linux-kernel - Re: [PATCH v2] power: bq24735-charger: Request status GPIO with initial input setup

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Message-ID: <1472766113.3813.1.camel@paulk.fr>
Date:   Thu, 01 Sep 2016 23:41:53 +0200
From:   Paul Kocialkowski <contact@...lk.fr>
To:     Sebastian Reichel <sre@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-tegra@...r.kernel.org,
        Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
        David Woodhouse <dwmw2@...radead.org>
Subject: Re: [PATCH v2] power: bq24735-charger: Request status GPIO with
 initial input setup

Le mardi 30 août 2016 à 01:32 +0200, Sebastian Reichel a écrit :
> Hi,
> 
> On Mon, Aug 29, 2016 at 08:15:03PM +0200, Paul Kocialkowski wrote:
> > 
> > This requests the status GPIO with initial input setup. it is required
> > to read the GPIO status at probe time and thus correctly avoid sending
> > i2c messages when AC is not plugged.
> > 
> > When requesting the GPIO without initial input setup, it always reads 0
> > which causes probe to fail as it assumes the charger is connected, sends
> > i2c messages and fails.
> 
> That looks mostly fine. I have some more comments, though.

Thanks for the review, v3 sent. Feel free to add your Signed-off-by line since
your suggestions heavily influenced v3!

> > While at it, this switches the driver over to devm and gpio consumer.
> 
> NIT: the driver was already using devm previously
> 
> > 
> > Signed-off-by: Paul Kocialkowski <contact@...lk.fr>
> > ---
> >  drivers/power/bq24735-charger.c       | 29 +++++++----------------------
> >  include/linux/power/bq24735-charger.h |  3 +--
> >  2 files changed, 8 insertions(+), 24 deletions(-)
> > 
> > diff --git a/drivers/power/bq24735-charger.c b/drivers/power/bq24735-
> > charger.c
> > index dc460bb..5744a88 100644
> > --- a/drivers/power/bq24735-charger.c
> > +++ b/drivers/power/bq24735-charger.c
> > @@ -25,7 +25,8 @@
> >  #include <linux/kernel.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> > -#include <linux/of_gpio.h>
> > +#include <linux/gpio.h>
> > +#include <linux/gpio/consumer.h>
> >  #include <linux/power_supply.h>
> >  #include <linux/slab.h>
> >  
> > @@ -181,8 +182,8 @@ static bool bq24735_charger_is_present(struct bq24735
> > *charger)
> >  	int ret;
> >  
> >  	if (pdata->status_gpio_valid) {
> > -		ret = gpio_get_value_cansleep(pdata->status_gpio);
> > -		return ret ^= pdata->status_gpio_active_low == 0;
> > +		ret = gpiod_get_value_cansleep(pdata->status_gpio);
> > +		return ret ^= gpiod_is_active_low(pdata->status_gpio) == 0;
> 
> This looks fishy. The gpiod API outputs converted values already (if
> one does not use the raw variant). I think you want to do:
> 
> return !gpiod_get_value_cansleep(pdata->status_gpio);
> 
> > 
> >  	} else {
> >  		int ac = 0;
> >  
> > @@ -308,7 +309,6 @@ static struct bq24735_platform
> > *bq24735_parse_dt_data(struct i2c_client *client)
> >  	struct device_node *np = client->dev.of_node;
> >  	u32 val;
> >  	int ret;
> > -	enum of_gpio_flags flags;
> >  
> >  	pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
> >  	if (!pdata) {
> > @@ -317,11 +317,9 @@ static struct bq24735_platform
> > *bq24735_parse_dt_data(struct i2c_client *client)
> >  		return NULL;
> >  	}
> >  
> > -	pdata->status_gpio = of_get_named_gpio_flags(np, "ti,ac-detect-
> > gpios",
> > -						     0, &flags);
> > -
> > -	if (flags & OF_GPIO_ACTIVE_LOW)
> > -		pdata->status_gpio_active_low = 1;
> > +	pdata->status_gpio = devm_gpiod_get(&client->dev, "ti,ac-detect",
> > +						GPIOD_IN);
> > +	pdata->status_gpio_valid = !IS_ERR(pdata->status_gpio);
> 
> Just use devm_gpiod_get_optional(). Then instead of
> checking if (pdata->status_gpio_valid) you do
> if (pdata->status_gpio).
> 
> Also you should check for EPROBE_DEFER. With the
> _optional() change you can just do
> 
> if (IS_ERR(pdata->status_gpio)) {
>     ret = PTR_ERR(pdata->status_gpio);
>     dev_err(&client->dev, "Could not get gpio: %d\n", ret);
>     return ret;
> }
> 
> > 
> >  	ret = of_property_read_u32(np, "ti,charge-current", &val);
> >  	if (!ret)
> > @@ -396,19 +394,6 @@ static int bq24735_charger_probe(struct i2c_client
> > *client,
> >  
> >  	i2c_set_clientdata(client, charger);
> >  
> > -	if (gpio_is_valid(charger->pdata->status_gpio)) {
> > -		ret = devm_gpio_request(&client->dev,
> > -					charger->pdata->status_gpio,
> > -					name);
> > -		if (ret) {
> > -			dev_err(&client->dev,
> > -				"Failed GPIO request for GPIO %d: %d\n",
> > -				charger->pdata->status_gpio, ret);
> > -		}
> > -
> > -		charger->pdata->status_gpio_valid = !ret;
> > -	}
> > -
> >  	if (!charger->pdata->status_gpio_valid
> >  	    || bq24735_charger_is_present(charger)) {
> >  		ret = bq24735_read_word(client, BQ24735_MANUFACTURER_ID);
> > diff --git a/include/linux/power/bq24735-charger.h
> > b/include/linux/power/bq24735-charger.h
> > index 6b750c1a..bbc284e 100644
> > --- a/include/linux/power/bq24735-charger.h
> > +++ b/include/linux/power/bq24735-charger.h
> > @@ -28,8 +28,7 @@ struct bq24735_platform {
> >  
> >  	const char *name;
> >  
> > -	int status_gpio;
> > -	int status_gpio_active_low;
> > +	struct gpio_desc *status_gpio;
> >  	bool status_gpio_valid;
> >  
> >  	bool ext_control;
> 
> Otherwise looks fine.
> 
> -- Sebastian
-- 
Paul Kocialkowski, developer of low-level free software for embedded devices

Website: https://www.paulk.fr/
Coding blog: https://code.paulk.fr/
Git repositories: https://git.paulk.fr/ https://git.code.paulk.fr/
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