diff mbox series

[08/10] power: supply: rt5033_charger: Make use of high impedance mode

Message ID 6b474e64f752ca6802dfb0bfc5571eb1adad8449.1677620677.git.jahau@rocketmail.com (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series Add RT5033 charger device driver | expand

Commit Message

Jakob Hauser Feb. 28, 2023, 10:32 p.m. UTC 
Enable high impedance mode to reduce power consumption. However, it needs to be
disabled in case of charging or OTG mode.

Tested-by: Raymond Hackley <raymondhackley@protonmail.com>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
---
 drivers/power/supply/rt5033_charger.c | 47 ++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

Comments

Jakob Hauser April 2, 2023, 10:14 a.m. UTC | #1 
Hi Sebastian,

On 28.02.23 23:32, Jakob Hauser wrote:
> Enable high impedance mode to reduce power consumption. However, it needs to be
> disabled in case of charging or OTG mode.
> 
> Tested-by: Raymond Hackley <raymondhackley@protonmail.com>
> Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
> ---
>   drivers/power/supply/rt5033_charger.c | 47 ++++++++++++++++++++++++++-
>   1 file changed, 46 insertions(+), 1 deletion(-)

...

Raymond (in copy) did some tests on the flash LEDs, which are also 
managed by the rt5033 chip. There is no driver for leds-rt5033 yet but 
Raymond got the rt5033 LEDs running via the similar driver leds-sgm3140.

However, to get the flash LEDs working, he had to disable the high 
impedance mode of rt5033.

I implemented the use of high impedance mode by this patch to improve 
power saving. It's kind of a sleep mode. Although it's not clear how 
much power it does save, it's generally worth trying to improve power 
saving on mobile devices as far as possible.

As it now turns out that the use of high impedance mode might complicate 
the handling of the flash LEDs, I would drop this patch in the next 
version v2 of the patchset. Let's skip this power saving attempt for 
now. It still can be added at a later date as an improvement.

Kind regards,
Jakob
diff mbox series

Patch

diff --git a/drivers/power/supply/rt5033_charger.c b/drivers/power/supply/rt5033_charger.c
index 79e7f75fe634..ab406fc9fa19 100644
--- a/drivers/power/supply/rt5033_charger.c
+++ b/drivers/power/supply/rt5033_charger.c
@@ -298,6 +298,17 @@  static int rt5033_charger_reg_init(struct rt5033_charger *charger)
 		return -EINVAL;
 	}
 
+	/*
+	 * Enable high impedance mode. It stops charging or boosting and
+	 * operates at a low current sinking to reduce power consumption.
+	 */
+	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL1,
+			RT5033_CHGCTRL1_HZ_MASK, RT5033_CHARGER_HZ_ENABLE);
+	if (ret) {
+		dev_err(charger->dev, "Failed to enable high impedance mode.\n");
+		return -EINVAL;
+	}
+
 	ret = rt5033_init_pre_charge(charger);
 	if (ret)
 		return ret;
@@ -319,6 +330,14 @@  static int rt5033_charger_set_otg(struct rt5033_charger *charger)
 
 	mutex_lock(&charger->lock);
 
+	/* Disable high impedance mode to allow OTG mode */
+	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL1,
+			RT5033_CHGCTRL1_HZ_MASK, RT5033_CHARGER_HZ_DISABLE);
+	if (ret) {
+		dev_err(charger->dev, "Failed to disable high impedance mode.\n");
+		return -EINVAL;
+	}
+
 	/* Set OTG boost v_out to 5 volts */
 	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL2,
 			RT5033_CHGCTRL2_CV_MASK,
@@ -381,6 +400,14 @@  static int rt5033_charger_set_charging(struct rt5033_charger *charger)
 
 	mutex_lock(&charger->lock);
 
+	/* Disable high impedance mode to allow charging mode */
+	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL1,
+			RT5033_CHGCTRL1_HZ_MASK, RT5033_CHARGER_HZ_DISABLE);
+	if (ret) {
+		dev_err(charger->dev, "Failed to disable high impedance mode.\n");
+		return -EINVAL;
+	}
+
 	/* In case someone switched from OTG to charging directly */
 	if (charger->otg) {
 		ret = rt5033_charger_unset_otg(charger);
@@ -431,6 +458,14 @@  static int rt5033_charger_set_disconnect(struct rt5033_charger *charger)
 
 	mutex_lock(&charger->lock);
 
+	/* Enable high impedance mode to reduce power consumption */
+	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL1,
+			RT5033_CHGCTRL1_HZ_MASK, RT5033_CHARGER_HZ_ENABLE);
+	if (ret) {
+		dev_err(charger->dev, "Failed to enable high impedance mode.\n");
+		return -EINVAL;
+	}
+
 	/* Disable MIVR if enabled */
 	if (charger->mivr_enabled) {
 		ret = regmap_update_bits(charger->rt5033->regmap,
@@ -671,11 +706,21 @@  static int rt5033_charger_probe(struct platform_device *pdev)
 
 	/*
 	 * Extcon support is not vital for the charger to work. If no extcon
-	 * is available, just emit a warning and leave the probe function.
+	 * is available, just emit a warning, disable high impedance mode and
+	 * leave the probe function.
 	 */
 	charger->edev = extcon_get_edev_by_phandle(&pdev->dev, 0);
 	if (IS_ERR(charger->edev)) {
 		dev_warn(&pdev->dev, "no extcon phandle found in device-tree\n");
+		ret = regmap_update_bits(charger->rt5033->regmap,
+					 RT5033_REG_CHG_CTRL1,
+					 RT5033_CHGCTRL1_HZ_MASK,
+					 RT5033_CHARGER_HZ_DISABLE);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Failed to disable high impedance mode.\n");
+			return -EINVAL;
+		}
 		goto out;
 	}