[PATCH] add-pcf50633-allow-force-charger-type.patch

[Andy Green]

This patch adds a sysfs node:

/sys/class/i2c-adapter/i2c-0/0-0073/force_usb_limit_dangerous

it allows to force the charging limit regardless of the one chosen
by pcf50633 kernel driver.  As such, if you write a charging limit
here that is not suitable for the power source, and the power source
is not current limited on its side, it could draw more current than
your power source can handle, burn down you house, etc.

If you're certain that your power supply can handle it, you can use
this on your own responsibility to make the amount drawn by the
PMU match what you believed your power supply could handle.

Example usage, in case where you have a dumb 500mA USB charger that
does not have the ID resistor:

# cat /sys/class/i2c-adapter/i2c-0/0-0073/charger_type
host/500mA usb mode 100mA   <=== dumb charger does not ennumerate us
# echo 500 > /sys/class/i2c-adapter/i2c-0/0-0073/force_usb_limit_dangerous
# cat /sys/class/i2c-adapter/i2c-0/0-0073/charger_type
host/500mA usb mode 500mA

Signed-off-by: Andy Green <andy at openmoko.com>
---

 drivers/i2c/chips/pcf50633.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/drivers/i2c/chips/pcf50633.c b/drivers/i2c/chips/pcf50633.c
index a116f9f..9f98ba1 100644
--- a/drivers/i2c/chips/pcf50633.c
+++ b/drivers/i2c/chips/pcf50633.c
@@ -1953,6 +1953,20 @@ static ssize_t show_charger_type(struct device *dev,
 
 static DEVICE_ATTR(charger_type, 0444, show_charger_type, NULL);
 
+static ssize_t force_usb_limit_dangerous(struct device *dev,
+		   struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct pcf50633_data *pcf = i2c_get_clientdata(client);
+	int ma = simple_strtoul(buf, NULL, 10);
+
+	pcf50633_usb_curlim_set(pcf, ma);
+	return count;
+}
+
+static DEVICE_ATTR(force_usb_limit_dangerous, 0600,
+					       NULL, force_usb_limit_dangerous);
+
 /*
  * Charger adc
  */
@@ -2030,6 +2044,7 @@ static struct attribute *pcf_sysfs_entries[] = {
 	&dev_attr_voltage_ldo6.attr,
 	&dev_attr_voltage_hcldo.attr,
 	&dev_attr_charger_type.attr,
+	&dev_attr_force_usb_limit_dangerous.attr,
 	&dev_attr_charger_adc.attr,
 	&dev_attr_dump_regs.attr,
 	NULL, /* going to add things at this point! */