[PATCH 0/3] Fixes for tps65090 for Samsung ARM Chromebook

[PATCH 0/3] Fixes for tps65090 for Samsung ARM Chromebook

[Doug Anderson]

These three patches bring tps65090 up to speed with what's currently
in the Chromium OS kernel 3.8 tree and running on the Samsung ARM
Chromebook.  Changes were tested atop the current linux tree
(v3.15-rc1).  FET retries were tested on a machine with a known flaky
tps65090.  Since display isn't working on pure upstream, I augmented
the code to turn FET1 (vcd_led) on/off 500 times at bootup.  When
testing I included <https://patchwork.kernel.org/patch/3980731/> to
make sure tps65090 was in exynos5250-snow's device tree.


Doug Anderson (3):
  mfd: tps65090: Allow charger module to be used when no irq
  mfd: tps65090: Stop caching registers
  regulator: tps65090: Make FETs more reliable

 .../devicetree/bindings/regulator/tps65090.txt     |   4 +
 drivers/mfd/tps65090.c                             |  24 ++-
 drivers/power/tps65090-charger.c                   |  76 ++++++--
 drivers/regulator/tps65090-regulator.c             | 197 +++++++++++++++++++--
 include/linux/mfd/tps65090.h                       |   5 +
 5 files changed, 264 insertions(+), 42 deletions(-)

-- 
1.9.1.423.g4596e3a

[PATCH 1/3] mfd: tps65090: Allow charger module to be used when no irq

[Doug Anderson]

On the ARM Chromebook tps65090 has two masters: the AP (the main
processor running linux) and the EC (the embedded controller).  The AP
is allowed to mess with FETs but the EC is in charge of charge control.

The tps65090 interupt line is routed to both the AP and the EC, which
can cause quite a headache.  Having two people adjusting masks and
acking interrupts is a recipe for disaster.

In the shipping kernel we had a hack to have the AP pay attention to
the IRQ but not to ack it.  It also wasn't supposed to configure the
IRQ in any way.  That hack allowed us to detect when the device was
charging without messing with the EC's state.

The current tps65090 infrastructure makes the above difficult, and it
was a bit of a hack to begin with.  Rather than uglify the driver to
support it, just extend the driver's existing notion of "no irq" to
the charger.  This makes the charger code poll every 2 seconds for AC
detect, which is sufficient.

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
 drivers/mfd/tps65090.c           | 14 ++++++--
 drivers/power/tps65090-charger.c | 76 +++++++++++++++++++++++++++++++---------
 2 files changed, 70 insertions(+), 20 deletions(-)

diff --git a/drivers/mfd/tps65090.c b/drivers/mfd/tps65090.c
index ba1a25d..c3cddb4 100644
--- a/drivers/mfd/tps65090.c
+++ b/drivers/mfd/tps65090.c
@@ -64,11 +64,16 @@ static struct resource charger_resources[] = {
 	}
 };
 
-static const struct mfd_cell tps65090s[] = {
-	{
+enum tps65090_cells {
+	PMIC = 0,
+	CHARGER = 1,
+};
+
+static struct mfd_cell tps65090s[] = {
+	[PMIC] = {
 		.name = "tps65090-pmic",
 	},
-	{
+	[CHARGER] = {
 		.name = "tps65090-charger",
 		.num_resources = ARRAY_SIZE(charger_resources),
 		.resources = &charger_resources[0],
@@ -211,6 +216,9 @@ static int tps65090_i2c_probe(struct i2c_client *client,
 					"IRQ init failed with err: %d\n", ret);
 			return ret;
 		}
+	} else {
+		/* Don't tell children they have an IRQ that'll never fire */
+		tps65090s[CHARGER].num_resources = 0;
 	}
 
 	ret = mfd_add_devices(tps65090->dev, -1, tps65090s,
diff --git a/drivers/power/tps65090-charger.c b/drivers/power/tps65090-charger.c
index 8fc9d6d..cc26c12 100644
--- a/drivers/power/tps65090-charger.c
+++ b/drivers/power/tps65090-charger.c
@@ -17,9 +17,11 @@
  */
 #include <linux/delay.h>
 #include <linux/err.h>
+#include <linux/freezer.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
+#include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
@@ -43,11 +45,15 @@
 #define TPS65090_VACG		BIT(1)
 #define TPS65090_NOITERM	BIT(5)
 
+#define POLL_INTERVAL		(HZ * 2)	/* Used when no irq */
+
 struct tps65090_charger {
 	struct	device	*dev;
 	int	ac_online;
 	int	prev_ac_online;
 	int	irq;
+	struct task_struct	*poll_task;
+	bool			passive_mode;
 	struct power_supply	ac;
 	struct tps65090_platform_data *pdata;
 };
@@ -60,6 +66,9 @@ static int tps65090_low_chrg_current(struct tps65090_charger *charger)
 {
 	int ret;
 
+	if (charger->passive_mode)
+		return 0;
+
 	ret = tps65090_write(charger->dev->parent, TPS65090_REG_CG_CTRL5,
 			TPS65090_NOITERM);
 	if (ret < 0) {
@@ -75,6 +84,9 @@ static int tps65090_enable_charging(struct tps65090_charger *charger)
 	int ret;
 	uint8_t ctrl0 = 0;
 
+	if (charger->passive_mode)
+		return 0;
+
 	ret = tps65090_read(charger->dev->parent, TPS65090_REG_CG_CTRL0,
 			    &ctrl0);
 	if (ret < 0) {
@@ -98,6 +110,9 @@ static int tps65090_config_charger(struct tps65090_charger *charger)
 	uint8_t intrmask = 0;
 	int ret;
 
+	if (charger->passive_mode)
+		return 0;
+
 	if (charger->pdata->enable_low_current_chrg) {
 		ret = tps65090_low_chrg_current(charger);
 		if (ret < 0) {
@@ -175,10 +190,14 @@ static irqreturn_t tps65090_charger_isr(int irq, void *dev_id)
 	}
 
 	/* Clear interrupts. */
-	ret = tps65090_write(charger->dev->parent, TPS65090_REG_INTR_STS, 0x00);
-	if (ret < 0) {
-		dev_err(charger->dev, "%s(): Error in writing reg 0x%x\n",
+	if (!charger->passive_mode) {
+		ret = tps65090_write(charger->dev->parent,
+				     TPS65090_REG_INTR_STS, 0x00);
+		if (ret < 0) {
+			dev_err(charger->dev,
+				"%s(): Error in writing reg 0x%x\n",
 				__func__, TPS65090_REG_INTR_STS);
+		}
 	}
 
 	if (charger->prev_ac_online != charger->ac_online)
@@ -209,6 +228,18 @@ static struct tps65090_platform_data *
 
 }
 
+static int tps65090_charger_poll_task(void *data)
+{
+	set_freezable();
+
+	while (!kthread_should_stop()) {
+		schedule_timeout_interruptible(POLL_INTERVAL);
+		try_to_freeze();
+		tps65090_charger_isr(-1, data);
+	}
+	return 0;
+}
+
 static int tps65090_charger_probe(struct platform_device *pdev)
 {
 	struct tps65090_charger *cdata;
@@ -255,22 +286,10 @@ static int tps65090_charger_probe(struct platform_device *pdev)
 	}
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq <= 0) {
-		dev_warn(&pdev->dev, "Unable to get charger irq = %d\n", irq);
-		ret = irq;
-		goto fail_unregister_supply;
-	}
-
+	if (irq < 0)
+		irq = NO_IRQ;
 	cdata->irq = irq;
 
-	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
-		tps65090_charger_isr, 0, "tps65090-charger", cdata);
-	if (ret) {
-		dev_err(cdata->dev, "Unable to register irq %d err %d\n", irq,
-			ret);
-		goto fail_unregister_supply;
-	}
-
 	ret = tps65090_config_charger(cdata);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "charger config failed, err %d\n", ret);
@@ -296,6 +315,27 @@ static int tps65090_charger_probe(struct platform_device *pdev)
 		power_supply_changed(&cdata->ac);
 	}
 
+	if (irq != NO_IRQ) {
+		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+			tps65090_charger_isr, 0, "tps65090-charger", cdata);
+		if (ret) {
+			dev_err(cdata->dev,
+				"Unable to register irq %d err %d\n", irq,
+				ret);
+			goto fail_unregister_supply;
+		}
+	} else {
+		cdata->poll_task = kthread_run(tps65090_charger_poll_task,
+					      cdata, "ktps65090charger");
+		cdata->passive_mode = true;
+		if (IS_ERR(cdata->poll_task)) {
+			ret = PTR_ERR(cdata->poll_task);
+			dev_err(cdata->dev,
+				"Unable to run kthread err %d\n", ret);
+			goto fail_unregister_supply;
+		}
+	}
+
 	return 0;
 
 fail_unregister_supply:
@@ -308,6 +348,8 @@ static int tps65090_charger_remove(struct platform_device *pdev)
 {
 	struct tps65090_charger *cdata = platform_get_drvdata(pdev);
 
+	if (cdata->irq == NO_IRQ)
+		kthread_stop(cdata->poll_task);
 	power_supply_unregister(&cdata->ac);
 
 	return 0;
-- 
1.9.1.423.g4596e3a

[PATCH 2/3] mfd: tps65090: Stop caching registers

[Doug Anderson]

Nearly all of the registers in tps65090 combine control bits and
status bits.  Turn off caching of registers so that we can read status
bits reliably.

NOTE: the IRQnMASK and CG_CTRLn registers are the exception and could
be cached.  If we find that we spend a lot of time reading those we
can turn on cache for just those registers.

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
 drivers/mfd/tps65090.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/drivers/mfd/tps65090.c b/drivers/mfd/tps65090.c
index c3cddb4..4cfdd07 100644
--- a/drivers/mfd/tps65090.c
+++ b/drivers/mfd/tps65090.c
@@ -149,21 +149,11 @@ static struct regmap_irq_chip tps65090_irq_chip = {
 	.mask_invert = true,
 };
 
-static bool is_volatile_reg(struct device *dev, unsigned int reg)
-{
-	if ((reg == TPS65090_INT_STS) || (reg == TPS65090_INT_STS2))
-		return true;
-	else
-		return false;
-}
-
 static const struct regmap_config tps65090_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = TOTAL_NUM_REG,
 	.num_reg_defaults_raw = TOTAL_NUM_REG,
-	.cache_type = REGCACHE_RBTREE,
-	.volatile_reg = is_volatile_reg,
 };
 
 #ifdef CONFIG_OF
-- 
1.9.1.423.g4596e3a

[PATCH 3/3] regulator: tps65090: Make FETs more reliable

[Doug Anderson]

An issue was discovered with tps65090 where sometimes the FETs
wouldn't actually turn on when requested.  The most problematic FET
was the one use for the LCD backlight on the Samsung ARM Chromebook
(FET1).  Problems were especially prevalent when the device was
plugged in to AC power, making the backlight voltage higher.

Mitigate the problem by:
* Allow setting the overcurrent wait time so devices with this problem
  can set it to the max.
* Add retry logic on enables of FETs.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Michael Spang <spang@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 .../devicetree/bindings/regulator/tps65090.txt     |   4 +
 drivers/regulator/tps65090-regulator.c             | 197 +++++++++++++++++++--
 include/linux/mfd/tps65090.h                       |   5 +
 3 files changed, 194 insertions(+), 12 deletions(-)

diff --git a/Documentation/devicetree/bindings/regulator/tps65090.txt b/Documentation/devicetree/bindings/regulator/tps65090.txt
index 313a60b..34098023 100644
--- a/Documentation/devicetree/bindings/regulator/tps65090.txt
+++ b/Documentation/devicetree/bindings/regulator/tps65090.txt
@@ -21,6 +21,10 @@ Optional properties:
   number should be provided. If it is externally controlled and no GPIO
   entry then driver will just configure this rails as external control
   and will not provide any enable/disable APIs.
+- ti,overcurrent-wait: This is applicable to FET registers, which have a
+  poorly defined "overcurrent wait" field.  If this property is present it
+  should be between 0 - 3.  If this property isn't present we won't touch the
+  "overcurrent wait" field and we'll leave it to the BIOS/EC to deal with.
 
