diff options
Diffstat (limited to 'drivers/i2c/mxc_i2c.c')
| -rw-r--r-- | drivers/i2c/mxc_i2c.c | 418 |
1 files changed, 287 insertions, 131 deletions
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c index ebde3c5ab..a805bf62d 100644 --- a/drivers/i2c/mxc_i2c.c +++ b/drivers/i2c/mxc_i2c.c @@ -1,7 +1,15 @@ /* - * i2c driver for Freescale mx31 + * i2c driver for Freescale i.MX series * * (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de> + * (c) 2011 Marek Vasut <marek.vasut@gmail.com> + * + * Based on i2c-imx.c from linux kernel: + * Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de> + * Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de> + * Copyright (C) 2007 RightHand Technologies, Inc. + * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt> + * * * See file CREDITS for list of people who contributed to this * project. @@ -30,11 +38,13 @@ #include <asm/arch/clock.h> #include <asm/arch/imx-regs.h> -#define IADR 0x00 -#define IFDR 0x04 -#define I2CR 0x08 -#define I2SR 0x0c -#define I2DR 0x10 +struct mxc_i2c_regs { + uint32_t iadr; + uint32_t ifdr; + uint32_t i2cr; + uint32_t i2sr; + uint32_t i2dr; +}; #define I2CR_IEN (1 << 7) #define I2CR_IIEN (1 << 6) @@ -68,215 +78,361 @@ #endif #define I2C_MAX_TIMEOUT 10000 -#define I2C_MAX_RETRIES 3 -static u16 div[] = { 30, 32, 36, 42, 48, 52, 60, 72, 80, 88, 104, 128, 144, - 160, 192, 240, 288, 320, 384, 480, 576, 640, 768, 960, - 1152, 1280, 1536, 1920, 2304, 2560, 3072, 3840}; +static u16 i2c_clk_div[50][2] = { + { 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 }, + { 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 }, + { 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 }, + { 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B }, + { 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A }, + { 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 }, + { 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 }, + { 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 }, + { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 }, + { 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B }, + { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E }, + { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D }, + { 3072, 0x1E }, { 3840, 0x1F } +}; -static inline void i2c_reset(void) -{ - writew(0, I2C_BASE + I2CR); /* Reset module */ - writew(0, I2C_BASE + I2SR); - writew(I2CR_IEN, I2C_BASE + I2CR); -} +static u8 clk_idx; -void i2c_init(int speed, int unused) +/* + * Calculate and set proper clock divider + */ +static void i2c_imx_set_clk(unsigned int rate) { - int freq; + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; + unsigned int i2c_clk_rate; + unsigned int div; int i; #if defined(CONFIG_MX31) struct clock_control_regs *sc_regs = (struct clock_control_regs *)CCM_BASE; + /* start the required I2C clock */ writel(readl(&sc_regs->cgr0) | (3 << I2C_CLK_OFFSET), &sc_regs->cgr0); #endif - freq = mxc_get_clock(MXC_IPG_PERCLK); - for (i = 0; i < 0x1f; i++) - if (freq / div[i] <= speed) - break; + /* Divider value calculation */ + i2c_clk_rate = mxc_get_clock(MXC_IPG_PERCLK); + div = (i2c_clk_rate + rate - 1) / rate; + if (div < i2c_clk_div[0][0]) + i = 0; + else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0]) + i = ARRAY_SIZE(i2c_clk_div) - 1; + else + for (i = 0; i2c_clk_div[i][0] < div; i++) + ; + + /* Store divider value */ + clk_idx = i2c_clk_div[i][1]; + writeb(clk_idx, &i2c_regs->ifdr); +} + +/* + * Reset I2C Controller + */ +void i2c_reset(void) +{ + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; - debug("%s: speed: %d\n", __func__, speed); + writeb(0, &i2c_regs->i2cr); /* Reset module */ + writeb(0, &i2c_regs->i2sr); +} - writew(i, I2C_BASE + IFDR); +/* + * Init I2C Bus + */ +void i2c_init(int speed, int unused) +{ + i2c_imx_set_clk(speed); i2c_reset(); } -static int wait_idle(void) +/* + * Wait for bus to be busy (or free if for_busy = 0) + * + * for_busy = 1: Wait for IBB to be asserted + * for_busy = 0: Wait for IBB to be de-asserted + */ +int i2c_imx_bus_busy(int for_busy) { + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; + unsigned int temp; + int timeout = I2C_MAX_TIMEOUT; - while ((readw(I2C_BASE + I2SR) & I2SR_IBB) && --timeout) { - writew(0, I2C_BASE + I2SR); + while (timeout--) { + temp = readb(&i2c_regs->i2sr); + + if (for_busy && (temp & I2SR_IBB)) + return 0; + if (!for_busy && !