diff options
Diffstat (limited to 'drivers/i2c/mxc_i2c.c')
| -rw-r--r-- | drivers/i2c/mxc_i2c.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c new file mode 100644 index 00000000000..a21832944d2 --- /dev/null +++ b/drivers/i2c/mxc_i2c.c @@ -0,0 +1,202 @@ +/* + * i2c driver for Freescale mx31 + * + * (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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> + +#if defined(CONFIG_HARD_I2C) && defined (CONFIG_I2C_MXC) + +#include <asm/arch/mx31.h> +#include <asm/arch/mx31-regs.h> + +#define IADR 0x00 +#define IFDR 0x04 +#define I2CR 0x08 +#define I2SR 0x0c +#define I2DR 0x10 + +#define I2CR_IEN (1 << 7) +#define I2CR_IIEN (1 << 6) +#define I2CR_MSTA (1 << 5) +#define I2CR_MTX (1 << 4) +#define I2CR_TX_NO_AK (1 << 3) +#define I2CR_RSTA (1 << 2) + +#define I2SR_ICF (1 << 7) +#define I2SR_IBB (1 << 5) +#define I2SR_IIF (1 << 1) +#define I2SR_RX_NO_AK (1 << 0) + +#ifdef CFG_I2C_MX31_PORT1 +#define I2C_BASE 0x43f80000 +#elif defined (CFG_I2C_MX31_PORT2) +#define I2C_BASE 0x43f98000 +#elif defined (CFG_I2C_MX31_PORT3) +#define I2C_BASE 0x43f84000 +#else +#error "define CFG_I2C_MX31_PORTx to use the mx31 I2C driver" +#endif + +#ifdef DEBUG +#define DPRINTF(args...) printf(args) +#else +#define DPRINTF(args...) +#endif + +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}; + +void i2c_init(int speed, int unused) +{ + int freq = mx31_get_ipg_clk(); + int i; + + for (i = 0; i < 0x1f; i++) + if (freq / div[i] <= speed) + break; + + DPRINTF("%s: speed: %d\n",__FUNCTION__, speed); + + __REG16(I2C_BASE + I2CR) = 0; /* Reset module */ + __REG16(I2C_BASE + IFDR) = i; + __REG16(I2C_BASE + I2CR) = I2CR_IEN; + __REG16(I2C_BASE + I2SR) = 0; +} + +static int wait_busy(void) +{ + int timeout = 10000; + + while (!(__REG16(I2C_BASE + I2SR) & I2SR_IIF) && --timeout) + udelay(1); + __REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */ + + return timeout; +} + +static int tx_byte(u8 byte) +{ + __REG16(I2C_BASE + I2DR) = byte; + + if (!wait_busy() || __REG16(I2C_BASE + I2SR) & I2SR_RX_NO_AK) + return -1; + return 0; +} + +static int rx_byte(void) +{ + if (!wait_busy()) + return -1; + + return __REG16(I2C_BASE + I2DR); +} + +int i2c_probe(uchar chip) +{ + int ret; + + __REG16(I2C_BASE + I2CR) = 0; /* Reset module */ + __REG16(I2C_BASE + I2CR) = I2CR_IEN; + + __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX; + ret = tx_byte(chip << 1); + __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MTX; + + return ret; +} + +static int i2c_addr(uchar chip, uint addr, int alen) +{ + __REG16(I2C_BASE + I2SR) = 0; /* clear interrupt */ + __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX; + + if (tx_byte(chip << 1)) + return -1; + + while (alen--) + if (tx_byte((addr >> (alen * 8)) & 0xff)) + return -1; + return 0; +} + +int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len) +{ + int timeout = 10000; + int ret; + + DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",__FUNCTION__, chip, addr, alen, len); + + if (i2c_addr(chip, addr, alen)) { + printf("i2c_addr failed\n"); + return -1; + } + + __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_MTX | I2CR_RSTA; + + if (tx_byte(chip << 1 | 1)) + return -1; + + __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | ((len == 1) ? I2CR_TX_NO_AK : 0); + + ret = __REG16(I2C_BASE + I2DR); + + while (len--) { + if ((ret = rx_byte()) < 0) + return -1; + *buf++ = ret; + if (len <= 1) + __REG16(I2C_BASE + I2CR) = I2CR_IEN | I2CR_MSTA | I2CR_TX_NO_AK; + } + + wait_busy(); + + __REG16(I2C_BASE + I2CR) = I2CR_IEN; + + while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout) + udelay(1); + + return 0; +} + +int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len) +{ + int timeout = 10000; + DPRINTF("%s chip: 0x%02x addr: 0x%04x alen: %d len: %d\n",__FUNCTION__, chip, addr, alen, len); + + if (i2c_addr(chip, addr, alen)) + return -1; + + while (len--) + if (tx_byte(*buf++)) + return -1; + + __REG16(I2C_BASE + I2CR) = I2CR_IEN; + + while (__REG16(I2C_BASE + I2SR) & I2SR_IBB && --timeout) + udelay(1); + + return 0; +} + +#endif /* CONFIG_HARD_I2C */ |