regulator: pickable ranges: don't always cache vsel

PATCH In review Matti Vaittinen 2 participants 2 messages May 20, 2024 Voltage and current regulator framework

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Matti Vaittinen

author

2024-05-20 12:31 UTC #0 lore raw

PATCH v2 1/2 regulator: pickable ranges: don't always cache vsel

Some PMICs treat the vsel_reg same as apply-bit. Eg, when voltage range is changed, the new voltage setting is not taking effect until the vsel register is written.

Add a flag 'range_applied_by_vsel' to the regulator desc to indicate this behaviour and to force the vsel value to be written to hardware if range was changed, even if the old selector was same as the new one.

Signed-off-by Matti Vaittinen <[email protected]>

---
I have a feeling this same thing should be done with the apply-bit writes. I just wonder why no-one has reported problems with it. Maybe all the hardware with the apply bit has 'self clearing' apply register marked as volatile? Anyways, I'll leave it out of this patch because I have no hardware to test the apply-bit stuff, and as I haven't seen any problem reports about it.

---
 drivers/regulator/helpers.c      | 43 ++++++++++++++++++++++----------
 include/linux/regulator/driver.h |  3 +++
 2 files changed, 33 insertions(+), 13 deletions(-)

drivers/regulator/helpers.c +30 ~~-13~~

index d49268336553..6e1ace660b8c 100644
@@ -161,6 +161,32 @@ int regulator_get_voltage_sel_pickable_regmap(struct regulator_dev *rdev)
 }
 EXPORT_SYMBOL_GPL(regulator_get_voltage_sel_pickable_regmap);
 
+static int write_separate_vsel_and_range(struct regulator_dev *rdev,
+					 unsigned int sel, unsigned int range)
+{
+	bool range_updated;
+	int ret;
+
+	ret = regmap_update_bits_base(rdev->regmap, rdev->desc->vsel_range_reg,
+				      rdev->desc->vsel_range_mask,
+				      range, &range_updated, false, false);
+	if (ret)
+		return ret;
+
+	/*
+	 * Some PMICs treat the vsel_reg same as apply-bit. Force it to be
+	 * written if the range changed, even if the old selector was same as
+	 * the new one
+	 */
+	if (rdev->desc->range_applied_by_vsel && range_updated)
+		return regmap_write_bits(rdev->regmap,
+					rdev->desc->vsel_reg,
+					rdev->desc->vsel_mask, sel);
+
+	return regmap_update_bits(rdev->regmap, rdev->desc->vsel_reg,
+				  rdev->desc->vsel_mask, sel);
+}
+
 /**
  * regulator_set_voltage_sel_pickable_regmap - pickable range set_voltage_sel
  *

@@ -199,21 +225,12 @@ int regulator_set_voltage_sel_pickable_regmap(struct regulator_dev *rdev,
 	range = rdev->desc->linear_range_selectors_bitfield[i];
 	range <<= ffs(rdev->desc->vsel_range_mask) - 1;
 
-	if (rdev->desc->vsel_reg == rdev->desc->vsel_range_reg) {
-		ret = regmap_update_bits(rdev->regmap,
-					 rdev->desc->vsel_reg,
+	if (rdev->desc->vsel_reg == rdev->desc->vsel_range_reg)
+		ret = regmap_update_bits(rdev->regmap, rdev->desc->vsel_reg,
 					 rdev->desc->vsel_range_mask |
 					 rdev->desc->vsel_mask, sel | range);
-	} else {
-		ret = regmap_update_bits(rdev->regmap,
-					 rdev->desc->vsel_range_reg,
-					 rdev->desc->vsel_range_mask, range);
-		if (ret)
-			return ret;
-
-		ret = regmap_update_bits(rdev->regmap, rdev->desc->vsel_reg,
-				  rdev->desc->vsel_mask, sel);
-	}
+	else
+		ret = write_separate_vsel_and_range(rdev, sel, range);
 
 	if (ret)
 		return ret;

include/linux/regulator/driver.h +3 -0

index 22a07c0900a4..f230a472ccd3 100644
@@ -299,6 +299,8 @@ enum regulator_type {
  * @vsel_range_reg: Register for range selector when using pickable ranges
  *		    and ``regulator_map_*_voltage_*_pickable`` functions.
  * @vsel_range_mask: Mask for register bitfield used for range selector
+ * @range_applied_by_vsel: A flag to indicate that changes to vsel_range_reg
+ *			   are only effective after vsel_reg is written
  * @vsel_reg: Register for selector when using ``regulator_map_*_voltage_*``
  * @vsel_mask: Mask for register bitfield used for selector
  * @vsel_step: Specify the resolution of selector stepping when setting

@@ -389,6 +391,7 @@ struct regulator_desc {
 
 	unsigned int vsel_range_reg;
 	unsigned int vsel_range_mask;
+	bool range_applied_by_vsel;
 	unsigned int vsel_reg;
 	unsigned int vsel_mask;
 	unsigned int vsel_step;

Signature · 14 lines

2.45.1


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]

Mark Brown

maintainer

2024-05-20 19:27 UTC #1 lore raw

Quoted 9 lines · Matti Vaittinen

Some PMICs treat the vsel_reg same as apply-bit. Eg, when voltage range is changed, the new voltage setting is not taking effect until the vsel register is written.
Add a flag 'range_applied_by_vsel' to the regulator desc to indicate this behaviour and to force the vsel value to be written to hardware if range was changed, even if the old selector was same as the new one.
[...]

Applied to

https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git for-next

Thanks!

[1/2] regulator: pickable ranges: don't always cache vsel

      commit: f4f4276f985a5aac7b310a4ed040b47e275e7591

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

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Thanks,
Mark