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![Marek Vasut](/assets/img/avatar_default.png)
Add support for I2C bus 1 on the i.MX28. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Stefano Babic <sbabic@denx.de> Cc: Heiko Schocher <hs@denx.de>
321 lines
7.8 KiB
C
321 lines
7.8 KiB
C
/*
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* Freescale i.MX28 I2C Driver
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*
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* Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
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* on behalf of DENX Software Engineering GmbH
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*
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* Partly based on Linux kernel i2c-mxs.c driver:
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* Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
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*
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* Which was based on a (non-working) driver which was:
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* Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
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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 <malloc.h>
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#include <i2c.h>
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#include <asm/errno.h>
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#include <asm/io.h>
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#include <asm/arch/clock.h>
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#include <asm/arch/imx-regs.h>
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#include <asm/arch/sys_proto.h>
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#define MXS_I2C_MAX_TIMEOUT 1000000
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static struct mxs_i2c_regs *mxs_i2c_get_base(struct i2c_adapter *adap)
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{
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if (adap->hwadapnr == 0)
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return (struct mxs_i2c_regs *)MXS_I2C0_BASE;
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else
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return (struct mxs_i2c_regs *)MXS_I2C1_BASE;
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}
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static unsigned int mxs_i2c_get_bus_speed(struct i2c_adapter *adap)
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{
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struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
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uint32_t clk = mxc_get_clock(MXC_XTAL_CLK);
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uint32_t timing0;
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timing0 = readl(&i2c_regs->hw_i2c_timing0);
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/*
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* This is a reverse version of the algorithm presented in
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* i2c_set_bus_speed(). Please refer there for details.
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*/
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return clk / ((((timing0 >> 16) - 3) * 2) + 38);
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}
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static uint mxs_i2c_set_bus_speed(struct i2c_adapter *adap, uint speed)
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{
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struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
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/*
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* The timing derivation algorithm. There is no documentation for this
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* algorithm available, it was derived by using the scope and fiddling
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* with constants until the result observed on the scope was good enough
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* for 20kHz, 50kHz, 100kHz, 200kHz, 300kHz and 400kHz. It should be
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* possible to assume the algorithm works for other frequencies as well.
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*
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* Note it was necessary to cap the frequency on both ends as it's not
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* possible to configure completely arbitrary frequency for the I2C bus
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* clock.
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*/
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uint32_t clk = mxc_get_clock(MXC_XTAL_CLK);
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uint32_t base = ((clk / speed) - 38) / 2;
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uint16_t high_count = base + 3;
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uint16_t low_count = base - 3;
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uint16_t rcv_count = (high_count * 3) / 4;
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uint16_t xmit_count = low_count / 4;
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if (speed > 540000) {
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printf("MXS I2C: Speed too high (%d Hz)\n", speed);
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return -EINVAL;
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}
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if (speed < 12000) {
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printf("MXS I2C: Speed too low (%d Hz)\n", speed);
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return -EINVAL;
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}
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writel((high_count << 16) | rcv_count, &i2c_regs->hw_i2c_timing0);
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writel((low_count << 16) | xmit_count, &i2c_regs->hw_i2c_timing1);
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writel((0x0030 << I2C_TIMING2_BUS_FREE_OFFSET) |
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(0x0030 << I2C_TIMING2_LEADIN_COUNT_OFFSET),
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&i2c_regs->hw_i2c_timing2);
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return 0;
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}
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static void mxs_i2c_reset(struct i2c_adapter *adap)
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{
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struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
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int ret;
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int speed = mxs_i2c_get_bus_speed(adap);
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ret = mxs_reset_block(&i2c_regs->hw_i2c_ctrl0_reg);
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if (ret) {
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debug("MXS I2C: Block reset timeout\n");
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return;
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}
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writel(I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | I2C_CTRL1_NO_SLAVE_ACK_IRQ |
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I2C_CTRL1_EARLY_TERM_IRQ | I2C_CTRL1_MASTER_LOSS_IRQ |
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I2C_CTRL1_SLAVE_STOP_IRQ | I2C_CTRL1_SLAVE_IRQ,
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&i2c_regs->hw_i2c_ctrl1_clr);
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writel(I2C_QUEUECTRL_PIO_QUEUE_MODE, &i2c_regs->hw_i2c_queuectrl_set);
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mxs_i2c_set_bus_speed(adap, speed);
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}
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static void mxs_i2c_setup_read(struct i2c_adapter *adap, uint8_t chip, int len)
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{
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struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
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writel(I2C_QUEUECMD_RETAIN_CLOCK | I2C_QUEUECMD_PRE_SEND_START |
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I2C_QUEUECMD_MASTER_MODE | I2C_QUEUECMD_DIRECTION |
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(1 << I2C_QUEUECMD_XFER_COUNT_OFFSET),
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&i2c_regs->hw_i2c_queuecmd);
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writel((chip << 1) | 1, &i2c_regs->hw_i2c_data);
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writel(I2C_QUEUECMD_SEND_NAK_ON_LAST | I2C_QUEUECMD_MASTER_MODE |
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(len << I2C_QUEUECMD_XFER_COUNT_OFFSET) |
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I2C_QUEUECMD_POST_SEND_STOP, &i2c_regs->hw_i2c_queuecmd);
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writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set);
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}
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static int mxs_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
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int alen, uchar *buf, int blen, int stop)
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{
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struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
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uint32_t data, tmp;
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int i, remain, off;
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int timeout = MXS_I2C_MAX_TIMEOUT;
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if ((alen > 4) || (alen == 0)) {
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debug("MXS I2C: Invalid address length\n");
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return -EINVAL;
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}
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if (stop)
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stop = I2C_QUEUECMD_POST_SEND_STOP;
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writel(I2C_QUEUECMD_PRE_SEND_START |
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I2C_QUEUECMD_MASTER_MODE | I2C_QUEUECMD_DIRECTION |
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((blen + alen + 1) << I2C_QUEUECMD_XFER_COUNT_OFFSET) | stop,
