[PATCH 0/3] bq24735-charger: allow gpio polling and sharing

[PATCH 0/3] bq24735-charger: allow gpio polling and sharing

[Peter Rosin]

Hi!

I have a board that features a couple of parallel bq24735 chargers.
However, only one of the chargers has its ACOK pin wired to a gpio,
the other parallel chargers are expected to just behave the same
as the charger that has been singled out like this. Another thing
with the board is that the gpio is not capable of generating an
interrupt.

This series fixes things for me (ok, the first patch was just a
fix for a thing that initially had me confused for a bit, and is
totally unrelated. Ignore if you want to, it's basically just churn).

One thing that I wonder about is if anything should be done to
prevent unloading of the instance that shares its gpio? I thought
about adding a device_link_add() call, but am unsure if that would
be approprite? I'm not unloading drivers at all so it's a total
non-issue for me...

Cheers,
Peter

Peter Rosin (3):
  power: supply: bq24735-charger: simplify register update to stop
    charging
  power: supply: bq24735-charger: optionally poll the ac-detect gpio
  power: supply: bq24735-charger: allow chargers to share the ac-detect
    gpio

 .../bindings/power/supply/ti,bq24735.txt           |   2 +
 drivers/power/supply/bq24735-charger.c             | 154 ++++++++++++++++++---
 2 files changed, 138 insertions(+), 18 deletions(-)

-- 
2.1.4

[PATCH 1/3] power: supply: bq24735-charger: simplify register update to stop charging

[Peter Rosin]

Providing value bits outside of the mask is pointless.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/power/supply/bq24735-charger.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/power/supply/bq24735-charger.c b/drivers/power/supply/bq24735-charger.c
index eb7783b42e0a..1d5c9206e0ed 100644
--- a/drivers/power/supply/bq24735-charger.c
+++ b/drivers/power/supply/bq24735-charger.c
@@ -111,8 +111,7 @@ static inline int bq24735_enable_charging(struct bq24735 *charger)
 		return 0;
 
 	return bq24735_update_word(charger->client, BQ24735_CHG_OPT,
-				   BQ24735_CHG_OPT_CHARGE_DISABLE,
-				   ~BQ24735_CHG_OPT_CHARGE_DISABLE);
+				   BQ24735_CHG_OPT_CHARGE_DISABLE, 0);
 }
 
 static inline int bq24735_disable_charging(struct bq24735 *charger)
-- 
2.1.4

[PATCH 2/3] power: supply: bq24735-charger: optionally poll the ac-detect gpio

[Peter Rosin]

If the ac-detect gpio does not support interrupts, provide a fallback
to poll the gpio at a configurable interval.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 .../bindings/power/supply/ti,bq24735.txt           |  2 +
 drivers/power/supply/bq24735-charger.c             | 50 +++++++++++++++++++---
 2 files changed, 47 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/power/supply/ti,bq24735.txt b/Documentation/devicetree/bindings/power/supply/ti,bq24735.txt
index 3bf55757ceec..59c4dde589cf 100644
--- a/Documentation/devicetree/bindings/power/supply/ti,bq24735.txt
+++ b/Documentation/devicetree/bindings/power/supply/ti,bq24735.txt
@@ -25,6 +25,8 @@ Optional properties :
  - ti,external-control : Indicates that the charger is configured externally
    and that the host should not attempt to enable/disable charging or set the
    charge voltage/current.
+ - ti,poll-interval-ms : In case there is no interrupts specified, poll AC
+   presense on the ti,ac-detect-gpios GPIO with this interval.
 
 Example:
 
diff --git a/drivers/power/supply/bq24735-charger.c b/drivers/power/supply/bq24735-charger.c
index 1d5c9206e0ed..3765806d5d46 100644
--- a/drivers/power/supply/bq24735-charger.c
+++ b/drivers/power/supply/bq24735-charger.c
@@ -50,6 +50,8 @@ struct bq24735 {
 	struct bq24735_platform		*pdata;
 	struct mutex			lock;
 	struct gpio_desc		*status_gpio;
+	struct delayed_work		poll;
+	u32				poll_interval;
 	bool				charging;
 };
 
@@ -209,11 +211,8 @@ static int bq24735_charger_is_charging(struct bq24735 *charger)
 	return !(ret & BQ24735_CHG_OPT_CHARGE_DISABLE);
 }
 