 Each regulator is defined using the standard binding for regulators.
 
diff --git a/drivers/regulator/tps65090-regulator.c b/drivers/regulator/tps65090-regulator.c
index 2e92ef6..e8d1c62 100644
--- a/drivers/regulator/tps65090-regulator.c
+++ b/drivers/regulator/tps65090-regulator.c
@@ -17,6 +17,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
@@ -28,21 +29,186 @@
 #include <linux/regulator/of_regulator.h>
 #include <linux/mfd/tps65090.h>
 
+#define MAX_CTRL_READ_TRIES	5
+#define MAX_FET_ENABLE_TRIES	1000
+
+#define CTRL_EN_BIT		0 /* Regulator enable bit, active high */
+#define CTRL_WT_BIT		2 /* Regulator wait time 0 bit */
+#define CTRL_PG_BIT		4 /* Regulator power good bit, 1=good */
+#define CTRL_TO_BIT		7 /* Regulator timeout bit, 1=wait */
+
+#define MAX_OVERCURRENT_WAIT	3 /* Overcurrent wait must be less than this */
+
+/**
+ * struct tps65090_regulator - Per-regulator data for a tps65090 regulator
+ *
+ * @dev: Pointer to our device.
+ * @desc: The struct regulator_desc for the regulator.
+ * @rdev: The struct regulator_dev for the regulator.
+ * @overcurrent_wait_valid: True if overcurrent_wait is valid.
+ * @overcurrent_wait: For FETs, the value to put in the WTFET bitfield.
+ */
+
 struct tps65090_regulator {
 	struct device		*dev;
 	struct regulator_desc	*desc;
 	struct regulator_dev	*rdev;
+	bool			overcurrent_wait_valid;
+	int			overcurrent_wait;
 };
 
 static struct regulator_ops tps65090_ext_control_ops = {
 };
 
-static struct regulator_ops tps65090_reg_contol_ops = {
+/**
+ * tps65090_fet_is_enabled - Tell if a fet is enabled
+ *
+ * @rdev:	Regulator device
+ * @return true if the fet is enabled and its power is good; false otherwise.
+ */
+static int tps65090_fet_is_enabled(struct regulator_dev *rdev)
+{
+	unsigned int control;
+	unsigned int expected = rdev->desc->enable_mask | BIT(CTRL_PG_BIT);
+	int ret;
+
+	ret = regmap_read(rdev->regmap, rdev->desc->enable_reg, &control);
+	if (ret != 0)
+		return ret;
+
+	return (control & expected) == expected;
+}
+
+/**
+ * tps65090_reg_set_overcurrent_wait - Setup overcurrent wait
+ *
+ * This will set the overcurrent wait time based on what's in the regulator
+ * info.
+ *
+ * @rdev:	Regulator device
+ * @return 0 if no error, non-zero if there was an error writing the register.
+ */
+static int tps65090_reg_set_overcurrent_wait(struct regulator_dev *rdev)
+{
+	struct tps65090_regulator *ri = rdev_get_drvdata(rdev);
+	int ret;
+
+	if (!ri->overcurrent_wait_valid)
+		return 0;
+
+	ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				 MAX_OVERCURRENT_WAIT << CTRL_WT_BIT,
+				 ri->overcurrent_wait << CTRL_WT_BIT);
+	if (ret) {
+		dev_err(&rdev->dev, "Error updating overcurrent wait %#x\n",
+			rdev->desc->enable_reg);
+	}
+
+	return ret;
+}
+
+/**
+ * tps6090_try_enable_fet - Try to enable a FET
+ *
+ * @rdev:	Regulator device
+ * @return 0 if ok, -ENOTRECOVERABLE if the FET power good bit did not get set,
+ * or some other -ve value if another error occurred (e.g. i2c error)
+ */
+static int tps6090_try_enable_fet(struct regulator_dev *rdev)
+{
+	unsigned int control;
+	int ret, i;
+
+	ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				 rdev->desc->enable_mask,
+				 rdev->desc->enable_mask);
+	if (ret < 0) {
+		dev_err(&rdev->dev, "Error in updating reg %#x\n",
+			rdev->desc->enable_reg);
+		return ret;
+	}
+
+	for (i = 0; i < MAX_CTRL_READ_TRIES; i++) {
+		ret = regmap_read(rdev->regmap, rdev->desc->enable_reg,
+				  &control);
+		if (ret < 0)
+			return ret;
+
+		if (!(control & BIT(CTRL_TO_BIT)))
+			break;
+
+		usleep_range(1000, 1500);
+	}
+	if (!(control & BIT(CTRL_PG_BIT)))
+		return -ENOTRECOVERABLE;
+
+	return 0;
+}
+
+/**
+ * tps65090_fet_enable - Enable a FET, trying a few times if it fails
+ *
+ * Some versions of the tps65090 have issues when turning on the FETs.
+ * This function goes through several steps to ensure the best chance of the
+ * FET going on.  Specifically:
+ * - We'll make sure that we bump the "overcurrent wait" to the maximum, which
+ *   increases the chances that we'll turn on properly.
+ * - We'll retry turning the FET on multiple times (turning off in between).
+ *
+ * @rdev:	Regulator device
+ * @return 0 if ok, non-zero if it fails.
+ */
+static int tps65090_fet_enable(struct regulator_dev *rdev)
+{
+	int ret, tries;
+
+	ret = tps65090_reg_set_overcurrent_wait(rdev);
+	if (ret)
+		goto err;
+
+	/*
+	 * Try enabling multiple times until we succeed since sometimes the
+	 * first try times out.
+	 */
+	for (tries = 0; ; tries++) {
+		ret = tps6090_try_enable_fet(rdev);
+		if (!ret)
+			break;
+		if (ret != -ENOTRECOVERABLE || tries == MAX_FET_ENABLE_TRIES)
+			goto err;
+
+		/* Try turning the FET off (and then on again) */
+		ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+					 rdev->desc->enable_mask, 0);
+		if (ret)
+			goto err;
+	}
+
+	if (tries) {
+		dev_warn(&rdev->dev, "reg %#x enable ok after %d tries\n",
+			 rdev->desc->enable_reg, tries);
+	}
+
+	return 0;
+err:
+	dev_warn(&rdev->dev, "reg %#x enable failed\n", rdev->desc->enable_reg);
+	WARN_ON(1);
+
+	return ret;
+}
+
+static struct regulator_ops tps65090_reg_control_ops = {
 	.enable		= regulator_enable_regmap,
 	.disable	= regulator_disable_regmap,
 	.is_enabled	= regulator_is_enabled_regmap,
 };
 
+static struct regulator_ops tps65090_fet_control_ops = {
+	.enable		= tps65090_fet_enable,
+	.disable	= regulator_disable_regmap,
+	.is_enabled	= tps65090_fet_is_enabled,
+};
+
 static struct regulator_ops tps65090_ldo_ops = {
 };
 
@@ -53,22 +219,22 @@ static struct regulator_ops tps65090_ldo_ops = {
 	.id = TPS65090_REGULATOR_##_id,			\
 	.ops = &_ops,					\
 	.enable_reg = _en_reg,				\
-	.enable_mask = BIT(0),				\
+	.enable_mask = BIT(CTRL_EN_BIT),		\
 	.type = REGULATOR_VOLTAGE,			\
 	.owner = THIS_MODULE,				\
 }
 
 static struct regulator_desc tps65090_regulator_desc[] = {
-	tps65090_REG_DESC(DCDC1, "vsys1",   0x0C, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(DCDC2, "vsys2",   0x0D, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(DCDC3, "vsys3",   0x0E, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET1,  "infet1",  0x0F, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET2,  "infet2",  0x10, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET3,  "infet3",  0x11, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET4,  "infet4",  0x12, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET5,  "infet5",  0x13, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET6,  "infet6",  0x14, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET7,  "infet7",  0x15, tps65090_reg_contol_ops),
+	tps65090_REG_DESC(DCDC1, "vsys1",   0x0C, tps65090_reg_control_ops),
+	tps65090_REG_DESC(DCDC2, "vsys2",   0x0D, tps65090_reg_control_ops),
+	tps65090_REG_DESC(DCDC3, "vsys3",   0x0E, tps65090_reg_control_ops),
+	tps65090_REG_DESC(FET1,  "infet1",  0x0F, tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET2,  "infet2",  0x10, tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET3,  "infet3",  0x11, tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET4,  "infet4",  0x12, tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET5,  "infet5",  0x13, tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET6,  "infet6",  0x14, tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET7,  "infet7",  0x15, tps65090_fet_control_ops),
 	tps65090_REG_DESC(LDO1,  "vsys-l1", 0,    tps65090_ldo_ops),
 	tps65090_REG_DESC(LDO2,  "vsys-l2", 0,    tps65090_ldo_ops),
 };
@@ -209,6 +375,11 @@ static struct tps65090_platform_data *tps65090_parse_dt_reg_data(
 			rpdata->gpio = of_get_named_gpio(np,
 					"dcdc-ext-control-gpios", 0);
 
+		if (of_property_read_u32(tps65090_matches[idx].of_node,
+					 "ti,overcurrent-wait",
+					 &rpdata->overcurrent_wait) == 0)
+			rpdata->overcurrent_wait_valid = true;
+
 		tps65090_pdata->reg_pdata[idx] = rpdata;
 	}
 	return tps65090_pdata;
@@ -258,6 +429,8 @@ static int tps65090_regulator_probe(struct platform_device *pdev)
 		ri = &pmic[num];
 		ri->dev = &pdev->dev;
 		ri->desc = &tps65090_regulator_desc[num];
+		ri->overcurrent_wait_valid = tps_pdata->overcurrent_wait_valid;
+		ri->overcurrent_wait = tps_pdata->overcurrent_wait;
 
 		/*
 		 * TPS5090 DCDC support the control from external digital input.
diff --git a/include/linux/mfd/tps65090.h b/include/linux/mfd/tps65090.h
index 3f43069..f25adfa 100644
--- a/include/linux/mfd/tps65090.h
+++ b/include/linux/mfd/tps65090.h
@@ -78,11 +78,16 @@ struct tps65090 {
  *     DCDC1, DCDC2 and DCDC3.
  * @gpio: Gpio number if external control is enabled and controlled through
  *     gpio.
+ * @overcurrent_wait_valid: True if the overcurrent_wait should be applied.
+ * @overcurrent_wait: Value to set as the overcurrent wait time.  This is the
+ *     actual bitfield value, not a time in ms (valid value are 0 - 3).
  */
 struct tps65090_regulator_plat_data {
 	struct regulator_init_data *reg_init_data;
 	bool enable_ext_control;
 	int gpio;
+	bool overcurrent_wait_valid;
+	int overcurrent_wait;
 };
 
 struct tps65090_platform_data {
-- 
1.9.1.423.g4596e3a

Re: [PATCH 3/3] regulator: tps65090: Make FETs more reliable

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 1933 bytes --]

On Tue, Apr 15, 2014 at 01:14:36PM -0700, Doug Anderson wrote:

> Mitigate the problem by:
> * Allow setting the overcurrent wait time so devices with this problem
>   can set it to the max.
> * Add retry logic on enables of FETs.

This is two changes, should really be two patches.

