u-boot/lib/fdtdec.c
Yen Lin 96a78ac0c4 tegra: i2c: Add I2C driver
Add basic i2c driver for Tegra2 with 8- and 16-bit address support.
The driver requires CONFIG_OF_CONTROL to obtain its configuration
from the device tree.

(Simon Glass: sjg@chromium.org modified for upstream)

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
2012-03-29 08:12:50 +02:00

451 lines
12 KiB
C

/*
* Copyright (c) 2011 The Chromium OS Authors.
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <serial.h>
#include <libfdt.h>
#include <fdtdec.h>
/* we need the generic GPIO interface here */
#include <asm-generic/gpio.h>
DECLARE_GLOBAL_DATA_PTR;
/*
* Here are the type we know about. One day we might allow drivers to
* register. For now we just put them here. The COMPAT macro allows us to
* turn this into a sparse list later, and keeps the ID with the name.
*/
#define COMPAT(id, name) name
static const char * const compat_names[COMPAT_COUNT] = {
COMPAT(UNKNOWN, "<none>"),
COMPAT(NVIDIA_TEGRA20_USB, "nvidia,tegra20-ehci"),
COMPAT(NVIDIA_TEGRA20_I2C, "nvidia,tegra20-i2c"),
COMPAT(NVIDIA_TEGRA20_DVC, "nvidia,tegra20-i2c-dvc"),
};
const char *fdtdec_get_compatible(enum fdt_compat_id id)
{
/* We allow reading of the 'unknown' ID for testing purposes */
assert(id >= 0 && id < COMPAT_COUNT);
return compat_names[id];
}
/**
* Look in the FDT for an alias with the given name and return its node.
*
* @param blob FDT blob
* @param name alias name to look up
* @return node offset if found, or an error code < 0 otherwise
*/
static int find_alias_node(const void *blob, const char *name)
{
const char *path;
int alias_node;
debug("find_alias_node: %s\n", name);
alias_node = fdt_path_offset(blob, "/aliases");
if (alias_node < 0)
return alias_node;
path = fdt_getprop(blob, alias_node, name, NULL);
if (!path)
return -FDT_ERR_NOTFOUND;
return fdt_path_offset(blob, path);
}
fdt_addr_t fdtdec_get_addr(const void *blob, int node,
const char *prop_name)
{
const fdt_addr_t *cell;
int len;
debug("get_addr: %s\n", prop_name);
cell = fdt_getprop(blob, node, prop_name, &len);
if (cell && (len == sizeof(fdt_addr_t) ||
len == sizeof(fdt_addr_t) * 2))
return fdt_addr_to_cpu(*cell);
return FDT_ADDR_T_NONE;
}
s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
s32 default_val)
{
const s32 *cell;
int len;
debug("get_size: %s\n", prop_name);
cell = fdt_getprop(blob, node, prop_name, &len);
if (cell && len >= sizeof(s32))
return fdt32_to_cpu(cell[0]);
return default_val;
}
int fdtdec_get_is_enabled(const void *blob, int node)
{
const char *cell;
/*
* It should say "okay", so only allow that. Some fdts use "ok" but
* this is a bug. Please fix your device tree source file. See here
* for discussion:
*
* http://www.mail-archive.com/u-boot@lists.denx.de/msg71598.html
*/
cell = fdt_getprop(blob, node, "status", NULL);
if (cell)
return 0 == strcmp(cell, "okay");
return 1;
}
enum fdt_compat_id fd_dec_lookup(const void *blob, int node)
{
enum fdt_compat_id id;
/* Search our drivers */
for (id = COMPAT_UNKNOWN; id < COMPAT_COUNT; id++)
if (0 == fdt_node_check_compatible(blob, node,
compat_names[id]))
return id;
return COMPAT_UNKNOWN;
}
int fdtdec_next_compatible(const void *blob, int node,
enum fdt_compat_id id)
{
return fdt_node_offset_by_compatible(blob, node, compat_names[id]);
}
int fdtdec_next_alias(const void *blob, const char *name,
enum fdt_compat_id id, int *upto)
{
#define MAX_STR_LEN 20
char str[MAX_STR_LEN + 20];
int node, err;
/* snprintf() is not available */
assert(strlen(name) < MAX_STR_LEN);
sprintf(str, "%.*s%d", MAX_STR_LEN, name, *upto);
