我正在查看内核源代码，并在 drivers/gpio/ 目录中找到了这个用于 Raspberry Pi 的 gpio 驱动程序
关于这个以及与使用 GPIO 线路编程相关的应用程序，我有几个问题。首先，如果我没有混淆，任何人都可以区分应用程序代码中提到的 gpio 行和 gpio 引脚之间的区别。他们一样吗。我相信是这样
但我的主要问题在于以下驱动程序代码/（或者它也称为固件？）它使用这个结构定义
static const struct of_device_id rpi_exp_gpio_ids[] = {
{ .compatible = "raspberrypi,firmware-gpio" },
{ }
}
以上of_device_id是否与从我的以下代码固件导出到 linux OS 的 pci_device_id 相同？所以肯定是有GPIO核心的，在linux内核哪里可以找到GPIO核心的代码
和这个结构struct rpi_exp_gpio *rpi_gpio;，所以它有这五个函数作为函数指针
rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in;
rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out;
rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction;
rpi_gpio->gc.get = rpi_exp_gpio_get;
rpi_gpio->gc.set = rpi_exp_gpio_set;
所以谁能告诉我kernel.org页面，这解释了上面的函数指针成员，rpi_gpio如果我使用不同版本的树莓派，那么在这种情况下，我需要为此编辑我的struct of_device_id对象吗，linux如何区分不同的pi版本
所以我想知道如果我有一个执行ioctl的应用程序，那么下面的驱动程序没有实现ioctl，这是否意味着我下面的应用程序代码将不起作用
司机
#include <linux/err.h>
#include <linux/gpio/driver.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <soc/bcm2835/raspberrypi-firmware.h>
#define MODULE_NAME "raspberrypi-exp-gpio"
#define NUM_GPIO 8
#define RPI_EXP_GPIO_BASE 128
#define RPI_EXP_GPIO_DIR_IN 0
#define RPI_EXP_GPIO_DIR_OUT 1
struct rpi_exp_gpio {
struct gpio_chip gc;
struct rpi_firmware *fw;
};
/* VC4 firmware mailbox interface data structures */
struct gpio_set_config {
u32 gpio;
u32 direction;
u32 polarity;
u32 term_en;
u32 term_pull_up;
u32 state;
};
struct gpio_get_config {
u32 gpio;
u32 direction;
u32 polarity;
u32 term_en;
u32 term_pull_up;
};
struct gpio_get_set_state {
u32 gpio;
u32 state;
};
static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off)
{
struct rpi_exp_gpio *gpio;
struct gpio_get_config get;
int ret;
gpio = gpiochip_get_data(gc);
get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
&get, sizeof(get));
if (ret || get.gpio != 0) {
dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n",
off, ret, get.gpio);
return ret ? ret : -EIO;
}
return get.polarity;
}
static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off)
{
struct rpi_exp_gpio *gpio;
struct gpio_set_config set_in;
int ret;
gpio = gpiochip_get_data(gc);
set_in.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
set_in.direction = RPI_EXP_GPIO_DIR_IN;
set_in.term_en = 0; /* termination disabled */
set_in.term_pull_up = 0; /* n/a as termination disabled */
set_in.state = 0; /* n/a as configured as an input */
ret = rpi_exp_gpio_get_polarity(gc, off);
if (ret < 0)
return ret;
set_in.polarity = ret; /* Retain existing setting */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,
&set_in, sizeof(set_in));
if (ret || set_in.gpio != 0) {
dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n",
off, ret, set_in.gpio);
return ret ? ret : -EIO;
}
return 0;
}
static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val)
{
struct rpi_exp_gpio *gpio;
struct gpio_set_config set_out;
int ret;
gpio = gpiochip_get_data(gc);
set_out.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
set_out.direction = RPI_EXP_GPIO_DIR_OUT;
set_out.term_en = 0; /* n/a as an output */
set_out.term_pull_up = 0; /* n/a as termination disabled */
set_out.state = val; /* Output state */
ret = rpi_exp_gpio_get_polarity(gc, off);
if (ret < 0)
return ret;
set_out.polarity = ret; /* Retain existing setting */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,
&set_out, sizeof(set_out));
if (ret || set_out.gpio != 0) {
dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n",
off, ret, set_out.gpio);
