diff options
Diffstat (limited to 'src/soc/samsung/exynos5250/i2c.c')
| -rw-r--r-- | src/soc/samsung/exynos5250/i2c.c | 403 |
1 files changed, 403 insertions, 0 deletions
diff --git a/src/soc/samsung/exynos5250/i2c.c b/src/soc/samsung/exynos5250/i2c.c new file mode 100644 index 0000000000..e83ab57014 --- /dev/null +++ b/src/soc/samsung/exynos5250/i2c.c @@ -0,0 +1,403 @@ +/* + * This file is part of the coreboot project. + * + * (C) Copyright 2002 + * David Mueller, ELSOFT AG, d.mueller@elsoft.ch + * + * 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; version 2 of the License. + * + * 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <console/console.h> +#include <delay.h> +#include <arch/io.h> +#include <device/i2c.h> +#include "clk.h" +#include "i2c.h" + +#define I2C_WRITE 0 +#define I2C_READ 1 + +#define I2C_OK 0 +#define I2C_NOK 1 +#define I2C_NACK 2 +#define I2C_NOK_LA 3 /* Lost arbitration */ +#define I2C_NOK_TOUT 4 /* time out */ + +#define I2CSTAT_BSY 0x20 /* Busy bit */ +#define I2CSTAT_NACK 0x01 /* Nack bit */ +#define I2CCON_ACKGEN 0x80 /* Acknowledge generation */ +#define I2CCON_IRPND 0x10 /* Interrupt pending bit */ +#define I2C_MODE_MT 0xC0 /* Master Transmit Mode */ +#define I2C_MODE_MR 0x80 /* Master Receive Mode */ +#define I2C_START_STOP 0x20 /* START / STOP */ +#define I2C_TXRX_ENA 0x10 /* I2C Tx/Rx enable */ + +/* The timeouts we live by */ +enum { + I2C_XFER_TIMEOUT_MS = 35, /* xfer to complete */ + I2C_INIT_TIMEOUT_MS = 1000, /* bus free on init */ + I2C_IDLE_TIMEOUT_MS = 100, /* waiting for bus idle */ + I2C_STOP_TIMEOUT_US = 200, /* waiting for stop events */ +}; + +static struct s3c24x0_i2c_bus i2c_buses[] = { + { + .bus_num = 0, + .regs = (struct s3c24x0_i2c *)0x12c60000, + .periph_id = PERIPH_ID_I2C0, + }, + { + .bus_num = 1, + .regs = (struct s3c24x0_i2c *)0x12c70000, + .periph_id = PERIPH_ID_I2C1, + }, + { + .bus_num = 2, + .regs = (struct s3c24x0_i2c *)0x12c80000, + .periph_id = PERIPH_ID_I2C2, + }, + { + .bus_num = 3, + .regs = (struct s3c24x0_i2c *)0x12c90000, + .periph_id = PERIPH_ID_I2C3, + }, + { + .bus_num = 4, + .regs = (struct s3c24x0_i2c *)0x12ca0000, + .periph_id = PERIPH_ID_I2C4, + }, + { + .bus_num = 5, + .regs = (struct s3c24x0_i2c *)0x12cb0000, + .periph_id = PERIPH_ID_I2C5, + }, + { + .bus_num = 6, + .regs = (struct s3c24x0_i2c *)0x12cc0000, + .periph_id = PERIPH_ID_I2C6, + }, + { + .bus_num = 7, + .regs = (struct s3c24x0_i2c *)0x12cd0000, + .periph_id = PERIPH_ID_I2C7, + }, +}; + +static int WaitForXfer(struct s3c24x0_i2c *i2c) +{ + int i; + + i = I2C_XFER_TIMEOUT_MS * 20; + while (!(readl(&i2c->iiccon) & I2CCON_IRPND)) { + if (i == 0) { + printk(BIOS_ERR, "%s: i2c xfer timeout\n", __func__); + return I2C_NOK_TOUT; + } + udelay(50); + i--; + } + + return I2C_OK; +} + +static int IsACK(struct s3c24x0_i2c *i2c) +{ + return !