Add a driver to support the special LDO access used by spring. This is a custom method in the cros_ec protocol - it does not use an I2C pass-through. There are two implementation choices: 1. Write a special LDO driver which can talk across the EC. Duplicate all the logic from TPS65090 for retrying when the LDO fails to come up. 2. Write a special I2C bus driver which pretends to be a TPS65090 and transfers reads and writes using the LDO message. Either is distasteful. The latter method is chosen since it results in less code duplication and a fairly simple (30-line) implementation of the core logic. The crosec 'ldo' subcommand could be removed (since i2c md/mw will work instead) but is retained as a convenience. Signed-off-by: Simon Glass <sjg@chromium.org>master
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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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* SPDX-License-Identifier: GPL-2.0+ |
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*/ |
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#include <common.h> |
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#include <dm.h> |
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#include <cros_ec.h> |
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#include <errno.h> |
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#include <i2c.h> |
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#include <power/tps65090.h> |
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static int cros_ec_ldo_set_bus_speed(struct udevice *dev, unsigned int speed) |
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{ |
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return 0; |
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} |
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static int cros_ec_ldo_xfer(struct udevice *dev, struct i2c_msg *msg, |
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int nmsgs) |
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{ |
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bool is_read = nmsgs > 1; |
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int fet_id, ret; |
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/*
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* Look for reads and writes of the LDO registers. In either case the |
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* first message is a write with the register number as the first byte. |
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*/ |
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if (!nmsgs || !msg->len || (msg->flags & I2C_M_RD)) { |
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debug("%s: Invalid message\n", __func__); |
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goto err; |
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} |
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fet_id = msg->buf[0] - REG_FET_BASE; |
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if (fet_id < 1 || fet_id > MAX_FET_NUM) { |
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debug("%s: Invalid FET %d\n", __func__, fet_id); |
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goto err; |
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} |
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if (is_read) { |
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uint8_t state; |
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ret = cros_ec_get_ldo(dev->parent, fet_id, &state); |
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if (!ret) |
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msg[1].buf[0] = state ? |
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FET_CTRL_ENFET | FET_CTRL_PGFET : 0; |
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} else { |
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bool on = msg->buf[1] & FET_CTRL_ENFET; |
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ret = cros_ec_set_ldo(dev->parent, fet_id, on); |
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} |
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return ret; |
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err: |
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/* Indicate that the message is unimplemented */ |
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return -ENOSYS; |
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} |
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static const struct dm_i2c_ops cros_ec_i2c_ops = { |
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.xfer = cros_ec_ldo_xfer, |
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.set_bus_speed = cros_ec_ldo_set_bus_speed, |
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}; |
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static const struct udevice_id cros_ec_i2c_ids[] = { |
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{ .compatible = "google,cros-ec-ldo-tunnel" }, |
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{ } |
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}; |
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U_BOOT_DRIVER(cros_ec_ldo) = { |
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.name = "cros_ec_ldo_tunnel", |
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.id = UCLASS_I2C, |
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.of_match = cros_ec_i2c_ids, |
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.per_child_auto_alloc_size = sizeof(struct dm_i2c_chip), |
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.ops = &cros_ec_i2c_ops, |
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}; |
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