node = find_alias_node(blob, str);
if (node < 0)
return node;
err = fdt_node_check_compatible(blob, node, compat_names[id]);
if (err < 0)
return err;
if (err)
return -FDT_ERR_NOTFOUND;
(*upto)++;
return node;
}
int fdtdec_find_aliases_for_id(const void *blob, const char *name,
enum fdt_compat_id id, int *node_list, int maxcount)
{
memset(node_list, '\0', sizeof(*node_list) * maxcount);
return fdtdec_add_aliases_for_id(blob, name, id, node_list, maxcount);
}
/* TODO: Can we tighten this code up a little? */
int fdtdec_add_aliases_for_id(const void *blob, const char *name,
enum fdt_compat_id id, int *node_list, int maxcount)
{
int name_len = strlen(name);
int nodes[maxcount];
int num_found = 0;
int offset, node;
int alias_node;
int count;
int i, j;
/* find the alias node if present */
alias_node = fdt_path_offset(blob, "/aliases");
/*
* start with nothing, and we can assume that the root node can't
* match
*/
memset(nodes, '\0', sizeof(nodes));
/* First find all the compatible nodes */
for (node = count = 0; node >= 0 && count < maxcount;) {
node = fdtdec_next_compatible(blob, node, id);
if (node >= 0)
nodes[count++] = node;
}
if (node >= 0)
debug("%s: warning: maxcount exceeded with alias '%s'\n",
__func__, name);
/* Now find all the aliases */
for (offset = fdt_first_property_offset(blob, alias_node);
offset > 0;
offset = fdt_next_property_offset(blob, offset)) {
const struct fdt_property *prop;
const char *path;
int number;
int found;
node = 0;
prop = fdt_get_property_by_offset(blob, offset, NULL);
path = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
if (prop->len && 0 == strncmp(path, name, name_len))
node = fdt_path_offset(blob, prop->data);
if (node <= 0)
continue;
/* Get the alias number */
number = simple_strtoul(path + name_len, NULL, 10);
if (number < 0 || number >= maxcount) {
debug("%s: warning: alias '%s' is out of range\n",
__func__, path);
continue;
}
/* Make sure the node we found is actually in our list! */
found = -1;
for (j = 0; j < count; j++)
if (nodes[j] == node) {
found = j;
break;
}
if (found == -1) {
debug("%s: warning: alias '%s' points to a node "
"'%s' that is missing or is not compatible "
" with '%s'\n", __func__, path,
fdt_get_name(blob, node, NULL),
compat_names[id]);
continue;
}
/*
* Add this node to our list in the right place, and mark
* it as done.
*/
if (fdtdec_get_is_enabled(blob, node)) {
if (node_list[number]) {
debug("%s: warning: alias '%s' requires that "
"a node be placed in the list in a "
"position which is already filled by "
"node '%s'\n", __func__, path,
fdt_get_name(blob, node, NULL));
continue;
}
node_list[number] = node;
if (number >= num_found)
num_found = number + 1;
}
nodes[found] = 0;
}
/* Add any nodes not mentioned by an alias */
for (i = j = 0; i < maxcount; i++) {
if (!node_list[i]) {
for (; j < maxcount; j++)
if (nodes[j] &&
fdtdec_get_is_enabled(blob, nodes[j]))
break;
/* Have we run out of nodes to add? */
if (j == maxcount)
break;
assert(!node_list[i]);
node_list[i] = nodes[j++];
if (i >= num_found)
num_found = i + 1;
}
}
return num_found;
}
int fdtdec_check_fdt(void)
{
/*
* We must have an FDT, but we cannot panic() yet since the console
* is not ready. So for now, just assert(). Boards which need an early
* FDT (prior to console ready) will need to make their own
* arrangements and do their own checks.
*/
assert(!fdtdec_prepare_fdt());
return 0;
}
/*
* This function is a little odd in that it accesses global data. At some
* point if the architecture board.c files merge this will make more sense.
* Even now, it is common code.
