mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-07-05 10:46:15 +09:00
83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
147 lines
3.3 KiB
C
147 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2015 Google, Inc
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* Written by Simon Glass <sjg@chromium.org>
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*/
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#include <common.h>
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#include <dm.h>
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#include <errno.h>
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#include <i2c.h>
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#include <asm/gpio.h>
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DECLARE_GLOBAL_DATA_PTR;
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struct i2c_arbitrator_priv {
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struct gpio_desc ap_claim;
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struct gpio_desc ec_claim;
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uint slew_delay_us;
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uint wait_retry_ms;
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uint wait_free_ms;
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};
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int i2c_arbitrator_deselect(struct udevice *mux, struct udevice *bus,
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uint channel)
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{
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struct i2c_arbitrator_priv *priv = dev_get_priv(mux);
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int ret;
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debug("%s: %s\n", __func__, mux->name);
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ret = dm_gpio_set_value(&priv->ap_claim, 0);
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udelay(priv->slew_delay_us);
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return ret;
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}
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int i2c_arbitrator_select(struct udevice *mux, struct udevice *bus,
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uint channel)
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{
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struct i2c_arbitrator_priv *priv = dev_get_priv(mux);
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unsigned start;
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int ret;
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debug("%s: %s\n", __func__, mux->name);
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/* Start a round of trying to claim the bus */
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start = get_timer(0);
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do {
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unsigned start_retry;
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int waiting = 0;
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/* Indicate that we want to claim the bus */
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ret = dm_gpio_set_value(&priv->ap_claim, 1);
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if (ret)
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goto err;
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udelay(priv->slew_delay_us);
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/* Wait for the EC to release it */
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start_retry = get_timer(0);
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while (get_timer(start_retry) < priv->wait_retry_ms) {
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ret = dm_gpio_get_value(&priv->ec_claim);
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if (ret < 0) {
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goto err;
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} else if (!ret) {
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/* We got it, so return */
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return 0;
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}
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if (!waiting)
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waiting = 1;
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}
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/* It didn't release, so give up, wait, and try again */
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ret = dm_gpio_set_value(&priv->ap_claim, 0);
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if (ret)
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goto err;
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mdelay(priv->wait_retry_ms);
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} while (get_timer(start) < priv->wait_free_ms);
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/* Give up, release our claim */
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printf("I2C: Could not claim bus, timeout %lu\n", get_timer(start));
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ret = -ETIMEDOUT;
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ret = 0;
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err:
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return ret;
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}
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static int i2c_arbitrator_probe(struct udevice *dev)
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{
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struct i2c_arbitrator_priv *priv = dev_get_priv(dev);
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const void *blob = gd->fdt_blob;
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int node = dev_of_offset(dev);
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int ret;
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debug("%s: %s\n", __func__, dev->name);
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priv->slew_delay_us = fdtdec_get_int(blob, node, "slew-delay-us", 0);
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priv->wait_retry_ms = fdtdec_get_int(blob, node, "wait-retry-us", 0) /
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1000;
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priv->wait_free_ms = fdtdec_get_int(blob, node, "wait-free-us", 0) /
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1000;
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ret = gpio_request_by_name(dev, "our-claim-gpio", 0, &priv->ap_claim,
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GPIOD_IS_OUT);
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if (ret)
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goto err;
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ret = gpio_request_by_name(dev, "their-claim-gpios", 0, &priv->ec_claim,
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GPIOD_IS_IN);
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if (ret)
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goto err_ec_gpio;
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return 0;
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err_ec_gpio:
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dm_gpio_free(dev, &priv->ap_claim);
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err:
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debug("%s: ret=%d\n", __func__, ret);
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return ret;
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}
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static int i2c_arbitrator_remove(struct udevice *dev)
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{
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struct i2c_arbitrator_priv *priv = dev_get_priv(dev);
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dm_gpio_free(dev, &priv->ap_claim);
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dm_gpio_free(dev, &priv->ec_claim);
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return 0;
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}
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static const struct i2c_mux_ops i2c_arbitrator_ops = {
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.select = i2c_arbitrator_select,
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.deselect = i2c_arbitrator_deselect,
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};
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static const struct udevice_id i2c_arbitrator_ids[] = {
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{ .compatible = "i2c-arb-gpio-challenge" },
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{ }
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};
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U_BOOT_DRIVER(i2c_arbitrator) = {
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.name = "i2c_arbitrator",
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.id = UCLASS_I2C_MUX,
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.of_match = i2c_arbitrator_ids,
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.probe = i2c_arbitrator_probe,
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.remove = i2c_arbitrator_remove,
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.ops = &i2c_arbitrator_ops,
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.priv_auto_alloc_size = sizeof(struct i2c_arbitrator_priv),
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};
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