u-boot/drivers/gpio/gpio-uclass.c
Simon Glass e5901c94e3 dm: gpio: Add a function to read an ID from a list of GPIOs
For board IDs a common approach is to set aside several GPIOs for use in
determining the board ID. This can provide information about board features
and the revision.

Add a function that turns a list of GPIOs into an integer by assigning
each GPIO to a single bit.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-11-21 07:24:11 +01:00

469 lines
11 KiB
C

/*
* Copyright (c) 2013 Google, Inc
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <malloc.h>
#include <asm/gpio.h>
#include <linux/ctype.h>
/**
* gpio_to_device() - Convert global GPIO number to device, number
* gpio: The numeric representation of the GPIO
*
* Convert the GPIO number to an entry in the list of GPIOs
* or GPIO blocks registered with the GPIO controller. Returns
* entry on success, NULL on error.
*/
static int gpio_to_device(unsigned int gpio, struct udevice **devp,
unsigned int *offset)
{
struct gpio_dev_priv *uc_priv;
struct udevice *dev;
int ret;
for (ret = uclass_first_device(UCLASS_GPIO, &dev);
dev;
ret = uclass_next_device(&dev)) {
uc_priv = dev->uclass_priv;
if (gpio >= uc_priv->gpio_base &&
gpio < uc_priv->gpio_base + uc_priv->gpio_count) {
*devp = dev;
*offset = gpio - uc_priv->gpio_base;
return 0;
}
}
/* No such GPIO */
return ret ? ret : -EINVAL;
}
int gpio_lookup_name(const char *name, struct udevice **devp,
unsigned int *offsetp, unsigned int *gpiop)
{
struct gpio_dev_priv *uc_priv = NULL;
struct udevice *dev;
ulong offset;
int numeric;
int ret;
if (devp)
*devp = NULL;
numeric = isdigit(*name) ? simple_strtoul(name, NULL, 10) : -1;
for (ret = uclass_first_device(UCLASS_GPIO, &dev);
dev;
ret = uclass_next_device(&dev)) {
int len;
uc_priv = dev->uclass_priv;
if (numeric != -1) {
offset = numeric - uc_priv->gpio_base;
/* Allow GPIOs to be numbered from 0 */
if (offset >= 0 && offset < uc_priv->gpio_count)
break;
}
len = uc_priv->bank_name ? strlen(uc_priv->bank_name) : 0;
if (!strncasecmp(name, uc_priv->bank_name, len)) {
if (!strict_strtoul(name + len, 10, &offset))
break;
}
}
if (!dev)
return ret ? ret : -EINVAL;
if (devp)
*devp = dev;
if (offsetp)
*offsetp = offset;
if (gpiop)
*gpiop = uc_priv->gpio_base + offset;
return 0;
}
/**
* gpio_request() - [COMPAT] Request GPIO
* gpio: GPIO number
* label: Name for the requested GPIO
*
* The label is copied and allocated so the caller does not need to keep
* the pointer around.
*
* This function implements the API that's compatible with current
* GPIO API used in U-Boot. The request is forwarded to particular
* GPIO driver. Returns 0 on success, negative value on error.
*/
int gpio_request(unsigned gpio, const char *label)
{
struct gpio_dev_priv *uc_priv;
unsigned int offset;
struct udevice *dev;
char *str;
int ret;
ret = gpio_to_device(gpio, &dev, &offset);
if (ret)
return ret;
uc_priv = dev->uclass_priv;
if (uc_priv->name[offset])
return -EBUSY;
str = strdup(label);
if (!str)
return -ENOMEM;
if (gpio_get_ops(dev)->request) {
ret = gpio_get_ops(dev)->request(dev, offset, label);
if (ret) {
free(str);
return ret;
}
}
uc_priv->name[offset] = str;
return 0;
}
/**
* gpio_requestf() - [COMPAT] Request GPIO
* @gpio: GPIO number
* @fmt: Format string for the requested GPIO
* @...: Arguments for the printf() format string
*
* This function implements the API that's compatible with current
* GPIO API used in U-Boot. The request is forwarded to particular
* GPIO driver. Returns 0 on success, negative value on error.
*/
int gpio_requestf(unsigned gpio, const char *fmt, ...)
