mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-01 17:10:11 +00:00
e160f7d430
At present devices use a simple integer offset to record the device tree node associated with the device. In preparation for supporting a live device tree, which uses a node pointer instead, refactor existing code to access this field through an inline function. Signed-off-by: Simon Glass <sjg@chromium.org>
147 lines
3.3 KiB
C
147 lines
3.3 KiB
C
/*
|
|
* Copyright (c) 2015 Google, Inc
|
|
* Written by Simon Glass <sjg@chromium.org>
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*/
|
|
|
|
#include <common.h>
|
|
#include <dm.h>
|
|
#include <errno.h>
|
|
#include <i2c.h>
|
|
#include <asm/gpio.h>
|
|
|
|
DECLARE_GLOBAL_DATA_PTR;
|
|
|
|
struct i2c_arbitrator_priv {
|
|
struct gpio_desc ap_claim;
|
|
struct gpio_desc ec_claim;
|
|
uint slew_delay_us;
|
|
uint wait_retry_ms;
|
|
uint wait_free_ms;
|
|
};
|
|
|
|
int i2c_arbitrator_deselect(struct udevice *mux, struct udevice *bus,
|
|
uint channel)
|
|
{
|
|
struct i2c_arbitrator_priv *priv = dev_get_priv(mux);
|
|
int ret;
|
|
|
|
debug("%s: %s\n", __func__, mux->name);
|
|
ret = dm_gpio_set_value(&priv->ap_claim, 0);
|
|
udelay(priv->slew_delay_us);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int i2c_arbitrator_select(struct udevice *mux, struct udevice *bus,
|
|
uint channel)
|
|
{
|
|
struct i2c_arbitrator_priv *priv = dev_get_priv(mux);
|
|
unsigned start;
|
|
int ret;
|
|
|
|
debug("%s: %s\n", __func__, mux->name);
|
|
/* Start a round of trying to claim the bus */
|
|
start = get_timer(0);
|
|
do {
|
|
unsigned start_retry;
|
|
int waiting = 0;
|
|
|
|
/* Indicate that we want to claim the bus */
|
|
ret = dm_gpio_set_value(&priv->ap_claim, 1);
|
|
if (ret)
|
|
goto err;
|
|
udelay(priv->slew_delay_us);
|
|
|
|
/* Wait for the EC to release it */
|
|
start_retry = get_timer(0);
|
|
while (get_timer(start_retry) < priv->wait_retry_ms) {
|
|
ret = dm_gpio_get_value(&priv->ec_claim);
|
|
if (ret < 0) {
|
|
goto err;
|
|
} else if (!ret) {
|
|
/* We got it, so return */
|
|
return 0;
|
|
}
|
|
|
|
if (!waiting)
|
|
waiting = 1;
|
|
}
|
|
|
|
/* It didn't release, so give up, wait, and try again */
|
|
ret = dm_gpio_set_value(&priv->ap_claim, 0);
|
|
if (ret)
|
|
goto err;
|
|
|
|
mdelay(priv->wait_retry_ms);
|
|
} while (get_timer(start) < priv->wait_free_ms);
|
|
|
|
/* Give up, release our claim */
|
|
printf("I2C: Could not claim bus, timeout %lu\n", get_timer(start));
|
|
ret = -ETIMEDOUT;
|
|
ret = 0;
|
|
err:
|
|
return ret;
|
|
}
|
|
|
|
static int i2c_arbitrator_probe(struct udevice *dev)
|
|
{
|
|
struct i2c_arbitrator_priv *priv = dev_get_priv(dev);
|
|
const void *blob = gd->fdt_blob;
|
|
int node = dev_of_offset(dev);
|
|
int ret;
|
|
|
|
debug("%s: %s\n", __func__, dev->name);
|
|
priv->slew_delay_us = fdtdec_get_int(blob, node, "slew-delay-us", 0);
|
|
priv->wait_retry_ms = fdtdec_get_int(blob, node, "wait-retry-us", 0) /
|
|
1000;
|
|
priv->wait_free_ms = fdtdec_get_int(blob, node, "wait-free-us", 0) /
|
|
1000;
|
|
ret = gpio_request_by_name(dev, "our-claim-gpio", 0, &priv->ap_claim,
|
|
GPIOD_IS_OUT);
|
|
if (ret)
|
|
goto err;
|
|
ret = gpio_request_by_name(dev, "their-claim-gpios", 0, &priv->ec_claim,
|
|
GPIOD_IS_IN);
|
|
if (ret)
|
|
goto err_ec_gpio;
|
|
|
|
return 0;
|
|
|
|
err_ec_gpio:
|
|
dm_gpio_free(dev, &priv->ap_claim);
|
|
err:
|
|
debug("%s: ret=%d\n", __func__, ret);
|
|
return ret;
|
|
}
|
|
|
|
static int i2c_arbitrator_remove(struct udevice *dev)
|
|
{
|
|
struct i2c_arbitrator_priv *priv = dev_get_priv(dev);
|
|
|
|
dm_gpio_free(dev, &priv->ap_claim);
|
|
dm_gpio_free(dev, &priv->ec_claim);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct i2c_mux_ops i2c_arbitrator_ops = {
|
|
.select = i2c_arbitrator_select,
|
|
.deselect = i2c_arbitrator_deselect,
|
|
};
|
|
|
|
static const struct udevice_id i2c_arbitrator_ids[] = {
|
|
{ .compatible = "i2c-arb-gpio-challenge" },
|
|
{ }
|
|
};
|
|
|
|
U_BOOT_DRIVER(i2c_arbitrator) = {
|
|
.name = "i2c_arbitrator",
|
|
.id = UCLASS_I2C_MUX,
|
|
.of_match = i2c_arbitrator_ids,
|
|
.probe = i2c_arbitrator_probe,
|
|
.remove = i2c_arbitrator_remove,
|
|
.ops = &i2c_arbitrator_ops,
|
|
.priv_auto_alloc_size = sizeof(struct i2c_arbitrator_priv),
|
|
};
|