From d06165b329c04c8050c4b744c05ec61046709490 Mon Sep 17 00:00:00 2001 From: Vladimir Zapolskiy Date: Wed, 11 Nov 2015 14:36:53 +0200 Subject: gpiolib: fix oops, if gpio name is NULL Commit c0017ed71966 ("gpio: Introduce gpio descriptor 'name'") causes OOPS on boot on LPC32xx boards: Unable to handle kernel NULL pointer dereference at virtual address 00000000 CPU: 0 PID: 1 Comm: swapper Not tainted 4.3.0+ #707 Hardware name: LPC32XX SoC (Flattened Device Tree) task: c381baa0 ti: c381e000 task.ti: c381e000 PC is at strcmp+0x10/0x40 LR is at gpiochip_add+0x3d0/0x4d4 pc : [<>] lr : [<>] psr: a0000093 sp : c381fd60 ip : c381fd70 fp : c381fd6c [snip] Backtrace: [<>] (strcmp) from [<>] (gpiochip_add+0x3d0/0x4d4) [<>] (gpiochip_add) from [<>] (lpc32xx_gpio_probe+0x44/0x60) [<>] (lpc32xx_gpio_probe) from [<>] (platform_drv_probe+0x40/0x8c) [<>] (platform_drv_probe) from [<>] (driver_probe_device+0x110/0x294) [<>] (driver_probe_device) from [<>] (__driver_attach+0x70/0x94) [<>] (__driver_attach) from [<>] (bus_for_each_dev+0x74/0x98) [<>] (bus_for_each_dev) from [<>] (driver_attach+0x20/0x28) [<>] (driver_attach) from [<>] (bus_add_driver+0xd4/0x1f0) [<>] (bus_add_driver) from [<>] (driver_register+0xa4/0xe8) [<>] (driver_register) from [<>] (__platform_driver_register+0x38/0x4c) [<>] (__platform_driver_register) from [<>] (lpc32xx_gpio_driver_init+0x18/0x20) [<>] (lpc32xx_gpio_driver_init) from [<>] (do_one_initcall+0x108/0x1c8) [<>] (do_one_initcall) from [<>] (kernel_init_freeable+0x10c/0x1d4) [<>] (kernel_init_freeable) from [<>] (kernel_init+0x10/0xec) [<>] (kernel_init) from [<>] (ret_from_fork+0x14/0x24) This is caused by the fact that at the moment some GPIO names are set to NULL, there is a hole in linear representation of one GPI bank, see drivers/gpio/gpio-lpc32xx.c / gpi_p3_names[] for details. The same problem most probably affects also gpio-cs5535.c, see cs5535_gpio_names[]. Signed-off-by: Vladimir Zapolskiy Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/gpio/gpiolib.c') diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index a18f00fc1bb8..2a91f3287e3b 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -233,7 +233,7 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name) for (i = 0; i != chip->ngpio; ++i) { struct gpio_desc *gpio = &chip->desc[i]; - if (!gpio->name) + if (!gpio->name || !name) continue; if (!strcmp(gpio->name, name)) { -- cgit v1.2.1 From 45ad7db90b42555c8107f18ec6d6a1e9bce34860 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Thu, 17 Dec 2015 10:14:24 +0100 Subject: gpio: revert get() to non-errorprogating behaviour commit e20538b82f1f ("gpio: Propagate errors from chip->get()") started to propagate errors from the .get() functions since we can get errors from the infrastructure of e.g. slowbus GPIO expanders. However it turns out a bunch of drivers relied on the core to clamp the value, so we need to revert to the old behaviour and go over all drivers and fix them to conform to the expectations of the core before we go back to propagating the error code. Cc: stable@vger.kernel.org # 4.3+ Cc: Bjorn Andersson Cc: Vladimir Zapolskiy Fixes: e20538b82f1f ("gpio: Propagate errors from chip->get()") Reported-by: Michael Trimarchi Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/gpio/gpiolib.c') diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 2a91f3287e3b..4e4c3083ae56 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1279,7 +1279,13 @@ static int _gpiod_get_raw_value(const struct gpio_desc *desc) chip = desc->chip; offset = gpio_chip_hwgpio(desc); value = chip->get ? chip->get(chip, offset) : -EIO; - value = value < 0 ? value : !!value; + /* + * FIXME: fix all drivers to clamp to [0,1] or return negative, + * then change this to: + * value = value < 0 ? value : !!value; + * so we can properly propagate error codes. + */ + value = !!value; trace_gpio_value(desc_to_gpio(desc), 1, value); return value; } -- cgit v1.2.1