From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Werner Subject: Re: [PATCH] gpio: menz127: use the new open drain callback Date: Wed, 11 May 2016 19:39:55 +0200 Message-ID: <20160511173955.GA3574@linux-ah44> References: <1460231815-8635-1-git-send-email-linus.walleij@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-out.m-online.net ([212.18.0.10]:42437 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752008AbcEKRkK (ORCPT ); Wed, 11 May 2016 13:40:10 -0400 Content-Disposition: inline In-Reply-To: <1460231815-8635-1-git-send-email-linus.walleij@linaro.org> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Linus Walleij Cc: linux-gpio@vger.kernel.org, Alexandre Courbot On Sat, Apr 09, 2016 at 09:56:55PM +0200, Linus Walleij wrote: > The menz127 driver tries to support open drain by detecting it > at request time. However: without the new callbacks from the > gpiolib it is not really working: the core will still just emulate > the open drain mode by switching the line to an input. > > By adding a hook into the new .set_single_ended() call rather than > trying to autodetect at request() time, proper open drain can be > supported. > > Cc: Andreas Werner > Signed-off-by: Linus Walleij > --- > drivers/gpio/gpio-menz127.c | 18 +++++++++++------- > 1 file changed, 11 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpio/gpio-menz127.c b/drivers/gpio/gpio-menz127.c > index 8c1ab8e1974f..334fe270dcf1 100644 > --- a/drivers/gpio/gpio-menz127.c > +++ b/drivers/gpio/gpio-menz127.c > @@ -88,21 +88,25 @@ static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio, > return 0; > } > > -static int men_z127_request(struct gpio_chip *gc, unsigned gpio_pin) > +static int men_z127_set_single_ended(struct gpio_chip *gc, > + unsigned offset, > + enum single_ended_mode mode) > { > struct men_z127_gpio *priv = gpiochip_get_data(gc); > u32 od_en; > > - if (gpio_pin >= gc->ngpio) > - return -EINVAL; > + if (mode != LINE_MODE_OPEN_DRAIN && > + mode != LINE_MODE_PUSH_PULL) > + return -ENOTSUPP; > > spin_lock(&priv->lock); > od_en = readl(priv->reg_base + MEN_Z127_ODER); > > - if (gpiochip_line_is_open_drain(gc, gpio_pin)) > - od_en |= BIT(gpio_pin); > + if (mode == LINE_MODE_OPEN_DRAIN) > + od_en |= BIT(offset); > else > - od_en &= ~BIT(gpio_pin); > + /* Implicitly LINE_MODE_PUSH_PULL */ > + od_en &= ~BIT(offset); > > writel(od_en, priv->reg_base + MEN_Z127_ODER); > spin_unlock(&priv->lock); > @@ -147,7 +151,7 @@ static int men_z127_probe(struct mcb_device *mdev, > goto err_unmap; > > men_z127_gpio->gc.set_debounce = men_z127_debounce; > - men_z127_gpio->gc.request = men_z127_request; > + men_z127_gpio->gc.set_single_ended = men_z127_set_single_ended; > > ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio); > if (ret) { > -- > 2.4.3 > Hi Linus, sorry for the late answer. I will try to get the hardware and will test the patch. I think this is exactly what I need to support the "real" open drain mode. Regards Andy