On 10/14/2017 05:43 PM, Linus Walleij wrote:
So I guess the driver needs to know what pin registers it can't
access so the user does not get a gun to shoot in the foot with.
If we augment gpiolib to just handle -EACCES or something
(-EIO?) from the driver .get_direction() callback for these lines,
things should be smooth?
You mean like this:
diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c
b/drivers/pinctrl/qcom/pinctrl-msm.c
index ff491da64dab..ca4ae3d76eb4 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -443,6 +443,14 @@ static int msm_gpio_get_direction(struct gpio_chip
*chip, unsigned int offset)
g = &pctrl->soc->groups[offset];
+ /*
+ * During initialization, gpiolib may query all GPIOs for their
+ * initial direction, regardless if they exist, so block access
+ * to those that are unavailable.
+ */
+ if (!g->npins)
+ return -ENODEV;
+
val = readl(pctrl->regs + g->ctl_reg);
/* 0 = output, 1 = input */
This is what I have in my patch already. I can return any error message
you like, but -ENODEV already works.
The problem is that it's insufficient. I also want the non-available
GPIOs to be as absent as possible. I don't want them to show up in
/sys/kernel/debug/gpio, and I don't want to be able to create them via
/sys/class/gpio/export.
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