{
va_list args;
char buf[40];
va_start(args, fmt);
vscnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
return gpio_request(gpio, buf);
}
/**
* gpio_free() - [COMPAT] Relinquish GPIO
* gpio: GPIO number
*
* This function implements the API that's compatible with current
* GPIO API used in U-Boot. The request is forwarded to particular
* GPIO driver. Returns 0 on success, negative value on error.
*/
int gpio_free(unsigned gpio)
{
struct gpio_dev_priv *uc_priv;
unsigned int offset;
struct udevice *dev;
int ret;
ret = gpio_to_device(gpio, &dev, &offset);
if (ret)
return ret;
uc_priv = dev->uclass_priv;
if (!uc_priv->name[offset])
return -ENXIO;
if (gpio_get_ops(dev)->free) {
ret = gpio_get_ops(dev)->free(dev, offset);
if (ret)
return ret;
}
free(uc_priv->name[offset]);
uc_priv->name[offset] = NULL;
return 0;
}
static int check_reserved(struct udevice *dev, unsigned offset,
const char *func)
{
struct gpio_dev_priv *uc_priv = dev->uclass_priv;
if (!uc_priv->name[offset]) {
printf("%s: %s: error: gpio %s%d not reserved\n",
dev->name, func,
uc_priv->bank_name ? uc_priv->bank_name : "", offset);
return -EBUSY;
}
return 0;
}
/**
* gpio_direction_input() - [COMPAT] Set GPIO direction to input
* gpio: GPIO number
*
* This function implements the API that's compatible with current
* GPIO API used in U-Boot. The request is forwarded to particular
* GPIO driver. Returns 0 on success, negative value on error.
*/
int gpio_direction_input(unsigned gpio)
{
unsigned int offset;
struct udevice *dev;
int ret;
ret = gpio_to_device(gpio, &dev, &offset);
if (ret)
return ret;
ret = check_reserved(dev, offset, "dir_input");
return ret ? ret : gpio_get_ops(dev)->direction_input(dev, offset);
}
/**
* gpio_direction_output() - [COMPAT] Set GPIO direction to output and set value
* gpio: GPIO number
* value: Logical value to be set on the GPIO pin
*
* This function implements the API that's compatible with current
* GPIO API used in U-Boot. The request is forwarded to particular
* GPIO driver. Returns 0 on success, negative value on error.
*/
int gpio_direction_output(unsigned gpio, int value)
{
unsigned int offset;
struct udevice *dev;
int ret;
ret = gpio_to_device(gpio, &dev, &offset);
if (ret)
return ret;
ret = check_reserved(dev, offset, "dir_output");
return ret ? ret :
gpio_get_ops(dev)->direction_output(dev, offset, value);
}
/**
* gpio_get_value() - [COMPAT] Sample GPIO pin and return it's value
* gpio: GPIO number
*
* This function implements the API that's compatible with current
* GPIO API used in U-Boot. The request is forwarded to particular
* GPIO driver. Returns the value of the GPIO pin, or negative value
* on error.
*/
int gpio_get_value(unsigned gpio)
{
unsigned int offset;
struct udevice *dev;
int ret;
ret = gpio_to_device(gpio, &dev, &offset);
if (ret)
return ret;
ret = check_reserved(dev, offset, "get_value");
return ret ? ret : gpio_get_ops(dev)->get_value(dev, offset);
}
/**
* gpio_set_value() - [COMPAT] Configure logical value on GPIO pin
* gpio: GPIO number
* value: Logical value to be set on the GPIO pin.
*
* This function implements the API that's compatible with current
* GPIO API used in U-Boot. The request is forwarded to particular
* GPIO driver. Returns 0 on success, negative value on error.