-static irqreturn_t bq24735_charger_isr(int irq, void *devid)
+static void bq24735_update(struct bq24735 *charger)
 {
-	struct power_supply *psy = devid;
-	struct bq24735 *charger = to_bq24735(psy);
-
 	mutex_lock(&charger->lock);
 
 	if (charger->charging && bq24735_charger_is_present(charger))
@@ -223,11 +222,29 @@ static irqreturn_t bq24735_charger_isr(int irq, void *devid)
 
 	mutex_unlock(&charger->lock);
 
-	power_supply_changed(psy);
+	power_supply_changed(charger->charger);
+}
+
+static irqreturn_t bq24735_charger_isr(int irq, void *devid)
+{
+	struct power_supply *psy = devid;
+	struct bq24735 *charger = to_bq24735(psy);
+
+	bq24735_update(charger);
 
 	return IRQ_HANDLED;
 }
 
+static void bq24735_poll(struct work_struct *work)
+{
+	struct bq24735 *charger = container_of(work, struct bq24735, poll.work);
+
+	bq24735_update(charger);
+
+	schedule_delayed_work(&charger->poll,
+			      msecs_to_jiffies(charger->poll_interval));
+}
+
 static int bq24735_charger_get_property(struct power_supply *psy,
 					enum power_supply_property psp,
 					union power_supply_propval *val)
@@ -455,11 +472,33 @@ static int bq24735_charger_probe(struct i2c_client *client,
 				client->irq, ret);
 			return ret;
 		}
+	} else if (charger->status_gpio) {
+		ret = of_property_read_u32(client->dev.of_node,
+					   "ti,poll-interval-ms",
+					   &charger->poll_interval);
+		if (ret)
+			return 0;
+		if (!charger->poll_interval)
+			return 0;
+
+		INIT_DELAYED_WORK(&charger->poll, bq24735_poll);
+		schedule_delayed_work(&charger->poll,
+				      msecs_to_jiffies(charger->poll_interval));
 	}
 
 	return 0;
 }
 
+static int bq24735_charger_remove(struct i2c_client *client)
+{
+	struct bq24735 *charger = i2c_get_clientdata(client);
+
+	if (charger->poll_interval)
+		cancel_delayed_work_sync(&charger->poll);
+
+	return 0;
+}
+
 static const struct i2c_device_id bq24735_charger_id[] = {
 	{ "bq24735-charger", 0 },
 	{}
@@ -478,6 +517,7 @@ static struct i2c_driver bq24735_charger_driver = {
 		.of_match_table = bq24735_match_ids,
 	},
 	.probe = bq24735_charger_probe,
+	.remove = bq24735_charger_remove,
 	.id_table = bq24735_charger_id,
 };
 
-- 
2.1.4

[PATCH 3/3] power: supply: bq24735-charger: allow chargers to share the ac-detect gpio

[Peter Rosin]

If several parallel bq24735 chargers have their ac-detect gpios wired
together (or if only one of the parallel bq24735 chargers have its
ac-detect pin wired to a gpio, and the others are assumed to react the
same), then all driver instances need to check the same gpio. But the
gpio subsystem does not allow sharing gpios, so handle that locally.

However, only do this for the polling case, sharing is not supported if
the ac detection is handled with interrupts.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/power/supply/bq24735-charger.c | 101 +++++++++++++++++++++++++++++----
 1 file changed, 90 insertions(+), 11 deletions(-)

diff --git a/drivers/power/supply/bq24735-charger.c b/drivers/power/supply/bq24735-charger.c
index 3765806d5d46..3b21a064a9a7 100644
--- a/drivers/power/supply/bq24735-charger.c
+++ b/drivers/power/supply/bq24735-charger.c
@@ -25,6 +25,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/power_supply.h>
 #include <linux/slab.h>
@@ -43,12 +44,24 @@
 #define BQ24735_MANUFACTURER_ID		0xfe
 #define BQ24735_DEVICE_ID		0xff
 
+struct bq24735;
+
+struct bq24735_shared {
+	struct list_head		list;
+	struct bq24735			*owner;
+	struct gpio_desc		*status_gpio;
+};
+
+static struct mutex shared_lock;
+static LIST_HEAD(shared_list);
+
 struct bq24735 {
 	struct power_supply		*charger;
 	struct power_supply_desc	charger_desc;
 	struct i2c_client		*client;
 	struct bq24735_platform		*pdata;
 	struct mutex			lock;
+	struct bq24735_shared		*shared;
 	struct gpio_desc		*status_gpio;
 	struct delayed_work		poll;
 	u32				poll_interval;
@@ -346,6 +359,65 @@ static struct bq24735_platform *bq24735_parse_dt_data(struct i2c_client *client)
 	return pdata;
 }
 
