diff options
| -rw-r--r-- | arch/blackfin/include/asm/twi.h | 15 | ||||
| -rw-r--r-- | drivers/i2c/adi_i2c.c | 378 |
2 files changed, 393 insertions, 0 deletions
diff --git a/arch/blackfin/include/asm/twi.h b/arch/blackfin/include/asm/twi.h new file mode 100644 index 0000000..922cdbd --- /dev/null +++ b/arch/blackfin/include/asm/twi.h @@ -0,0 +1,15 @@ +/* + * i2c.c - driver for Blackfin on-chip TWI/I2C + * + * Copyright (c) 2006-2010 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#ifndef __ARCH_TWI_H +#define __ARCH_TWI_H + +#include <asm/blackfin.h> +#include <asm/mach-common/bits/twi.h> + +#endif diff --git a/drivers/i2c/adi_i2c.c b/drivers/i2c/adi_i2c.c new file mode 100644 index 0000000..743aa25 --- /dev/null +++ b/drivers/i2c/adi_i2c.c @@ -0,0 +1,378 @@ +/* + * i2c.c - driver for Blackfin on-chip TWI/I2C + * + * Copyright (c) 2006-2010 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#include <common.h> +#include <i2c.h> + +#include <asm/clock.h> +#include <asm/twi.h> + +/* Every register is 32bit aligned, but only 16bits in size */ +#define ureg(name) u16 name; u16 __pad_##name; +struct twi_regs { + ureg(clkdiv); + ureg(control); + ureg(slave_ctl); + ureg(slave_stat); + ureg(slave_addr); + ureg(master_ctl); + ureg(master_stat); + ureg(master_addr); + ureg(int_stat); + ureg(int_mask); + ureg(fifo_ctl); + ureg(fifo_stat); + char __pad[0x50]; + ureg(xmt_data8); + ureg(xmt_data16); + ureg(rcv_data8); + ureg(rcv_data16); +}; +#undef ureg + +/* U-Boot I2C framework allows only one active device at a time. */ +#ifdef TWI_CLKDIV +#define TWI0_CLKDIV TWI_CLKDIV +#endif +static volatile struct twi_regs *twi = (void *)TWI0_CLKDIV; + +#ifdef DEBUG +# define dmemset(s, c, n) memset(s, c, n) +#else +# define dmemset(s, c, n) +#endif +#define debugi(fmt, args...) \ + debug( \ + "MSTAT:0x%03x FSTAT:0x%x ISTAT:0x%02x\t%-20s:%-3i: " fmt "\n", \ + twi->master_stat, twi->fifo_stat, twi->int_stat, \ + __func__, __LINE__, ## args) + +#ifdef CONFIG_TWICLK_KHZ +# error do not define CONFIG_TWICLK_KHZ ... use CONFIG_SYS_I2C_SPEED +#endif + +/* + * The way speed is changed into duty often results in integer truncation + * with 50% duty, so we'll force rounding up to the next duty by adding 1 + * to the max. In practice this will get us a speed of something like + * 385 KHz. The other limit is easy to handle as it is only 8 bits. + */ +#define I2C_SPEED_MAX 400000 +#define I2C_SPEED_TO_DUTY(speed) (5000000 / (speed)) +#define I2C_DUTY_MAX (I2C_SPEED_TO_DUTY(I2C_SPEED_MAX) + 1) +#define I2C_DUTY_MIN 0xff /* 8 bit limited */ +#define SYS_I2C_DUTY I2C_SPEED_TO_DUTY(CONFIG_SYS_I2C_SPEED) +/* Note: duty is inverse of speed, so the comparisons below are correct */ +#if SYS_I2C_DUTY < I2C_DUTY_MAX || SYS_I2C_DUTY > I2C_DUTY_MIN +# error "The Blackfin I2C hardware can only operate 20KHz - 400KHz" +#endif + +/* All transfers are described by this data structure */ +struct i2c_msg { + u8 flags; +#define I2C_M_COMBO 0x4 +#define I2C_M_STOP 0x2 +#define I2C_M_READ 0x1 + int len; /* msg length */ + u8 *buf; /* pointer to msg data */ + int alen; /* addr length */ + u8 *abuf; /* addr buffer */ +}; + +/* Allow msec timeout per ~byte transfer */ +#define I2C_TIMEOUT 10 + +/** + * wait_for_completion - manage the actual i2c transfer + * @msg: the i2c msg + */ +static int wait_for_completion(struct i2c_msg *msg) +{ + uint16_t int_stat; + ulong timebase = get_timer(0); + + do { + int_stat = twi->int_stat; + + if (int_stat & XMTSERV) { + debugi("processing XMTSERV"); + twi->int_stat = XMTSERV; + SSYNC(); + if (msg->alen) { + twi->xmt_data8 = *(msg->abuf++); + --msg->alen; + } else if (!