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authorStephen Warren <swarren@nvidia.com>2012-03-06 04:22:15 +0400
committerLinus Walleij <linus.walleij@linaro.org>2012-03-13 01:43:09 +0400
commit652162d469a73450a66b6c8049b16c2b7828fa24 (patch)
tree4df09c6e5e370a4bd73569503d1a124599871db5 /drivers/pinctrl/pinmux.c
parenta6c3b33f02c799db69a3cd82545e45e9df3d69ca (diff)
downloadlinux-652162d469a73450a66b6c8049b16c2b7828fa24.tar.xz
pinctrl: allow concurrent gpio and mux function ownership of pins
Per recent updates to Documentation/gpio.txt, gpiolib drivers should inform pinctrl when a GPIO is requested. pinctrl then marks that pin as in-use for that GPIO function. When an SoC muxes pins in a group, it's quite possible for the group to contain e.g. 6 pins, but only 4 of them actually be needed by the HW module that's mux'd to them. In this case, the other 2 pins could be used as GPIOs. However, pinctrl marks all the pins within the group as in-use by the selected mux function. To allow the expected gpiolib interaction, separate the concepts of pin ownership into two parts: One for the mux function and one for GPIO usage. Finally, allow those two ownerships to exist in parallel. Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl/pinmux.c')
-rw-r--r--drivers/pinctrl/pinmux.c72
1 files changed, 49 insertions, 23 deletions
diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index 86e401754116..4e62783a573a 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -94,17 +94,28 @@ static int pin_request(struct pinctrl_dev *pctldev,
goto out;
}
- if (desc->usecount && strcmp(desc->owner, owner)) {
- dev_err(pctldev->dev,
- "pin already requested\n");
- goto out;
- }
+ if (gpio_range) {
+ /* There's no need to support multiple GPIO requests */
+ if (desc->gpio_owner) {
+ dev_err(pctldev->dev,
+ "pin already requested\n");
+ goto out;
+ }
- desc->usecount++;
- if (desc->usecount > 1)
- return 0;
+ desc->gpio_owner = owner;
+ } else {
+ if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
+ dev_err(pctldev->dev,
+ "pin already requested\n");
+ goto out;
+ }
- desc->owner = owner;
+ desc->mux_usecount++;
+ if (desc->mux_usecount > 1)
+ return 0;
+
+ desc->mux_owner = owner;
+ }
/* Let each pin increase references to this module */
if (!try_module_get(pctldev->owner)) {
@@ -135,9 +146,13 @@ static int pin_request(struct pinctrl_dev *pctldev,
out_free_pin:
if (status) {
- desc->usecount--;
- if (!desc->usecount)
- desc->owner = NULL;
+ if (gpio_range) {
+ desc->gpio_owner = NULL;
+ } else {
+ desc->mux_usecount--;
+ if (!desc->mux_usecount)
+ desc->mux_owner = NULL;
+ }
}
out:
if (status)
@@ -172,9 +187,11 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
return NULL;
}
- desc->usecount--;
- if (desc->usecount)
- return NULL;
+ if (!gpio_range) {
+ desc->mux_usecount--;
+ if (desc->mux_usecount)
+ return NULL;
+ }
/*
* If there is no kind of request function for the pin we just assume
@@ -185,9 +202,15 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
else if (ops->free)
ops->free(pctldev, pin);
- owner = desc->owner;
- desc->owner = NULL;
- desc->mux_setting = NULL;
+ if (gpio_range) {
+ owner = desc->gpio_owner;
+ desc->gpio_owner = NULL;
+ } else {
+ owner = desc->mux_owner;
+ desc->mux_owner = NULL;
+ desc->mux_setting = NULL;
+ }
+
module_put(pctldev->owner);
return owner;
@@ -493,7 +516,7 @@ static int pinmux_pins_show(struct seq_file *s, void *what)
unsigned i, pin;
seq_puts(s, "Pinmux settings per pin\n");
- seq_puts(s, "Format: pin (name): owner\n");
+ seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
mutex_lock(&pinctrl_mutex);
@@ -508,13 +531,16 @@ static int pinmux_pins_show(struct seq_file *s, void *what)
if (desc == NULL)
continue;
- if (desc->owner &&
- !strcmp(desc->owner, pinctrl_dev_get_name(pctldev)))
+ if (desc->mux_owner &&
+ !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
is_hog = true;
- seq_printf(s, "pin %d (%s): %s%s", pin,
+ seq_printf(s, "pin %d (%s): %s %s%s", pin,
desc->name ? desc->name : "unnamed",
- desc->owner ? desc->owner : "UNCLAIMED",
+ desc->mux_owner ? desc->mux_owner
+ : "(MUX UNCLAIMED)",
+ desc->gpio_owner ? desc->gpio_owner
+ : "(GPIO UNCLAIMED)",
is_hog ? " (HOG)" : "");
if (desc->mux_setting)