return ret ? ret : -EIO;
}
return 0;
}
static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
{
struct rpi_exp_gpio *gpio;
struct gpio_get_config get;
int ret;
gpio = gpiochip_get_data(gc);
get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
&get, sizeof(get));
if (ret || get.gpio != 0) {
dev_err(gc->parent,
"Failed to get GPIO %u config (%d %x)\n", off, ret,
get.gpio);
return ret ? ret : -EIO;
}
if (get.direction)
return GPIO_LINE_DIRECTION_OUT;
return GPIO_LINE_DIRECTION_IN;
}
static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off)
{
struct rpi_exp_gpio *gpio;
struct gpio_get_set_state get;
int ret;
gpio = gpiochip_get_data(gc);
get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
get.state = 0; /* storage for returned value */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE,
&get, sizeof(get));
if (ret || get.gpio != 0) {
dev_err(gc->parent,
"Failed to get GPIO %u state (%d %x)\n", off, ret,
get.gpio);
return ret ? ret : -EIO;
}
return !!get.state;
}
static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
{
struct rpi_exp_gpio *gpio;
struct gpio_get_set_state set;
int ret;
gpio = gpiochip_get_data(gc);
set.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
set.state = val; /* Output state */
ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE,
&set, sizeof(set));
if (ret || set.gpio != 0)
dev_err(gc->parent,
"Failed to set GPIO %u state (%d %x)\n", off, ret,
set.gpio);
}
static int rpi_exp_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct device_node *fw_node;
struct rpi_firmware *fw;
struct rpi_exp_gpio *rpi_gpio;
fw_node = of_get_parent(np);
if (!fw_node) {
dev_err(dev, "Missing firmware node\n");
return -ENOENT;
}
fw = devm_rpi_firmware_get(&pdev->dev, fw_node);
of_node_put(fw_node);
if (!fw)
return -EPROBE_DEFER;
rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL);
if (!rpi_gpio)
return -ENOMEM;
rpi_gpio->fw = fw;
rpi_gpio->gc.parent = dev;
rpi_gpio->gc.label = MODULE_NAME;
rpi_gpio->gc.owner = THIS_MODULE;
rpi_gpio->gc.of_node = np;
rpi_gpio->gc.base = -1;
rpi_gpio->gc.ngpio = NUM_GPIO;
rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in;
rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out;
rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction;
rpi_gpio->gc.get = rpi_exp_gpio_get;
rpi_gpio->gc.set = rpi_exp_gpio_set;
rpi_gpio->gc.can_sleep = true;
return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio);
}
static const struct of_device_id rpi_exp_gpio_ids[] = {
{ .compatible = "raspberrypi,firmware-gpio" },
{ }
};
MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids);
static struct platform_driver rpi_exp_gpio_driver = {
.driver = {
.name = MODULE_NAME,
.of_match_table = of_match_ptr(rpi_exp_gpio_ids),
},
.probe = rpi_exp_gpio_probe,
};
module_platform_driver(rpi_exp_gpio_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>");
MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver");
MODULE_ALIAS("platform:rpi-exp-gpio");
GPIO 应用
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/gpio.h>
#define CONSUMER "gpio-mockup-cdev"
static int request_line_v2(int cfd, unsigned int offset,
uint64_t flags, unsigned int val)
{
struct gpio_v2_line_request req;
int ret;
memset(&req, 0, sizeof(req));
req.num_lines = 1;
req.offsets[0] = offset;
req.config.flags = flags;
strcpy(req.consumer, CONSUMER);
if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
req.config.num_attrs = 1;
req.config.attrs[0].mask = 1;