(msg->flags & I2C_M_COMBO) && msg->len) { + twi->xmt_data8 = *(msg->buf++); + --msg->len; + } else { + twi->master_ctl |= (msg->flags & I2C_M_COMBO) ? RSTART | MDIR : STOP; + SSYNC(); + } + } + if (int_stat & RCVSERV) { + debugi("processing RCVSERV"); + twi->int_stat = RCVSERV; + SSYNC(); + if (msg->len) { + *(msg->buf++) = twi->rcv_data8; + --msg->len; + } else if (msg->flags & I2C_M_STOP) { + twi->master_ctl |= STOP; + SSYNC(); + } + } + if (int_stat & MERR) { + debugi("processing MERR"); + twi->int_stat = MERR; + SSYNC(); + return msg->len; + } + if (int_stat & MCOMP) { + debugi("processing MCOMP"); + twi->int_stat = MCOMP; + SSYNC(); + if (msg->flags & I2C_M_COMBO && msg->len) { + twi->master_ctl = (twi->master_ctl & ~RSTART) | + (min(msg->len, 0xff) << 6) | MEN | MDIR; + SSYNC(); + } else + break; + } + + /* If we were able to do something, reset timeout */ + if (int_stat) + timebase = get_timer(0); + + } while (get_timer(timebase) < I2C_TIMEOUT); + + return msg->len; +} + +/** + * i2c_transfer - setup an i2c transfer + * @return: 0 if things worked, non-0 if things failed + * + * Here we just get the i2c stuff all prepped and ready, and then tail off + * into wait_for_completion() for all the bits to go. + */ +static int i2c_transfer(uchar chip, uint addr, int alen, uchar *buffer, int len, u8 flags) +{ + uchar addr_buffer[] = { + (addr >> 0), + (addr >> 8), + (addr >> 16), + }; + struct i2c_msg msg = { + .flags = flags | (len >= 0xff ? I2C_M_STOP : 0), + .buf = buffer, + .len = len, + .abuf = addr_buffer, + .alen = alen, + }; + int ret; + + dmemset(buffer, 0xff, len); + debugi("chip=0x%x addr=0x%02x alen=%i buf[0]=0x%02x len=%i flags=0x%02x[%s] ", + chip, addr, alen, buffer[0], len, flags, (flags & I2C_M_READ ? "rd" : "wr")); + + /* wait for things to settle */ + while (twi->master_stat & BUSBUSY) + if (ctrlc()) + return 1; + + /* Set Transmit device address */ + twi->master_addr = chip; + + /* Clear the FIFO before starting things */ + twi->fifo_ctl = XMTFLUSH | RCVFLUSH; + SSYNC(); + twi->fifo_ctl = 0; + SSYNC(); + + /* prime the pump */ + if (msg.alen) { + len = (msg.flags & I2C_M_COMBO) ? msg.alen : msg.alen + len; + debugi("first byte=0x%02x", *msg.abuf); + twi->xmt_data8 = *(msg.abuf++); + --msg.alen; + } else if (!(msg.flags & I2C_M_READ) && msg.len) { + debugi("first byte=0x%02x", *msg.buf); + twi->xmt_data8 = *(msg.buf++); + --msg.len; + } + + /* clear int stat */ + twi->master_stat = -1; + twi->int_stat = -1; + twi->int_mask = 0; + SSYNC(); + + /* Master enable */ + twi->master_ctl = + (twi->master_ctl & FAST) | + (min(len, 0xff) << 6) | MEN | + ((msg.flags & I2C_M_READ) ? MDIR : 0); + SSYNC(); + debugi("CTL=0x%04x", twi->master_ctl); + + /* process the rest */ + ret = wait_for_completion(&msg); + debugi("ret=%d", ret); + + if (ret) { + twi->master_ctl &= ~MEN; + twi->control &= ~TWI_ENA; + SSYNC(); + twi->control |= TWI_ENA; + SSYNC(); + } + + return ret; +} + +/** + * i2c_set_bus_speed - set i2c bus speed + * @speed: bus speed (in HZ) + */ +int i2c_set_bus_speed(unsigned