> +- ti,overcurrent-wait: This is applicable to FET registers, which have a
> +  poorly defined "overcurrent wait" field.  If this property is present it
> +  should be between 0 - 3.  If this property isn't present we won't touch the
> +  "overcurrent wait" field and we'll leave it to the BIOS/EC to deal with.

I take it this is the raw value to write to the register?

> +static int tps65090_fet_is_enabled(struct regulator_dev *rdev)
> +{
> +	unsigned int control;
> +	unsigned int expected = rdev->desc->enable_mask | BIT(CTRL_PG_BIT);
> +	int ret;
> +
> +	ret = regmap_read(rdev->regmap, rdev->desc->enable_reg, &control);
> +	if (ret != 0)
> +		return ret;
> +
> +	return (control & expected) == expected;
> +}

No need to open code this, regulator_is_enabled_regmap() can check for
any value in a bitfield.

> +static int tps6090_try_enable_fet(struct regulator_dev *rdev)

Why is this called tps6090_try_enable_fet(), looks like a missing 5?

> +	/*
> +	 * Try enabling multiple times until we succeed since sometimes the
> +	 * first try times out.
> +	 */
> +	for (tries = 0; ; tries++) {
> +		ret = tps6090_try_enable_fet(rdev);
> +		if (!ret)
> +			break;
> +		if (ret != -ENOTRECOVERABLE || tries == MAX_FET_ENABLE_TRIES)
> +			goto err;

Make this a do { } while so we don't have the exit condition missing in
the for loop please, it's doing the right thing but it's not as obvious
as it could be.

> +	if (tries) {
> +		dev_warn(&rdev->dev, "reg %#x enable ok after %d tries\n",
> +			 rdev->desc->enable_reg, tries);
> +	}

No need for braces here, and I guess that ought to be retries rather
than tries (though that is pedantry).

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Re: [PATCH 3/3] regulator: tps65090: Make FETs more reliable

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 1933 bytes --]

On Tue, Apr 15, 2014 at 01:14:36PM -0700, Doug Anderson wrote:

> Mitigate the problem by:
> * Allow setting the overcurrent wait time so devices with this problem
>   can set it to the max.
> * Add retry logic on enables of FETs.

This is two changes, should really be two patches.

> +- ti,overcurrent-wait: This is applicable to FET registers, which have a
> +  poorly defined "overcurrent wait" field.  If this property is present it
> +  should be between 0 - 3.  If this property isn't present we won't touch the
> +  "overcurrent wait" field and we'll leave it to the BIOS/EC to deal with.

I take it this is the raw value to write to the register?

> +static int tps65090_fet_is_enabled(struct regulator_dev *rdev)
> +{
> +	unsigned int control;
> +	unsigned int expected = rdev->desc->enable_mask | BIT(CTRL_PG_BIT);
> +	int ret;
> +
> +	ret = regmap_read(rdev->regmap, rdev->desc->enable_reg, &control);
> +	if (ret != 0)
> +		return ret;
> +
> +	return (control & expected) == expected;
> +}

No need to open code this, regulator_is_enabled_regmap() can check for
any value in a bitfield.

> +static int tps6090_try_enable_fet(struct regulator_dev *rdev)

Why is this called tps6090_try_enable_fet(), looks like a missing 5?

> +	/*
> +	 * Try enabling multiple times until we succeed since sometimes the
> +	 * first try times out.
> +	 */
> +	for (tries = 0; ; tries++) {
> +		ret = tps6090_try_enable_fet(rdev);
> +		if (!ret)
> +			break;
> +		if (ret != -ENOTRECOVERABLE || tries == MAX_FET_ENABLE_TRIES)
> +			goto err;

Make this a do { } while so we don't have the exit condition missing in
the for loop please, it's doing the right thing but it's not as obvious
as it could be.

> +	if (tries) {
> +		dev_warn(&rdev->dev, "reg %#x enable ok after %d tries\n",
> +			 rdev->desc->enable_reg, tries);
> +	}

No need for braces here, and I guess that ought to be retries rather
than tries (though that is pedantry).

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Re: [PATCH 1/3] mfd: tps65090: Allow charger module to be used when no irq

[Lee Jones]

> On the ARM Chromebook tps65090 has two masters: the AP (the main
> processor running linux) and the EC (the embedded controller).  The AP
> is allowed to mess with FETs but the EC is in charge of charge control.
> 
> The tps65090 interupt line is routed to both the AP and the EC, which
> can cause quite a headache.  Having two people adjusting masks and
> acking interrupts is a recipe for disaster.
> 
> In the shipping kernel we had a hack to have the AP pay attention to
> the IRQ but not to ack it.  It also wasn't supposed to configure the
> IRQ in any way.  That hack allowed us to detect when the device was
> charging without messing with the EC's state.
> 
> The current tps65090 infrastructure makes the above difficult, and it
> was a bit of a hack to begin with.  Rather than uglify the driver to
> support it, just extend the driver's existing notion of "no irq" to
> the charger.  This makes the charger code poll every 2 seconds for AC
> detect, which is sufficient.
> 
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
>  drivers/mfd/tps65090.c           | 14 ++++++--
>  drivers/power/tps65090-charger.c | 76 +++++++++++++++++++++++++++++++---------
>  2 files changed, 70 insertions(+), 20 deletions(-)

For the MFD part:
  Acked-by: Lee Jones <lee.jones@linaro.org>

Anton,
  If you are okay with this patch I'd be happy to create an immutable
branch for you to pull from?

Doug,
  What is the relationship (dependencies) between this and the other
patches in the set?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 2/3] mfd: tps65090: Stop caching registers

[Lee Jones]

> Nearly all of the registers in tps65090 combine control bits and
> status bits.  Turn off caching of registers so that we can read status
> bits reliably.
> 
> NOTE: the IRQnMASK and CG_CTRLn registers are the exception and could
> be cached.  If we find that we spend a lot of time reading those we
> can turn on cache for just those registers.
> 
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
>  drivers/mfd/tps65090.c | 10 ----------
>  1 file changed, 10 deletions(-)
> 
> diff --git a/drivers/mfd/tps65090.c b/drivers/mfd/tps65090.c
> index c3cddb4..4cfdd07 100644
> --- a/drivers/mfd/tps65090.c
> +++ b/drivers/mfd/tps65090.c
> @@ -149,21 +149,11 @@ static struct regmap_irq_chip tps65090_irq_chip = {
>  	.mask_invert = true,
>  };
>  
> -static bool is_volatile_reg(struct device *dev, unsigned int reg)
> -{
> -	if ((reg == TPS65090_INT_STS) || (reg == TPS65090_INT_STS2))
> -		return true;
> -	else
> -		return false;
> -}
> -

I don't know enough about Regmap internals to know what this actually
affects in real terms.

Mark,
  Does this change seem sane to you?

>  static const struct regmap_config tps65090_regmap_config = {
>  	.reg_bits = 8,
>  	.val_bits = 8,
>  	.max_register = TOTAL_NUM_REG,
>  	.num_reg_defaults_raw = TOTAL_NUM_REG,
> -	.cache_type = REGCACHE_RBTREE,
> -	.volatile_reg = is_volatile_reg,
>  };
>  
>  #ifdef CONFIG_OF

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 2/3] mfd: tps65090: Stop caching registers

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 896 bytes --]

On Wed, Apr 16, 2014 at 10:59:22AM +0100, Lee Jones wrote:

> > NOTE: the IRQnMASK and CG_CTRLn registers are the exception and could
> > be cached.  If we find that we spend a lot of time reading those we
> > can turn on cache for just those registers.

> > -static bool is_volatile_reg(struct device *dev, unsigned int reg)
> > -{
> > -	if ((reg == TPS65090_INT_STS) || (reg == TPS65090_INT_STS2))
> > -		return true;
> > -	else
> > -		return false;
> > -}
> > -

> I don't know enough about Regmap internals to know what this actually
> affects in real terms.

> Mark,
>   Does this change seem sane to you?

It does what it says, it stops us caching stuff.  It would seem better
to do what the changelog suggests above and keep caching the registers
that can be cached - especially the interrupt masks, they should get
read in the interrupt path and that tends to be a bit latency sensitive.

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Re: [PATCH 1/3] mfd: tps65090: Allow charger module to be used when no irq

[Doug Anderson]

Lee

On Wed, Apr 16, 2014 at 2:52 AM, Lee Jones <lee.jones@linaro.org> wrote:
>> On the ARM Chromebook tps65090 has two masters: the AP (the main
>> processor running linux) and the EC (the embedded controller).  The AP
>> is allowed to mess with FETs but the EC is in charge of charge control.
>>
>> The tps65090 interupt line is routed to both the AP and the EC, which
>> can cause quite a headache.  Having two people adjusting masks and
>> acking interrupts is a recipe for disaster.
>>
>> In the shipping kernel we had a hack to have the AP pay attention to
>> the IRQ but not to ack it.  It also wasn't supposed to configure the
>> IRQ in any way.  That hack allowed us to detect when the device was
>> charging without messing with the EC's state.
>>
>> The current tps65090 infrastructure makes the above difficult, and it
>> was a bit of a hack to begin with.  Rather than uglify the driver to
>> support it, just extend the driver's existing notion of "no irq" to
>> the charger.  This makes the charger code poll every 2 seconds for AC
>> detect, which is sufficient.
>>
>> Signed-off-by: Doug Anderson <dianders@chromium.org>
>> ---
>>  drivers/mfd/tps65090.c           | 14 ++++++--
>>  drivers/power/tps65090-charger.c | 76 +++++++++++++++++++++++++++++++---------
>>  2 files changed, 70 insertions(+), 20 deletions(-)
>
> For the MFD part:
>   Acked-by: Lee Jones <lee.jones@linaro.org>
>
> Anton,
>   If you are okay with this patch I'd be happy to create an immutable
> branch for you to pull from?
>
> Doug,
>   What is the relationship (dependencies) between this and the other
> patches in the set?

This patch can be applied irrespective of other others in the series.

-Doug

Re: [PATCH 1/3] mfd: tps65090: Allow charger module to be used when no irq

[Lee Jones]

> >> On the ARM Chromebook tps65090 has two masters: the AP (the main
> >> processor running linux) and the EC (the embedded controller).  The AP
> >> is allowed to mess with FETs but the EC is in charge of charge control.
> >>
> >> The tps65090 interupt line is routed to both the AP and the EC, which
> >> can cause quite a headache.  Having two people adjusting masks and
> >> acking interrupts is a recipe for disaster.
> >>
> >> In the shipping kernel we had a hack to have the AP pay attention to
> >> the IRQ but not to ack it.  It also wasn't supposed to configure the
> >> IRQ in any way.  That hack allowed us to detect when the device was
> >> charging without messing with the EC's state.
> >>
> >> The current tps65090 infrastructure makes the above difficult, and it
> >> was a bit of a hack to begin with.  Rather than uglify the driver to
> >> support it, just extend the driver's existing notion of "no irq" to
> >> the charger.  This makes the charger code poll every 2 seconds for AC
> >> detect, which is sufficient.
> >>
> >> Signed-off-by: Doug Anderson <dianders@chromium.org>
> >> ---
> >>  drivers/mfd/tps65090.c           | 14 ++++++--
> >>  drivers/power/tps65090-charger.c | 76 +++++++++++++++++++++++++++++++---------
> >>  2 files changed, 70 insertions(+), 20 deletions(-)
> >
> > For the MFD part:
> >   Acked-by: Lee Jones <lee.jones@linaro.org>
> >
> > Anton,
> >   If you are okay with this patch I'd be happy to create an immutable
> > branch for you to pull from?
> >
> > Doug,
> >   What is the relationship (dependencies) between this and the other
> > patches in the set?
> 
> This patch can be applied irrespective of other others in the series.

