mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-14 23:33:00 +00:00
7208396bbf
This reverts commit5d3a21df66
, reversing changes made to56d37f1c56
. Unfortunately this is causing CI failures: https://travis-ci.org/github/trini/u-boot/jobs/711313649 Signed-off-by: Tom Rini <trini@konsulko.com>
219 lines
5.1 KiB
C
219 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2014 Panasonic Corporation
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* Copyright (C) 2015-2016 Socionext Inc.
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* Author: Masahiro Yamada <yamada.masahiro@socionext.com>
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*/
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#include <dm/device_compat.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/io.h>
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#include <linux/sizes.h>
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#include <linux/types.h>
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#include <dm.h>
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#include <fdtdec.h>
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#include <i2c.h>
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struct uniphier_i2c_regs {
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u32 dtrm; /* data transmission */
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#define I2C_DTRM_STA (1 << 10)
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#define I2C_DTRM_STO (1 << 9)
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#define I2C_DTRM_NACK (1 << 8)
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#define I2C_DTRM_RD (1 << 0)
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u32 drec; /* data reception */
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#define I2C_DREC_STS (1 << 12)
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#define I2C_DREC_LRB (1 << 11)
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#define I2C_DREC_LAB (1 << 9)
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u32 myad; /* slave address */
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u32 clk; /* clock frequency control */
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u32 brst; /* bus reset */
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#define I2C_BRST_FOEN (1 << 1)
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#define I2C_BRST_BRST (1 << 0)
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u32 hold; /* hold time control */
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u32 bsts; /* bus status monitor */
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u32 noise; /* noise filter control */
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u32 setup; /* setup time control */
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};
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#define IOBUS_FREQ 100000000
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struct uniphier_i2c_priv {
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struct udevice *dev;
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struct uniphier_i2c_regs __iomem *regs; /* register base */
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unsigned long input_clk; /* master clock (Hz) */
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unsigned long wait_us; /* wait for every byte transfer (us) */
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};
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static int uniphier_i2c_probe(struct udevice *dev)
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{
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fdt_addr_t addr;
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struct uniphier_i2c_priv *priv = dev_get_priv(dev);
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addr = devfdt_get_addr(dev);
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if (addr == FDT_ADDR_T_NONE)
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return -EINVAL;
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priv->regs = devm_ioremap(dev, addr, SZ_64);
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if (!priv->regs)
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return -ENOMEM;
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priv->input_clk = IOBUS_FREQ;
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priv->dev = dev;
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/* deassert reset */
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writel(0x3, &priv->regs->brst);
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return 0;
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}
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static int send_and_recv_byte(struct uniphier_i2c_priv *priv, u32 dtrm)
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{
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writel(dtrm, &priv->regs->dtrm);
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/*
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* This controller only provides interruption to inform the completion
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* of each byte transfer. (No status register to poll it.)
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* Unfortunately, U-Boot does not have a good support of interrupt.
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* Wait for a while.
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*/
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udelay(priv->wait_us);
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return readl(&priv->regs->drec);
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}
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static int send_byte(struct uniphier_i2c_priv *priv, u32 dtrm, bool *stop)
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{
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int ret = 0;
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u32 drec;
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drec = send_and_recv_byte(priv, dtrm);
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if (drec & I2C_DREC_LAB) {
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dev_dbg(priv->dev, "uniphier_i2c: bus arbitration failed\n");
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*stop = false;
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ret = -EREMOTEIO;
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}
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if (drec & I2C_DREC_LRB) {
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dev_dbg(priv->dev, "uniphier_i2c: slave did not return ACK\n");
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ret = -EREMOTEIO;
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}
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return ret;
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}
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static int uniphier_i2c_transmit(struct uniphier_i2c_priv *priv, uint addr,
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uint len, const u8 *buf, bool *stop)
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{
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int ret;
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dev_dbg(priv->dev, "%s: addr = %x, len = %d\n", __func__, addr, len);
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ret = send_byte(priv, I2C_DTRM_STA | I2C_DTRM_NACK | addr << 1, stop);
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if (ret < 0)
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goto fail;
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while (len--) {
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ret = send_byte(priv, I2C_DTRM_NACK | *buf++, stop);
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if (ret < 0)
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goto fail;
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}
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fail:
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if (*stop)
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writel(I2C_DTRM_STO | I2C_DTRM_NACK, &priv->regs->dtrm);
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return ret;
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}
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static int uniphier_i2c_receive(struct uniphier_i2c_priv *priv, uint addr,
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uint len, u8 *buf, bool *stop)
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{
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int ret;
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dev_dbg(priv->dev, "%s: addr = %x, len = %d\n", __func__, addr, len);
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ret = send_byte(priv, I2C_DTRM_STA | I2C_DTRM_NACK |
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I2C_DTRM_RD | addr << 1, stop);
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if (ret < 0)
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goto fail;
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while (len--)
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*buf++ = send_and_recv_byte(priv, len ? 0 : I2C_DTRM_NACK);
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fail:
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if (*stop)
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writel(I2C_DTRM_STO | I2C_DTRM_NACK, &priv->regs->dtrm);
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return ret;
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}
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static int uniphier_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
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int nmsgs)
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{
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int ret = 0;
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struct uniphier_i2c_priv *priv = dev_get_priv(bus);
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bool stop;
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for (; nmsgs > 0; nmsgs--, msg++) {
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/* If next message is read, skip the stop condition */
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stop = nmsgs > 1 && msg[1].flags & I2C_M_RD ? false : true;
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if (msg->flags & I2C_M_RD)
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ret = uniphier_i2c_receive(priv, msg->addr, msg->len,
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msg->buf, &stop);
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else
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ret = uniphier_i2c_transmit(priv, msg->addr, msg->len,
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msg->buf, &stop);
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if (ret < 0)
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break;
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}
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return ret;
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}
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static int uniphier_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
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{
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struct uniphier_i2c_priv *priv = dev_get_priv(bus);
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/* max supported frequency is 400 kHz */
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if (speed > I2C_SPEED_FAST_RATE)
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return -EINVAL;
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/* bus reset: make sure the bus is idle when change the frequency */
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writel(0x1, &priv->regs->brst);
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writel((priv->input_clk / speed / 2 << 16) | (priv->input_clk / speed),
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&priv->regs->clk);
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writel(0x3, &priv->regs->brst);
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/*
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* Theoretically, each byte can be transferred in
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* 1000000 * 9 / speed usec. For safety, wait more than double.
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*/
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priv->wait_us = 20000000 / speed;
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return 0;
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}
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static const struct dm_i2c_ops uniphier_i2c_ops = {
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.xfer = uniphier_i2c_xfer,
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.set_bus_speed = uniphier_i2c_set_bus_speed,
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};
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static const struct udevice_id uniphier_i2c_of_match[] = {
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{ .compatible = "socionext,uniphier-i2c" },
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{ /* sentinel */ }
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};
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U_BOOT_DRIVER(uniphier_i2c) = {
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.name = "uniphier-i2c",
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.id = UCLASS_I2C,
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.of_match = uniphier_i2c_of_match,
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.probe = uniphier_i2c_probe,
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.priv_auto_alloc_size = sizeof(struct uniphier_i2c_priv),
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.ops = &uniphier_i2c_ops,
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};
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