATTR_MANUFACTURER(iManufacturer, manufacturer_string)
 DESCRIPTOR_STRING_ATTR(iProduct, product_string)
 DESCRIPTOR_STRING_ATTR(iSerial, serial_string)
 
@@ -1343,6 +1365,45 @@ static void android_unbind_config(struct usb_configuration *c)
        android_unbind_enabled_functions(dev, c);
 }
 
+/* set maximum and minimum voltage for maxim */
+static void android_maxim14675_set_voltage(void)
+{
+       unsigned int min_voltage = 5000;
+       unsigned int max_voltage;
+       unsigned int voltage = 0;
+       char buf[20];
+       struct device_node *np;
+
+       np = of_find_node_by_path("/usb-devices/maxim-charger");
+       if (np  && !of_property_read_u32(np,
+                       "maxim,max-board-vbus-voltage-uv",
+                       &voltage))
+               pr_info("%s: max_voltage (vbus) = %d\n",
+                       __func__, voltage);
+
+       /* convert DT microvolts to millivolts */
+       voltage = voltage/1000;
+       if (voltage < min_voltage)
+               max_voltage = min_voltage;
+       else if (voltage > 20000)
+               max_voltage = 20000;
+       else
+               max_voltage = voltage;
+
+       pr_info("%s: max_voltage (vbus) = %d\n",
+                       __func__, max_voltage);
+       min_voltage = ((min_voltage - 2000) / 1000) * 20;
+       max_voltage = ((max_voltage - 2000) / 1000) * 20;
+
+       memset(buf, 0, sizeof(buf));
+       strcpy(maxim_string, "    gr8rFiV8US");
+       snprintf(buf, 4, "%03X", max_voltage);
+       strncat(maxim_string, buf, 3);
+       snprintf(buf, 4, "%03X", min_voltage);
+       strncat(maxim_string, buf, 3);
+       strncat(maxim_string, "00", 2);
+}
+
 static int android_bind(struct usb_composite_dev *cdev)
 {
        struct android_dev *dev = _android_dev;
@@ -1359,6 +1420,9 @@ static int android_bind(struct usb_composite_dev *cdev)
        if (ret)
                return ret;
 
+       /* maxim 14675 voltage */
+       android_maxim14675_set_voltage();
+
        /* Allocate string descriptor numbers ... note that string
         * contents can be overridden by the composite_dev glue.
         */
@@ -1376,6 +1440,7 @@ static int android_bind(struct usb_composite_dev *cdev)
 
        /* Default strings - should be updated by userspace */
        strncpy(manufacturer_string, "Android", sizeof(manufacturer_string)-1);
+       strncat(manufacturer_string, maxim_string, strlen(maxim_string));
        strncpy(product_string, "Android", sizeof(product_string) - 1);
        strncpy(serial_string, "0123456789ABCDEF", sizeof(serial_string) - 1);