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https://github.com/AsahiLinux/u-boot
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81687212ee
There is sporadic failures when more as one I2C slave is on the bus and the processor tries to communicate with more as one slave. The problem was seen on a mx35pdk (two I2C slaves, PMIC controller and CAN/RTC chip). The current driver uses the IIF bit in the status register to check if the bus is busy or not. According to the manual, this is not correct, because the IIB bit should be checked. Not only, to check if a transfer is finished must be checked the ICF bit, and this is not tested at all. This patch comes from analyse with a corresponding driver provided by Freescale as part of the LTIB tool. Comparing the two drivers, it appears that the current u-boot driver checks the wrong bits, and depending on race condition, the transfer can be successful or not. The patch gets rid also of own debug function (DPRINTF), replaced with the general debug(). Tested on Freescale mx35pdk. Signed-off-by: Stefano Babic <sbabic@denx.de> CC: Heiko Schocher <hs@denx.de> Acked-by: Heiko Schocher <hs@denx.de>
290 lines
6.4 KiB
C
290 lines
6.4 KiB
C
/*
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* i2c driver for Freescale mx31
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*
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* (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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#include <asm/io.h>
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#if defined(CONFIG_HARD_I2C)
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#if defined(CONFIG_MX31)
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#include <asm/arch/mx31.h>
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#include <asm/arch/mx31-regs.h>
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#else
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#include <asm/arch/imx-regs.h>
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#include <asm/arch/clock.h>
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#endif
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#define IADR 0x00
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#define IFDR 0x04
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#define I2CR 0x08
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#define I2SR 0x0c
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#define I2DR 0x10
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#define I2CR_IEN (1 << 7)
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#define I2CR_IIEN (1 << 6)
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#define I2CR_MSTA (1 << 5)
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#define I2CR_MTX (1 << 4)
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#define I2CR_TX_NO_AK (1 << 3)
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#define I2CR_RSTA (1 << 2)
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#define I2SR_ICF (1 << 7)
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#define I2SR_IBB (1 << 5)
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#define I2SR_IIF (1 << 1)
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#define I2SR_RX_NO_AK (1 << 0)
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#if defined(CONFIG_SYS_I2C_MX31_PORT1)
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#define I2C_BASE 0x43f80000
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#define I2C_CLK_OFFSET 26
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#elif defined (CONFIG_SYS_I2C_MX31_PORT2)
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#define I2C_BASE 0x43f98000
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#define I2C_CLK_OFFSET 28
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#elif defined (CONFIG_SYS_I2C_MX31_PORT3)
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#define I2C_BASE 0x43f84000
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#define I2C_CLK_OFFSET 30
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#elif defined(CONFIG_SYS_I2C_MX53_PORT1)
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#define I2C_BASE I2C1_BASE_ADDR
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#elif defined(CONFIG_SYS_I2C_MX53_PORT2)
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#define I2C_BASE I2C2_BASE_ADDR
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#elif defined(CONFIG_SYS_I2C_MX35_PORT1)
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#define I2C_BASE I2C_BASE_ADDR
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#else
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#error "define CONFIG_SYS_I2C_MX<Processor>_PORTx to use the mx I2C driver"
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#endif
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#define I2C_MAX_TIMEOUT 10000
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#define I2C_MAX_RETRIES 3
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static u16 div[] = { 30, 32, 36, 42, 48, 52, 60, 72, 80, 88, 104, 128, 144,
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160, 192, 240, 288, 320, 384, 480, 576, 640, 768, 960,
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1152, 1280, 1536, 1920, 2304, 2560, 3072, 3840};
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static inline void i2c_reset(void)
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{
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writew(0, I2C_BASE + I2CR); /* Reset module */
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writew(0, I2C_BASE + I2SR);
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writew(I2CR_IEN, I2C_BASE + I2CR);
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}
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void i2c_init(int speed, int unused)
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{
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int freq;
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int i;
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#if defined(CONFIG_MX31)
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struct clock_control_regs *sc_regs =
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(struct clock_control_regs *)CCM_BASE;
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freq = mx31_get_ipg_clk();
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/* start the required I2C clock */
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writel(readl(&sc_regs->cgr0) | (3 << I2C_CLK_OFFSET),
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&sc_regs->cgr0);
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#else
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freq = mxc_get_clock(MXC_IPG_PERCLK);
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#endif
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for (i = 0; i < 0x1f; i++)
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if (freq / div[i] <= speed)
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break;
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debug("%s: speed: %d\n", __func__, speed);
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writew(i, I2C_BASE + IFDR);
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i2c_reset();
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}
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static int wait_idle(void)
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{
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int timeout = I2C_MAX_TIMEOUT;
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while ((readw(I2C_BASE + I2SR) & I2SR_IBB) && --timeout) {
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writew(0, I2C_BASE + I2SR);
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udelay(1);
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}
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return timeout ? timeout : (!(readw(I2C_BASE + I2SR) & I2SR_IBB));
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}
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static int wait_busy(void)
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{
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int timeout = I2C_MAX_TIMEOUT;
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while (!(readw(I2C_BASE + I2SR) & I2SR_IBB) && --timeout)
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udelay(1);
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writew(0, I2C_BASE + I2SR); /* clear interrupt */
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return timeout;
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}
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static int wait_complete(void)
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{
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int timeout = I2C_MAX_TIMEOUT;