+static struct gpio_desc *bq24735_get_status_gpio(struct bq24735 *charger)
+{
+	struct device *dev = &charger->client->dev;
+	struct bq24735_shared *shared;
+	int gpio;
+	struct list_head *pos;
+
+	if (!of_property_read_bool(dev->of_node, "ti,ac-detect-gpios"))
+		return NULL;
+
+	gpio = of_get_named_gpio(dev->of_node, "ti,ac-detect-gpios", 0);
+	if (gpio < 0)
+		return ERR_PTR(gpio);
+
+	mutex_lock(&shared_lock);
+	list_for_each(pos, &shared_list) {
+		shared = list_entry(pos, struct bq24735_shared, list);
+		if (gpio != desc_to_gpio(shared->status_gpio))
+			continue;
+
+		get_device(&shared->owner->client->dev);
+		dev_dbg(dev, "sharing gpio with %s\n",
+			shared->owner->pdata->name);
+		charger->shared = shared;
+		mutex_unlock(&shared_lock);
+		return shared->status_gpio;
+	}
+
+	shared = devm_kzalloc(dev, sizeof(*shared), GFP_KERNEL);
+	if (!shared) {
+		mutex_unlock(&shared_lock);
+		return ERR_PTR(-ENOMEM);
+	}
+	shared->owner = charger;
+	shared->status_gpio = gpiod_get(dev, "ti,ac-detect", GPIOD_IN);
+	if (!IS_ERR(shared->status_gpio)) {
+		charger->shared = shared;
+		list_add(&shared->list, &shared_list);
+	}
+	mutex_unlock(&shared_lock);
+
+	return shared->status_gpio;
+}
+
+static void bq24735_put_status_gpio(struct bq24735 *charger)
+{
+	if (!charger->shared)
+		return;
+
+	mutex_lock(&shared_lock);
+	if (charger->shared->owner != charger) {
+		put_device(&charger->shared->owner->client->dev);
+	} else {
+		list_del(&charger->shared->list);
+		gpiod_put(charger->shared->status_gpio);
+	}
+	mutex_unlock(&shared_lock);
+}
+
 static int bq24735_charger_probe(struct i2c_client *client,
 				 const struct i2c_device_id *id)
 {
@@ -402,9 +474,7 @@ static int bq24735_charger_probe(struct i2c_client *client,
 
 	i2c_set_clientdata(client, charger);
 
-	charger->status_gpio = devm_gpiod_get_optional(&client->dev,
-						       "ti,ac-detect",
-						       GPIOD_IN);
+	charger->status_gpio = bq24735_get_status_gpio(charger);
 	if (IS_ERR(charger->status_gpio)) {
 		ret = PTR_ERR(charger->status_gpio);
 		dev_err(&client->dev, "Getting gpio failed: %d\n", ret);
@@ -416,28 +486,30 @@ static int bq24735_charger_probe(struct i2c_client *client,
 		if (ret < 0) {
 			dev_err(&client->dev, "Failed to read manufacturer id : %d\n",
 				ret);
-			return ret;
+			goto out;
 		} else if (ret != 0x0040) {
 			dev_err(&client->dev,
 				"manufacturer id mismatch. 0x0040 != 0x%04x\n", ret);
-			return -ENODEV;
+			ret = -ENODEV;
+			goto out;
 		}
 
 		ret = bq24735_read_word(client, BQ24735_DEVICE_ID);
 		if (ret < 0) {
 			dev_err(&client->dev, "Failed to read device id : %d\n", ret);
-			return ret;
+			goto out;
 		} else if (ret != 0x000B) {
 			dev_err(&client->dev,
 				"device id mismatch. 0x000b != 0x%04x\n", ret);
-			return -ENODEV;
+			ret = -ENODEV;
+			goto out;
 		}
 	}
 
 	ret = bq24735_config_charger(charger);
 	if (ret < 0) {
 		dev_err(&client->dev, "failed in configuring charger");
-		return ret;
+		goto out;
 	}
 
 	/* check for AC adapter presence */
@@ -445,7 +517,7 @@ static int bq24735_charger_probe(struct i2c_client *client,
 		ret = bq24735_enable_charging(charger);
 		if (ret < 0) {
 			dev_err(&client->dev, "Failed to enable charging\n");
-			return ret;
+			goto out;
 		}
 	}
 
