This is a note to let you know that I've just added the patch titled

Bluetooth: hci_bcm: Mandate presence of shutdown and device wake GPIO

to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: bluetooth-hci_bcm-mandate-presence-of-shutdown-and-device-wake-gpio.patch and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Mon Apr 9 10:16:32 CEST 2018

From: Lukas Wunner lukas@wunner.de Date: Wed, 10 Jan 2018 16:32:10 +0100 Subject: Bluetooth: hci_bcm: Mandate presence of shutdown and device wake GPIO

From: Lukas Wunner lukas@wunner.de

[ Upstream commit 3e81a4ca51a1172253078ca7abd6a91040b8fcf4 ]

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: Frédéric Danis frederic.danis.oss@gmail.com Cc: Loic Poulain loic.poulain@linaro.org Cc: Hans de Goede hdegoede@redhat.com Cc: Uwe Kleine-König u.kleine-koenig@pengutronix.de Cc: Linus Walleij linus.walleij@linaro.org Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Signed-off-by: Lukas Wunner lukas@wunner.de Signed-off-by: Marcel Holtmann marcel@holtmann.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/bluetooth/hci_bcm.c | 24 +++++++++--------------- 1 file changed, 9 insertions(+), 15 deletions(-)

--- a/drivers/bluetooth/hci_bcm.c +++ b/drivers/bluetooth/hci_bcm.c @@ -577,11 +577,9 @@ static int bcm_suspend_device(struct 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 devi

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_

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);

Patches currently in stable-queue which might be from lukas@wunner.de are

queue-4.15/bluetooth-hci_bcm-mandate-presence-of-shutdown-and-device-wake-gpio.patch queue-4.15/bluetooth-hci_bcm-validate-irq-before-using-it.patch