pinctrl/gpio: Take MUX usage into account

The user space like gpioinfo only see the GPIO usage but not the
MUX usage (e.g. I2C or SPI usage) of a pin. As a user we want
to know which pin is free/safe to use. So take the MUX usage of
strict pinmux controllers into account to get a more realistic
view for ioctl GPIO_GET_LINEINFO_IOCTL.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Ramon Fried <rfried.dev@gmail.com>
Link: https://lore.kernel.org/r/20190814110035.13451-1-ramon.fried@linux.intel.com
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Stefan Wahren 2019-08-14 14:00:35 +03:00 committed by Linus Walleij
parent 2dc889a884
commit 472a61e777
5 changed files with 68 additions and 1 deletions

View File

@ -1084,7 +1084,8 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
test_bit(FLAG_IS_HOGGED, &desc->flags) ||
test_bit(FLAG_USED_AS_IRQ, &desc->flags) ||
test_bit(FLAG_EXPORT, &desc->flags) ||
test_bit(FLAG_SYSFS, &desc->flags))
test_bit(FLAG_SYSFS, &desc->flags) ||
!pinctrl_gpio_can_use_line(chip->base + lineinfo.line_offset))
lineinfo.flags |= GPIOLINE_FLAG_KERNEL;
if (test_bit(FLAG_IS_OUT, &desc->flags))
lineinfo.flags |= GPIOLINE_FLAG_IS_OUT;

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@ -736,6 +736,34 @@ int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
return -EINVAL;
}
bool pinctrl_gpio_can_use_line(unsigned gpio)
{
struct pinctrl_dev *pctldev;
struct pinctrl_gpio_range *range;
bool result;
int pin;
/*
* Try to obtain GPIO range, if it fails
* we're probably dealing with GPIO driver
* without a backing pin controller - bail out.
*/
if (pinctrl_get_device_gpio_range(gpio, &pctldev, &range))
return true;
mutex_lock(&pctldev->mutex);
/* Convert to the pin controllers number space */
pin = gpio_to_pin(range, gpio);
result = pinmux_can_be_used_for_gpio(pctldev, pin);
mutex_unlock(&pctldev->mutex);
return result;
}
EXPORT_SYMBOL_GPL(pinctrl_gpio_can_use_line);
/**
* pinctrl_gpio_request() - request a single pin to be used as GPIO
* @gpio: the GPIO pin number from the GPIO subsystem number space

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@ -70,6 +70,30 @@ int pinmux_validate_map(const struct pinctrl_map *map, int i)
return 0;
}
/**
* pinmux_can_be_used_for_gpio() - check if a specific pin
* is either muxed to a different function or used as gpio.
*
* @pin: the pin number in the global pin space
*
* Controllers not defined as strict will always return true,
* menaning that the gpio can be used.
*/
bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned pin)
{
struct pin_desc *desc = pin_desc_get(pctldev, pin);
const struct pinmux_ops *ops = pctldev->desc->pmxops;
/* Can't inspect pin, assume it can be used */
if (!desc)
return true;
if (ops->strict && desc->mux_usecount)
return false;
return !(ops->strict && !!desc->gpio_owner);
}
/**
* pin_request() - request a single pin to be muxed in, typically for GPIO
* @pin: the pin number in the global pin space

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@ -15,6 +15,8 @@ int pinmux_check_ops(struct pinctrl_dev *pctldev);
int pinmux_validate_map(const struct pinctrl_map *map, int i);
bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned pin);
int pinmux_request_gpio(struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *range,
unsigned pin, unsigned gpio);
@ -42,6 +44,12 @@ static inline int pinmux_validate_map(const struct pinctrl_map *map, int i)
return 0;
}
static inline bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev,
unsigned pin)
{
return true;
}
static inline int pinmux_request_gpio(struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *range,
unsigned pin, unsigned gpio)

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@ -24,6 +24,7 @@ struct device;
#ifdef CONFIG_PINCTRL
/* External interface to pin control */
extern bool pinctrl_gpio_can_use_line(unsigned gpio);
extern int pinctrl_gpio_request(unsigned gpio);
extern void pinctrl_gpio_free(unsigned gpio);
extern int pinctrl_gpio_direction_input(unsigned gpio);
@ -61,6 +62,11 @@ static inline int pinctrl_pm_select_idle_state(struct device *dev)
#else /* !CONFIG_PINCTRL */
static inline bool pinctrl_gpio_can_use_line(unsigned gpio)
{
return true;
}
static inline int pinctrl_gpio_request(unsigned gpio)
{
return 0;