From a54756cb24eafac70ce92bfbd9bb4a4195689fb4 Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:57 +0800 Subject: gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL Add support for GPIO_V2_LINE_SET_CONFIG_IOCTL, the uAPI v2 line set config ioctl. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-cdev.c | 88 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) (limited to 'drivers/gpio/gpiolib-cdev.c') diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 868fcf89478c..608cdbd1d579 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -444,6 +445,8 @@ 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 { @@ -454,6 +457,7 @@ struct linereq { u32 event_buffer_size; DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); atomic_t seqno; + struct mutex config_mutex; struct line lines[]; }; @@ -574,6 +578,8 @@ static void edge_detector_stop(struct line *line) free_irq(line->irq, line); line->irq = 0; } + + line->eflags = 0; } static int edge_detector_setup(struct line *line, @@ -615,6 +621,17 @@ static int edge_detector_setup(struct line *line, return 0; } +static int edge_detector_update(struct line *line, u64 eflags, + bool polarity_change) +{ + if ((line->eflags == eflags) && !polarity_change) + return 0; + + edge_detector_stop(line); + + return edge_detector_setup(line, eflags); +} + static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc, unsigned int line_idx) { @@ -799,6 +816,74 @@ 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; + bool polarity_change; + int ret; + + for (i = 0; i < lr->num_lines; i++) { + desc = lr->lines[i].desc; + flags = gpio_v2_line_config_flags(lc, i); + polarity_change = + (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) != + ((flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW) != 0)); + + 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; + + ret = edge_detector_update(&lr->lines[i], + flags & GPIO_V2_LINE_EDGE_FLAGS, + polarity_change); + 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) { @@ -807,6 +892,8 @@ 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; } @@ -968,6 +1055,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) } } + mutex_init(&lr->config_mutex); init_waitqueue_head(&lr->wait); lr->event_buffer_size = ulr.event_buffer_size; if (lr->event_buffer_size == 0) -- cgit v1.2.3-59-g8ed1b