diff options
author | Kent Gibson <warthog618@gmail.com> | 2019-11-05 10:04:29 +0800 |
---|---|---|
committer | Bartosz Golaszewski <bgolaszewski@baylibre.com> | 2019-11-12 16:30:31 +0100 |
commit | e588bb1eae31be73fbec2b731be986a7c09635a4 (patch) | |
tree | 6dad3bb5d9f7e13813b63bd8459eb38df01219b1 /drivers | |
parent | b043ed7ef0b358d7f32dc57c218f925fd2802aba (diff) |
gpio: add new SET_CONFIG ioctl() to gpio chardev
Add the GPIOHANDLE_SET_CONFIG_IOCTL to the gpio chardev.
The ioctl allows some of the configuration of a requested handle to be
changed without having to release the line.
The primary use case is the changing of direction for bi-directional
lines.
Based on initial work by Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/gpio/gpiolib.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index a9826627f347..dba5f08f308c 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -476,6 +476,73 @@ static int linehandle_validate_flags(u32 flags) return 0; } +static void linehandle_configure_flag(unsigned long *flagsp, + u32 bit, bool active) +{ + if (active) + set_bit(bit, flagsp); + else + clear_bit(bit, flagsp); +} + +static long linehandle_set_config(struct linehandle_state *lh, + void __user *ip) +{ + struct gpiohandle_config gcnf; + struct gpio_desc *desc; + int i, ret; + u32 lflags; + unsigned long *flagsp; + + if (copy_from_user(&gcnf, ip, sizeof(gcnf))) + return -EFAULT; + + lflags = gcnf.flags; + ret = linehandle_validate_flags(lflags); + if (ret) + return ret; + + for (i = 0; i < lh->numdescs; i++) { + desc = lh->descs[i]; + flagsp = &desc->flags; + + linehandle_configure_flag(flagsp, FLAG_ACTIVE_LOW, + lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW); + + linehandle_configure_flag(flagsp, FLAG_OPEN_DRAIN, + lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN); + + linehandle_configure_flag(flagsp, FLAG_OPEN_SOURCE, + lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE); + + linehandle_configure_flag(flagsp, FLAG_PULL_UP, + lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP); + + linehandle_configure_flag(flagsp, FLAG_PULL_DOWN, + lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN); + + linehandle_configure_flag(flagsp, FLAG_BIAS_DISABLE, + lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE); + + /* + * Lines have to be requested explicitly for input + * or output, else the line will be treated "as is". + */ + if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { + int val = !!gcnf.default_values[i]; + + ret = gpiod_direction_output(desc, val); + if (ret) + return ret; + } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { + ret = gpiod_direction_input(desc); + if (ret) + return ret; + } + } + return 0; +} + static long linehandle_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) { @@ -526,6 +593,8 @@ static long linehandle_ioctl(struct file *filep, unsigned int cmd, lh->descs, NULL, vals); + } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) { + return linehandle_set_config(lh, ip); } return -EINVAL; } |