On 28/05/2020 14:24, Hans Verkuil wrote:
On 27/05/2020 16:07, Linus Walleij wrote:
We provided the right semantics on open drain lines being by definition output but incidentally the irq set up function would only allow IRQs on lines that were "not output".
Fix the semantics to allow output open drain lines to be used for IRQs.
Reported-by: Hans Verkuil hverkuil@xs4all.nl
Tested-by: Hans Verkuil hverkuil@xs4all.nl
Whether this is the right/best fix or not, I cannot tell, but it certainly fixes the cec-gpio driver!
Close, but no cigar. I didn't check the kernel log and I now see this warning:
[ 4.157000] ------------[ cut here ]------------ [ 4.161699] WARNING: CPU: 0 PID: 1 at drivers/gpio/gpiolib.c:4260 gpiochip_enable_irq+0x6c/0x78 [ 4.170522] Modules linked in: [ 4.173626] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc2-rpi3 #179 [ 4.180510] Hardware name: Raspberry Pi 3 Model B (DT) [ 4.185724] pstate: 80000085 (Nzcv daIf -PAN -UAO) [ 4.190585] pc : gpiochip_enable_irq+0x6c/0x78 [ 4.195094] lr : gpiochip_irq_enable+0x20/0x58 [ 4.199597] sp : ffff8000100239e0 [ 4.202956] x29: ffff8000100239e0 x28: 0000000000000000 [ 4.208346] x27: ffff0000042b9808 x26: ffff00000425eca4 [ 4.213735] x25: 0000000000000000 x24: ffff00000425ed58 [ 4.219124] x23: 0000000000000000 x22: 0000000000000000 [ 4.224512] x21: 0000000000000001 x20: ffff0000041d1b00 [ 4.229902] x19: ffff00000425ec00 x18: 0000000000000000 [ 4.235291] x17: ffff8000107ddce0 x16: ffff8000107dd1b8 [ 4.240680] x15: ffff000037870450 x14: ffffffffffffffff [ 4.246070] x13: ffff0000041d1a87 x12: ffff0000041d1a85 [ 4.251459] x11: 0000000000000000 x10: 0000000000000040 [ 4.256848] x9 : 0000000000000000 x8 : 0000000000000080 [ 4.262237] x7 : 0000000000000000 x6 : 000000000000003f [ 4.267626] x5 : 0000000000000000 x4 : ffff0000372d3990 [ 4.273014] x3 : ffff00000425ec28 x2 : 0000000000000036 [ 4.278403] x1 : ffff0000372d40e0 x0 : 0000000000000683 [ 4.283793] Call trace: [ 4.286274] gpiochip_enable_irq+0x6c/0x78 [ 4.290432] irq_enable+0x3c/0x80 [ 4.293795] __irq_startup+0x7c/0xa8 [ 4.297419] irq_startup+0x5c/0x138 [ 4.300957] __setup_irq+0x82c/0x8f8 [ 4.304583] request_threaded_irq+0xd8/0x198 [ 4.308913] devm_request_threaded_irq+0x78/0xf8 [ 4.313599] cec_gpio_probe+0x118/0x288 [ 4.317490] platform_drv_probe+0x54/0xb0 [ 4.321558] really_probe+0xd8/0x330 [ 4.325184] driver_probe_device+0x58/0xf8 [ 4.329339] device_driver_attach+0x74/0x80 [ 4.333582] __driver_attach+0x58/0xe0 [ 4.337383] bus_for_each_dev+0x70/0xc0 [ 4.341273] driver_attach+0x24/0x30 [ 4.344899] bus_add_driver+0x150/0x1e0 [ 4.348789] driver_register+0x64/0x128 [ 4.352678] __platform_driver_register+0x48/0x58 [ 4.357452] cec_gpio_pdrv_init+0x1c/0x28 [ 4.361519] do_one_initcall+0x54/0x1b8 [ 4.365412] kernel_init_freeable+0x1cc/0x244 [ 4.369833] kernel_init+0x14/0x108 [ 4.373371] ret_from_fork+0x10/0x1c [ 4.377000] ---[ end trace 49bf91ba04222a1a ]--- [ 4.382253] Registered IR keymap rc-cec [ 4.386344] rc rc0: cec-gpio@7 as /devices/platform/cec-gpio@7/rc/rc0 [ 4.393135] input: cec-gpio@7 as /devices/platform/cec-gpio@7/rc/rc0/input0
The fix seems to be to just add this change to the patch:
Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl --- diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 40f2d7f69be2..5a8214d5e927 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -4255,7 +4257,8 @@ void gpiochip_enable_irq(struct gpio_chip *gc, unsigned int offset)
if (!IS_ERR(desc) && !WARN_ON(!test_bit(FLAG_USED_AS_IRQ, &desc->flags))) { - WARN_ON(test_bit(FLAG_IS_OUT, &desc->flags)); + WARN_ON(test_bit(FLAG_IS_OUT, &desc->flags) && + !test_bit(FLAG_OPEN_DRAIN, &desc->flags)); set_bit(FLAG_IRQ_IS_ENABLED, &desc->flags); } }
I wish I could test this on the BeagleBone Black, which is the other use-case, but it's in another country and the earliest I can test is probably August or September (depending on how long the travel restrictions stay in place).
If someone else has a BBB handy, then it would be nice if this patch can be tested.
Regards,
Hans
Regards,
Hans
Cc: Russell King linux@armlinux.org.uk Cc: stable@vger.kernel.org Fixes: 256efaea1fdc ("gpiolib: fix up emulated open drain outputs") Signed-off-by: Linus Walleij linus.walleij@linaro.org
drivers/gpio/gpiolib.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index b4b5792fe2ff..edd74ff31cea 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -4220,7 +4220,9 @@ int gpiochip_lock_as_irq(struct gpio_chip *gc, unsigned int offset) } }
- if (test_bit(FLAG_IS_OUT, &desc->flags)) {
- /* To be valid for IRQ the line needs to be input or open drain */
- if (test_bit(FLAG_IS_OUT, &desc->flags) &&
!test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {