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Date: Wed, 14 Dec 2016 18:01:14 +0100
From: Sebastian Reichel <sre@...nel.org>
To: Peter Rosin <peda@...ntia.se>,
Linus Walleij <linus.walleij@...aro.org>,
Alexandre Courbot <gnurou@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
devicetree@...r.kernel.org, linux-gpio@...r.kernel.org
Subject: Re: [PATCH v2 3/3] power: supply: bq24735-charger: allow chargers to
share the ac-detect gpio
[of course I forgot to actually add gpio people, let's try again]
On Wed, Dec 14, 2016 at 05:59:21PM +0100, Sebastian Reichel wrote:
> Hi,
>
> On Wed, Dec 14, 2016 at 12:56:45AM +0100, 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.
>
> Adding GPIO subsystem people to see if they can come up with
> something in the gpiod API for this usecase.
>
> > However, only do this for the polling case, sharing is not supported if
> > the ac detection is handled with interrupts.
>
> Why? I guess you only added the gpio polling stuff for the shared
> gpio feature, so we can skip the gpio polling if we add shared irq
> support instead?
>
> > Signed-off-by: Peter Rosin <peda@...ntia.se>
> > ---
> > drivers/power/supply/bq24735-charger.c | 111 +++++++++++++++++++++++++++++----
> > 1 file changed, 100 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/power/supply/bq24735-charger.c b/drivers/power/supply/bq24735-charger.c
> > index f45876927676..c2403c4d5ece 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 DEFINE_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 +359,75 @@ 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;
> > + enum of_gpio_flags flags;
> > + int active_low;
> > + struct list_head *pos;
> > +
> > + if (of_property_read_bool(dev->of_node, "ti,ac-detect-gpios"))
> > + gpio = of_get_named_gpio_flags(dev->of_node,
> > + "ti,ac-detect-gpios", 0, &flags);
> > + else if (of_property_read_bool(dev->of_node, "ti,ac-detect-gpio"))
> > + gpio = of_get_named_gpio_flags(dev->of_node,
> > + "ti,ac-detect-gpio", 0, &flags);
> > + else
> > + return NULL;
> > +
> > + if (!gpio_is_valid(gpio))
> > + return ERR_PTR(gpio);
> > + active_low = flags & OF_GPIO_ACTIVE_LOW;
> > +
> > + 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;
> > + if (!active_low ^ !gpiod_is_active_low(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 +484,7 @@ 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 +496,30 @@ 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 +527,7 @@ 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 +537,7 @@ 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 +552,7 @@ 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 +569,11 @@ 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 +583,8 @@ 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
> >
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