req.config.attrs[0].attr.id = GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES;
if (val)
req.config.attrs[0].attr.values = 1;
}
ret = ioctl(cfd, GPIO_V2_GET_LINE_IOCTL, &req);
if (ret == -1)
return -errno;
return req.fd;
}
static int get_value_v2(int lfd)
{
struct gpio_v2_line_values vals;
int ret;
memset(&vals, 0, sizeof(vals));
vals.mask = 1;
ret = ioctl(lfd, GPIO_V2_LINE_GET_VALUES_IOCTL, &vals);
if (ret == -1)
return -errno;
return vals.bits & 0x1;
}
static int request_line_v1(int cfd, unsigned int offset,
uint32_t flags, unsigned int val)
{
struct gpiohandle_request req;
int ret;
memset(&req, 0, sizeof(req));
req.lines = 1;
req.lineoffsets[0] = offset;
req.flags = flags;
strcpy(req.consumer_label, CONSUMER);
if (flags & GPIOHANDLE_REQUEST_OUTPUT)
req.default_values[0] = val;
ret = ioctl(cfd, GPIO_GET_LINEHANDLE_IOCTL, &req);
if (ret == -1)
return -errno;
return req.fd;
}
static int get_value_v1(int lfd)
{
struct gpiohandle_data vals;
int ret;
memset(&vals, 0, sizeof(vals));
ret = ioctl(lfd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &vals);
if (ret == -1)
return -errno;
return vals.values[0];
}
static void usage(char *prog)
{
printf("Usage: %s [-l] [-b <bias>] [-s <value>] [-u <uAPI>] <gpiochip> <offset>\n", prog);
printf(" -b: set line bias to one of pull-down, pull-up, disabled\n");
printf(" (default is to leave bias unchanged):\n");
printf(" -l: set line active low (default is active high)\n");
printf(" -s: set line value (default is to get line value)\n");
printf(" -u: uAPI version to use (default is 2)\n");
exit(-1);
}
static int wait_signal(void)
{
int sig;
sigset_t wset;
sigemptyset(&wset);
sigaddset(&wset, SIGHUP);
sigaddset(&wset, SIGINT);
sigaddset(&wset, SIGTERM);
sigwait(&wset, &sig);
return sig;
}
int main(int argc, char *argv[])
{
char *chip;
int opt, ret, cfd, lfd;
unsigned int offset, val, abiv;
uint32_t flags_v1;
uint64_t flags_v2;
abiv = 2;
ret = 0;
flags_v1 = GPIOHANDLE_REQUEST_INPUT;
flags_v2 = GPIO_V2_LINE_FLAG_INPUT;
while ((opt = getopt(argc, argv, "lb:s:u:")) != -1) {
switch (opt) {
case 'l':
flags_v1 |= GPIOHANDLE_REQUEST_ACTIVE_LOW;
flags_v2 |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
break;
case 'b':
if (strcmp("pull-up", optarg) == 0) {
flags_v1 |= GPIOHANDLE_REQUEST_BIAS_PULL_UP;
flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
} else if (strcmp("pull-down", optarg) == 0) {
flags_v1 |= GPIOHANDLE_REQUEST_BIAS_PULL_DOWN;
flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
} else if (strcmp("disabled", optarg) == 0) {
flags_v1 |= GPIOHANDLE_REQUEST_BIAS_DISABLE;
flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
}
break;
case 's':
val = atoi(optarg);
flags_v1 &= ~GPIOHANDLE_REQUEST_INPUT;
flags_v1 |= GPIOHANDLE_REQUEST_OUTPUT;
flags_v2 &= ~GPIO_V2_LINE_FLAG_INPUT;
flags_v2 |= GPIO_V2_LINE_FLAG_OUTPUT;
break;
case 'u':
abiv = atoi(optarg);
break;
default:
usage(argv[0]);
}
}
if (argc < optind + 2)
usage(argv[0]);
chip = argv[optind];
offset = atoi(argv[optind + 1]);
cfd = open(chip, 0);
if (cfd == -1) {
fprintf(stderr, "Failed to open %s: %s\n", chip, strerror(errno));
return -errno;
}
if (abiv == 1)
lfd = request_line_v1(cfd, offset, flags_v1, val);
else
lfd = request_line_v2(cfd, offset, flags_v2, val);
close(cfd);
if (lfd < 0) {
fprintf(stderr, "Failed to request %s:%d: %s\n", chip, offset, strerror(-lfd));
return lfd;
}
if (flags_v2 & GPIO_V2_LINE_FLAG_OUTPUT) {
wait_signal();
} else {
if (abiv == 1)
ret = get_value_v1(lfd);
else
ret = get_value_v2(lfd);
}
close(lfd);
return ret;
}