*/
int gpio_set_value(unsigned gpio, int value)
{
unsigned int offset;
struct udevice *dev;
int ret;
ret = gpio_to_device(gpio, &dev, &offset);
if (ret)
return ret;
ret = check_reserved(dev, offset, "set_value");
return ret ? ret : gpio_get_ops(dev)->set_value(dev, offset, value);
}
const char *gpio_get_bank_info(struct udevice *dev, int *bit_count)
{
struct gpio_dev_priv *priv;
/* Must be called on an active device */
priv = dev->uclass_priv;
assert(priv);
*bit_count = priv->gpio_count;
return priv->bank_name;
}
static const char * const gpio_function[GPIOF_COUNT] = {
"input",
"output",
"unused",
"unknown",
"func",
};
int get_function(struct udevice *dev, int offset, bool skip_unused,
const char **namep)
{
struct gpio_dev_priv *uc_priv = dev->uclass_priv;
struct dm_gpio_ops *ops = gpio_get_ops(dev);
BUILD_BUG_ON(GPIOF_COUNT != ARRAY_SIZE(gpio_function));
if (!device_active(dev))
return -ENODEV;
if (offset < 0 || offset >= uc_priv->gpio_count)
return -EINVAL;
if (namep)
*namep = uc_priv->name[offset];
if (skip_unused && !uc_priv->name[offset])
return GPIOF_UNUSED;
if (ops->get_function) {
int ret;
ret = ops->get_function(dev, offset);
if (ret < 0)
return ret;
if (ret >= ARRAY_SIZE(gpio_function))
return -ENODATA;
return ret;
}
return GPIOF_UNKNOWN;
}
int gpio_get_function(struct udevice *dev, int offset, const char **namep)
{
return get_function(dev, offset, true, namep);
}
int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep)
{
return get_function(dev, offset, false, namep);
}
int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize)
{
struct dm_gpio_ops *ops = gpio_get_ops(dev);
struct gpio_dev_priv *priv;
char *str = buf;
int func;
int ret;
int len;
BUILD_BUG_ON(GPIOF_COUNT != ARRAY_SIZE(gpio_function));
*buf = 0;
priv = dev->uclass_priv;
ret = gpio_get_raw_function(dev, offset, NULL);
if (ret < 0)
return ret;
func = ret;
len = snprintf(str, buffsize, "%s%d: %s",
priv->bank_name ? priv->bank_name : "",
offset, gpio_function[func]);
if (func == GPIOF_INPUT || func == GPIOF_OUTPUT ||
func == GPIOF_UNUSED) {
const char *label;
bool used;
ret = ops->get_value(dev, offset);
if (ret < 0)
return ret;
used = gpio_get_function(dev, offset, &label) != GPIOF_UNUSED;
snprintf(str + len, buffsize - len, ": %d [%c]%s%s",
ret,
used ? 'x' : ' ',
used ? " " : "",
label ? label : "");
}
return 0;
}
/*
* get a number comprised of multiple GPIO values. gpio_num_array points to
* the array of gpio pin numbers to scan, terminated by -1.
*/
unsigned gpio_get_values_as_int(const int *gpio_num_array)
{
int gpio;
unsigned bitmask = 1;
unsigned vector = 0;
while (bitmask &&
((gpio = *gpio_num_array++) != -1)) {
if (gpio_get_value(gpio))
vector |= bitmask;
bitmask <<= 1;
}
return vector;
}
/* We need to renumber the GPIOs when any driver is probed/removed */
static int gpio_renumber(struct udevice *removed_dev)
{
struct gpio_dev_priv *uc_priv;
struct udevice *dev;
struct uclass *uc;
unsigned base;
int ret;
ret = uclass_get(UCLASS_GPIO, &uc);
if (ret)
return ret;
/* Ensure that we have a base for each bank */
base = 0;
uclass_foreach_dev(dev, uc) {
if (device_active(dev) && dev != removed_dev) {
uc_priv = dev->uclass_priv;
uc_priv->gpio_base = base;
base += uc_priv->gpio_count;
}
}
return 0;
}
static int gpio_post_probe(struct udevice *dev)
{
struct gpio_dev_priv *uc_priv = dev->uclass_priv;
uc_priv->name = calloc(uc_priv->gpio_count, sizeof(char *));
if (!uc_priv->name)
return -ENOMEM;
return gpio_renumber(NULL);
}
static int gpio_pre_remove(struct udevice *dev)
{
struct gpio_dev_priv *uc_priv = dev->uclass_priv;
int i;
for (i = 0; i < uc_priv->gpio_count; i++) {
if (uc_priv->name[i])
free(uc_priv->name[i]);
}
free(uc_priv->name);
return gpio_renumber(dev);
}
UCLASS_DRIVER(gpio) = {
.id = UCLASS_GPIO,
.name = "gpio",
.post_probe = gpio_post_probe,
.pre_remove = gpio_pre_remove,
.per_device_auto_alloc_size = sizeof(struct gpio_dev_priv),
};