Add support for GPIO_V2_LINE_SET_CONFIG_IOCTL, the uAPI v2 line set config ioctl.
Signed-off-by: Kent Gibson <[email protected]> --- drivers/gpio/gpiolib-cdev.c | 92 +++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 05b15f20fe2c..9c1e3f5f01af 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -16,6 +16,7 @@ #include <linux/kernel.h> #include <linux/kfifo.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/pinctrl/consumer.h> #include <linux/poll.h> #include <linux/spinlock.h> @@ -423,6 +424,8 @@ struct line { * @seqno: the sequence number for edge events generated on all lines in * this line request. Note that this is not used when @num_lines is 1, as * the line_seqno is then the same and is cheaper to calculate. + * @config_mutex: mutex for serializing ioctl() calls to ensure consistency + * of configuration, particularly multi-step accesses to desc flags. * @lines: the lines held by this line request, with @num_lines elements. */ struct linereq { @@ -432,6 +435,7 @@ struct linereq { wait_queue_head_t wait; DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); atomic_t seqno; + struct mutex config_mutex; struct line lines[]; }; @@ -693,6 +697,29 @@ static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc, return 0; } +static int gpio_v2_line_config_change_validate(struct linereq *lr, + struct gpio_v2_line_config *lc) +{ + unsigned int i; + u64 flags; + + for (i = 0; i < lr->num_lines; i++) { + flags = gpio_v2_line_config_flags(lc, i); + /* disallow edge detection changes */ + if (lr->lines[i].eflags != (flags & GPIO_V2_LINE_EDGE_FLAGS)) + return -EINVAL; + + if (lr->lines[i].eflags & GPIO_V2_LINE_EDGE_FLAGS) { + /* disallow polarity changes */ + if (test_bit(FLAG_ACTIVE_LOW, + &lr->lines[i].desc->flags) != + ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0)) + return -EINVAL; + } + } + return 0; +} + static void gpio_v2_line_config_flags_to_desc_flags(u64 flags, unsigned long *flagsp) { @@ -772,6 +799,68 @@ static long linereq_get_values(struct linereq *lr, void __user *ip) return 0; } +static long linereq_set_config_unlocked(struct linereq *lr, + struct gpio_v2_line_config *lc) +{ + struct gpio_desc *desc; + unsigned int i; + u64 flags; + int ret; + + ret = gpio_v2_line_config_change_validate(lr, lc); + if (ret) + return ret; + + for (i = 0; i < lr->num_lines; i++) { + desc = lr->lines[i].desc; + flags = gpio_v2_line_config_flags(lc, i); + + gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags); + /* + * Lines have to be requested explicitly for input + * or output, else the line will be treated "as is". + */ + if (flags & GPIO_V2_LINE_FLAG_OUTPUT) { + int val = gpio_v2_line_config_output_value(lc, i); + + edge_detector_stop(&lr->lines[i]); + ret = gpiod_direction_output(desc, val); + if (ret) + return ret; + } else if (flags & GPIO_V2_LINE_FLAG_INPUT) { + ret = gpiod_direction_input(desc); + if (ret) + return ret; + } + + blocking_notifier_call_chain(&desc->gdev->notifier, + GPIO_V2_LINE_CHANGED_CONFIG, + desc); + } + return 0; +} + +static long linereq_set_config(struct linereq *lr, void __user *ip) +{ + struct gpio_v2_line_config lc; + int ret; + + if (copy_from_user(&lc, ip, sizeof(lc))) + return -EFAULT; + + ret = gpio_v2_line_config_validate(&lc, lr->num_lines); + if (ret) + return ret; + + mutex_lock(&lr->config_mutex); + + ret = linereq_set_config_unlocked(lr, &lc); + + mutex_unlock(&lr->config_mutex); + + return ret; +} + static long linereq_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -780,6 +869,8 @@ static long linereq_ioctl(struct file *file, unsigned int cmd, if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL) return linereq_get_values(lr, ip); + else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL) + return linereq_set_config(lr, ip); return -EINVAL; } @@ -946,6 +1037,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) } } + mutex_init(&lr->config_mutex); init_waitqueue_head(&lr->wait); if (has_edge_detection) { size = ulr.event_buffer_size; -- 2.28.0
