From a8002a35935aaefcd6a42ad3289f62bab947f2ca Mon Sep 17 00:00:00 2001
From: Maxim Kiselev <bigunclemax@gmail.com>
Date: Wed, 17 Feb 2021 14:10:00 +0100
Subject: [PATCH] gpio: pcf857x: Fix missing first interrupt
If no n_latch value will be provided at driver probe then all pins will
be used as an input:
gpio->out = ~n_latch;
In that case initial state for all pins is "one":
gpio->status = gpio->out;
So if pcf857x IRQ happens with change pin value from "zero" to "one"
then we miss it, because of "one" from IRQ and "one" from initial state
leaves corresponding pin unchanged:
change = (gpio->status ^ status) & gpio->irq_enabled;
The right solution will be to read actual state at driver probe.
Cc: stable@vger.kernel.org
Fixes: 6e20a0a429bd ("gpio: pcf857x: enable gpio_to_irq() support")
Signed-off-by: Maxim Kiselev <bigunclemax@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
drivers/gpio/gpio-pcf857x.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index a2a8d155c75e3..b7568ee33696d 100644
--- a/drivers/gpio/gpio-pcf857x.c
+++ b/drivers/gpio/gpio-pcf857x.c
@@ -332,7 +332,7 @@ static int pcf857x_probe(struct i2c_client *client,
* reset state. Otherwise it flags pins to be driven low.
*/
gpio->out = ~n_latch;
- gpio->status = gpio->out;
+ gpio->status = gpio->read(gpio->client);
/* Enable irqchip if we have an interrupt */
if (client->irq) {
--
2.39.5