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gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL

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Add support for GPIO_V2_LINE_SET_CONFIG_IOCTL, the uAPI v2
line set config ioctl.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
This commit is contained in:
Kent Gibson 2020-09-28 08:27:57 +08:00 committed by Bartosz Golaszewski
parent 73e0341992
commit a54756cb24
1 changed files with 88 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

88
drivers/gpio/gpiolib-cdev.c
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@ -16,6 +16,7 @@
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/kfifo.h> #include <linux/kfifo.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pinctrl/consumer.h> #include <linux/pinctrl/consumer.h>
#include <linux/poll.h> #include <linux/poll.h>
#include <linux/spinlock.h> #include <linux/spinlock.h>
@ -444,6 +445,8 @@ struct line {
* @seqno: the sequence number for edge events generated on all lines in * @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 * 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. * 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. * @lines: the lines held by this line request, with @num_lines elements.
*/ */
struct linereq { struct linereq {
@ -454,6 +457,7 @@ struct linereq {
u32 event_buffer_size; u32 event_buffer_size;
DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
atomic_t seqno; atomic_t seqno;
struct mutex config_mutex;
struct line lines[]; struct line lines[];
}; };
@ -574,6 +578,8 @@ static void edge_detector_stop(struct line *line)
free_irq(line->irq, line); free_irq(line->irq, line);
line->irq = 0; line->irq = 0;
} }
line->eflags = 0;
} }
static int edge_detector_setup(struct line *line, static int edge_detector_setup(struct line *line,
@ -615,6 +621,17 @@ static int edge_detector_setup(struct line *line,
return 0; 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, static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
unsigned int line_idx) unsigned int line_idx)
{ {
@ -799,6 +816,74 @@ static long linereq_get_values(struct linereq *lr, void __user *ip)
return 0; 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, static long linereq_ioctl(struct file *file, unsigned int cmd,
unsigned long arg) 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) if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
return linereq_get_values(lr, ip); return linereq_get_values(lr, ip);
else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
return linereq_set_config(lr, ip);
return -EINVAL; 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); init_waitqueue_head(&lr->wait);
lr->event_buffer_size = ulr.event_buffer_size; lr->event_buffer_size = ulr.event_buffer_size;
if (lr->event_buffer_size == 0) if (lr->event_buffer_size == 0)