What about the files in the patch? Could you make two separate patches
from this one patch and it would still compile okay? I'm _guessing_
the answer is yes?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 1/3] mfd: tps65090: Allow charger module to be used when no irq

[Doug Anderson]

Lee,

On Wed, Apr 16, 2014 at 9:26 AM, Lee Jones <lee.jones@linaro.org> wrote:
>> >> On the ARM Chromebook tps65090 has two masters: the AP (the main
>> >> processor running linux) and the EC (the embedded controller).  The AP
>> >> is allowed to mess with FETs but the EC is in charge of charge control.
>> >>
>> >> The tps65090 interupt line is routed to both the AP and the EC, which
>> >> can cause quite a headache.  Having two people adjusting masks and
>> >> acking interrupts is a recipe for disaster.
>> >>
>> >> In the shipping kernel we had a hack to have the AP pay attention to
>> >> the IRQ but not to ack it.  It also wasn't supposed to configure the
>> >> IRQ in any way.  That hack allowed us to detect when the device was
>> >> charging without messing with the EC's state.
>> >>
>> >> The current tps65090 infrastructure makes the above difficult, and it
>> >> was a bit of a hack to begin with.  Rather than uglify the driver to
>> >> support it, just extend the driver's existing notion of "no irq" to
>> >> the charger.  This makes the charger code poll every 2 seconds for AC
>> >> detect, which is sufficient.
>> >>
>> >> Signed-off-by: Doug Anderson <dianders@chromium.org>
>> >> ---
>> >>  drivers/mfd/tps65090.c           | 14 ++++++--
>> >>  drivers/power/tps65090-charger.c | 76 +++++++++++++++++++++++++++++++---------
>> >>  2 files changed, 70 insertions(+), 20 deletions(-)
>> >
>> > For the MFD part:
>> >   Acked-by: Lee Jones <lee.jones@linaro.org>
>> >
>> > Anton,
>> >   If you are okay with this patch I'd be happy to create an immutable
>> > branch for you to pull from?
>> >
>> > Doug,
>> >   What is the relationship (dependencies) between this and the other
>> > patches in the set?
>>
>> This patch can be applied irrespective of other others in the series.
>
> What about the files in the patch? Could you make two separate patches
> from this one patch and it would still compile okay? I'm _guessing_
> the answer is yes?

Yes, they'll compile and even boot on their own.  I just tested it.

If I put only the MFD part in, then at boot I see:
  tps65090-charger tps65090-charger: Unable to get charger irq = -6
...but otherwise the system functions.

If I put only the charger part in, then at boot:
  tps65090-charger tps65090-charger: Unable to register irq 1 err -22
  tps65090-charger: probe of tps65090-charger failed with error -22

...so you need both patches in order to make things function, but they
can be applied separately.  I'll assume it will make your life easier
if I split this into two patches so I'll do that.

-Doug

[PATCH v2 0/5] Fixes for tps65090 for Samsung ARM Chromebook

[Doug Anderson]

These five patches bring tps65090 up to speed with what's currently
in the Chromium OS kernel 3.8 tree and running on the Samsung ARM
Chromebook.  Changes were tested atop the current linux tree
(v3.15-rc1).  FET retries were tested on a machine with a known flaky
tps65090.  Since display isn't working on pure upstream, I augmented
the code to turn FET1 (vcd_led) on/off 500 times at bootup.  When
testing I included <https://patchwork.kernel.org/patch/3980731/> to
make sure tps65090 was in exynos5250-snow's device tree.

Dependencies:
- Patch #1 (mfd no irq) has no dependencies, though patch #2 won't
  work without it.
- Patch #2 (charger polling) can be applied without patch #1 but won't
  actually make charger polling work without it.
- Patch #3 (caching) can be applied before retries patch but not
  after.
- Patch #4 (overcurrent wait time) can be applied before retries patch
  but not after (just due to merge conflicts, no other reason).
- Patch #5 (retries) absolutely requires patch #3 (caching).

Changes in v2:
- Split noirq (polling mode) changes into MFD and charger
- Leave cache on for the registers that can be cached.
- Move register offsets to mfd header file.
- Separated the overcurrent and retries changes into two patches.
- Now set overcurrent at probe time since it doesn't change.
- Separated the overcurrent and retries changes into two patches.
- No longer open code fet_is_enabled().
- Fixed tps6090 typo.
- For loop => "while true".
- Removed a set of braces.

Doug Anderson (5):
  mfd: tps65090: Don't tell child devices we have an IRQ if we don't
  charger: tps65090: Allow charger module to be used when no irq
  mfd: tps65090: Stop caching most registers
  regulator: tps65090: Allow setting the overcurrent wait time
  regulator: tps65090: Make FETs more reliable by adding retries

 .../devicetree/bindings/regulator/tps65090.txt     |   4 +
 drivers/mfd/tps65090.c                             |  41 ++--
 drivers/power/tps65090-charger.c                   |  87 ++++++---
 drivers/regulator/tps65090-regulator.c             | 208 +++++++++++++++++++--
 include/linux/mfd/tps65090.h                       |  19 ++
 5 files changed, 300 insertions(+), 59 deletions(-)

-- 
1.9.1.423.g4596e3a

[PATCH v2 1/5] mfd: tps65090: Don't tell child devices we have an IRQ if we don't

[Doug Anderson]

If we weren't given an interrupt we shouldn't tell child devices (like
the tps65090 charger) that they have an interrupt.  This is needed so
that we can support polling mode in the tps65090 charger driver.

See also (charger: tps65090: Allow charger module to be used when no
irq).

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
---
Changes in v2:
- Split noirq (polling mode) changes into MFD and charger

 drivers/mfd/tps65090.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/mfd/tps65090.c b/drivers/mfd/tps65090.c
index ba1a25d..c3cddb4 100644
--- a/drivers/mfd/tps65090.c
+++ b/drivers/mfd/tps65090.c
@@ -64,11 +64,16 @@ static struct resource charger_resources[] = {
 	}
 };
 
-static const struct mfd_cell tps65090s[] = {
-	{
+enum tps65090_cells {
+	PMIC = 0,
+	CHARGER = 1,
+};
+
+static struct mfd_cell tps65090s[] = {
+	[PMIC] = {
 		.name = "tps65090-pmic",
 	},
-	{
+	[CHARGER] = {
 		.name = "tps65090-charger",
 		.num_resources = ARRAY_SIZE(charger_resources),
 		.resources = &charger_resources[0],
@@ -211,6 +216,9 @@ static int tps65090_i2c_probe(struct i2c_client *client,
 					"IRQ init failed with err: %d\n", ret);
 			return ret;
 		}
+	} else {
+		/* Don't tell children they have an IRQ that'll never fire */
+		tps65090s[CHARGER].num_resources = 0;
 	}
 
 	ret = mfd_add_devices(tps65090->dev, -1, tps65090s,
-- 
1.9.1.423.g4596e3a

[PATCH v2 2/5] charger: tps65090: Allow charger module to be used when no irq

[Doug Anderson]

On the ARM Chromebook tps65090 has two masters: the AP (the main
processor running linux) and the EC (the embedded controller).  The AP
is allowed to mess with FETs but the EC is in charge of charge control.

The tps65090 interupt line is routed to both the AP and the EC, which
can cause quite a headache.  Having two people adjusting masks and
acking interrupts is a recipe for disaster.

In the shipping kernel we had a hack to have the AP pay attention to
the IRQ but not to ack it.  It also wasn't supposed to configure the
IRQ in any way.  That hack allowed us to detect when the device was
charging without messing with the EC's state.

The current tps65090 infrastructure makes the above difficult, and it
was a bit of a hack to begin with.  Rather than uglify the driver to
support it, just extend the driver's existing notion of "no irq" to
the charger.  This makes the charger code poll every 2 seconds for AC
detect, which is sufficient.

For proper functioning, requires (mfd: tps65090: Don't tell child
devices we have an IRQ if we don't).  If we don't have that patch
we'll simply fail to probe on devices without an interrupt (just like
we did before this patch).

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
Changes in v2:
- Split noirq (polling mode) changes into MFD and charger

 drivers/power/tps65090-charger.c | 76 +++++++++++++++++++++++++++++++---------
 1 file changed, 59 insertions(+), 17 deletions(-)

diff --git a/drivers/power/tps65090-charger.c b/drivers/power/tps65090-charger.c
index 8fc9d6d..cc26c12 100644
--- a/drivers/power/tps65090-charger.c
+++ b/drivers/power/tps65090-charger.c
@@ -17,9 +17,11 @@
  */
 #include <linux/delay.h>
 #include <linux/err.h>
+#include <linux/freezer.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
+#include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
@@ -43,11 +45,15 @@
 #define TPS65090_VACG		BIT(1)
 #define TPS65090_NOITERM	BIT(5)
 
+#define POLL_INTERVAL		(HZ * 2)	/* Used when no irq */
+
 struct tps65090_charger {
 	struct	device	*dev;
 	int	ac_online;
 	int	prev_ac_online;
 	int	irq;
+	struct task_struct	*poll_task;
+	bool			passive_mode;
 	struct power_supply	ac;
 	struct tps65090_platform_data *pdata;
 };
@@ -60,6 +66,9 @@ static int tps65090_low_chrg_current(struct tps65090_charger *charger)
 {
 	int ret;
 
+	if (charger->passive_mode)
+		return 0;
+
 	ret = tps65090_write(charger->dev->parent, TPS65090_REG_CG_CTRL5,
 			TPS65090_NOITERM);
 	if (ret < 0) {
@@ -75,6 +84,9 @@ static int tps65090_enable_charging(struct tps65090_charger *charger)
 	int ret;
 	uint8_t ctrl0 = 0;
 
+	if (charger->passive_mode)
+		return 0;
+
 	ret = tps65090_read(charger->dev->parent, TPS65090_REG_CG_CTRL0,
 			    &ctrl0);
 	if (ret < 0) {
@@ -98,6 +110,9 @@ static int tps65090_config_charger(struct tps65090_charger *charger)
 	uint8_t intrmask = 0;
 	int ret;
 
+	if (charger->passive_mode)
+		return 0;
+
 	if (charger->pdata->enable_low_current_chrg) {
 		ret = tps65090_low_chrg_current(charger);
 		if (ret < 0) {
@@ -175,10 +190,14 @@ static irqreturn_t tps65090_charger_isr(int irq, void *dev_id)
 	}
 
 	/* Clear interrupts. */
-	ret = tps65090_write(charger->dev->parent, TPS65090_REG_INTR_STS, 0x00);
-	if (ret < 0) {
-		dev_err(charger->dev, "%s(): Error in writing reg 0x%x\n",
+	if (!charger->passive_mode) {
+		ret = tps65090_write(charger->dev->parent,
+				     TPS65090_REG_INTR_STS, 0x00);
+		if (ret < 0) {
+			dev_err(charger->dev,
+				"%s(): Error in writing reg 0x%x\n",
 				__func__, TPS65090_REG_INTR_STS);
+		}
 	}
 
 	if (charger->prev_ac_online != charger->ac_online)
@@ -209,6 +228,18 @@ static struct tps65090_platform_data *
 
 }
 
+static int tps65090_charger_poll_task(void *data)
+{
+	set_freezable();
+
+	while (!kthread_should_stop()) {
+		schedule_timeout_interruptible(POLL_INTERVAL);
+		try_to_freeze();
+		tps65090_charger_isr(-1, data);
+	}
+	return 0;
+}
+
 static int tps65090_charger_probe(struct platform_device *pdev)
 {
 	struct tps65090_charger *cdata;
@@ -255,22 +286,10 @@ static int tps65090_charger_probe(struct platform_device *pdev)
 	}
 
 	irq = platform_get_irq(pdev, 0);
-	if (irq <= 0) {
-		dev_warn(&pdev->dev, "Unable to get charger irq = %d\n", irq);
-		ret = irq;
-		goto fail_unregister_supply;
-	}
-
+	if (irq < 0)
+		irq = NO_IRQ;
 	cdata->irq = irq;
 
