diff options
| -rw-r--r-- | drivers/gpio/gpiolib.c | 193 | ||||
| -rw-r--r-- | include/uapi/linux/gpio.h | 61 |
2 files changed, 251 insertions, 3 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 24f60d28f0c0..5f2e73e99fa1 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -21,6 +21,7 @@ #include <linux/fs.h> #include <linux/uaccess.h> #include <linux/compat.h> +#include <linux/anon_inodes.h> #include <uapi/linux/gpio.h> #include "gpiolib.h" @@ -310,6 +311,196 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc) return 0; } +/* + * GPIO line handle management + */ + +/** + * struct linehandle_state - contains the state of a userspace handle + * @gdev: the GPIO device the handle pertains to + * @label: consumer label used to tag descriptors + * @descs: the GPIO descriptors held by this handle + * @numdescs: the number of descriptors held in the descs array + */ +struct linehandle_state { + struct gpio_device *gdev; + const char *label; + struct gpio_desc *descs[GPIOHANDLES_MAX]; + u32 numdescs; +}; + +static long linehandle_ioctl(struct file *filep, unsigned int cmd, + unsigned long arg) +{ + struct linehandle_state *lh = filep->private_data; + void __user *ip = (void __user *)arg; + struct gpiohandle_data ghd; + int i; + + if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { + int val; + + /* TODO: check if descriptors are really input */ + for (i = 0; i < lh->numdescs; i++) { + val = gpiod_get_value_cansleep(lh->descs[i]); + if (val < 0) + return val; + ghd.values[i] = val; + } + + if (copy_to_user(ip, &ghd, sizeof(ghd))) + return -EFAULT; + + return 0; + } else if (cmd == GPIOHANDLE_SET_LINE_VALUES_IOCTL) { + int vals[GPIOHANDLES_MAX]; + + /* TODO: check if descriptors are really output */ + if (copy_from_user(&ghd, ip, sizeof(ghd))) + return -EFAULT; + + /* Clamp all values to [0,1] */ + for (i = 0; i < lh->numdescs; i++) + vals[i] = !!ghd.values[i]; + + /* Reuse the array setting function */ + gpiod_set_array_value_complex(false, + true, + lh->numdescs, + lh->descs, + vals); + return 0; + } + return -EINVAL; +} + +#ifdef CONFIG_COMPAT +static long linehandle_ioctl_compat(struct file *filep, unsigned int cmd, + unsigned long arg) +{ + return linehandle_ioctl(filep, cmd, (unsigned long)compat_ptr(arg)); +} +#endif + +static int linehandle_release(struct inode *inode, struct file *filep) +{ + struct linehandle_state *lh = filep->private_data; + struct gpio_device *gdev = lh->gdev; + int i; + + for (i = 0; i < lh->numdescs; i++) + gpiod_free(lh->descs[i]); + kfree(lh->label); + kfree(lh); + put_device(&gdev->dev); + return 0; +} + +static const struct file_operations linehandle_fileops = { + .release = linehandle_release, + .owner = THIS_MODULE, + .llseek = noop_llseek, + .unlocked_ioctl = linehandle_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = linehandle_ioctl_compat, +#endif +}; + +static int linehandle_create(struct gpio_device *gdev, void __user *ip) +{ + struct gpiohandle_request handlereq; + struct linehandle_state *lh; + int fd, i, ret; + + if (copy_from_user(&handlereq, ip, sizeof(handlereq))) + return -EFAULT; + if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX)) + return -EINVAL; + + lh = kzalloc(sizeof(*lh), GFP_KERNEL); + if (!lh) + return -ENOMEM; + lh->gdev = gdev; + get_device(&gdev->dev); + + /* Make sure this is terminated */ + handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0'; + if (strlen(handlereq.consumer_label)) { + lh->label = kstrdup(handlereq.consumer_label, + GFP_KERNEL); + if (!lh->label) { + ret = -ENOMEM; + goto out_free_lh; + } + } + + /* Request each GPIO */ + for (i = 0; i < handlereq.lines; i++) { + u32 offset = handlereq.lineoffsets[i]; + u32 lflags = handlereq.flags; + struct gpio_desc *desc; + + desc = &gdev->descs[offset]; + ret = gpiod_request(desc, lh->label); + if (ret) + goto out_free_descs; + lh->descs[i] = desc; + + if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW) + set_bit(FLAG_ACTIVE_LOW, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) + set_bit(FLAG_OPEN_DRAIN, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) + set_bit(FLAG_OPEN_SOURCE, &desc->flags); + + /* + * 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 = !!handlereq.default_values[i]; + + ret = gpiod_direction_output(desc, val); + if (ret) + goto out_free_descs; + } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { + ret = gpiod_direction_input(desc); + if (ret) + goto out_free_descs; + } + dev_dbg(&gdev->dev, "registered chardev handle for line %d\n", + offset); + } + lh->numdescs = handlereq.lines; + + fd = anon_inode_getfd("gpio-linehandle", + &linehandle_fileops, + lh, + O_RDONLY | O_CLOEXEC); + if (fd < 0) { + ret = fd; + goto out_free_descs; + } + + handlereq.fd = fd; + if (copy_to_user(ip, &handlereq, sizeof(handlereq))) + return -EFAULT; + + dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n", + lh->numdescs); + + return 0; + +out_free_descs: + for (; i >= 0; i--) + gpiod_free(lh->descs[i]); + kfree(lh->label); +out_free_lh: + kfree(lh); + put_device(&gdev->dev); + return ret; +} + /** * gpio_ioctl() - ioctl handler for the GPIO chardev */ @@ -385,6 +576,8 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) return -EFAULT; return 0; + } else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) { + return linehandle_create(gdev, ip); } return -EINVAL; } diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h index d0a3cac72250..21905531dcf4 100644 --- a/include/uapi/linux/gpio.h +++ b/include/uapi/linux/gpio.h @@ -1,7 +1,7 @@ /* * <linux/gpio.h> - userspace ABI for the GPIO character devices * - * Copyright (C) 2015 Linus Walleij + * Copyright (C) 2016 Linus Walleij * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published by @@ -26,8 +26,8 @@ struct gpiochip_info { __u32 lines; }; -/* Line is in use by the kernel */ -#define GPIOLINE_FLAG_KERNEL (1UL << 0) +/* Informational flags */ +#define GPIOLINE_FLAG_KERNEL (1UL << 0) /* Line used by the kernel */ #define GPIOLINE_FLAG_IS_OUT (1UL << 1) #define GPIOLINE_FLAG_ACTIVE_LOW (1UL << 2) #define GPIOLINE_FLAG_OPEN_DRAIN (1UL << 3) @@ -52,7 +52,62 @@ struct gpioline_info { char consumer[32]; }; +/* Maximum number of requested handles */ +#define GPIOHANDLES_MAX 64 + +/* Request flags */ +#define GPIOHANDLE_REQUEST_INPUT (1UL << 0) +#define GPIOHANDLE_REQUEST_OUTPUT (1UL << 1) +#define GPIOHANDLE_REQUEST_ACTIVE_LOW (1UL << 2) +#define GPIOHANDLE_REQUEST_OPEN_DRAIN (1UL << 3) +#define GPIOHANDLE_REQUEST_OPEN_SOURCE (1UL << 4) + +/** + * struct gpiohandle_request - Information about a GPIO handle request + * @lineoffsets: an array desired lines, specified by offset index for the + * associated GPIO device + * @flags: desired flags for the desired GPIO lines, such as + * GPIOHANDLE_REQUEST_OUTPUT, GPIOHANDLE_REQUEST_ACTIVE_LOW etc, OR:ed + * together. Note that even if multiple lines are requested, the same flags + * must be applicable to all of them, if you want lines with individual + * flags set, request them one by one. It is possible to select + * a batch of input or output lines, but they must all have the same + * characteristics, i.e. all inputs or all outputs, all active low etc + * @default_values: if the GPIOHANDLE_REQUEST_OUTPUT is set for a requested + * line, this specifies the default output value, should be 0 (low) or + * 1 (high), anything else than 0 or 1 will be interpreted as 1 (high) + * @consumer_label: a desired consumer label for the selected GPIO line(s) + * such as "my-bitbanged-relay" + * @lines: number of lines requested in this request, i.e. the number of + * valid fields in the above arrays, set to 1 to request a single line + * @fd: if successful this field will contain a valid anonymous file handle + * after a GPIO_GET_LINEHANDLE_IOCTL operation, zero or negative value + * means error + */ +struct gpiohandle_request { + __u32 lineoffsets[GPIOHANDLES_MAX]; + __u32 flags; + __u8 default_values[GPIOHANDLES_MAX]; + char consumer_label[32]; + __u32 lines; + int fd; +}; + #define GPIO_GET_CHIPINFO_IOCTL _IOR(0xB4, 0x01, struct gpiochip_info) #define GPIO_GET_LINEINFO_IOCTL _IOWR(0xB4, 0x02, struct gpioline_info) +#define GPIO_GET_LINEHANDLE_IOCTL _IOWR(0xB4, 0x03, struct gpiohandle_request) + +/** + * struct gpiohandle_data - Information of values on a GPIO handle + * @values: when getting the state of lines this contains the current + * state of a line, when setting the state of lines these should contain + * the desired target state + */ +struct gpiohandle_data { + __u8 values[GPIOHANDLES_MAX]; +}; + +#define GPIOHANDLE_GET_LINE_VALUES_IOCTL _IOWR(0xB4, 0x08, struct gpiohandle_data) +#define GPIOHANDLE_SET_LINE_VALUES_IOCTL _IOWR(0xB4, 0x09, struct gpiohandle_data) #endif /* _UAPI_GPIO_H_ */ |