(readl(&i2c->iicstat) & I2CSTAT_NACK); +} + +static void ReadWriteByte(struct s3c24x0_i2c *i2c) +{ + uint32_t x; + + x = readl(&i2c->iiccon); + writel(x & ~I2CCON_IRPND, &i2c->iiccon); +} + +static void i2c_ch_init(struct s3c24x0_i2c_bus *bus, int speed, int slaveadd) +{ + unsigned long freq, pres = 16, div; + unsigned long val; + + freq = clock_get_periph_rate(bus->periph_id); + /* calculate prescaler and divisor values */ + if ((freq / pres / (16 + 1)) > speed) + /* set prescaler to 512 */ + pres = 512; + + div = 0; + + while ((freq / pres / (div + 1)) > speed) + div++; + + /* set prescaler, divisor according to freq, also set ACKGEN, IRQ */ + val = (div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0); + writel(val, &bus->regs->iiccon); + + /* init to SLAVE RECEIVE mode and clear I2CADDn */ + writel(0, &bus->regs->iicstat); + writel(slaveadd, &bus->regs->iicadd); + /* program Master Transmit (and implicit STOP) */ + writel(I2C_MODE_MT | I2C_TXRX_ENA, &bus->regs->iicstat); +} + +/* + * MULTI BUS I2C support + */ +static void i2c_bus_init(struct s3c24x0_i2c_bus *bus, int speed, int slaveadd) +{ + i2c_ch_init(bus, speed, slaveadd); +} + +/* + * Verify the whether I2C ACK was received or not + * + * @param i2c pointer to I2C register base + * @param buf array of data + * @param len length of data + * return I2C_OK when transmission done + * I2C_NACK otherwise + */ +static int i2c_send_verify(struct s3c24x0_i2c *i2c, unsigned char buf[], + unsigned char len) +{ + int i, result = I2C_OK; + + if (IsACK(i2c)) { + for (i = 0; (i < len) && (result == I2C_OK); i++) { + writel(buf[i], &i2c->iicds); + ReadWriteByte(i2c); + result = WaitForXfer(i2c); + if (result == I2C_OK && !IsACK(i2c)) + result = I2C_NACK; + } + } else { + result = I2C_NACK; + } + + return result; +} + +void i2c_init(unsigned bus_num, int speed, int slaveadd) +{ + struct s3c24x0_i2c_bus *i2c; + int i; + + i2c = &i2c_buses[bus_num]; + i2c_bus_init(i2c, speed, slaveadd); + + /* wait for some time to give previous transfer a chance to finish */ + i = I2C_INIT_TIMEOUT_MS * 20; + while ((readl(&i2c->regs->iicstat) & I2CSTAT_BSY) && (i > 0)) { + udelay(50); + i--; + } + + i2c_ch_init(i2c, speed, slaveadd); +} + +/* + * Send a STOP event and wait for it to have completed + * + * @param mode If it is a master transmitter or receiver + * @return I2C_OK if the line became idle before timeout I2C_NOK_TOUT otherwise + */ +static int i2c_send_stop(struct s3c24x0_i2c *i2c, int mode) +{ + int timeout; + + /* Setting the STOP event to fire */ + writel(mode | I2C_TXRX_ENA, &i2c->iicstat); + ReadWriteByte(i2c); + + /* Wait for the STOP to send and the bus to go idle */ + for (timeout = I2C_STOP_TIMEOUT_US; timeout > 0; timeout -= 5) { + if (!