Hi Bartosz,
On 10.02.2025 11:51, Bartosz Golaszewski wrote:
From: Bartosz Golaszewski bartosz.golaszewski@linaro.org
As per the API contract - gpio_chip::get_direction() may fail and return a negative error number. However, we treat it as if it always returned 0 or 1. Check the return value of the callback and propagate the error number up the stack.
Cc: stable@vger.kernel.org Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@linaro.org
drivers/gpio/gpiolib.c | 44 +++++++++++++++++++++++++++++--------------- 1 file changed, 29 insertions(+), 15 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 679ed764cb14..5d3774dc748b 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1057,8 +1057,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, desc->gdev = gdev; if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index)) {
assign_bit(FLAG_IS_OUT,&desc->flags, !gc->get_direction(gc, desc_index));
ret = gc->get_direction(gc, desc_index);if (ret < 0)goto err_cleanup_desc_srcu;assign_bit(FLAG_IS_OUT, &desc->flags, !ret);
This change breaks bcm2835 pincontrol/gpio driver (and probably others) in next-20250218. The problem is that some gpio lines are initially configured as alternate function (i.e. uart) and .get_direction returns -EINVAL for them, what in turn causes the whole gpio chip fail to register. Here is the log with WARN_ON() added to line drivers/pinctrl/bcm/pinctrl-bcm2835.c:350 from Raspberry Pi 4B:
------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at drivers/pinctrl/bcm/pinctrl-bcm2835.c:350 bcm2835_gpio_get_direction+0x80/0x98 Modules linked in: CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.14.0-rc3-next-20250218-dirty #9817 Hardware name: Raspberry Pi 4 Model B (DT) pstate: 00000005 (nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : bcm2835_gpio_get_direction+0x80/0x98 lr : bcm2835_gpio_get_direction+0x18/0x98 ... Call trace: bcm2835_gpio_get_direction+0x80/0x98 (P) gpiochip_add_data_with_key+0x874/0xef0 bcm2835_pinctrl_probe+0x354/0x53c platform_probe+0x68/0xdc really_probe+0xbc/0x298 __driver_probe_device+0x78/0x12c driver_probe_device+0xdc/0x164 __driver_attach+0x9c/0x1ac bus_for_each_dev+0x74/0xd4 driver_attach+0x24/0x30 bus_add_driver+0xe4/0x208 driver_register+0x60/0x128 __platform_driver_register+0x24/0x30 bcm2835_pinctrl_driver_init+0x20/0x2c do_one_initcall+0x64/0x308 kernel_init_freeable+0x280/0x4e8 kernel_init+0x20/0x1d8 ret_from_fork+0x10/0x20 irq event stamp: 100380 hardirqs last enabled at (100379): [<ffff8000812d7d5c>] _raw_spin_unlock_irqrestore+0x74/0x78 hardirqs last disabled at (100380): [<ffff8000812c8918>] el1_dbg+0x24/0x8c softirqs last enabled at (93674): [<ffff80008005ed4c>] handle_softirqs+0x4c4/0x4dc softirqs last disabled at (93669): [<ffff8000800105a0>] __do_softirq+0x14/0x20 ---[ end trace 0000000000000000 ]--- gpiochip_add_data_with_key: GPIOs 512..569 (pinctrl-bcm2711) failed to register, -22 pinctrl-bcm2835 fe200000.gpio: could not add GPIO chip pinctrl-bcm2835 fe200000.gpio: probe with driver pinctrl-bcm2835 failed with error -22
Any suggestions how to fix this issue? Should we add GPIO_LINE_DIRECTION_UNKNOWN?
@@ -2728,13 +2731,18 @@ int gpiod_direction_input_nonotify(struct gpio_desc *desc) if (guard.gc->direction_input) { ret = guard.gc->direction_input(guard.gc, gpio_chip_hwgpio(desc));
- } else if (guard.gc->get_direction &&
(guard.gc->get_direction(guard.gc,gpio_chip_hwgpio(desc)) != 1)) {gpiod_warn(desc,"%s: missing direction_input() operation and line is output\n",__func__);return -EIO;
- } else if (guard.gc->get_direction) {
ret = guard.gc->get_direction(guard.gc,gpio_chip_hwgpio(desc));if (ret < 0)return ret;if (ret != GPIO_LINE_DIRECTION_IN) {gpiod_warn(desc,"%s: missing direction_input() operation and line is output\n",__func__);return -EIO;}@@ -2771,12 +2779,18 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) gpio_chip_hwgpio(desc), val); } else { /* Check that we are in output mode if we can */
if (guard.gc->get_direction &&guard.gc->get_direction(guard.gc, gpio_chip_hwgpio(desc))) {gpiod_warn(desc,"%s: missing direction_output() operation\n",__func__);return -EIO;
if (guard.gc->get_direction) {ret = guard.gc->get_direction(guard.gc,gpio_chip_hwgpio(desc));if (ret < 0)return ret;if (ret != GPIO_LINE_DIRECTION_OUT) {gpiod_warn(desc,"%s: missing direction_output() operation\n",__func__);return -EIO;}
- If we can't actively set the direction, we are some
Best regards