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while ((!(readw(I2C_BASE + I2SR) & I2SR_ICF)) && (--timeout)) {
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writew(0, I2C_BASE + I2SR);
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udelay(1);
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}
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udelay(200);
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writew(0, I2C_BASE + I2SR); /* clear interrupt */
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return timeout;
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}
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static int tx_byte(u8 byte)
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{
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writew(byte, I2C_BASE + I2DR);
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if (!wait_complete() || readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)
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return -1;
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return 0;
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}
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static int rx_byte(int last)
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{
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if (!wait_complete())
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return -1;
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if (last)
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writew(I2CR_IEN, I2C_BASE + I2CR);
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return readw(I2C_BASE + I2DR);
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}
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int i2c_probe(uchar chip)
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{
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int ret;
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writew(0, I2C_BASE + I2CR); /* Reset module */
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writew(I2CR_IEN, I2C_BASE + I2CR);
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writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX, I2C_BASE + I2CR);
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ret = tx_byte(chip << 1);
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writew(I2CR_IEN | I2CR_MTX, I2C_BASE + I2CR);
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return ret;
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}
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static int i2c_addr(uchar chip, uint addr, int alen)
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{
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int i, retry = 0;
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for (retry = 0; retry < 3; retry++) {
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if (wait_idle())
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break;
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i2c_reset();
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for (i = 0; i < I2C_MAX_TIMEOUT; i++)
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udelay(1);
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}
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if (retry >= I2C_MAX_RETRIES) {
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debug("%s:bus is busy(%x)\n",
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__func__, readw(I2C_BASE + I2SR));
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return -1;
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}
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writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX, I2C_BASE + I2CR);
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if (!wait_busy()) {
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debug("%s:trigger start fail(%x)\n",
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__func__, readw(I2C_BASE + I2SR));
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return -1;
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}
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if (tx_byte(chip << 1) || (readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)) {
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debug("%s:chip address cycle fail(%x)\n",
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__func__, readw(I2C_BASE + I2SR));
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return -1;
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}
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while (alen--)
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if (tx_byte((addr >> (alen * 8)) & 0xff) ||
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(readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)) {
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debug("%s:device address cycle fail(%x)\n",
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__func__, readw(I2C_BASE + I2SR));
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return -1;
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}
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return 0;
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}
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int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
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{
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int timeout = I2C_MAX_TIMEOUT;
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int ret;
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debug("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",
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__func__, chip, addr, alen, len);
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if (i2c_addr(chip, addr, alen)) {
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printf("i2c_addr failed\n");
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return -1;
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}
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writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX | I2CR_RSTA, I2C_BASE + I2CR);
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if (tx_byte(chip << 1 | 1))
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return -1;
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writew(I2CR_IEN | I2CR_MSTA |
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((len == 1) ? I2CR_TX_NO_AK : 0),
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I2C_BASE + I2CR);
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ret = readw(I2C_BASE + I2DR);
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while (len--) {
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ret = rx_byte(len == 0);
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if (ret < 0)
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return -1;
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*buf++ = ret;
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if (len <= 1)
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writew(I2CR_IEN | I2CR_MSTA |
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I2CR_TX_NO_AK,
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I2C_BASE + I2CR);
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}
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writew(I2CR_IEN, I2C_BASE + I2CR);
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while (readw(I2C_BASE + I2SR) & I2SR_IBB && --timeout)
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udelay(1);
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return 0;
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}
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int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
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{
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int timeout = I2C_MAX_TIMEOUT;
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debug("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",
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__func__, chip, addr, alen, len);
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if (i2c_addr(chip, addr, alen))
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return -1;
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while (len--)
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if (tx_byte(*buf++))
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return -1;
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writew(I2CR_IEN, I2C_BASE + I2CR);
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while (readw(I2C_BASE + I2SR) & I2SR_IBB && --timeout)
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udelay(1);
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return 0;
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}
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#endif /* CONFIG_HARD_I2C */
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