From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bmailout2.hostsharing.net ([83.223.90.240]:47907 "EHLO bmailout2.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S970563AbeCSSyA (ORCPT ); Mon, 19 Mar 2018 14:54:00 -0400 Date: Mon, 19 Mar 2018 19:53:58 +0100 From: Lukas Wunner To: Sasha Levin Cc: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , =?iso-8859-1?Q?Fr=E9d=E9ric?= Danis , Loic Poulain , Hans de Goede , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Linus Walleij , Marcel Holtmann , Stefan Wahren Subject: Re: [PATCH AUTOSEL for 4.15 099/124] Bluetooth: hci_bcm: Mandate presence of shutdown and device wake GPIO Message-ID: <20180319185358.GA13467@wunner.de> References: <20180319154645.11350-1-alexander.levin@microsoft.com> <20180319154645.11350-99-alexander.levin@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180319154645.11350-99-alexander.levin@microsoft.com> Sender: stable-owner@vger.kernel.org List-ID: On Mon, Mar 19, 2018 at 03:48:50PM +0000, Sasha Levin wrote: > From: Lukas Wunner > > [ Upstream commit 3e81a4ca51a1172253078ca7abd6a91040b8fcf4 ] > Unfortunately this commit had to be fixed up with ab2f336cb7e6 ("Bluetooth: hci_bcm: Make shutdown and device wake GPIO optional") by Stefan Wahren (+cc). Please be sure to apply that one on top. Thanks! > Commit 0395ffc1ee05 ("Bluetooth: hci_bcm: Add PM for BCM devices") > amended this driver to request a shutdown and device wake GPIO on probe, > but mandated that only one of them need to be present: > > /* Make sure at-least one of the GPIO is defined and that > * a name is specified for this instance > */ > if ((!dev->device_wakeup && !dev->shutdown) || !dev->name) { > dev_err(&pdev->dev, "invalid platform data\n"); > return -EINVAL; > } > > However the same commit added a call to bcm_gpio_set_power() to the > ->probe hook, which unconditionally accesses *both* GPIOs. Luckily, > the resulting NULL pointer deref was never reported, suggesting there's > no machine where either GPIO is missing. > > Commit 8a92056837fd ("Bluetooth: hci_bcm: Add (runtime)pm support to the > serdev driver") removed the check whether at least one of the GPIOs is > present without specifying a reason. > > Because commit 62aaefa7d038 ("Bluetooth: hci_bcm: improve use of gpios > API") refactored the driver to use devm_gpiod_get_optional() instead of > devm_gpiod_get(), one is now tempted to believe that the driver doesn't > require *any* of the two GPIOs. > > Which is wrong, the driver still requires both GPIOs to avoid a NULL > pointer deref. To this end, establish the status quo ante and request > the GPIOs with devm_gpiod_get() again. Bail out of ->probe if either > of them is missing. > > Oddly enough, whereas bcm_gpio_set_power() accesses the device wake pin > unconditionally, bcm_suspend_device() and bcm_resume_device() do check > for its presence before accessing it. Those checks are superfluous, > so remove them. > > Cc: Fr�d�ric Danis > Cc: Loic Poulain > Cc: Hans de Goede > Cc: Uwe Kleine-K�nig > Cc: Linus Walleij > Reviewed-by: Andy Shevchenko > Signed-off-by: Lukas Wunner > Signed-off-by: Marcel Holtmann > Signed-off-by: Sasha Levin > --- > drivers/bluetooth/hci_bcm.c | 24 +++++++++--------------- > 1 file changed, 9 insertions(+), 15 deletions(-) > > diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c > index 707c2d1b84c7..b8eeac4e6f35 100644 > --- a/drivers/bluetooth/hci_bcm.c > +++ b/drivers/bluetooth/hci_bcm.c > @@ -577,11 +577,9 @@ static int bcm_suspend_device(struct device *dev) > } > > /* Suspend the device */ > - if (bdev->device_wakeup) { > - gpiod_set_value(bdev->device_wakeup, false); > - bt_dev_dbg(bdev, "suspend, delaying 15 ms"); > - mdelay(15); > - } > + gpiod_set_value(bdev->device_wakeup, false); > + bt_dev_dbg(bdev, "suspend, delaying 15 ms"); > + mdelay(15); > > return 0; > } > @@ -592,11 +590,9 @@ static int bcm_resume_device(struct device *dev) > > bt_dev_dbg(bdev, ""); > > - if (bdev->device_wakeup) { > - gpiod_set_value(bdev->device_wakeup, true); > - bt_dev_dbg(bdev, "resume, delaying 15 ms"); > - mdelay(15); > - } > + gpiod_set_value(bdev->device_wakeup, true); > + bt_dev_dbg(bdev, "resume, delaying 15 ms"); > + mdelay(15); > > /* When this executes, the device has woken up already */ > if (bdev->is_suspended && bdev->hu) { > @@ -779,14 +775,12 @@ static int bcm_get_resources(struct bcm_device *dev) > > dev->clk = devm_clk_get(dev->dev, NULL); > > - dev->device_wakeup = devm_gpiod_get_optional(dev->dev, > - "device-wakeup", > - GPIOD_OUT_LOW); > + dev->device_wakeup = devm_gpiod_get(dev->dev, "device-wakeup", > + GPIOD_OUT_LOW); > if (IS_ERR(dev->device_wakeup)) > return PTR_ERR(dev->device_wakeup); > > - dev->shutdown = devm_gpiod_get_optional(dev->dev, "shutdown", > - GPIOD_OUT_LOW); > + dev->shutdown = devm_gpiod_get(dev->dev, "shutdown", GPIOD_OUT_LOW); > if (IS_ERR(dev->shutdown)) > return PTR_ERR(dev->shutdown); > > -- > 2.14.1