From 472a61e777fe78cdcb6cb6f25efee0ae9f629aca Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Wed, 14 Aug 2019 14:00:35 +0300 Subject: [PATCH] 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 Tested-by: Ramon Fried Signed-off-by: Ramon Fried Link: https://lore.kernel.org/r/20190814110035.13451-1-ramon.fried@linux.intel.com Acked-by: Stefan Wahren Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 3 ++- drivers/pinctrl/core.c | 28 ++++++++++++++++++++++++++++ drivers/pinctrl/pinmux.c | 24 ++++++++++++++++++++++++ drivers/pinctrl/pinmux.h | 8 ++++++++ include/linux/pinctrl/consumer.h | 6 ++++++ 5 files changed, 68 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index f497003f119c..52937bf8e514 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -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; diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index b70df27874d1..2bbd8ee93507 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -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 diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c index 020e54f843f9..e914f6efd39e 100644 --- a/drivers/pinctrl/pinmux.c +++ b/drivers/pinctrl/pinmux.c @@ -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 diff --git a/drivers/pinctrl/pinmux.h b/drivers/pinctrl/pinmux.h index 794cb3a003ff..78c3a31be882 100644 --- a/drivers/pinctrl/pinmux.h +++ b/drivers/pinctrl/pinmux.h @@ -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) diff --git a/include/linux/pinctrl/consumer.h b/include/linux/pinctrl/consumer.h index 86720a5a384f..7f8c7d9583d3 100644 --- a/include/linux/pinctrl/consumer.h +++ b/include/linux/pinctrl/consumer.h @@ -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;