[PATCH] power: bq27x00_battery: Export all battery registers via sysfs

From: Pali RohÃr
Date: Sat Jan 19 2013 - 09:04:01 EST


bq27xxx batteries have a lot of properties, more than power_supply interface.
Some of them can be usefull for userspace applications (like CI bit) but
does not make sense to add bq specified property to power_supply interface.
When bq27x00_battery is not loaded userspace application (like i2cget) can
use /dev/i2c-* interface for raw access. But when kernel module is attached
to i2c device, userspace applications cannot access it via /dev/i2c-*.
Also it is not usefull for userspace to unload module before reading values
form /dev/i2c-* and then load it again.

This patch exporting all battery registers to sysfs entry "registers" in
battery power_supply directory. Format is "register=value" on separate line.
Because length of registers are different for each bq battery more for loops
are needed.

Signed-off-by: Pali RohÃr <pali.rohar@xxxxxxxxx>
---
drivers/power/bq27x00_battery.c | 98 +++++++++++++++++++++++++++++++++++++--
1 file changed, 95 insertions(+), 3 deletions(-)

diff --git a/drivers/power/bq27x00_battery.c b/drivers/power/bq27x00_battery.c
index 7087d0d..af0f68f 100644
--- a/drivers/power/bq27x00_battery.c
+++ b/drivers/power/bq27x00_battery.c
@@ -690,6 +690,90 @@ static void bq27x00_external_power_changed(struct power_supply *psy)
schedule_delayed_work(&di->work, 0);
}

+/* code for register device access via sysfs */
+
+static ssize_t bq27x00_battery_sysfs_print_reg(struct bq27x00_device_info *di,
+ u8 reg, bool single, char *buf)
+{
+ int ret = bq27x00_read(di, reg, single);
+ if (ret < 0)
+ return sprintf(buf, "%#.2x=error %d\n", reg, ret);
+ else
+ return sprintf(buf, "%#.2x=%#.2x\n", reg, ret);
+}
+
+static ssize_t bq27x00_battery_sysfs_show_registers(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct power_supply *psy = dev_get_drvdata(dev);
+ struct bq27x00_device_info *di = container_of(psy,
+ struct bq27x00_device_info,
+ bat);
+ u8 reg;
+ ssize_t ret = 0;
+
+ switch (di->chip) {
+
+ case BQ27000:
+ for (reg=0x00; reg<=0x01; reg+=1)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, true, buf+ret);
+ for (reg=0x02; reg<=0x08; reg+=2)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, false, buf+ret);
+ for (reg=0x0A; reg<=0x0B; reg+=1)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, true, buf+ret);
+ for (reg=0x0C; reg<=0x2A; reg+=2)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, false, buf+ret);
+ for (reg=0x2C; reg<=0x7F; reg+=1)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, true, buf+ret);
+ break;
+
+ case BQ27500:
+ for (reg=0x00; reg<=0x2C; reg+=2)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, false, buf+ret);
+ for (reg=0x2E; reg<=0x3B; reg+=1)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, true, buf+ret);
+ for (reg=0x3C; reg<=0x3C; reg+=2)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, false, buf+ret);
+ for (reg=0x3E; reg<=0x7F; reg+=1)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, true, buf+ret);
+ break;
+
+ case BQ27425:
+ for (reg=0x00; reg<=0x3C; reg+=2)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, false, buf+ret);
+ for (reg=0x3E; reg<=0x7F; reg+=1)
+ ret += bq27x00_battery_sysfs_print_reg(di, reg, true, buf+ret);
+ break;
+
+ }
+
+ return ret;
+}
+
+static DEVICE_ATTR(registers, S_IRUGO,
+ bq27x00_battery_sysfs_show_registers, NULL);
+
+static struct attribute *bq27x00_battery_sysfs_attributes[] = {
+ &dev_attr_registers.attr,
+ NULL,
+};
+
+static const struct attribute_group bq27x00_battery_sysfs_attr_group = {
+ .attrs = bq27x00_battery_sysfs_attributes,
+};
+
+static int bq27x00_battery_sysfs_init(struct bq27x00_device_info *di)
+{
+ return sysfs_create_group(&di->bat.dev->kobj,
+ &bq27x00_battery_sysfs_attr_group);
+}
+
+static void bq27x00_battery_sysfs_exit(struct bq27x00_device_info *di)
+{
+ sysfs_remove_group(&di->bat.dev->kobj,
+ &bq27x00_battery_sysfs_attr_group);
+}
+
static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
{
int ret;
@@ -705,15 +789,22 @@ static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
di->bat.get_property = bq27x00_battery_get_property;
di->bat.external_power_changed = bq27x00_external_power_changed;

- INIT_DELAYED_WORK(&di->work, bq27x00_battery_poll);
- mutex_init(&di->lock);
-
ret = power_supply_register(di->dev, &di->bat);
if (ret) {
dev_err(di->dev, "failed to register battery: %d\n", ret);
return ret;
}

+ ret = bq27x00_battery_sysfs_init(di);
+ if (ret) {
+ dev_err(di->dev, "failed to register battery: %d\n", ret);
+ power_supply_unregister(&di->bat);
+ return ret;
+ }
+
+ INIT_DELAYED_WORK(&di->work, bq27x00_battery_poll);
+ mutex_init(&di->lock);
+
dev_info(di->dev, "support ver. %s enabled\n", DRIVER_VERSION);

bq27x00_update(di);
@@ -733,6 +824,7 @@ static void bq27x00_powersupply_unregister(struct bq27x00_device_info *di)

cancel_delayed_work_sync(&di->work);

+ bq27x00_battery_sysfs_exit(di);
power_supply_unregister(&di->bat);

mutex_destroy(&di->lock);
--
1.7.10.4

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