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&i2c_regs->hw_i2c_queuecmd);
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data = (chip << 1) << 24;
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for (i = 0; i < alen; i++) {
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data >>= 8;
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data |= ((char *)&addr)[alen - i - 1] << 24;
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if ((i & 3) == 2)
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writel(data, &i2c_regs->hw_i2c_data);
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}
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off = i;
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for (; i < off + blen; i++) {
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data >>= 8;
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data |= buf[i - off] << 24;
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if ((i & 3) == 2)
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writel(data, &i2c_regs->hw_i2c_data);
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}
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remain = 24 - ((i & 3) * 8);
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if (remain)
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writel(data >> remain, &i2c_regs->hw_i2c_data);
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writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set);
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while (--timeout) {
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tmp = readl(&i2c_regs->hw_i2c_queuestat);
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if (tmp & I2C_QUEUESTAT_WR_QUEUE_EMPTY)
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break;
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}
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if (!timeout) {
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debug("MXS I2C: Failed transmitting data!\n");
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return -EINVAL;
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}
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return 0;
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}
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static int mxs_i2c_wait_for_ack(struct i2c_adapter *adap)
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{
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struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
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uint32_t tmp;
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int timeout = MXS_I2C_MAX_TIMEOUT;
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for (;;) {
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tmp = readl(&i2c_regs->hw_i2c_ctrl1);
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if (tmp & I2C_CTRL1_NO_SLAVE_ACK_IRQ) {
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debug("MXS I2C: No slave ACK\n");
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goto err;
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}
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if (tmp & (
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I2C_CTRL1_EARLY_TERM_IRQ | I2C_CTRL1_MASTER_LOSS_IRQ |
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I2C_CTRL1_SLAVE_STOP_IRQ | I2C_CTRL1_SLAVE_IRQ)) {
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debug("MXS I2C: Error (CTRL1 = %08x)\n", tmp);
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goto err;
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}
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if (tmp & I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ)
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break;
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if (!timeout--) {
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debug("MXS I2C: Operation timed out\n");
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goto err;
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}
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udelay(1);
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}
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return 0;
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err:
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mxs_i2c_reset(adap);
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return 1;
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}
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static int mxs_i2c_if_read(struct i2c_adapter *adap, uint8_t chip,
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uint addr, int alen, uint8_t *buffer,
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int len)
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{
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struct mxs_i2c_regs *i2c_regs = mxs_i2c_get_base(adap);
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uint32_t tmp = 0;
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int timeout = MXS_I2C_MAX_TIMEOUT;
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int ret;
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int i;
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ret = mxs_i2c_write(adap, chip, addr, alen, NULL, 0, 0);
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if (ret) {
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debug("MXS I2C: Failed writing address\n");
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return ret;
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}
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ret = mxs_i2c_wait_for_ack(adap);
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if (ret) {
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debug("MXS I2C: Failed writing address\n");
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return ret;
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}
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mxs_i2c_setup_read(adap, chip, len);
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ret = mxs_i2c_wait_for_ack(adap);
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if (ret) {
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debug("MXS I2C: Failed reading address\n");
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return ret;
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}
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for (i = 0; i < len; i++) {
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if (!(i & 3)) {
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while (--timeout) {
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tmp = readl(&i2c_regs->hw_i2c_queuestat);
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if (!(tmp & I2C_QUEUESTAT_RD_QUEUE_EMPTY))
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break;
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}
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if (!timeout) {
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debug("MXS I2C: Failed receiving data!\n");
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return -ETIMEDOUT;
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}
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tmp = readl(&i2c_regs->hw_i2c_queuedata);
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}
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buffer[i] = tmp & 0xff;
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tmp >>= 8;
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}
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return 0;
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}
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static int mxs_i2c_if_write(struct i2c_adapter *adap, uint8_t chip,
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uint addr, int alen, uint8_t *buffer,
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int len)
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{
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int ret;
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ret = mxs_i2c_write(adap, chip, addr, alen, buffer, len, 1);
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if (ret) {
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debug("MXS I2C: Failed writing address\n");
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return ret;
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}
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ret = mxs_i2c_wait_for_ack(adap);
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if (ret)
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debug("MXS I2C: Failed writing address\n");
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return ret;
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}
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static int mxs_i2c_probe(struct i2c_adapter *adap, uint8_t chip)
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{
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int ret;
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ret = mxs_i2c_write(adap, chip, 0, 1, NULL, 0, 1);
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if (!ret)
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ret = mxs_i2c_wait_for_ack(adap);
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mxs_i2c_reset(adap);
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return ret;
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}
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static void mxs_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
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{
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mxs_i2c_reset(adap);
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mxs_i2c_set_bus_speed(adap, speed);
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return;
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}
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U_BOOT_I2C_ADAP_COMPLETE(mxs0, mxs_i2c_init, mxs_i2c_probe,
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mxs_i2c_if_read, mxs_i2c_if_write,
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mxs_i2c_set_bus_speed,
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CONFIG_SYS_I2C_SPEED, 0, 0)
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U_BOOT_I2C_ADAP_COMPLETE(mxs1, mxs_i2c_init, mxs_i2c_probe,
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mxs_i2c_if_read, mxs_i2c_if_write,
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mxs_i2c_set_bus_speed,
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CONFIG_SYS_I2C_SPEED, 0, 1)
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