From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: [PATCH v2 4/7] power: supply: bq24190_charger: Never reset the charger chip Date: Wed, 22 Mar 2017 15:55:33 +0100 Message-ID: <20170322145536.30570-5-hdegoede@redhat.com> References: <20170322145536.30570-1-hdegoede@redhat.com> Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50536 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759512AbdCVOzq (ORCPT ); Wed, 22 Mar 2017 10:55:46 -0400 In-Reply-To: <20170322145536.30570-1-hdegoede@redhat.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Sebastian Reichel Cc: Hans de Goede , Takashi Iwai , linux-pm@vger.kernel.org, Liam Breck , Tony Lindgren Resetting the charger should never be necessary it should always have sane values programmed. If it is running with invalid values while we are not running (system turned off or suspended) there is a big problem as that may lead to overcharging the battery. The reset in suspend() is meant to put the charger back into default mode, but this is not necessary and not a good idea. If the charger has been programmed with a higher max charge_current / charge_voltage then putting it back in default-mode will reset those to the safe power-on defaults, leading to slower charging, or charging to a lower voltage (and thus not using the full capacity) while suspended which is undesirable. Reprogramming the max charge_current / charge_voltage after the reset will not help here as that will put the charger back in host mode and start the i2c watchdog if the host then does not do anything for 40s (iow if we're suspended for more then 40s) the watchdog expires resetting the device to default-mode, including resetting all the registers to there safe power-on defaults. So the only way to keep using custom charge settings while suspending is to keep the charger in its normal running state with the i2c watchdog disabled. This is fine as the charger will still automatically switch from constant current to constant voltage and stop charging when the battery is full. Besides never being necessary resetting the charger also causes problems on systems where the charge voltage limit is set higher then the reset value, if this is the case and the charger is reset while charging and the battery voltage is between the 2 voltages, then about half the time the charger gets confused and claims to be charging (REG08 contains 0x64) but in reality the charger has decoupled itself from VBUS (Q1 off) and is drawing 0A from VBUS, leaving the system running from the battery. Cc: Liam Breck Cc: Tony Lindgren Signed-off-by: Hans de Goede --- Changes in v2: -This is a new patch in v2 of this patch-set --- drivers/power/supply/bq24190_charger.c | 58 ---------------------------------- 1 file changed, 58 deletions(-) diff --git a/drivers/power/supply/bq24190_charger.c b/drivers/power/supply/bq24190_charger.c index 7a2a496..b535f24 100644 --- a/drivers/power/supply/bq24190_charger.c +++ b/drivers/power/supply/bq24190_charger.c @@ -526,40 +526,6 @@ static int bq24190_set_mode_host(struct bq24190_dev_info *bdi) return bq24190_write(bdi, BQ24190_REG_CTTC, v); } -static int bq24190_register_reset(struct bq24190_dev_info *bdi) -{ - int ret, limit = 100; - u8 v; - - /* Reset the registers */ - ret = bq24190_write_mask(bdi, BQ24190_REG_POC, - BQ24190_REG_POC_RESET_MASK, - BQ24190_REG_POC_RESET_SHIFT, - 0x1); - if (ret < 0) - return ret; - - /* Reset bit will be cleared by hardware so poll until it is */ - do { - ret = bq24190_read_mask(bdi, BQ24190_REG_POC, - BQ24190_REG_POC_RESET_MASK, - BQ24190_REG_POC_RESET_SHIFT, - &v); - if (ret < 0) - return ret; - - if (!v) - break; - - udelay(10); - } while (--limit); - - if (!limit) - return -EIO; - - return 0; -} - /* Charger power supply property routines */ static int bq24190_charger_get_charge_type(struct bq24190_dev_info *bdi, @@ -1380,10 +1346,6 @@ static int bq24190_hw_init(struct bq24190_dev_info *bdi) return -ENODEV; } - ret = bq24190_register_reset(bdi); - if (ret < 0) - return ret; - ret = bq24190_set_mode_host(bdi); if (ret < 0) return ret; @@ -1534,7 +1496,6 @@ static int bq24190_remove(struct i2c_client *client) pm_runtime_put_noidle(bdi->dev); } - bq24190_register_reset(bdi); bq24190_sysfs_remove_group(bdi); power_supply_unregister(bdi->battery); power_supply_unregister(bdi->charger); @@ -1577,23 +1538,6 @@ static __maybe_unused int bq24190_runtime_resume(struct device *dev) static __maybe_unused int bq24190_pm_suspend(struct device *dev) { - struct i2c_client *client = to_i2c_client(dev); - struct bq24190_dev_info *bdi = i2c_get_clientdata(client); - int error; - - error = pm_runtime_get_sync(bdi->dev); - if (error < 0) { - dev_warn(bdi->dev, "pm_runtime_get failed: %i\n", error); - pm_runtime_put_noidle(bdi->dev); - } - - bq24190_register_reset(bdi); - - if (error >= 0) { - pm_runtime_mark_last_busy(bdi->dev); - pm_runtime_put_autosuspend(bdi->dev); - } - return 0; } @@ -1612,8 +1556,6 @@ static __maybe_unused int bq24190_pm_resume(struct device *dev) pm_runtime_put_noidle(bdi->dev); } - bq24190_register_reset(bdi); - bq24190_set_mode_host(bdi); bq24190_read(bdi, BQ24190_REG_SS, &bdi->ss_reg); if (error >= 0) { -- 2.9.3