From mboxrd@z Thu Jan 1 00:00:00 1970 From: Markus Pargmann Subject: Re: [PATCH v2 3/3] gpiolib: Add GPIO initialization Date: Mon, 21 Sep 2015 13:01:00 +0200 Message-ID: <20150921110100.GC32203@pengutronix.de> References: <1440920686-6892-1-git-send-email-mpa@pengutronix.de> <1440920686-6892-4-git-send-email-mpa@pengutronix.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="KN5l+BnMqAQyZLvT" Return-path: Content-Disposition: inline In-Reply-To: <1440920686-6892-4-git-send-email-mpa@pengutronix.de> Sender: linux-gpio-owner@vger.kernel.org To: Linus Walleij Cc: Alexandre Courbot , Arun Bharadwaj , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , Johan Hovold , chrisrfq@gmail.com, linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, kernel@pengutronix.de List-Id: devicetree@vger.kernel.org --KN5l+BnMqAQyZLvT Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Aug 30, 2015 at 09:44:46AM +0200, Markus Pargmann wrote: > This functions adds a way to initialize a GPIO without hogging it. >=20 > Signed-off-by: Markus Pargmann > --- > Documentation/devicetree/bindings/gpio/gpio.txt | 29 +++++++------ > drivers/gpio/gpiolib-of.c | 9 ++++ > drivers/gpio/gpiolib.c | 55 +++++++++++++++++++= +----- > drivers/gpio/gpiolib.h | 2 + > 4 files changed, 73 insertions(+), 22 deletions(-) >=20 > diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentat= ion/devicetree/bindings/gpio/gpio.txt > index 5788d5cf1252..55d58983ba43 100644 > --- a/Documentation/devicetree/bindings/gpio/gpio.txt > +++ b/Documentation/devicetree/bindings/gpio/gpio.txt > @@ -116,29 +116,34 @@ Every GPIO controller node must contain both an emp= ty "gpio-controller" > property, and a #gpio-cells integer property, which indicates the number= of > cells in a gpio-specifier. > =20 > -The GPIO chip may contain GPIO hog definitions. GPIO hogging is a mechan= ism > -providing automatic GPIO request and configuration as part of the > -gpio-controller's driver probe function. > +The GPIO chip may contain GPIO definitions. These define properties for = single > +GPIOs of this controller. > =20 > -Each GPIO hog definition is represented as a child node of the GPIO cont= roller. > +GPIO hogging is a mechanism providing automatic GPIO request and configu= ration > +as part of the gpio-controller's driver probe function. > + > +GPIO initialization provides an automatic initialization to known save v= alues. > +Instead of GPIO hogging the GPIO's value and direction can be modified b= y other > +users after it was initialized. > + > +Each GPIO definition is represented as a child node of the GPIO controll= er. > Required properties: > -- gpio-hog: A property specifying that this child node represent a GPI= O hog. > - gpios: Store the GPIO information (id, flags, ...). Shall contain= the > number of cells specified in its parent node (GPIO controller > node). > -Only one of the following properties scanned in the order shown below. > -This means that when multiple properties are present they will be search= ed > -in the order presented below and the first match is taken as the intended > -configuration. > + > +Optional properties: > +- line-name: The GPIO label name. If not present the node name is used. > + Only one of gpio-hog and gpio-initval may be specified. > +- gpio-hog: A property specifying that this child node represent a GPI= O hog. > +- gpio-initval: This GPIO should be initialized to the specified configu= ration. Any feedback on this new DT binding? Best Regards, Markus > + Only one of input, output-low and output-high may be specified: > - input: A property specifying to set the GPIO direction as input. > - output-low A property specifying to set the GPIO direction as output = with > the value low. > - output-high A property specifying to set the GPIO direction as output = with > the value high. > =20 > -Optional properties: > -- line-name: The GPIO label name. If not present the node name is used. > - > Example of two SOC GPIO banks defined as gpio-controller nodes: > =20 > qe_pio_a: gpio-controller@1400 { > diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c > index f1fe5123da28..ee00c2c63f57 100644 > --- a/drivers/gpio/gpiolib-of.c > +++ b/drivers/gpio/gpiolib-of.c > @@ -234,6 +234,15 @@ static void of_gpiochip_scan_gpios(struct gpio_chip = *chip) > =20 > if (gpiod_hog(desc, lflags, dflags)) > continue; > + } else if (of_property_read_bool(np, "gpio-initval")) { > + if (!dflags) { > + dev_warn(chip->dev, "GPIO line %d (%s): no initialization state spec= ified, bailing out\n", > + desc_to_gpio(desc), np->name); > + continue; > + } > + > + if (gpiod_initialize(desc, lflags, dflags)) > + continue; > } > } > } > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index f1559fa72c36..d7aa27a92e82 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -2178,15 +2178,8 @@ struct gpio_desc *__must_check __gpiod_get_index_o= ptional(struct device *dev, > } > EXPORT_SYMBOL_GPL(__gpiod_get_index_optional); > =20 > -/** > - * gpiod_hog - Hog the specified GPIO desc given the provided flags > - * @desc: gpio whose value will be assigned > - * @lflags: gpio_lookup_flags - returned from of_find_gpio() or > - * of_get_gpio_hog() > - * @dflags: gpiod_flags - optional GPIO initialization flags > - */ > -int gpiod_hog(struct gpio_desc *desc, unsigned long lflags, > - enum gpiod_flags dflags) > +static int _gpiod_initialize(struct gpio_desc *desc, unsigned long lflag= s, > + enum gpiod_flags dflags) > { > int status; > const char *name =3D desc->name; > @@ -2202,11 +2195,31 @@ int gpiod_hog(struct gpio_desc *desc, unsigned lo= ng lflags, > status =3D gpiod_configure_flags(desc, name, lflags, dflags); > if (status < 0) { > pr_err("setup of hog GPIO %s (chip %s, offset %d) failed\n", > - name, gpiod_to_chip(desc)->label, gpio_chip_hwgpio(desc)); > + name, gpiod_to_chip(desc)->label, > + gpio_chip_hwgpio(desc)); > gpiochip_free_own_desc(desc); > return status; > } > =20 > + return 0; > +} > + > +/** > + * gpiod_hog - Hog the specified GPIO desc given the provided flags > + * @desc: gpio whose value will be assigned > + * @lflags: gpio_lookup_flags - returned from of_find_gpio() or > + * of_get_gpio_hog() > + * @dflags: gpiod_flags - optional GPIO initialization flags > + */ > +int gpiod_hog(struct gpio_desc *desc, unsigned long lflags, > + enum gpiod_flags dflags) > +{ > + int ret; > + > + ret =3D _gpiod_initialize(desc, lflags, dflags); > + if (ret) > + return ret; > + > /* Mark GPIO as hogged so it can be identified and removed later */ > set_bit(FLAG_IS_HOGGED, &desc->flags); > =20 > @@ -2236,6 +2249,28 @@ static void gpiochip_free_hogs(struct gpio_chip *c= hip) > } > =20 > /** > + * gpiod_initialize - Initialize a GPIO with a given value > + * @desc: gpio whose value will be assigned > + * @lflags: gpio_lookup_flags - returned from of_find_gpio() or > + * of_get_gpio_hog() > + * @dflags: gpiod_flags - optional GPIO initialization flags > + * > + * This is used to initialize GPIOs that were defined in DT > + */ > +int gpiod_initialize(struct gpio_desc *desc, unsigned long lflags, > + enum gpiod_flags dflags) > +{ > + int ret; > + > + ret =3D _gpiod_initialize(desc, lflags, dflags); > + if (ret) > + return ret; > + > + __gpiod_free(desc); > + return ret; > +} > + > +/** > * gpiod_get_array - obtain multiple GPIOs from a multi-index GPIO funct= ion > * @dev: GPIO consumer, can be NULL for system-global GPIOs > * @con_id: function within the GPIO consumer > diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h > index 6c2aeff59f86..b6dfa3526e3a 100644 > --- a/drivers/gpio/gpiolib.h > +++ b/drivers/gpio/gpiolib.h > @@ -99,6 +99,8 @@ int gpiod_request(struct gpio_desc *desc, const char *l= abel); > void gpiod_free(struct gpio_desc *desc); > int gpiod_hog(struct gpio_desc *desc, unsigned long lflags, > enum gpiod_flags dflags); > +int gpiod_initialize(struct gpio_desc *desc, unsigned long lflags, > + enum gpiod_flags dflags); > =20 > /* > * Return the GPIO number of the passed descriptor relative to its chip > --=20 > 2.5.0 >=20 >=20 --=20 Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | --KN5l+BnMqAQyZLvT Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJV/+NsAAoJEEpcgKtcEGQQrfkP/31lxL/0Bdipll/lwjJj7vq+ 5kc58hHbiinIc4s/kqmn4JQb6y6afy+7llzFbhzVhc3pCTUyZYx/tkAoghFV8+kk VuJLg3Nyv9UKzPvuR1xZN4ZdHqdzwVAo5va8Q3AQwE8/hkPa3TEZz7OAkpoV6kct py/EL9dxBl9+bLdIgNNJlYxNQzd6a4LCVRTCjSW97yD84iHAJQsPw/uI5t9PqGY2 ltFTKVgwpjrFKOt5snx1BfW+e3+r9ysqNvtvvbHmiM69dF5e2W9Re6z8h1DmzCcF zGD/ZNEZIuYtZpbR7JPbe7buU1FCDxloaVqcaiHz2yB08G4YVytUg1UyMrK1Wvv3 FLeeuHPotJWOmFSuHR/LqlSQceE0z00KF2xW3+YZU/4YxC8QiffbOgnrmZfHWq2x EMA3q79B+j1k99ZJvdQazmGUiT+PLplPePyLdP4q2q0sQJjBhfWgGKUbaQsfvMPh rLlzCaAoO38cwxK9s+SH0BrKuevsMd5noC0MxADH0kiZaEdkCJJXF23obGPONE0j qLJOGHGSvfVaztvdaLreKXzDxG+RyTCzzshXdjQtr3YBymKqpIKX3DOwwdQIX3F6 12SEuoQ6oEtRx+1+Sif2LAqB7nw8OW/+T2llpSJiWy52Kyl3WUEwknSBkEMGJdQM fcn/A8ytDVUCHsCtJcS9 =I+QW -----END PGP SIGNATURE----- --KN5l+BnMqAQyZLvT--