u-boot/cmd/gpio.c
Diego Rondini dd2b8c1155 cmd: gpio: Add gpio read subcommand
As explained in commit 4af2a33ee5 ("cmd: gpio: Make `gpio input`
return pin value again") the `gpio input` is used in scripts to obtain
the value of a pin, despite the fact that CMD_RET_FAILURE is
indistinguishable from a valid pin value.
To be able to detect failures and properly use the value of a GPIO in
scripts we introduce the `gpio read` command that sets the variable
`name` to the value of the pin. Return code of the `gpio read` command
can be used to check for CMD_RET_SUCCESS or CMD_RET_FAILURE.
CONFIG_CMD_GPIO_READ is used to enable the `gpio read` command.

Signed-off-by: Diego Rondini <diego.rondini@kynetics.com>
2022-04-20 11:14:39 -04:00

309 lines
6.4 KiB
C

/*
* Control GPIO pins on the fly
*
* Copyright (c) 2008-2011 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <common.h>
#include <command.h>
#include <errno.h>
#include <dm.h>
#include <log.h>
#include <malloc.h>
#ifdef CONFIG_CMD_GPIO_READ
#include <env.h>
#endif
#include <asm/gpio.h>
#include <linux/err.h>
__weak int name_to_gpio(const char *name)
{
return dectoul(name, NULL);
}
enum gpio_cmd {
GPIOC_INPUT,
GPIOC_SET,
GPIOC_CLEAR,
GPIOC_TOGGLE,
#ifdef CONFIG_CMD_GPIO_READ
GPIOC_READ,
#endif
};
#if defined(CONFIG_DM_GPIO) && !defined(gpio_status)
/* A few flags used by show_gpio() */
enum {
FLAG_SHOW_ALL = 1 << 0,
FLAG_SHOW_BANK = 1 << 1,
FLAG_SHOW_NEWLINE = 1 << 2,
};
static void gpio_get_description(struct udevice *dev, const char *bank_name,
int offset, int *flagsp, bool show_all)
{
char buf[80];
int ret;
ret = gpio_get_function(dev, offset, NULL);
if (ret < 0)
goto err;
if (!show_all && !(*flagsp & FLAG_SHOW_ALL) && ret == GPIOF_UNUSED)
return;
if ((*flagsp & FLAG_SHOW_BANK) && bank_name) {
if (*flagsp & FLAG_SHOW_NEWLINE) {
putc('\n');
*flagsp &= ~FLAG_SHOW_NEWLINE;
}
printf("Bank %s:\n", bank_name);
*flagsp &= ~FLAG_SHOW_BANK;
}
ret = gpio_get_status(dev, offset, buf, sizeof(buf));
if (ret)
goto err;
printf("%s\n", buf);
return;
err:
printf("Error %d\n", ret);
}
static int do_gpio_status(bool all, const char *gpio_name)
{
struct udevice *dev;
int banklen;
int flags;
int ret;
flags = 0;
if (gpio_name && !*gpio_name)
gpio_name = NULL;
for (ret = uclass_first_device(UCLASS_GPIO, &dev);
dev;
ret = uclass_next_device(&dev)) {
const char *bank_name;
int num_bits;
flags |= FLAG_SHOW_BANK;
if (all)
flags |= FLAG_SHOW_ALL;
bank_name = gpio_get_bank_info(dev, &num_bits);
if (!num_bits) {
debug("GPIO device %s has no bits\n", dev->name);
continue;
}
banklen = bank_name ? strlen(bank_name) : 0;
if (!gpio_name || !bank_name ||
!strncasecmp(gpio_name, bank_name, banklen)) {
const char *p;
int offset;
p = gpio_name + banklen;
if (gpio_name && *p) {
offset = dectoul(p, NULL);
gpio_get_description(dev, bank_name, offset,
&flags, true);
} else {
for (offset = 0; offset < num_bits; offset++) {
gpio_get_description(dev, bank_name,
offset, &flags, false);
}
}
}
/* Add a newline between bank names */
if (!(flags & FLAG_SHOW_BANK))
flags |= FLAG_SHOW_NEWLINE;
}
return ret;
}
#endif
static int do_gpio(struct cmd_tbl *cmdtp, int flag, int argc,
char *const argv[])
{
unsigned int gpio;
enum gpio_cmd sub_cmd;
int value;
const char *str_cmd, *str_gpio = NULL;
#ifdef CONFIG_CMD_GPIO_READ
const char *str_var = NULL;
#endif
int ret;
#ifdef CONFIG_DM_GPIO
bool all = false;
#endif
if (argc < 2)
show_usage:
return CMD_RET_USAGE;
str_cmd = argv[1];