int speed) +{ + u16 clkdiv = I2C_SPEED_TO_DUTY(speed); + + /* Set TWI interface clock */ + if (clkdiv < I2C_DUTY_MAX || clkdiv > I2C_DUTY_MIN) + return -1; + twi->clkdiv = (clkdiv << 8) | (clkdiv & 0xff); + + /* Don't turn it on */ + twi->master_ctl = (speed > 100000 ? FAST : 0); + + return 0; +} + +/** + * i2c_get_bus_speed - get i2c bus speed + * @speed: bus speed (in HZ) + */ +unsigned int i2c_get_bus_speed(void) +{ + /* 10 MHz / (2 * CLKDIV) -> 5 MHz / CLKDIV */ + return 5000000 / (twi->clkdiv & 0xff); +} + +/** + * i2c_init - initialize the i2c bus + * @speed: bus speed (in HZ) + * @slaveaddr: address of device in slave mode (0 - not slave) + * + * Slave mode isn't actually implemented. It'll stay that way until + * we get a real request for it. + */ +void i2c_init(int speed, int slaveaddr) +{ + uint8_t prescale = ((get_i2c_clk() / 1000 / 1000 + 5) / 10) & 0x7F; + + /* Set TWI internal clock as 10MHz */ + twi->control = prescale; + + /* Set TWI interface clock as specified */ + i2c_set_bus_speed(speed); + + /* Enable it */ + twi->control = TWI_ENA | prescale; + SSYNC(); + + debugi("CONTROL:0x%04x CLKDIV:0x%04x", twi->control, twi->clkdiv); + +#if CONFIG_SYS_I2C_SLAVE +# error I2C slave support not tested/supported + /* If they want us as a slave, do it */ + if (slaveaddr) { + twi->slave_addr = slaveaddr; + twi->slave_ctl = SEN; + } +#endif +} + +/** + * i2c_probe - test if a chip exists at a given i2c address + * @chip: i2c chip addr to search for + * @return: 0 if found, non-0 if not found + */ +int i2c_probe(uchar chip) +{ + u8 byte; + return i2c_read(chip, 0, 0, &byte, 1); +} + +/** + * i2c_read - read data from an i2c device + * @chip: i2c chip addr + * @addr: memory (register) address in the chip + * @alen: byte size of address + * @buffer: buffer to store data read from chip + * @len: how many bytes to read + * @return: 0 on success, non-0 on failure + */ +int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len) +{ + return i2c_transfer(chip, addr, alen, buffer, len, (alen ? I2C_M_COMBO : I2C_M_READ)); +} + +/** + * i2c_write - write data to an i2c device + * @chip: i2c chip addr + * @addr: memory (register) address in the chip + * @alen: byte size of address + * @buffer: buffer holding data to write to chip + * @len: how many bytes to write + * @return: 0 on success, non-0 on failure + */ +int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len) +{ + return i2c_transfer(chip, addr, alen, buffer, len, 0); +} + +/** + * i2c_set_bus_num - change active I2C bus + * @bus: bus index, zero based + * @returns: 0 on success, non-0 on failure + */ +int i2c_set_bus_num(unsigned int bus) +{ + switch (bus) { +#if CONFIG_SYS_MAX_I2C_BUS > 0 + case 0: twi = (void *)TWI0_CLKDIV; return 0; +#endif +#if CONFIG_SYS_MAX_I2C_BUS > 1 + case 1: twi = (void *)TWI1_CLKDIV; return 0; +#endif +#if CONFIG_SYS_MAX_I2C_BUS > 2 + case 2: twi = (void *)TWI2_CLKDIV; return 0; +#endif + default: return -1; + } +} + +/** + * i2c_get_bus_num - returns index of active I2C bus + */ +unsigned int i2c_get_bus_num(void) +{ + switch ((unsigned long)twi) { +#if CONFIG_SYS_MAX_I2C_BUS > 0 + case TWI0_CLKDIV: return 0; +#endif +#if CONFIG_SYS_MAX_I2C_BUS > 1 + case TWI1_CLKDIV: return 1; +#endif +#if CONFIG_SYS_MAX_I2C_BUS > 2 + case TWI2_CLKDIV: return 2; +#endif + default: return -1; + } +} |