-	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
-		tps65090_charger_isr, 0, "tps65090-charger", cdata);
-	if (ret) {
-		dev_err(cdata->dev, "Unable to register irq %d err %d\n", irq,
-			ret);
-		goto fail_unregister_supply;
-	}
-
 	ret = tps65090_config_charger(cdata);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "charger config failed, err %d\n", ret);
@@ -296,6 +315,27 @@ static int tps65090_charger_probe(struct platform_device *pdev)
 		power_supply_changed(&cdata->ac);
 	}
 
+	if (irq != NO_IRQ) {
+		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+			tps65090_charger_isr, 0, "tps65090-charger", cdata);
+		if (ret) {
+			dev_err(cdata->dev,
+				"Unable to register irq %d err %d\n", irq,
+				ret);
+			goto fail_unregister_supply;
+		}
+	} else {
+		cdata->poll_task = kthread_run(tps65090_charger_poll_task,
+					      cdata, "ktps65090charger");
+		cdata->passive_mode = true;
+		if (IS_ERR(cdata->poll_task)) {
+			ret = PTR_ERR(cdata->poll_task);
+			dev_err(cdata->dev,
+				"Unable to run kthread err %d\n", ret);
+			goto fail_unregister_supply;
+		}
+	}
+
 	return 0;
 
 fail_unregister_supply:
@@ -308,6 +348,8 @@ static int tps65090_charger_remove(struct platform_device *pdev)
 {
 	struct tps65090_charger *cdata = platform_get_drvdata(pdev);
 
+	if (cdata->irq == NO_IRQ)
+		kthread_stop(cdata->poll_task);
 	power_supply_unregister(&cdata->ac);
 
 	return 0;
-- 
1.9.1.423.g4596e3a

[PATCH v2 3/5] mfd: tps65090: Stop caching most registers

[Doug Anderson]

Nearly all of the registers in tps65090 combine control bits and
status bits.  Turn off caching of all registers except the select few
that can be cached.

In order to avoid adding more duplicate #defines, we also move some
register offset definitions to the mfd driver (and resolve
inconsistent names).

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
Changes in v2:
- Leave cache on for the registers that can be cached.
- Move register offsets to mfd header file.

 drivers/mfd/tps65090.c           | 27 ++++++++++++++-------------
 drivers/power/tps65090-charger.c | 11 -----------
 include/linux/mfd/tps65090.h     | 14 ++++++++++++++
 3 files changed, 28 insertions(+), 24 deletions(-)

diff --git a/drivers/mfd/tps65090.c b/drivers/mfd/tps65090.c
index c3cddb4..1c3e6e2 100644
--- a/drivers/mfd/tps65090.c
+++ b/drivers/mfd/tps65090.c
@@ -32,14 +32,6 @@
 #define NUM_INT_REG 2
 #define TOTAL_NUM_REG 0x18
 
-/* interrupt status registers */
-#define TPS65090_INT_STS	0x0
-#define TPS65090_INT_STS2	0x1
-
-/* interrupt mask registers */
-#define TPS65090_INT_MSK	0x2
-#define TPS65090_INT_MSK2	0x3
-
 #define TPS65090_INT1_MASK_VAC_STATUS_CHANGE		1
 #define TPS65090_INT1_MASK_VSYS_STATUS_CHANGE		2
 #define TPS65090_INT1_MASK_BAT_STATUS_CHANGE		3
@@ -144,17 +136,26 @@ static struct regmap_irq_chip tps65090_irq_chip = {
 	.irqs = tps65090_irqs,
 	.num_irqs = ARRAY_SIZE(tps65090_irqs),
 	.num_regs = NUM_INT_REG,
-	.status_base = TPS65090_INT_STS,
-	.mask_base = TPS65090_INT_MSK,
+	.status_base = TPS65090_REG_INTR_STS,
+	.mask_base = TPS65090_REG_INTR_MASK,
 	.mask_invert = true,
 };
 
 static bool is_volatile_reg(struct device *dev, unsigned int reg)
 {
-	if ((reg == TPS65090_INT_STS) || (reg == TPS65090_INT_STS2))
-		return true;
-	else
+	/* Nearly all registers have status bits mixed in, except a few */
+	switch (reg) {
+	case TPS65090_REG_INTR_MASK:
+	case TPS65090_REG_INTR_MASK2:
+	case TPS65090_REG_CG_CTRL0:
+	case TPS65090_REG_CG_CTRL1:
+	case TPS65090_REG_CG_CTRL2:
+	case TPS65090_REG_CG_CTRL3:
+	case TPS65090_REG_CG_CTRL4:
+	case TPS65090_REG_CG_CTRL5:
 		return false;
+	}
+	return true;
 }
 
 static const struct regmap_config tps65090_regmap_config = {
diff --git a/drivers/power/tps65090-charger.c b/drivers/power/tps65090-charger.c
index cc26c12..31a3ba4 100644
--- a/drivers/power/tps65090-charger.c
+++ b/drivers/power/tps65090-charger.c
@@ -30,17 +30,6 @@
 
 #include <linux/mfd/tps65090.h>
 
-#define TPS65090_REG_INTR_STS	0x00
-#define TPS65090_REG_INTR_MASK	0x02
-#define TPS65090_REG_CG_CTRL0	0x04
-#define TPS65090_REG_CG_CTRL1	0x05
-#define TPS65090_REG_CG_CTRL2	0x06
-#define TPS65090_REG_CG_CTRL3	0x07
-#define TPS65090_REG_CG_CTRL4	0x08
-#define TPS65090_REG_CG_CTRL5	0x09
-#define TPS65090_REG_CG_STATUS1	0x0a
-#define TPS65090_REG_CG_STATUS2	0x0b
-
 #define TPS65090_CHARGER_ENABLE	BIT(0)
 #define TPS65090_VACG		BIT(1)
 #define TPS65090_NOITERM	BIT(5)
diff --git a/include/linux/mfd/tps65090.h b/include/linux/mfd/tps65090.h
index 3f43069..45f0f9d 100644
--- a/include/linux/mfd/tps65090.h
+++ b/include/linux/mfd/tps65090.h
@@ -64,6 +64,20 @@ enum {
 	TPS65090_REGULATOR_MAX,
 };
 
+/* Register addresses */
+#define TPS65090_REG_INTR_STS	0x00
+#define TPS65090_REG_INTR_STS2	0x01
+#define TPS65090_REG_INTR_MASK	0x02
+#define TPS65090_REG_INTR_MASK2	0x03
+#define TPS65090_REG_CG_CTRL0	0x04
+#define TPS65090_REG_CG_CTRL1	0x05
+#define TPS65090_REG_CG_CTRL2	0x06
+#define TPS65090_REG_CG_CTRL3	0x07
+#define TPS65090_REG_CG_CTRL4	0x08
+#define TPS65090_REG_CG_CTRL5	0x09
+#define TPS65090_REG_CG_STATUS1	0x0a
+#define TPS65090_REG_CG_STATUS2	0x0b
+
 struct tps65090 {
 	struct device		*dev;
 	struct regmap		*rmap;
-- 
1.9.1.423.g4596e3a

[PATCH v2 4/5] regulator: tps65090: Allow setting the overcurrent wait time

[Doug Anderson]

The tps65090 regulator allows you to specify how long you want it to
wait before detecting an overcurrent condition.  Allow specifying that
through the device tree (or through platform data).

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Michael Spang <spang@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
Changes in v2:
- Separated the overcurrent and retries changes into two patches.
- Now set overcurrent at probe time since it doesn't change.

 .../devicetree/bindings/regulator/tps65090.txt     |  4 ++
 drivers/regulator/tps65090-regulator.c             | 55 ++++++++++++++++++++++
 include/linux/mfd/tps65090.h                       |  5 ++
 3 files changed, 64 insertions(+)

diff --git a/Documentation/devicetree/bindings/regulator/tps65090.txt b/Documentation/devicetree/bindings/regulator/tps65090.txt
index 313a60b..34098023 100644
--- a/Documentation/devicetree/bindings/regulator/tps65090.txt
+++ b/Documentation/devicetree/bindings/regulator/tps65090.txt
@@ -21,6 +21,10 @@ Optional properties:
   number should be provided. If it is externally controlled and no GPIO
   entry then driver will just configure this rails as external control
   and will not provide any enable/disable APIs.
+- ti,overcurrent-wait: This is applicable to FET registers, which have a
+  poorly defined "overcurrent wait" field.  If this property is present it
+  should be between 0 - 3.  If this property isn't present we won't touch the
+  "overcurrent wait" field and we'll leave it to the BIOS/EC to deal with.
 
 Each regulator is defined using the standard binding for regulators.
 
diff --git a/drivers/regulator/tps65090-regulator.c b/drivers/regulator/tps65090-regulator.c
index 2e92ef6..ca13a1a 100644
--- a/drivers/regulator/tps65090-regulator.c
+++ b/drivers/regulator/tps65090-regulator.c
@@ -28,15 +28,57 @@
 #include <linux/regulator/of_regulator.h>
 #include <linux/mfd/tps65090.h>
 
+#define CTRL_WT_BIT		2 /* Regulator wait time 0 bit */
+
+#define MAX_OVERCURRENT_WAIT	3 /* Overcurrent wait must be <= this */
+
+/**
+ * struct tps65090_regulator - Per-regulator data for a tps65090 regulator
+ *
+ * @dev: Pointer to our device.
+ * @desc: The struct regulator_desc for the regulator.
+ * @rdev: The struct regulator_dev for the regulator.
+ * @overcurrent_wait_valid: True if overcurrent_wait is valid.
+ * @overcurrent_wait: For FETs, the value to put in the WTFET bitfield.
+ */
+
 struct tps65090_regulator {
 	struct device		*dev;
 	struct regulator_desc	*desc;
 	struct regulator_dev	*rdev;
+	bool			overcurrent_wait_valid;
+	int			overcurrent_wait;
 };
 
 static struct regulator_ops tps65090_ext_control_ops = {
 };
 
+/**
+ * tps65090_reg_set_overcurrent_wait - Setup overcurrent wait
+ *
+ * This will set the overcurrent wait time based on what's in the regulator
+ * info.
+ *
+ * @ri:		Overall regulator data
+ * @rdev:	Regulator device
+ * @return 0 if no error, non-zero if there was an error writing the register.
+ */
+static int tps65090_reg_set_overcurrent_wait(struct tps65090_regulator *ri,
+					     struct regulator_dev *rdev)
+{
+	int ret;
+
+	ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				 MAX_OVERCURRENT_WAIT << CTRL_WT_BIT,
+				 ri->overcurrent_wait << CTRL_WT_BIT);
+	if (ret) {
+		dev_err(&rdev->dev, "Error updating overcurrent wait %#x\n",
+			rdev->desc->enable_reg);
+	}
+
+	return ret;
+}
+
 static struct regulator_ops tps65090_reg_contol_ops = {
 	.enable		= regulator_enable_regmap,
 	.disable	= regulator_disable_regmap,
@@ -209,6 +251,11 @@ static struct tps65090_platform_data *tps65090_parse_dt_reg_data(
 			rpdata->gpio = of_get_named_gpio(np,
 					"dcdc-ext-control-gpios", 0);
 