argc -= 2;
argv += 2;
#ifdef CONFIG_DM_GPIO
if (argc > 0 && !strncmp(str_cmd, "status", 2) && !strcmp(*argv, "-a")) {
all = true;
argc--;
argv++;
}
#endif
#ifdef CONFIG_CMD_GPIO_READ
if (argc > 0 && !strncmp(str_cmd, "read", 2)) {
if (argc < 2)
goto show_usage;
str_var = *argv;
argc--;
argv++;
}
#endif
if (argc > 0)
str_gpio = *argv;
if (!strncmp(str_cmd, "status", 2)) {
/* Support deprecated gpio_status() */
#ifdef gpio_status
gpio_status();
return 0;
#elif defined(CONFIG_DM_GPIO)
return cmd_process_error(cmdtp, do_gpio_status(all, str_gpio));
#else
goto show_usage;
#endif
}
if (!str_gpio)
goto show_usage;
/* parse the behavior */
switch (*str_cmd) {
case 'i':
sub_cmd = GPIOC_INPUT;
break;
case 's':
sub_cmd = GPIOC_SET;
break;
case 'c':
sub_cmd = GPIOC_CLEAR;
break;
case 't':
sub_cmd = GPIOC_TOGGLE;
break;
#ifdef CONFIG_CMD_GPIO_READ
case 'r':
sub_cmd = GPIOC_READ;
break;
#endif
default:
goto show_usage;
}
#if defined(CONFIG_DM_GPIO)
/*
* TODO(sjg@chromium.org): For now we must fit into the existing GPIO
* framework, so we look up the name here and convert it to a GPIO number.
* Once all GPIO drivers are converted to driver model, we can change the
* code here to use the GPIO uclass interface instead of the numbered
* GPIO compatibility layer.
*/
ret = gpio_lookup_name(str_gpio, NULL, NULL, &gpio);
if (ret) {
printf("GPIO: '%s' not found\n", str_gpio);
return cmd_process_error(cmdtp, ret);
}
#else
/* turn the gpio name into a gpio number */
gpio = name_to_gpio(str_gpio);
if (gpio < 0)
goto show_usage;
#endif
/* grab the pin before we tweak it */
ret = gpio_request(gpio, "cmd_gpio");
if (ret && ret != -EBUSY) {
printf("gpio: requesting pin %u failed\n", gpio);
return -1;
}
/* finally, let's do it: set direction and exec command */
if (sub_cmd == GPIOC_INPUT
#ifdef CONFIG_CMD_GPIO_READ
|| sub_cmd == GPIOC_READ
#endif
) {
gpio_direction_input(gpio);
value = gpio_get_value(gpio);
} else {
switch (sub_cmd) {
case GPIOC_SET:
value = 1;
break;
case GPIOC_CLEAR:
value = 0;
break;
case GPIOC_TOGGLE:
value = gpio_get_value(gpio);
if (!IS_ERR_VALUE(value))
value = !value;
break;
default:
goto show_usage;
}
gpio_direction_output(gpio, value);
}
printf("gpio: pin %s (gpio %u) value is ", str_gpio, gpio);
if (IS_ERR_VALUE(value)) {
printf("unknown (ret=%d)\n", value);
goto err;
} else {
printf("%d\n", value);
#ifdef CONFIG_CMD_GPIO_READ
if (sub_cmd == GPIOC_READ)
env_set_ulong(str_var, (ulong)value);
#endif
}
if (sub_cmd != GPIOC_INPUT && !IS_ERR_VALUE(value)
#ifdef CONFIG_CMD_GPIO_READ
&& sub_cmd != GPIOC_READ
#endif
) {
int nval = gpio_get_value(gpio);
if (IS_ERR_VALUE(nval)) {
printf(" Warning: no access to GPIO output value\n");
goto err;
} else if (nval != value) {
printf(" Warning: value of pin is still %d\n", nval);
goto err;
}
}
if (ret != -EBUSY)
gpio_free(gpio);
/*
* Whilst wrong, the legacy gpio input command returns the pin
* value, or CMD_RET_FAILURE (which is indistinguishable from a
* valid pin value).
*/
return (sub_cmd == GPIOC_INPUT) ? value : CMD_RET_SUCCESS;
err:
if (ret != -EBUSY)
gpio_free(gpio);
return CMD_RET_FAILURE;
}
U_BOOT_CMD(gpio, 4, 0, do_gpio,
"query and control gpio pins",
"<input|set|clear|toggle> <pin>\n"
" - input/set/clear/toggle the specified pin\n"
#ifdef CONFIG_CMD_GPIO_READ
"gpio read <name> <pin>\n"
" - set environment variable 'name' to the specified pin\n"
#endif
"gpio status [-a] [<bank> | <pin>] - show [all/claimed] GPIOs");