According to the Smart Battery Data Specification, the use of ManufacturerAcess (register 0x0) is implementation-defined. It appears that some batteries use writes to this register in order to implement certain functionality, but others may simply NAK all writes to it. As a result, write failures to ManufacturerAccess should not be used as an indicator of battery presence, nor as a failure to enter sleep mode.
The failed write access was seen with SANYO AP13J3K. Cc: Brian Norris <[email protected]> Signed-off-by: Guenter Roeck <[email protected]> --- drivers/power/sbs-battery.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/drivers/power/sbs-battery.c b/drivers/power/sbs-battery.c index 768b9fcb58ea..5621b8c048cf 100644 --- a/drivers/power/sbs-battery.c +++ b/drivers/power/sbs-battery.c @@ -313,21 +313,22 @@ static int sbs_get_battery_presence_and_health( return ret; } - /* Write to ManufacturerAccess with - * ManufacturerAccess command and then - * read the status */ - ret = sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr, - MANUFACTURER_ACCESS_STATUS); + /* + * Write to ManufacturerAccess with ManufacturerAccess command + * and then read the status. Do not check for error on the write + * since not all batteries implement write access to this command, + * while others mandate it. + */ + sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr, + MANUFACTURER_ACCESS_STATUS); + + ret = sbs_read_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr); if (ret < 0) { if (psp == POWER_SUPPLY_PROP_PRESENT) val->intval = 0; /* battery removed */ return ret; } - ret = sbs_read_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr); - if (ret < 0) - return ret; - if (ret < sbs_data[REG_MANUFACTURER_DATA].min_value || ret > sbs_data[REG_MANUFACTURER_DATA].max_value) { val->intval = 0; @@ -950,16 +951,16 @@ static int sbs_suspend(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); struct sbs_info *chip = i2c_get_clientdata(client); - s32 ret; if (chip->poll_time > 0) cancel_delayed_work_sync(&chip->work); - /* write to manufacturer access with sleep command */ - ret = sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr, + /* + * Write to manufacturer access with sleep command. + * Support is manufacturer dependend, so ignore errors. + */ + sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr, MANUFACTURER_ACCESS_SLEEP); - if (chip->is_present && ret < 0) - return ret; return 0; } -- 2.5.0
