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Date: Fri, 21 Oct 2011 12:25:53 -0600
From: Stephen Warren <swarren@...dia.com>
To: Linus Walleij <linus.walleij@...ricsson.com>,
Linus Walleij <linus.walleij@...aro.org>
Cc: linux-kernel@...r.kernel.org, Barry Song <21cnbao@...il.com>,
Shawn Guo <shawn.guo@...escale.com>,
Sascha Hauer <s.hauer@...gutronix.de>,
David Brown <davidb@...eaurora.org>,
Grant Likely <grant.likely@...retlab.ca>,
Rongjun Ying <Rongjun.Ying@....com>,
Linaro Dev <linaro-dev@...ts.linaro.org>,
Stephen Warren <swarren@...dia.com>
Subject: [PATCH] pinctrl: Add explicit gpio_disable_free pinmux_op
Some pinctrl drivers (Tegra at least) program a pin to be a GPIO in a
completely different manner than they select which function to mux out of
that pin. In order to support a single "free" pinmux_op, the driver would
need to maintain a per-pin state of requested-for-gpio vs. requested-for-
function. However, that's a lot of work when the core already has explicit
separate paths for gpio request/free and function request/free.
So, add a gpio_disable_free op to struct pinmux_ops, and make pin_free()
call it when appropriate.
When doing this, I noticed that when calling pin_request():
!!gpio == (gpio_range != NULL)
... and so I collapsed those two parameters in both pin_request(), and
when adding writing the new code in pin_free().
Also, for pin_free():
!!free_func == (gpio_range != NULL)
However, I didn't want pin_free() to know about the GPIO function naming
special case, so instead, I reworked pin_free() to always return the pin's
previously requested function, and now pinmux_free_gpio() calls
kfree(function). This is much more balanced with the allocation having
been performed in pinmux_request_gpio().
Signed-off-by: Stephen Warren <swarren@...dia.com>
---
drivers/pinctrl/pinmux.c | 39 +++++++++++++++++++++++++--------------
include/linux/pinctrl/pinmux.h | 3 +++
2 files changed, 28 insertions(+), 14 deletions(-)
diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index a5467f8..8a95e45 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -98,12 +98,11 @@ struct pinmux_hog {
* @function: a functional name to give to this pin, passed to the driver
* so it knows what function to mux in, e.g. the string "gpioNN"
* means that you want to mux in the pin for use as GPIO number NN
- * @gpio: if this request concerns a single GPIO pin
* @gpio_range: the range matching the GPIO pin if this is a request for a
* single GPIO pin
*/
static int pin_request(struct pinctrl_dev *pctldev,
- int pin, const char *function, bool gpio,
+ int pin, const char *function,
struct pinctrl_gpio_range *gpio_range)
{
struct pin_desc *desc;
@@ -152,7 +151,7 @@ static int pin_request(struct pinctrl_dev *pctldev,
* If there is no kind of request function for the pin we just assume
* we got it by default and proceed.
*/
- if (gpio && ops->gpio_request_enable)
+ if (gpio_range && ops->gpio_request_enable)
/* This requests and enables a single GPIO pin */
status = ops->gpio_request_enable(pctldev, gpio_range, pin);
else if (ops->request)
@@ -182,29 +181,39 @@ out:
* pin_free() - release a single muxed in pin so something else can be muxed
* @pctldev: pin controller device handling this pin
* @pin: the pin to free
- * @free_func: whether to free the pin's assigned function name string
+ * @gpio_range: the range matching the GPIO pin if this is a request for a
+ * single GPIO pin
*/
-static void pin_free(struct pinctrl_dev *pctldev, int pin, int free_func)
+static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
+ struct pinctrl_gpio_range *gpio_range)
{
const struct pinmux_ops *ops = pctldev->desc->pmxops;
struct pin_desc *desc;
+ const char *func;
desc = pin_desc_get(pctldev, pin);
if (desc == NULL) {
dev_err(&pctldev->dev,
"pin is not registered so it cannot be freed\n");
- return;
+ return NULL;
}
- if (ops->free)
+ /*
+ * If there is no kind of request function for the pin we just assume
+ * we got it by default and proceed.
+ */
+ if (gpio_range && ops->gpio_disable_free)
+ ops->gpio_disable_free(pctldev, gpio_range, pin);
+ else if (ops->free)
ops->free(pctldev, pin);
spin_lock(&desc->lock);
- if (free_func)
- kfree(desc->mux_function);
+ func = desc->mux_function;
desc->mux_function = NULL;
spin_unlock(&desc->lock);
module_put(pctldev->owner);
+
+ return func;
}
/**
@@ -234,7 +243,7 @@ int pinmux_request_gpio(unsigned gpio)
if (!function)
return -EINVAL;
- ret = pin_request(pctldev, pin, function, true, range);
+ ret = pin_request(pctldev, pin, function, range);
if (ret < 0)
kfree(function);
@@ -252,6 +261,7 @@ void pinmux_free_gpio(unsigned gpio)
struct pinctrl_gpio_range *range;
int ret;
int pin;
+ const char *func;
ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);
if (ret)
@@ -260,7 +270,8 @@ void pinmux_free_gpio(unsigned gpio)
/* Convert to the pin controllers number space */
pin = gpio - range->base;
- pin_free(pctldev, pin, true);
+ func = pin_free(pctldev, pin, range);
+ kfree(func);
}
EXPORT_SYMBOL_GPL(pinmux_free_gpio);
@@ -350,7 +361,7 @@ static int acquire_pins(struct pinctrl_dev *pctldev,
/* Try to allocate all pins in this group, one by one */
for (i = 0; i < num_pins; i++) {
- ret = pin_request(pctldev, pins[i], func, false, NULL);
+ ret = pin_request(pctldev, pins[i], func, NULL);
if (ret) {
dev_err(&pctldev->dev,
"could not get pin %d for function %s "
@@ -360,7 +371,7 @@ static int acquire_pins(struct pinctrl_dev *pctldev,
/* On error release all taken pins */
i--; /* this pin just failed */
for (; i >= 0; i--)
- pin_free(pctldev, pins[i], false);
+ pin_free(pctldev, pins[i], NULL);
return -ENODEV;
}
}
@@ -390,7 +401,7 @@ static void release_pins(struct pinctrl_dev *pctldev,
return;
}
for (i = 0; i < num_pins; i++)
- pin_free(pctldev, pins[i], false);
+ pin_free(pctldev, pins[i], NULL);
}
/**
diff --git a/include/linux/pinctrl/pinmux.h b/include/linux/pinctrl/pinmux.h
index 3c430e7..350e32a 100644
--- a/include/linux/pinctrl/pinmux.h
+++ b/include/linux/pinctrl/pinmux.h
@@ -73,6 +73,9 @@ struct pinmux_ops {
int (*gpio_request_enable) (struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *range,
unsigned offset);
+ void (*gpio_disable_free) (struct pinctrl_dev *pctldev,
+ struct pinctrl_gpio_range *range,
+ unsigned offset);
};
/* External interface to pinmux */
--
1.7.0.4
--
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