(temp & I2SR_IBB)) + return 0; + udelay(1); } - return timeout ? timeout : (!(readw(I2C_BASE + I2SR) & I2SR_IBB)); + + return 1; } -static int wait_busy(void) +/* + * Wait for transaction to complete + */ +int i2c_imx_trx_complete(void) { + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; int timeout = I2C_MAX_TIMEOUT; - while (!(readw(I2C_BASE + I2SR) & I2SR_IBB) && --timeout) + while (timeout--) { + if (readb(&i2c_regs->i2sr) & I2SR_IIF) { + writeb(0, &i2c_regs->i2sr); + return 0; + } + udelay(1); - writew(0, I2C_BASE + I2SR); /* clear interrupt */ + } - return timeout; + return 1; } -static int wait_complete(void) +/* + * Check if the transaction was ACKed + */ +int i2c_imx_acked(void) { - int timeout = I2C_MAX_TIMEOUT; + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; - while ((!(readw(I2C_BASE + I2SR) & I2SR_ICF)) && (--timeout)) { - writew(0, I2C_BASE + I2SR); - udelay(1); - } - udelay(200); + return readb(&i2c_regs->i2sr) & I2SR_RX_NO_AK; +} + +/* + * Start the controller + */ +int i2c_imx_start(void) +{ + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; + unsigned int temp = 0; + int result; - writew(0, I2C_BASE + I2SR); /* clear interrupt */ + writeb(clk_idx, &i2c_regs->ifdr); - return timeout; -} + /* Enable I2C controller */ + writeb(0, &i2c_regs->i2sr); + writeb(I2CR_IEN, &i2c_regs->i2cr); + /* Wait controller to be stable */ + udelay(50); -static int tx_byte(u8 byte) -{ - writew(byte, I2C_BASE + I2DR); + /* Start I2C transaction */ + temp = readb(&i2c_regs->i2cr); + temp |= I2CR_MSTA; + writeb(temp, &i2c_regs->i2cr); + + result = i2c_imx_bus_busy(1); + if (result) + return result; + + temp |= I2CR_MTX | I2CR_TX_NO_AK; + writeb(temp, &i2c_regs->i2cr); - if (!wait_complete() || readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK) - return -1; return 0; } -static int rx_byte(int last) +/* + * Stop the controller + */ +void i2c_imx_stop(void) { - if (!wait_complete()) - return -1; + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; + unsigned int temp = 0; + + /* Stop I2C transaction */ + temp = readb(&i2c_regs->i2cr); + temp |= ~(I2CR_MSTA | I2CR_MTX); + writeb(temp, &i2c_regs->i2cr); - if (last) - writew(I2CR_IEN, I2C_BASE + I2CR); + i2c_imx_bus_busy(0); - return readw(I2C_BASE + I2DR); + /* Disable I2C controller */ + writeb(0, &i2c_regs->i2cr); } -int i2c_probe(uchar chip) +/* + * Set chip address and access mode + * + * read = 1: READ access + * read = 0: WRITE access + */ +int i2c_imx_set_chip_addr(uchar chip, int read) { + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; int ret; - writew(0, I2C_BASE + I2CR); /* Reset module */ - writew(I2CR_IEN, I2C_BASE + I2CR); + writeb((chip << 1) | read, &i2c_regs->i2dr); + + ret = i2c_imx_trx_complete(); + if (ret) + return ret; - writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX, I2C_BASE + I2CR); - ret = tx_byte(chip << 1); - writew(I2CR_IEN | I2CR_MTX, I2C_BASE + I2CR); + ret = i2c_imx_acked(); + if (ret) + return ret; return ret; } -static int i2c_addr(uchar chip, uint addr, int alen) +/* + * Write register address + */ +int i2c_imx_set_reg_addr(uint addr, int alen) { - int i, retry = 0; - for (retry = 0; retry < 3; retry++) { - if (wait_idle()) + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; + int ret; + int i; + + for (i = 0; i < (8 * alen); i += 8) { + writeb((addr >> i) & 0xff, &i2c_regs->i2dr); + + ret = i2c_imx_trx_complete(); + if (ret) break; - i2c_reset(); - for (i = 0; i < I2C_MAX_TIMEOUT; i++) - udelay(1); - } - if (retry >= I2C_MAX_RETRIES) { - debug("%s:bus is busy(%x)\n", - __func__, readw(I2C_BASE + I2SR)); - return -1; - } - writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX, I2C_BASE + I2CR); - if (!wait_busy()) { - debug("%s:trigger start fail(%x)\n", - __func__, readw(I2C_BASE + I2SR)); - return -1; + ret = i2c_imx_acked(); + if (ret) + break; } - if (tx_byte(chip << 1) || (readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)) { - debug("%s:chip address cycle fail(%x)\n", - __func__, readw(I2C_BASE + I2SR)); - return -1; - } - while (alen--) - if (tx_byte((addr >> (alen * 8)) & 0xff) || - (readw(I2C_BASE + I2SR) & I2SR_RX_NO_AK)) { - debug("%s:device address cycle fail(%x)\n", - __func__, readw(I2C_BASE + I2SR)); - return -1; - } - return 0; + return ret; +} + +/* + * Try if a chip add given address responds (probe the chip) + */ +int i2c_probe(uchar chip) +{ + int ret; + + ret = i2c_imx_start(); + if (ret) + return ret; + + ret = i2c_imx_set_chip_addr(chip, 0); + if (ret) + return ret; + + i2c_imx_stop(); + + return ret; } +/* + * Read data from I2C device + */ int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) { - int timeout = I2C_MAX_TIMEOUT; + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; int ret; + unsigned int temp; + int i; - debug("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n", - __func__, chip, addr, alen, len); + ret = i2c_imx_start(); + if (ret) + return ret; - if (i2c_addr(chip, addr, alen)) { - printf("i2c_addr failed\n"); - return -1; - } + /* write slave address */ + ret = i2c_imx_set_chip_addr(chip, 0); + if (ret) + return ret; - writew(I2CR_IEN | I2CR_MSTA | I2CR_MTX | I2CR_RSTA, I2C_BASE + I2CR); + ret = i2c_imx_set_reg_addr(addr, alen); + if (ret) + return ret; - if (tx_byte(chip << 1 | 1)) - return -1; + temp = readb(&i2c_regs->i2cr); + temp |= I2CR_RSTA; + writeb(temp, &i2c_regs->i2cr); - writew(I2CR_IEN | I2CR_MSTA | - ((len == 1) ? I2CR_TX_NO_AK : 0), - I2C_BASE + I2CR); + ret = i2c_imx_set_chip_addr(chip, 1); + if (ret) + return ret; - ret = readw(I2C_BASE + I2DR); + /* setup bus to read data */ + temp = readb(&i2c_regs->i2cr); + temp &= ~(I2CR_MTX | I2CR_TX_NO_AK); + if (len == 1) + temp |= I2CR_TX_NO_AK; + writeb(temp, &i2c_regs->i2cr); + readb(&i2c_regs->i2dr); - while (len--) { - ret = rx_byte(len == 0); - if (ret < 0) - return -1; - *buf++ = ret; - if (len <= 1) - writew(I2CR_IEN | I2CR_MSTA | - I2CR_TX_NO_AK, - I2C_BASE + I2CR); - } + /* read data */ + for (i = 0; i < len; i++) { + ret = i2c_imx_trx_complete(); + if (ret) + return ret; - writew(I2CR_IEN, I2C_BASE + I2CR); + /* + * It must generate STOP before read I2DR to prevent + * controller from generating another clock cycle + */ + if (i == (len - 1)) { + temp = readb(&i2c_regs->i2cr); + temp &= ~(I2CR_MSTA | I2CR_MTX); + writeb(temp, &i2c_regs->i2cr); + i2c_imx_bus_busy(0); + } else if (i == (len - 2)) { + temp = readb(&i2c_regs->i2cr); + temp |= I2CR_TX_NO_AK; + writeb(temp, &i2c_regs->i2cr); + } - while (readw(I2C_BASE + I2SR) & I2SR_IBB && --timeout) - udelay(1); + buf[i] = readb(&i2c_regs->i2dr); + } - return 0; + i2c_imx_stop(); + + return ret; } +/* + * Write data to I2C device + */ int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len) { - int timeout = I2C_MAX_TIMEOUT; - debug("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n", - __func__, chip, addr, alen, len); + struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE; + int ret; + int i; - if (i2c_addr(chip, addr, alen)) - return -1; + ret = i2c_imx_start(); + if (ret) + return ret; - while (len--) - if (tx_byte(*buf++)) - return -1; + /* write slave address */ + ret = i2c_imx_set_chip_addr(chip, 0); + if (ret) + return ret; - writew(I2CR_IEN, I2C_BASE + I2CR); + ret = i2c_imx_set_reg_addr(addr, alen); + if (ret) + return ret; - while (readw(I2C_BASE + I2SR) & I2SR_IBB && --timeout) - udelay(1); + for (i = 0; i < len; i++) { + writeb(buf[i], &i2c_regs->i2dr); - return 0; -} + ret = i2c_imx_trx_complete(); + if (ret) + return ret; + + ret = i2c_imx_acked(); + if (ret) + return ret; + } + i2c_imx_stop(); + + return ret; +} #endif /* CONFIG_HARD_I2C */ |