[v2] gpio: add userspace ABI for GPIO line information

Message ID	1455542435-3182-1-git-send-email-linus.walleij@linaro.org
State	Superseded
Headers	show Delivered-To: patch@linaro.org Received-SPF: pass (google.com: best guess record for domain of linux-gpio-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; From: Linus Walleij <linus.walleij@linaro.org> To: linux-gpio@vger.kernel.org, Alexandre Courbot <acourbot@nvidia.com>, Johan Hovold <johan@kernel.org>, Michael Welling <mwelling@ieee.org>, Markus Pargmann <mpa@pengutronix.de> Cc: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>, Grant Likely <grant.likely@linaro.org>, Linus Walleij <linus.walleij@linaro.org> Subject: [PATCH v2] gpio: add userspace ABI for GPIO line information Date: Mon, 15 Feb 2016 14:20:35 +0100 Message-Id: <1455542435-3182-1-git-send-email-linus.walleij@linaro.org> Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index a022e9249f69..a38265dec794 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -331,14 +331,15 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) struct gpio_device *gdev = filp->private_data; struct gpio_chip *chip = gdev->chip; int __user *ip = (int __user *)arg; - struct gpiochip_info chipinfo; /* We fail any subsequent ioctl():s when the chip is gone */ if (!chip) return -ENODEV; + /* Fill in the struct and pass to userspace */ if (cmd == GPIO_GET_CHIPINFO_IOCTL) { - /* Fill in the struct and pass to userspace */ + struct gpiochip_info chipinfo; + strncpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name)); chipinfo.name[sizeof(chipinfo.name)-1] = '\0'; @@ -349,6 +350,52 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) if (copy_to_user(ip, &chipinfo, sizeof(chipinfo))) return -EFAULT; return 0; + } else if (cmd == GPIO_GET_LINEINFO_IOCTL) { + struct gpioline_info lineinfo; + struct gpio_desc *desc; + + if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) + return -EFAULT; + if (lineinfo.line_offset > gdev->ngpio) + return -EINVAL; + + desc = &gdev->descs[lineinfo.line_offset]; + if (desc->name) { + strncpy(lineinfo.name, desc->name, + sizeof(lineinfo.name)); + lineinfo.name[sizeof(lineinfo.name)-1] = '\0'; + } else { + lineinfo.name[0] = '\0'; + } + if (desc->label) { + strncpy(lineinfo.label, desc->label, + sizeof(lineinfo.label)); + lineinfo.label[sizeof(lineinfo.label)-1] = '\0'; + } else { + lineinfo.label[0] = '\0'; + } + + /* + * Userspace only need to know that the kernel is using + * this GPIO so it can't use it. + */ + lineinfo.flags = 0; + if (desc->flags & (FLAG_REQUESTED | FLAG_IS_HOGGED | + FLAG_USED_AS_IRQ | FLAG_EXPORT | + FLAG_SYSFS)) + lineinfo.flags |= GPIOLINE_FLAG_KERNEL; + if (desc->flags & FLAG_IS_OUT) + lineinfo.flags |= GPIOLINE_FLAG_IS_OUT; + if (desc->flags & FLAG_ACTIVE_LOW) + lineinfo.flags |= GPIOLINE_FLAG_ACTIVE_LOW; + if (desc->flags & FLAG_OPEN_DRAIN) + lineinfo.flags |= GPIOLINE_FLAG_OPEN_DRAIN; + if (desc->flags & FLAG_OPEN_SOURCE) + lineinfo.flags |= GPIOLINE_FLAG_OPEN_SOURCE; + + if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) + return -EFAULT; + return 0; } return -EINVAL; } diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h index 3f93e1bcd3dd..416ce47f2291 100644 --- a/include/uapi/linux/gpio.h +++ b/include/uapi/linux/gpio.h @@ -25,6 +25,32 @@ struct gpiochip_info { __u32 lines; }; +/* Line is in use by the kernel */ +#define GPIOLINE_FLAG_KERNEL (1UL << 0) +#define GPIOLINE_FLAG_IS_OUT (1UL << 1) +#define GPIOLINE_FLAG_ACTIVE_LOW (1UL << 2) +#define GPIOLINE_FLAG_OPEN_DRAIN (1UL << 3) +#define GPIOLINE_FLAG_OPEN_SOURCE (1UL << 4) + +/** + * struct gpioline_info - Information about a certain GPIO line + * @line_offset: the local offset on this GPIO device, fill in when + * requesting