@@ -455,7 +527,7 @@ static int bq24735_charger_probe(struct i2c_client *client,
 		ret = PTR_ERR(charger->charger);
 		dev_err(&client->dev, "Failed to register power supply: %d\n",
 			ret);
-		return ret;
+		goto out;
 	}
 
 	if (client->irq) {
@@ -470,7 +542,7 @@ static int bq24735_charger_probe(struct i2c_client *client,
 			dev_err(&client->dev,
 				"Unable to register IRQ %d err %d\n",
 				client->irq, ret);
-			return ret;
+			goto out;
 		}
 	} else if (charger->status_gpio) {
 		ret = of_property_read_u32(client->dev.of_node,
@@ -487,6 +559,11 @@ static int bq24735_charger_probe(struct i2c_client *client,
 	}
 
 	return 0;
+
+out:
+	bq24735_put_status_gpio(charger);
+
+	return ret;
 }
 
 static int bq24735_charger_remove(struct i2c_client *client)
@@ -496,6 +573,8 @@ static int bq24735_charger_remove(struct i2c_client *client)
 	if (charger->poll_interval)
 		cancel_delayed_work_sync(&charger->poll);
 
+	bq24735_put_status_gpio(charger);
+
 	return 0;
 }
 
-- 
2.1.4

Re: [PATCH 3/3] power: supply: bq24735-charger: allow chargers to share the ac-detect gpio

[Peter Rosin]

On 2016-12-12 12:00, Peter Rosin wrote:
> If several parallel bq24735 chargers have their ac-detect gpios wired
> together (or if only one of the parallel bq24735 chargers have its
> ac-detect pin wired to a gpio, and the others are assumed to react the
> same), then all driver instances need to check the same gpio. But the
> gpio subsystem does not allow sharing gpios, so handle that locally.
> 
> However, only do this for the polling case, sharing is not supported if
> the ac detection is handled with interrupts.
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
>  drivers/power/supply/bq24735-charger.c | 101 +++++++++++++++++++++++++++++----
>  1 file changed, 90 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/power/supply/bq24735-charger.c b/drivers/power/supply/bq24735-charger.c
> index 3765806d5d46..3b21a064a9a7 100644
> --- a/drivers/power/supply/bq24735-charger.c
> +++ b/drivers/power/supply/bq24735-charger.c
> @@ -25,6 +25,7 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/of_gpio.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/power_supply.h>
>  #include <linux/slab.h>
> @@ -43,12 +44,24 @@
>  #define BQ24735_MANUFACTURER_ID		0xfe
>  #define BQ24735_DEVICE_ID		0xff
>  
> +struct bq24735;
> +
> +struct bq24735_shared {
> +	struct list_head		list;
> +	struct bq24735			*owner;
> +	struct gpio_desc		*status_gpio;
> +};
> +
> +static struct mutex shared_lock;

Aww crap, that should of course be

static DEFINE_MUTEX(shared_lock);

Will fix in v2, but I'll wait for other feedback first. Why is it
impossible to see these things before hitting send?

Cheers,
peda

Re: [PATCH 2/3] power: supply: bq24735-charger: optionally poll the ac-detect gpio

[Rob Herring]

On Mon, Dec 12, 2016 at 12:00:23PM +0100, Peter Rosin wrote:
> If the ac-detect gpio does not support interrupts, provide a fallback
> to poll the gpio at a configurable interval.
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
>  .../bindings/power/supply/ti,bq24735.txt           |  2 +
>  drivers/power/supply/bq24735-charger.c             | 50 +++++++++++++++++++---
>  2 files changed, 47 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/power/supply/ti,bq24735.txt b/Documentation/devicetree/bindings/power/supply/ti,bq24735.txt
> index 3bf55757ceec..59c4dde589cf 100644
> --- a/Documentation/devicetree/bindings/power/supply/ti,bq24735.txt
> +++ b/Documentation/devicetree/bindings/power/supply/ti,bq24735.txt
> @@ -25,6 +25,8 @@ Optional properties :
>   - ti,external-control : Indicates that the charger is configured externally
>     and that the host should not attempt to enable/disable charging or set the
>     charge voltage/current.
> + - ti,poll-interval-ms : In case there is no interrupts specified, poll AC
> +   presense on the ti,ac-detect-gpios GPIO with this interval.

We already have poll-interval and cm-poll-interval properties. Just use 
poll-interval here.

Rob