twl4030_charger: enable manual enable/disable of usb charging.

'off' or 'auto' to

 /sys/class/power/twl4030_usb/mode

will now enable or disable charging from USB port.  Normally this is
enabled on 'plug' and disabled on 'unplug'.
Unplug will still disable charging.  'plug' will only enable it if
'auto' if selected.

Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

2 files changed, 70 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-power-twl4030 b/Documentation/ABI/testing/sysfs-class-power-twl4030
index 0331bba4605d..40e0f919cbde 100644
--- a/Documentation/ABI/testing/sysfs-class-power-twl4030
+++ b/Documentation/ABI/testing/sysfs-class-power-twl4030
@@ -13,3 +13,14 @@ Description:
         Value can the set by writing to the attribute.
         The change will only persist until the next
         plug event.  These event are reported via udev.
+
+
+What: /sys/class/power_supply/twl4030_usb/mode
+Description:
+        Changing mode for USB port.
+        Writing to this can disable charging.
+
+        Possible values are:
+                "auto" - draw power as appropriate for detected
+                         power source and battery status.
+                "off"  - do not draw any power.
diff --git a/drivers/power/twl4030_charger.c b/drivers/power/twl4030_charger.c
index b0a50adebfda..6fa928ed3128 100644
--- a/drivers/power/twl4030_charger.c
+++ b/drivers/power/twl4030_charger.c
@@ -109,10 +109,16 @@ struct twl4030_bci {
         unsigned int            ichg_eoc, ichg_lo, ichg_hi;
         unsigned int            usb_cur, ac_cur;
         bool                    ac_is_active;
+        int                     usb_mode; /* charging mode requested */
+#define CHARGE_OFF      0
+#define CHARGE_AUTO     1
 
         unsigned long           event;
 };
 
+/* strings for 'usb_mode' values */
+static char *modes[] = { "off", "auto" };
+
 /*
  * clear and set bits on an given register on a given module
  */
@@ -386,6 +392,8 @@ static int twl4030_charger_enable_usb(struct twl4030_bci *bci, bool enable)
 {
         int ret;
 
+        if (bci->usb_mode == CHARGE_OFF)
+                enable = false;
         if (enable && !IS_ERR_OR_NULL(bci->transceiver)) {
 
                 twl4030_charger_update_current(bci);
@@ -629,6 +637,53 @@ static int twl4030_bci_usb_ncb(struct notifier_block *nb, unsigned long val,
         return NOTIFY_OK;
 }
 
+/*
+ * sysfs charger enabled store
+ */
+static ssize_t
+twl4030_bci_mode_store(struct device *dev, struct device_attribute *attr,
+                          const char *buf, size_t n)
+{
+        struct twl4030_bci *bci = dev_get_drvdata(dev->parent);
+        int mode;
+        int status;
+
+        if (sysfs_streq(buf, modes[0]))
+                mode = 0;
+        else if (sysfs_streq(buf, modes[1]))
+                mode = 1;
+        else
+                return -EINVAL;
+        twl4030_charger_enable_usb(bci, false);
+        bci->usb_mode = mode;
+        status = twl4030_charger_enable_usb(bci, true);
+        return (status == 0) ? n : status;
+}
+
+/*
+ * sysfs charger enabled show
+ */
+static ssize_t
+twl4030_bci_mode_show(struct device *dev,
+                             struct device_attribute *attr, char *buf)
+{
+        struct twl4030_bci *bci = dev_get_drvdata(dev->parent);
+        int len = 0;
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(modes); i++)
+                if (bci->usb_mode == i)
+                        len += snprintf(buf+len, PAGE_SIZE-len,
+                                        "[%s] ", modes[i]);
+                else
+                        len += snprintf(buf+len, PAGE_SIZE-len,
+                                        "%s ", modes[i]);
+        buf[len-1] = '\n';
+        return len;
+}
+static DEVICE_ATTR(mode, 0644, twl4030_bci_mode_show,
+                   twl4030_bci_mode_store);
+
 static int twl4030_charger_get_current(void)
 {
         int curr;
@@ -815,6 +870,7 @@ static int twl4030_bci_probe(struct platform_device *pdev)
                 bci->usb_cur = 500000;  /* 500mA */
         else
                 bci->usb_cur = 100000;  /* 100mA */
+        bci->usb_mode = CHARGE_AUTO;
 
         bci->dev = &pdev->dev;
         bci->irq_chg = platform_get_irq(pdev, 0);
@@ -898,6 +954,8 @@ static int twl4030_bci_probe(struct platform_device *pdev)
         twl4030_charger_update_current(bci);
         if (device_create_file(&bci->usb->dev, &dev_attr_max_current))
                 dev_warn(&pdev->dev, "could not create sysfs file\n");
+        if (device_create_file(&bci->usb->dev, &dev_attr_mode))
+                dev_warn(&pdev->dev, "could not create sysfs file\n");
         if (device_create_file(&bci->ac->dev, &dev_attr_max_current))
                 dev_warn(&pdev->dev, "could not create sysfs file\n");
 
@@ -926,6 +984,7 @@ static int __exit twl4030_bci_remove(struct platform_device *pdev)
         twl4030_charger_enable_backup(0, 0);
 
         device_remove_file(&bci->usb->dev, &dev_attr_max_current);
+        device_remove_file(&bci->usb->dev, &dev_attr_mode);
         device_remove_file(&bci->ac->dev, &dev_attr_max_current);
         /* mask interrupts */
         twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,