+		if (of_property_read_u32(tps65090_matches[idx].of_node,
+					 "ti,overcurrent-wait",
+					 &rpdata->overcurrent_wait) == 0)
+			rpdata->overcurrent_wait_valid = true;
+
 		tps65090_pdata->reg_pdata[idx] = rpdata;
 	}
 	return tps65090_pdata;
@@ -258,6 +305,8 @@ static int tps65090_regulator_probe(struct platform_device *pdev)
 		ri = &pmic[num];
 		ri->dev = &pdev->dev;
 		ri->desc = &tps65090_regulator_desc[num];
+		ri->overcurrent_wait_valid = tps_pdata->overcurrent_wait_valid;
+		ri->overcurrent_wait = tps_pdata->overcurrent_wait;
 
 		/*
 		 * TPS5090 DCDC support the control from external digital input.
@@ -299,6 +348,12 @@ static int tps65090_regulator_probe(struct platform_device *pdev)
 		}
 		ri->rdev = rdev;
 
+		if (ri->overcurrent_wait_valid) {
+			ret = tps65090_reg_set_overcurrent_wait(ri, rdev);
+			if (ret < 0)
+				return ret;
+		}
+
 		/* Enable external control if it is require */
 		if (tps_pdata && is_dcdc(num) && tps_pdata->reg_init_data &&
 				tps_pdata->enable_ext_control) {
diff --git a/include/linux/mfd/tps65090.h b/include/linux/mfd/tps65090.h
index 45f0f9d..0bf2708 100644
--- a/include/linux/mfd/tps65090.h
+++ b/include/linux/mfd/tps65090.h
@@ -92,11 +92,16 @@ struct tps65090 {
  *     DCDC1, DCDC2 and DCDC3.
  * @gpio: Gpio number if external control is enabled and controlled through
  *     gpio.
+ * @overcurrent_wait_valid: True if the overcurrent_wait should be applied.
+ * @overcurrent_wait: Value to set as the overcurrent wait time.  This is the
+ *     actual bitfield value, not a time in ms (valid value are 0 - 3).
  */
 struct tps65090_regulator_plat_data {
 	struct regulator_init_data *reg_init_data;
 	bool enable_ext_control;
 	int gpio;
+	bool overcurrent_wait_valid;
+	int overcurrent_wait;
 };
 
 struct tps65090_platform_data {
-- 
1.9.1.423.g4596e3a

[PATCH v2 5/5] regulator: tps65090: Make FETs more reliable by adding retries

[Doug Anderson]

An issue was discovered with tps65090 where sometimes the FETs
wouldn't actually turn on when requested (they would report
overcurrent).  The most problematic FET was the one used for the LCD
backlight on the Samsung ARM Chromebook (FET1).  Problems were
especially prevalent when the device was plugged in to AC power (when
the backlight voltage was higher).

Mitigate the problem by adding retries on the enables of the FETs,
which works around the problem fairly effectively.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Michael Spang <spang@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
Changes in v2:
- Separated the overcurrent and retries changes into two patches.
- No longer open code fet_is_enabled().
- Fixed tps6090 typo.
- For loop => "while true".
- Removed a set of braces.

 drivers/regulator/tps65090-regulator.c | 153 +++++++++++++++++++++++++++++----
 1 file changed, 138 insertions(+), 15 deletions(-)

diff --git a/drivers/regulator/tps65090-regulator.c b/drivers/regulator/tps65090-regulator.c
index ca13a1a..c37ffb72 100644
--- a/drivers/regulator/tps65090-regulator.c
+++ b/drivers/regulator/tps65090-regulator.c
@@ -17,6 +17,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
@@ -28,7 +29,13 @@
 #include <linux/regulator/of_regulator.h>
 #include <linux/mfd/tps65090.h>
 
+#define MAX_CTRL_READ_TRIES	5
+#define MAX_FET_ENABLE_TRIES	1000
+
+#define CTRL_EN_BIT		0 /* Regulator enable bit, active high */
 #define CTRL_WT_BIT		2 /* Regulator wait time 0 bit */
+#define CTRL_PG_BIT		4 /* Regulator power good bit, 1=good */
+#define CTRL_TO_BIT		7 /* Regulator timeout bit, 1=wait */
 
 #define MAX_OVERCURRENT_WAIT	3 /* Overcurrent wait must be <= this */
 
@@ -79,40 +86,156 @@ static int tps65090_reg_set_overcurrent_wait(struct tps65090_regulator *ri,
 	return ret;
 }
 
-static struct regulator_ops tps65090_reg_contol_ops = {
+/**
+ * tps65090_try_enable_fet - Try to enable a FET
+ *
+ * @rdev:	Regulator device
+ * @return 0 if ok, -ENOTRECOVERABLE if the FET power good bit did not get set,
+ * or some other -ve value if another error occurred (e.g. i2c error)
+ */
+static int tps65090_try_enable_fet(struct regulator_dev *rdev)
+{
+	unsigned int control;
+	int ret, i;
+
+	ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				 rdev->desc->enable_mask,
+				 rdev->desc->enable_mask);
+	if (ret < 0) {
+		dev_err(&rdev->dev, "Error in updating reg %#x\n",
+			rdev->desc->enable_reg);
+		return ret;
+	}
+
+	for (i = 0; i < MAX_CTRL_READ_TRIES; i++) {
+		ret = regmap_read(rdev->regmap, rdev->desc->enable_reg,
+				  &control);
+		if (ret < 0)
+			return ret;
+
+		if (!(control & BIT(CTRL_TO_BIT)))
+			break;
+
+		usleep_range(1000, 1500);
+	}
+	if (!(control & BIT(CTRL_PG_BIT)))
+		return -ENOTRECOVERABLE;
+
+	return 0;
+}
+
+/**
+ * tps65090_fet_enable - Enable a FET, trying a few times if it fails
+ *
+ * Some versions of the tps65090 have issues when turning on the FETs.
+ * This function goes through several steps to ensure the best chance of the
+ * FET going on.  Specifically:
+ * - We'll make sure that we bump the "overcurrent wait" to the maximum, which
+ *   increases the chances that we'll turn on properly.
+ * - We'll retry turning the FET on multiple times (turning off in between).
+ *
+ * @rdev:	Regulator device
+ * @return 0 if ok, non-zero if it fails.
+ */
+static int tps65090_fet_enable(struct regulator_dev *rdev)
+{
+	int ret, tries;
+
+	/*
+	 * Try enabling multiple times until we succeed since sometimes the
+	 * first try times out.
+	 */
+	tries = 0;
+	while (true) {
+		ret = tps65090_try_enable_fet(rdev);
+		if (!ret)
+			break;
+		if (ret != -ENOTRECOVERABLE || tries == MAX_FET_ENABLE_TRIES)
+			goto err;
+
+		/* Try turning the FET off (and then on again) */
+		ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+					 rdev->desc->enable_mask, 0);
+		if (ret)
+			goto err;
+
+		tries++;
+	}
+
+	if (tries)
+		dev_warn(&rdev->dev, "reg %#x enable ok after %d tries\n",
+			 rdev->desc->enable_reg, tries);
+
+	return 0;
+err:
+	dev_warn(&rdev->dev, "reg %#x enable failed\n", rdev->desc->enable_reg);
+	WARN_ON(1);
+
+	return ret;
+}
+
+static struct regulator_ops tps65090_reg_control_ops = {
 	.enable		= regulator_enable_regmap,
 	.disable	= regulator_disable_regmap,
 	.is_enabled	= regulator_is_enabled_regmap,
 };
 
+static struct regulator_ops tps65090_fet_control_ops = {
+	.enable		= tps65090_fet_enable,
+	.disable	= regulator_disable_regmap,
+	.is_enabled	= regulator_is_enabled_regmap,
+};
+
 static struct regulator_ops tps65090_ldo_ops = {
 };
 
-#define tps65090_REG_DESC(_id, _sname, _en_reg, _ops)	\
+#define tps65090_REG_DESC(_id, _sname, _en_reg, _en_bits, _ops)	\
 {							\
 	.name = "TPS65090_RAILS"#_id,			\
 	.supply_name = _sname,				\
 	.id = TPS65090_REGULATOR_##_id,			\
 	.ops = &_ops,					\
 	.enable_reg = _en_reg,				\
-	.enable_mask = BIT(0),				\
+	.enable_val = _en_bits,				\
+	.enable_mask = _en_bits,			\
 	.type = REGULATOR_VOLTAGE,			\
 	.owner = THIS_MODULE,				\
 }
 
 static struct regulator_desc tps65090_regulator_desc[] = {
-	tps65090_REG_DESC(DCDC1, "vsys1",   0x0C, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(DCDC2, "vsys2",   0x0D, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(DCDC3, "vsys3",   0x0E, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET1,  "infet1",  0x0F, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET2,  "infet2",  0x10, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET3,  "infet3",  0x11, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET4,  "infet4",  0x12, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET5,  "infet5",  0x13, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET6,  "infet6",  0x14, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(FET7,  "infet7",  0x15, tps65090_reg_contol_ops),
-	tps65090_REG_DESC(LDO1,  "vsys-l1", 0,    tps65090_ldo_ops),
-	tps65090_REG_DESC(LDO2,  "vsys-l2", 0,    tps65090_ldo_ops),
+	tps65090_REG_DESC(DCDC1, "vsys1",   0x0C, BIT(CTRL_EN_BIT),
+			  tps65090_reg_control_ops),
+	tps65090_REG_DESC(DCDC2, "vsys2",   0x0D, BIT(CTRL_EN_BIT),
+			  tps65090_reg_control_ops),
+	tps65090_REG_DESC(DCDC3, "vsys3",   0x0E, BIT(CTRL_EN_BIT),
+			  tps65090_reg_control_ops),
+
+	tps65090_REG_DESC(FET1,  "infet1",  0x0F,
+			  BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
+			  tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET2,  "infet2",  0x10,
+			  BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
+			  tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET3,  "infet3",  0x11,
+			  BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
+			  tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET4,  "infet4",  0x12,
+			  BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
+			  tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET5,  "infet5",  0x13,
+			  BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
+			  tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET6,  "infet6",  0x14,
+			  BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
+			  tps65090_fet_control_ops),
+	tps65090_REG_DESC(FET7,  "infet7",  0x15,
+			  BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
+			  tps65090_fet_control_ops),
+
+	tps65090_REG_DESC(LDO1,  "vsys-l1", 0, 0,
+			  tps65090_ldo_ops),
+	tps65090_REG_DESC(LDO2,  "vsys-l2", 0, 0,
+			  tps65090_ldo_ops),
 };
 
 static inline bool is_dcdc(int id)
-- 
1.9.1.423.g4596e3a

Re: [PATCH 2/3] mfd: tps65090: Stop caching registers

[Doug Anderson]

Mark,

On Wed, Apr 16, 2014 at 3:13 AM, Mark Brown <broonie@kernel.org> wrote:
> On Wed, Apr 16, 2014 at 10:59:22AM +0100, Lee Jones wrote:
>
>> > NOTE: the IRQnMASK and CG_CTRLn registers are the exception and could
>> > be cached.  If we find that we spend a lot of time reading those we
>> > can turn on cache for just those registers.
>
>> > -static bool is_volatile_reg(struct device *dev, unsigned int reg)
>> > -{
>> > -   if ((reg == TPS65090_INT_STS) || (reg == TPS65090_INT_STS2))
>> > -           return true;
>> > -   else
>> > -           return false;
>> > -}
>> > -
>
>> I don't know enough about Regmap internals to know what this actually
>> affects in real terms.
>
>> Mark,
>>   Does this change seem sane to you?
>
> It does what it says, it stops us caching stuff.  It would seem better
> to do what the changelog suggests above and keep caching the registers
> that can be cached - especially the interrupt masks, they should get
> read in the interrupt path and that tends to be a bit latency sensitive.