information from the kernel + * @flags: various flags for this line + * @name: the name of this GPIO line + * @label: a functional name for this GPIO line + * @kernel: this GPIO is in use by the kernel + * @out: this GPIO is an output line (false means it is an input) + * @active_low: this GPIO is active low + */ +struct gpioline_info { + __u32 line_offset; + __u32 flags; + char name[32]; + char label[32]; +}; + #define GPIO_GET_CHIPINFO_IOCTL _IOR('o', 0x01, struct gpiochip_info) +#define GPIO_GET_LINEINFO_IOCTL _IOWR('o', 0x02, struct gpioline_info) #endif /* _UAPI_GPIO_H_ */ diff --git a/tools/gpio/gpio-utils.h b/tools/gpio/gpio-utils.h index b18209a45ad3..5f57133b8c04 100644 --- a/tools/gpio/gpio-utils.h +++ b/tools/gpio/gpio-utils.h @@ -16,6 +16,8 @@ #include <string.h> +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) + static inline int check_prefix(const char *str, const char *prefix) { return strlen(str) > strlen(prefix) && diff --git a/tools/gpio/lsgpio.c b/tools/gpio/lsgpio.c index 692233f561fb..5535ce81f8f7 100644 --- a/tools/gpio/lsgpio.c +++ b/tools/gpio/lsgpio.c @@ -26,12 +26,56 @@ #include "gpio-utils.h" +struct gpio_flag { + char *name; + unsigned long mask; +}; + +struct gpio_flag flagnames[] = { + { + .name = "kernel", + .mask = GPIOLINE_FLAG_KERNEL, + }, + { + .name = "output", + .mask = GPIOLINE_FLAG_IS_OUT, + }, + { + .name = "active-low", + .mask = GPIOLINE_FLAG_ACTIVE_LOW, + }, + { + .name = "open-drain", + .mask = GPIOLINE_FLAG_OPEN_DRAIN, + }, + { + .name = "open-source", + .mask = GPIOLINE_FLAG_OPEN_SOURCE, + }, +}; + +void print_flags(unsigned long flags) +{ + int i; + int printed = 0; + + for (i = 0; i < ARRAY_SIZE(flagnames); i++) { + if (flags & flagnames[i].mask) { + if (printed) + fprintf(stdout, " "); + fprintf(stdout, "%s", flagnames[i].name); + printed++; + } + } +} + int list_device(const char *device_name) { struct gpiochip_info cinfo; char *chrdev_name; int fd; int ret; + int i; ret = asprintf(&chrdev_name, "/dev/%s", device_name); if (ret < 0) @@ -41,32 +85,55 @@ int list_device(const char *device_name) if (fd == -1) { ret = -errno; fprintf(stderr, "Failed to open %s\n", chrdev_name); - goto free_chrdev_name; + goto exit_close_error; } /* Inspect this GPIO chip */ ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo); if (ret == -1) { ret = -errno; - fprintf(stderr, "Failed to retrieve GPIO fd\n"); - if (close(fd) == -1) - perror("Failed to close GPIO character device file"); - - goto free_chrdev_name; + perror("Failed to issue CHIPINFO IOCTL\n"); + goto exit_close_error; } fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n", cinfo.name, cinfo.label, cinfo.lines); - if (close(fd) == -1) { - ret = -errno; - goto free_chrdev_name; + /* Loop over the lines and print info */ + for (i = 0; i < cinfo.lines; i++) { + struct gpioline_info linfo; + + memset(&linfo, 0, sizeof(linfo)); + linfo.line_offset = i; + + ret = ioctl(fd, GPIO_GET_LINEINFO_IOCTL, &linfo); + if (ret == -1) { + ret = -errno; + perror("Failed to issue LINEINFO IOCTL\n"); + goto exit_close_error; + } + fprintf(stdout, "\tline %d:", linfo.line_offset); + if (linfo.name[0]) + fprintf(stdout, " %s", linfo.name); + else + fprintf(stdout, " unnamed"); + if (linfo.label[0]) + fprintf(stdout, " \"%s\"", linfo.label); + else + fprintf(stdout, " unlabeled"); + if (linfo.flags) { + fprintf(stdout, " ["); + print_flags(linfo.flags); + fprintf(stdout, "]"); + } + fprintf(stdout, "\n"); + } -free_chrdev_name: +exit_close_error: + if (close(fd) == -1) + perror("Failed to close GPIO character device file"); free(chrdev_name); - return ret; - } void print_usage(void)

[v2] gpio: add userspace ABI for GPIO line information

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