*/
int fdtdec_prepare_fdt(void)
{
if (((uintptr_t)gd->fdt_blob & 3) || fdt_check_header(gd->fdt_blob)) {
printf("No valid FDT found - please append one to U-Boot "
"binary, use u-boot-dtb.bin or define "
"CONFIG_OF_EMBED\n");
return -1;
}
return 0;
}
int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name)
{
const u32 *phandle;
int lookup;
phandle = fdt_getprop(blob, node, prop_name, NULL);
if (!phandle)
return -FDT_ERR_NOTFOUND;
lookup = fdt_node_offset_by_phandle(blob, fdt32_to_cpu(*phandle));
return lookup;
}
/**
* Look up a property in a node and check that it has a minimum length.
*
* @param blob FDT blob
* @param node node to examine
* @param prop_name name of property to find
* @param min_len minimum property length in bytes
* @param err 0 if ok, or -FDT_ERR_NOTFOUND if the property is not
found, or -FDT_ERR_BADLAYOUT if not enough data
* @return pointer to cell, which is only valid if err == 0
*/
static const void *get_prop_check_min_len(const void *blob, int node,
const char *prop_name, int min_len, int *err)
{
const void *cell;
int len;
debug("%s: %s\n", __func__, prop_name);
cell = fdt_getprop(blob, node, prop_name, &len);
if (!cell)
*err = -FDT_ERR_NOTFOUND;
else if (len < min_len)
*err = -FDT_ERR_BADLAYOUT;
else
*err = 0;
return cell;
}
int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
u32 *array, int count)
{
const u32 *cell;
int i, err = 0;
debug("%s: %s\n", __func__, prop_name);
cell = get_prop_check_min_len(blob, node, prop_name,
sizeof(u32) * count, &err);
if (!err) {
for (i = 0; i < count; i++)
array[i] = fdt32_to_cpu(cell[i]);
}
return err;
}
int fdtdec_get_bool(const void *blob, int node, const char *prop_name)
{
const s32 *cell;
int len;
debug("%s: %s\n", __func__, prop_name);
cell = fdt_getprop(blob, node, prop_name, &len);
return cell != NULL;
}
/**
* Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
* terminating item.
*
* @param blob FDT blob to use
* @param node Node to look at
* @param prop_name Node property name
* @param gpio Array of gpio elements to fill from FDT. This will be
* untouched if either 0 or an error is returned
* @param max_count Maximum number of elements allowed
* @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
* be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
*/
static int fdtdec_decode_gpios(const void *blob, int node,
const char *prop_name, struct fdt_gpio_state *gpio,
int max_count)
{
const struct fdt_property *prop;
const u32 *cell;
const char *name;
int len, i;
debug("%s: %s\n", __func__, prop_name);
assert(max_count > 0);
prop = fdt_get_property(blob, node, prop_name, &len);
if (!prop) {
debug("FDT: %s: property '%s' missing\n", __func__, prop_name);
return -FDT_ERR_NOTFOUND;
}
/* We will use the name to tag the GPIO */
name = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
cell = (u32 *)prop->data;
len /= sizeof(u32) * 3; /* 3 cells per GPIO record */
if (len > max_count) {
debug("FDT: %s: too many GPIOs / cells for "
"property '%s'\n", __func__, prop_name);
return -FDT_ERR_BADLAYOUT;
}
/* Read out the GPIO data from the cells */
for (i = 0; i < len; i++, cell += 3) {
gpio[i].gpio = fdt32_to_cpu(cell[1]);
gpio[i].flags = fdt32_to_cpu(cell[2]);
gpio[i].name = name;
}
return len;
}
int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
struct fdt_gpio_state *gpio)
{
int err;
debug("%s: %s\n", __func__, prop_name);
gpio->gpio = FDT_GPIO_NONE;
gpio->name = NULL;
err = fdtdec_decode_gpios(blob, node, prop_name, gpio, 1);
return err == 1 ? 0 : err;
}
int fdtdec_setup_gpio(struct fdt_gpio_state *gpio)
{
/*
* Return success if there is no GPIO defined. This is used for
* optional GPIOs)
*/
if (!fdt_gpio_isvalid(gpio))
return 0;
if (gpio_request(gpio->gpio, gpio->name))
return -1;
return 0;
}