Done

Re: [PATCH 3/3] regulator: tps65090: Make FETs more reliable

[Doug Anderson]

Mark,

On Tue, Apr 15, 2014 at 3:52 PM, Mark Brown <broonie@kernel.org> wrote:
> On Tue, Apr 15, 2014 at 01:14:36PM -0700, Doug Anderson wrote:
>
>> Mitigate the problem by:
>> * Allow setting the overcurrent wait time so devices with this problem
>>   can set it to the max.
>> * Add retry logic on enables of FETs.
>
> This is two changes, should really be two patches.

OK, sure.


>> +- ti,overcurrent-wait: This is applicable to FET registers, which have a
>> +  poorly defined "overcurrent wait" field.  If this property is present it
>> +  should be between 0 - 3.  If this property isn't present we won't touch the
>> +  "overcurrent wait" field and we'll leave it to the BIOS/EC to deal with.
>
> I take it this is the raw value to write to the register?

Yes.


>> +static int tps65090_fet_is_enabled(struct regulator_dev *rdev)
>> +{
>> +     unsigned int control;
>> +     unsigned int expected = rdev->desc->enable_mask | BIT(CTRL_PG_BIT);
>> +     int ret;
>> +
>> +     ret = regmap_read(rdev->regmap, rdev->desc->enable_reg, &control);
>> +     if (ret != 0)
>> +             return ret;
>> +
>> +     return (control & expected) == expected;
>> +}
>
> No need to open code this, regulator_is_enabled_regmap() can check for
> any value in a bitfield.

The overall problem was that we were checking a different bit than we
were setting.  We set "enabled" to turn things on and then we check
"power good".

I can avoid the open coding by doing something that's slightly a hack.
 I'll put that in V2 and you can tell me if you like it better.  I'll
set "enable_mask" and "enable_val" to include both bits.  The "power
good" is read only so it won't hurt to set it.  ...and it doesn't hurt
to check the enabled bit in addition to the power good bit.


>> +static int tps6090_try_enable_fet(struct regulator_dev *rdev)
>
> Why is this called tps6090_try_enable_fet(), looks like a missing 5?

typo.  fixed.

>
>> +     /*
>> +      * Try enabling multiple times until we succeed since sometimes the
>> +      * first try times out.
>> +      */
>> +     for (tries = 0; ; tries++) {
>> +             ret = tps6090_try_enable_fet(rdev);
>> +             if (!ret)
>> +                     break;
>> +             if (ret != -ENOTRECOVERABLE || tries == MAX_FET_ENABLE_TRIES)
>> +                     goto err;
>
> Make this a do { } while so we don't have the exit condition missing in
> the for loop please, it's doing the right thing but it's not as obvious
> as it could be.

It's not quite a "do { } while" since the break is in the middle, but
happy to change to a "while (true)".  Hope that's OK.

>
>> +     if (tries) {
>> +             dev_warn(&rdev->dev, "reg %#x enable ok after %d tries\n",
>> +                      rdev->desc->enable_reg, tries);
>> +     }
>
> No need for braces here, and I guess that ought to be retries rather
> than tries (though that is pedantry).

LOL.  I've been yelled at for the opposite.  ;)  There's at least
someone out there who thinks that we should have braces if you've got
a single statement like this that wraps to two lines, but I can't
remember who.

In any case, fixed.

-Doug

Re: [PATCH 1/3] mfd: tps65090: Allow charger module to be used when no irq

[Lee Jones]

> >> >> On the ARM Chromebook tps65090 has two masters: the AP (the main
> >> >> processor running linux) and the EC (the embedded controller).  The AP
> >> >> is allowed to mess with FETs but the EC is in charge of charge control.
> >> >>
> >> >> The tps65090 interupt line is routed to both the AP and the EC, which
> >> >> can cause quite a headache.  Having two people adjusting masks and
> >> >> acking interrupts is a recipe for disaster.
> >> >>
> >> >> In the shipping kernel we had a hack to have the AP pay attention to
> >> >> the IRQ but not to ack it.  It also wasn't supposed to configure the
> >> >> IRQ in any way.  That hack allowed us to detect when the device was
> >> >> charging without messing with the EC's state.
> >> >>
> >> >> The current tps65090 infrastructure makes the above difficult, and it
> >> >> was a bit of a hack to begin with.  Rather than uglify the driver to
> >> >> support it, just extend the driver's existing notion of "no irq" to
> >> >> the charger.  This makes the charger code poll every 2 seconds for AC
> >> >> detect, which is sufficient.
> >> >>
> >> >> Signed-off-by: Doug Anderson <dianders@chromium.org>
> >> >> ---
> >> >>  drivers/mfd/tps65090.c           | 14 ++++++--
> >> >>  drivers/power/tps65090-charger.c | 76 +++++++++++++++++++++++++++++++---------
> >> >>  2 files changed, 70 insertions(+), 20 deletions(-)
> >> >
> >> > For the MFD part:
> >> >   Acked-by: Lee Jones <lee.jones@linaro.org>
> >> >
> >> > Anton,
> >> >   If you are okay with this patch I'd be happy to create an immutable
> >> > branch for you to pull from?
> >> >
> >> > Doug,
> >> >   What is the relationship (dependencies) between this and the other
> >> > patches in the set?
> >>
> >> This patch can be applied irrespective of other others in the series.
> >
> > What about the files in the patch? Could you make two separate patches
> > from this one patch and it would still compile okay? I'm _guessing_
> > the answer is yes?
> 
> Yes, they'll compile and even boot on their own.  I just tested it.
> 
> If I put only the MFD part in, then at boot I see:
>   tps65090-charger tps65090-charger: Unable to get charger irq = -6
> ...but otherwise the system functions.
> 
> If I put only the charger part in, then at boot:
>   tps65090-charger tps65090-charger: Unable to register irq 1 err -22
>   tps65090-charger: probe of tps65090-charger failed with error -22
> 
> ...so you need both patches in order to make things function, but they
> can be applied separately.  I'll assume it will make your life easier
> if I split this into two patches so I'll do that.

Yes please.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v2 4/5] regulator: tps65090: Allow setting the overcurrent wait time

[Randy Dunlap]

On 04/16/2014 11:25 AM, Doug Anderson wrote:
> diff --git a/drivers/regulator/tps65090-regulator.c b/drivers/regulator/tps65090-regulator.c
> index 2e92ef6..ca13a1a 100644
> --- a/drivers/regulator/tps65090-regulator.c
> +++ b/drivers/regulator/tps65090-regulator.c
> @@ -28,15 +28,57 @@

> +/**
> + * tps65090_reg_set_overcurrent_wait - Setup overcurrent wait
> + *
> + * This will set the overcurrent wait time based on what's in the regulator
> + * info.
> + *
> + * @ri:		Overall regulator data
> + * @rdev:	Regulator device
> + * @return 0 if no error, non-zero if there was an error writing the register.

kernel-doc notation here should be:

 * Return: 0 if no error, non-zero if there was an error writing the register.

> + */
> +static int tps65090_reg_set_overcurrent_wait(struct tps65090_regulator *ri,
> +					     struct regulator_dev *rdev)
> +{


-- 
~Randy

Re: [PATCH v2 5/5] regulator: tps65090: Make FETs more reliable by adding retries

[Simon Glass]

Hi Doug, (take 2)

On 16 April 2014 12:25, Doug Anderson <dianders@chromium.org> wrote:
> An issue was discovered with tps65090 where sometimes the FETs
> wouldn't actually turn on when requested (they would report
> overcurrent).  The most problematic FET was the one used for the LCD
> backlight on the Samsung ARM Chromebook (FET1).  Problems were
> especially prevalent when the device was plugged in to AC power (when
> the backlight voltage was higher).
>
> Mitigate the problem by adding retries on the enables of the FETs,
> which works around the problem fairly effectively.
>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Michael Spang <spang@chromium.org>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> ---
> Changes in v2:
> - Separated the overcurrent and retries changes into two patches.
> - No longer open code fet_is_enabled().
> - Fixed tps6090 typo.
> - For loop => "while true".
> - Removed a set of braces.
>
>  drivers/regulator/tps65090-regulator.c | 153 +++++++++++++++++++++++++++++----
>  1 file changed, 138 insertions(+), 15 deletions(-)

Reviewed-by: Simon Glass <sjg@chromium.org>

(see minor comment below)

>
> diff --git a/drivers/regulator/tps65090-regulator.c b/drivers/regulator/tps65090-regulator.c
> index ca13a1a..c37ffb72 100644
> --- a/drivers/regulator/tps65090-regulator.c
> +++ b/drivers/regulator/tps65090-regulator.c
> @@ -17,6 +17,7 @@
>   */
>
>  #include <linux/module.h>
> +#include <linux/delay.h>
>  #include <linux/init.h>
>  #include <linux/gpio.h>
>  #include <linux/of_gpio.h>
> @@ -28,7 +29,13 @@
>  #include <linux/regulator/of_regulator.h>
>  #include <linux/mfd/tps65090.h>
>
> +#define MAX_CTRL_READ_TRIES    5
> +#define MAX_FET_ENABLE_TRIES   1000

Gosh that is a lot of tries - should we maybe give up sooner?

