diff options
Diffstat (limited to 'drivers/i2c/mxs_i2c.c')
| -rw-r--r-- | drivers/i2c/mxs_i2c.c | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/drivers/i2c/mxs_i2c.c b/drivers/i2c/mxs_i2c.c new file mode 100644 index 0000000..c8fea32 --- /dev/null +++ b/drivers/i2c/mxs_i2c.c @@ -0,0 +1,246 @@ +/* + * Freescale i.MX28 I2C Driver + * + * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com> + * on behalf of DENX Software Engineering GmbH + * + * Partly based on Linux kernel i2c-mxs.c driver: + * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K. + * + * Which was based on a (non-working) driver which was: + * Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +#include <common.h> +#include <malloc.h> +#include <asm/errno.h> +#include <asm/io.h> +#include <asm/arch/clock.h> +#include <asm/arch/imx-regs.h> +#include <asm/arch/sys_proto.h> + +#define MXS_I2C_MAX_TIMEOUT 1000000 + +void mxs_i2c_reset(void) +{ + struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE; + int ret; + + ret = mx28_reset_block(&i2c_regs->hw_i2c_ctrl0_reg); + if (ret) { + debug("MXS I2C: Block reset timeout\n"); + return; + } + + writel(I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | I2C_CTRL1_NO_SLAVE_ACK_IRQ | + I2C_CTRL1_EARLY_TERM_IRQ | I2C_CTRL1_MASTER_LOSS_IRQ | + I2C_CTRL1_SLAVE_STOP_IRQ | I2C_CTRL1_SLAVE_IRQ, + &i2c_regs->hw_i2c_ctrl1_clr); + + writel(I2C_QUEUECTRL_PIO_QUEUE_MODE, &i2c_regs->hw_i2c_queuectrl_set); +} + +void mxs_i2c_setup_read(uint8_t chip, int len) +{ + struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE; + + writel(I2C_QUEUECMD_RETAIN_CLOCK | I2C_QUEUECMD_PRE_SEND_START | + I2C_QUEUECMD_MASTER_MODE | I2C_QUEUECMD_DIRECTION | + (1 << I2C_QUEUECMD_XFER_COUNT_OFFSET), + &i2c_regs->hw_i2c_queuecmd); + + writel((chip << 1) | 1, &i2c_regs->hw_i2c_data); + + writel(I2C_QUEUECMD_SEND_NAK_ON_LAST | I2C_QUEUECMD_MASTER_MODE | + (len << I2C_QUEUECMD_XFER_COUNT_OFFSET) | + I2C_QUEUECMD_POST_SEND_STOP, &i2c_regs->hw_i2c_queuecmd); + + writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set); +} + +void mxs_i2c_write(uchar chip, uint addr, int alen, + uchar *buf, int blen, int stop) +{ + struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE; + uint32_t data; + int i, remain, off; + + if ((alen > 4) || (alen == 0)) { + debug("MXS I2C: Invalid address length\n"); + return; + } + + if (stop) + stop = I2C_QUEUECMD_POST_SEND_STOP; + + writel(I2C_QUEUECMD_PRE_SEND_START | + I2C_QUEUECMD_MASTER_MODE | I2C_QUEUECMD_DIRECTION | + ((blen + alen + 1) << I2C_QUEUECMD_XFER_COUNT_OFFSET) | stop, + &i2c_regs->hw_i2c_queuecmd); + + data = (chip << 1) << 24; + + for (i = 0; i < alen; i++) { + data >>= 8; + data |= ((char *)&addr)[i] << 24; + if ((i & 3) == 2) + writel(data, &i2c_regs->hw_i2c_data); + } + + off = i; + for (; i < off + blen; i++) { + data >>= 8; + data |= buf[i - off] << 24; + if ((i & 3) == 2) + writel(data, &i2c_regs->hw_i2c_data); + } + + remain = 24 - ((i & 3) * 8); + if (remain) + writel(data >> remain, &i2c_regs->hw_i2c_data); + + writel(I2C_QUEUECTRL_QUEUE_RUN, &i2c_regs->hw_i2c_queuectrl_set); +} + +int mxs_i2c_wait_for_ack(void) +{ + struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE; + uint32_t tmp; + int timeout = MXS_I2C_MAX_TIMEOUT; + + for (;;) { + tmp = readl(&i2c_regs->hw_i2c_ctrl1); + if (tmp & I2C_CTRL1_NO_SLAVE_ACK_IRQ) { + debug("MXS I2C: No slave ACK\n"); + goto err; + } + + if (tmp & ( + I2C_CTRL1_EARLY_TERM_IRQ | I2C_CTRL1_MASTER_LOSS_IRQ | + I2C_CTRL1_SLAVE_STOP_IRQ | I2C_CTRL1_SLAVE_IRQ)) { + debug("MXS I2C: Error (CTRL1 = %08x)\n", tmp); + goto err; + } + + if (tmp & I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ) + break; + + if (!timeout--) { + debug("MXS I2C: Operation timed out\n"); + goto err; + } + + udelay(1); + } + + return 0; + +err: + mxs_i2c_reset(); + return 1; +} + +int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len) +{ + struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE; + uint32_t tmp = 0; + int ret; + int i; + + mxs_i2c_write(chip, addr, alen, NULL, 0, 0); + ret = mxs_i2c_wait_for_ack(); + if (ret) { + debug("MXS I2C: Failed writing address\n"); + return ret; + } + + mxs_i2c_setup_read(chip, len); + ret = mxs_i2c_wait_for_ack(); + if (ret) { + debug("MXS I2C: Failed reading address\n"); + return ret; + } + + for (i = 0; i < len; i++) { + if (!(i & 3)) { + while (readl(&i2c_regs->hw_i2c_queuestat) & + I2C_QUEUESTAT_RD_QUEUE_EMPTY) + ; + tmp = readl(&i2c_regs->hw_i2c_queuedata); + } + buffer[i] = tmp & 0xff; + tmp >>= 8; + } + + return 0; +} + +int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len) +{ + int ret; + mxs_i2c_write(chip, addr, alen, buffer, len, 1); + ret = mxs_i2c_wait_for_ack(); + if (ret) + debug("MXS I2C: Failed writing address\n"); + + return ret; +} + +int i2c_probe(uchar chip) +{ + int ret; + mxs_i2c_write(chip, 0, 1, NULL, 0, 1); + ret = mxs_i2c_wait_for_ack(); + mxs_i2c_reset(); + return ret; +} + +void i2c_init(int speed, int slaveadd) +{ + struct mx28_i2c_regs *i2c_regs = (struct mx28_i2c_regs *)MXS_I2C0_BASE; + + mxs_i2c_reset(); + + switch (speed) { + case 100000: + writel((0x0078 << I2C_TIMING0_HIGH_COUNT_OFFSET) | + (0x0030 << I2C_TIMING0_RCV_COUNT_OFFSET), + &i2c_regs->hw_i2c_timing0); + writel((0x0080 << I2C_TIMING1_LOW_COUNT_OFFSET) | + (0x0030 << I2C_TIMING1_XMIT_COUNT_OFFSET), + &i2c_regs->hw_i2c_timing1); + break; + case 400000: + writel((0x000f << I2C_TIMING0_HIGH_COUNT_OFFSET) | + (0x0007 << I2C_TIMING0_RCV_COUNT_OFFSET), + &i2c_regs->hw_i2c_timing0); + writel((0x001f << I2C_TIMING1_LOW_COUNT_OFFSET) | + (0x000f << I2C_TIMING1_XMIT_COUNT_OFFSET), + &i2c_regs->hw_i2c_timing1); + break; + default: + printf("MXS I2C: Invalid speed selected (%d Hz)\n", speed); + return; + } + + writel((0x0015 << I2C_TIMING2_BUS_FREE_OFFSET) | + (0x000d << I2C_TIMING2_LEADIN_COUNT_OFFSET), + &i2c_regs->hw_i2c_timing2); + + return; +} |