> +
> +#define CTRL_EN_BIT            0 /* Regulator enable bit, active high */
>  #define CTRL_WT_BIT            2 /* Regulator wait time 0 bit */
> +#define CTRL_PG_BIT            4 /* Regulator power good bit, 1=good */
> +#define CTRL_TO_BIT            7 /* Regulator timeout bit, 1=wait */
>
>  #define MAX_OVERCURRENT_WAIT   3 /* Overcurrent wait must be <= this */
>
> @@ -79,40 +86,156 @@ static int tps65090_reg_set_overcurrent_wait(struct tps65090_regulator *ri,
>         return ret;
>  }
>
> -static struct regulator_ops tps65090_reg_contol_ops = {
> +/**
> + * tps65090_try_enable_fet - Try to enable a FET
> + *
> + * @rdev:      Regulator device
> + * @return 0 if ok, -ENOTRECOVERABLE if the FET power good bit did not get set,
> + * or some other -ve value if another error occurred (e.g. i2c error)
> + */
> +static int tps65090_try_enable_fet(struct regulator_dev *rdev)
> +{
> +       unsigned int control;
> +       int ret, i;
> +
> +       ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
> +                                rdev->desc->enable_mask,
> +                                rdev->desc->enable_mask);
> +       if (ret < 0) {
> +               dev_err(&rdev->dev, "Error in updating reg %#x\n",
> +                       rdev->desc->enable_reg);
> +               return ret;
> +       }
> +
> +       for (i = 0; i < MAX_CTRL_READ_TRIES; i++) {
> +               ret = regmap_read(rdev->regmap, rdev->desc->enable_reg,
> +                                 &control);
> +               if (ret < 0)
> +                       return ret;
> +
> +               if (!(control & BIT(CTRL_TO_BIT)))
> +                       break;
> +
> +               usleep_range(1000, 1500);
> +       }
> +       if (!(control & BIT(CTRL_PG_BIT)))
> +               return -ENOTRECOVERABLE;
> +
> +       return 0;
> +}
> +
> +/**
> + * tps65090_fet_enable - Enable a FET, trying a few times if it fails
> + *
> + * Some versions of the tps65090 have issues when turning on the FETs.
> + * This function goes through several steps to ensure the best chance of the
> + * FET going on.  Specifically:
> + * - We'll make sure that we bump the "overcurrent wait" to the maximum, which
> + *   increases the chances that we'll turn on properly.
> + * - We'll retry turning the FET on multiple times (turning off in between).
> + *
> + * @rdev:      Regulator device
> + * @return 0 if ok, non-zero if it fails.
> + */
> +static int tps65090_fet_enable(struct regulator_dev *rdev)
> +{
> +       int ret, tries;
> +
> +       /*
> +        * Try enabling multiple times until we succeed since sometimes the
> +        * first try times out.
> +        */
> +       tries = 0;
> +       while (true) {
> +               ret = tps65090_try_enable_fet(rdev);
> +               if (!ret)
> +                       break;
> +               if (ret != -ENOTRECOVERABLE || tries == MAX_FET_ENABLE_TRIES)
> +                       goto err;
> +
> +               /* Try turning the FET off (and then on again) */
> +               ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
> +                                        rdev->desc->enable_mask, 0);
> +               if (ret)
> +                       goto err;
> +
> +               tries++;
> +       }
> +
> +       if (tries)
> +               dev_warn(&rdev->dev, "reg %#x enable ok after %d tries\n",
> +                        rdev->desc->enable_reg, tries);
> +
> +       return 0;
> +err:
> +       dev_warn(&rdev->dev, "reg %#x enable failed\n", rdev->desc->enable_reg);
> +       WARN_ON(1);
> +
> +       return ret;
> +}
> +
> +static struct regulator_ops tps65090_reg_control_ops = {
>         .enable         = regulator_enable_regmap,
>         .disable        = regulator_disable_regmap,
>         .is_enabled     = regulator_is_enabled_regmap,
>  };
>
> +static struct regulator_ops tps65090_fet_control_ops = {
> +       .enable         = tps65090_fet_enable,
> +       .disable        = regulator_disable_regmap,
> +       .is_enabled     = regulator_is_enabled_regmap,
> +};
> +
>  static struct regulator_ops tps65090_ldo_ops = {
>  };
>
> -#define tps65090_REG_DESC(_id, _sname, _en_reg, _ops)  \
> +#define tps65090_REG_DESC(_id, _sname, _en_reg, _en_bits, _ops)        \
>  {                                                      \
>         .name = "TPS65090_RAILS"#_id,                   \
>         .supply_name = _sname,                          \
>         .id = TPS65090_REGULATOR_##_id,                 \
>         .ops = &_ops,                                   \
>         .enable_reg = _en_reg,                          \
> -       .enable_mask = BIT(0),                          \
> +       .enable_val = _en_bits,                         \
> +       .enable_mask = _en_bits,                        \
>         .type = REGULATOR_VOLTAGE,                      \
>         .owner = THIS_MODULE,                           \
>  }
>
>  static struct regulator_desc tps65090_regulator_desc[] = {
> -       tps65090_REG_DESC(DCDC1, "vsys1",   0x0C, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(DCDC2, "vsys2",   0x0D, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(DCDC3, "vsys3",   0x0E, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(FET1,  "infet1",  0x0F, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(FET2,  "infet2",  0x10, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(FET3,  "infet3",  0x11, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(FET4,  "infet4",  0x12, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(FET5,  "infet5",  0x13, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(FET6,  "infet6",  0x14, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(FET7,  "infet7",  0x15, tps65090_reg_contol_ops),
> -       tps65090_REG_DESC(LDO1,  "vsys-l1", 0,    tps65090_ldo_ops),
> -       tps65090_REG_DESC(LDO2,  "vsys-l2", 0,    tps65090_ldo_ops),
> +       tps65090_REG_DESC(DCDC1, "vsys1",   0x0C, BIT(CTRL_EN_BIT),
> +                         tps65090_reg_control_ops),
> +       tps65090_REG_DESC(DCDC2, "vsys2",   0x0D, BIT(CTRL_EN_BIT),
> +                         tps65090_reg_control_ops),
> +       tps65090_REG_DESC(DCDC3, "vsys3",   0x0E, BIT(CTRL_EN_BIT),
> +                         tps65090_reg_control_ops),
> +
> +       tps65090_REG_DESC(FET1,  "infet1",  0x0F,
> +                         BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
> +                         tps65090_fet_control_ops),
> +       tps65090_REG_DESC(FET2,  "infet2",  0x10,
> +                         BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
> +                         tps65090_fet_control_ops),
> +       tps65090_REG_DESC(FET3,  "infet3",  0x11,
> +                         BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
> +                         tps65090_fet_control_ops),
> +       tps65090_REG_DESC(FET4,  "infet4",  0x12,
> +                         BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
> +                         tps65090_fet_control_ops),
> +       tps65090_REG_DESC(FET5,  "infet5",  0x13,
> +                         BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
> +                         tps65090_fet_control_ops),
> +       tps65090_REG_DESC(FET6,  "infet6",  0x14,
> +                         BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
> +                         tps65090_fet_control_ops),
> +       tps65090_REG_DESC(FET7,  "infet7",  0x15,
> +                         BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
> +                         tps65090_fet_control_ops),
> +
> +       tps65090_REG_DESC(LDO1,  "vsys-l1", 0, 0,
> +                         tps65090_ldo_ops),
> +       tps65090_REG_DESC(LDO2,  "vsys-l2", 0, 0,
> +                         tps65090_ldo_ops),
>  };
>
>  static inline bool is_dcdc(int id)
> --
> 1.9.1.423.g4596e3a
>

Regards,
Simon

Re: [PATCH v2 5/5] regulator: tps65090: Make FETs more reliable by adding retries

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 414 bytes --]

On Wed, Apr 16, 2014 at 11:25:24AM -0700, Doug Anderson wrote:
> An issue was discovered with tps65090 where sometimes the FETs
> wouldn't actually turn on when requested (they would report
> overcurrent).  The most problematic FET was the one used for the LCD

Please don't send new patches as replies in the middle of threads, it
makes it confusing trying to work out which versions of things should be
applied.

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]

Re: [PATCH v2 5/5] regulator: tps65090: Make FETs more reliable by adding retries

[Doug Anderson]

Simon,

On Wed, Apr 16, 2014 at 1:50 PM, Simon Glass <sjg@chromium.org> wrote:
>> +#define MAX_CTRL_READ_TRIES    5
>> +#define MAX_FET_ENABLE_TRIES   1000
>
> Gosh that is a lot of tries - should we maybe give up sooner?

That's actually a squash of a recent patch.  See
<https://chromium-review.googlesource.com/189239>.  I've specifically
seen at least one case on my device where it needed 888 retries at
bootup!

...on my really old Chromebook, it seems to get into a bad state if it
sits on my desk for a long time.  After I use it a bit it rarely needs
more than 10 retries.

-Doug

Re: [PATCH v2 5/5] regulator: tps65090: Make FETs more reliable by adding retries

[Doug Anderson]

Mark,

On Wed, Apr 16, 2014 at 1:51 PM, Mark Brown <broonie@kernel.org> wrote:
> On Wed, Apr 16, 2014 at 11:25:24AM -0700, Doug Anderson wrote:
>> An issue was discovered with tps65090 where sometimes the FETs
>> wouldn't actually turn on when requested (they would report
>> overcurrent).  The most problematic FET was the one used for the LCD
>
> Please don't send new patches as replies in the middle of threads, it
> makes it confusing trying to work out which versions of things should be
> applied.

I'm a little confused about what I did wrong.  Can you give more details?

* V1 had 3 patches plus a cover letter.

* I was asked to split two patches, so V2 has 5 patches plus a cover letter.

* My v2 series was all "in reply to" the v1 cover letter, which I
thought was best practice.

* All of my v2 patches were marked with v2 and included changes
between v1 and v2.

* Everyone was CCed on the cover letter.  Only appropriate people were
CCed on the individual patches (as per get_maintainer, automated by
patman).

* All patches were resent at v2.


If I had to answer your question, I'd say that you should now
completely ignore v1 and look at v2.

-Doug

Re: [PATCH v2 5/5] regulator: tps65090: Make FETs more reliable by adding retries

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 790 bytes --]

On Wed, Apr 16, 2014 at 02:34:47PM -0700, Doug Anderson wrote:
> On Wed, Apr 16, 2014 at 1:51 PM, Mark Brown <broonie@kernel.org> wrote:

> > Please don't send new patches as replies in the middle of threads, it
> > makes it confusing trying to work out which versions of things should be
> > applied.

> I'm a little confused about what I did wrong.  Can you give more details?

I'm seeing a reply which looks like it was sent as a followup to Randy's
comment, although now I look at everything together I think that's due
to you sending your new thread in reply to the old thread (that can also
be a problem due to threading either burying the new mail or putting
things in odd places) and my mailer trying to tie the one mail from your
first series that I'd not deleted into the thread.

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Re: [PATCH v2 5/5] regulator: tps65090: Make FETs more reliable by adding retries

[Doug Anderson]

Mark,

On Wed, Apr 16, 2014 at 2:54 PM, Mark Brown <broonie@kernel.org> wrote:
> On Wed, Apr 16, 2014 at 02:34:47PM -0700, Doug Anderson wrote:
>> On Wed, Apr 16, 2014 at 1:51 PM, Mark Brown <broonie@kernel.org> wrote:
>
>> > Please don't send new patches as replies in the middle of threads, it
>> > makes it confusing trying to work out which versions of things should be
>> > applied.
>
>> I'm a little confused about what I did wrong.  Can you give more details?
>
> I'm seeing a reply which looks like it was sent as a followup to Randy's
> comment, although now I look at everything together I think that's due
> to you sending your new thread in reply to the old thread (that can also
> be a problem due to threading either burying the new mail or putting
> things in odd places) and my mailer trying to tie the one mail from your
> first series that I'd not deleted into the thread.

OK, I'm about to send my v3 of the thread taking Randy's comments
about kernel-doc into account.  I'll explicitly not mark it as
"in-reply-to" the previous thread and hope that solves the problems
you were seeing.

-Doug

Re: [PATCH v2 4/5] regulator: tps65090: Allow setting the overcurrent wait time

[Doug Anderson]

Randy,

On Wed, Apr 16, 2014 at 1:33 PM, Randy Dunlap <rdunlap@infradead.org> wrote:
> On 04/16/2014 11:25 AM, Doug Anderson wrote:
>> diff --git a/drivers/regulator/tps65090-regulator.c b/drivers/regulator/tps65090-regulator.c
>> index 2e92ef6..ca13a1a 100644
>> --- a/drivers/regulator/tps65090-regulator.c
>> +++ b/drivers/regulator/tps65090-regulator.c
>> @@ -28,15 +28,57 @@
>
>> +/**
>> + * tps65090_reg_set_overcurrent_wait - Setup overcurrent wait
>> + *
>> + * This will set the overcurrent wait time based on what's in the regulator
>> + * info.
>> + *
>> + * @ri:              Overall regulator data
>> + * @rdev:    Regulator device
>> + * @return 0 if no error, non-zero if there was an error writing the register.
>
> kernel-doc notation here should be:
>
>  * Return: 0 if no error, non-zero if there was an error writing the register.

Done in v3.

Re: [PATCH v2 5/5] regulator: tps65090: Make FETs more reliable by adding retries

[Simon Glass]

Hi Doug,

On 16 April 2014 15:25, Doug Anderson <dianders@chromium.org> wrote:
> Simon,
>
> On Wed, Apr 16, 2014 at 1:50 PM, Simon Glass <sjg@chromium.org> wrote:
>>> +#define MAX_CTRL_READ_TRIES    5
>>> +#define MAX_FET_ENABLE_TRIES   1000
>>
>> Gosh that is a lot of tries - should we maybe give up sooner?
>
> That's actually a squash of a recent patch.  See
> <https://chromium-review.googlesource.com/189239>.  I've specifically
> seen at least one case on my device where it needed 888 retries at
> bootup!
>
> ...on my really old Chromebook, it seems to get into a bad state if it
> sits on my desk for a long time.  After I use it a bit it rarely needs
> more than 10 retries.

Try to be kinder to your hardware?

Anyway, fair enough, if you've seen 888 then we need to deal with that case.

Regards,
Simon