(readl(&i2c->iicstat) & I2CSTAT_BSY)) + return I2C_OK; + udelay(5); + } + + return I2C_NOK_TOUT; +} + +/* + * cmd_type is 0 for write, 1 for read. + * + * addr_len can take any value from 0-255, it is only limited + * by the char, we could make it larger if needed. If it is + * 0 we skip the address write cycle. + */ +static int i2c_transfer(struct s3c24x0_i2c *i2c, + unsigned char cmd_type, + unsigned char chip, + unsigned char addr[], + unsigned char addr_len, + unsigned char data[], + unsigned short data_len) +{ + int i, result, stop_bit_result; + uint32_t x; + + if (data == 0 || data_len == 0) { + /* Don't support data transfer of no length or to address 0 */ + printk(BIOS_ERR, "i2c_transfer: bad call\n"); + return I2C_NOK; + } + + /* Check I2C bus idle */ + i = I2C_IDLE_TIMEOUT_MS * 20; + while ((readl(&i2c->iicstat) & I2CSTAT_BSY) && (i > 0)) { + udelay(50); + i--; + } + + if (readl(&i2c->iicstat) & I2CSTAT_BSY) { + printk(BIOS_ERR, "%s: bus busy\n", __func__); + return I2C_NOK_TOUT; + } + + x = readl(&i2c->iiccon); + writel(x | I2CCON_ACKGEN, &i2c->iiccon); + + if (addr && addr_len) { + writel(chip, &i2c->iicds); + /* send START */ + writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP, + &i2c->iicstat); + if (WaitForXfer(i2c) == I2C_OK) + result = i2c_send_verify(i2c, addr, addr_len); + else + result = I2C_NACK; + } else + result = I2C_NACK; + + switch (cmd_type) { + case I2C_WRITE: + if (result == I2C_OK) + result = i2c_send_verify(i2c, data, data_len); + else { + writel(chip, &i2c->iicds); + /* send START */ + writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP, + &i2c->iicstat); + if (WaitForXfer(i2c) == I2C_OK) + result = i2c_send_verify(i2c, data, data_len); + } + + if (result == I2C_OK) + result = WaitForXfer(i2c); + + stop_bit_result = i2c_send_stop(i2c, I2C_MODE_MT); + break; + + case I2C_READ: + { + int was_ok = (result == I2C_OK); + + writel(chip, &i2c->iicds); + /* resend START */ + writel(I2C_MODE_MR | I2C_TXRX_ENA | + I2C_START_STOP, &i2c->iicstat); + ReadWriteByte(i2c); + result = WaitForXfer(i2c); + + if (was_ok || IsACK(i2c)) { + i = 0; + while ((i < data_len) && (result == I2C_OK)) { + /* disable ACK for final READ */ + if (i == data_len - 1) { + x = readl(&i2c->iiccon) & ~I2CCON_ACKGEN; + writel(x, &i2c->iiccon); + } + ReadWriteByte(i2c); + result = WaitForXfer(i2c); + data[i] = readl(&i2c->iicds); + i++; + } + } else { + result = I2C_NACK; + } + + stop_bit_result = i2c_send_stop(i2c, I2C_MODE_MR); + break; + } + + default: + printk(BIOS_ERR, "i2c_transfer: bad call\n"); + result = stop_bit_result = I2C_NOK; + break; + } + + /* + * If the transmission went fine, then only the stop bit was left to + * fail. Otherwise, the real failure we're interested in came before + * that, during the actual transmission. + */ + return (result == I2C_OK) ? stop_bit_result : result; +} + +int i2c_read(unsigned bus, unsigned chip, unsigned addr, + unsigned alen, uint8_t *buf, unsigned len) +{ + struct s3c24x0_i2c_bus *i2c; + unsigned char xaddr[4]; + int ret; + + if (alen > 4) { + printk(BIOS_ERR, "I2C read: addr len %d not supported\n", alen); + return 1; + } + + if (alen > 0) { + xaddr[0] = (addr >> 24) & 0xFF; + xaddr[1] = (addr >> 16) & 0xFF; + xaddr[2] = (addr >> 8) & 0xFF; + xaddr[3] = addr & 0xFF; + } + + i2c = &i2c_buses[bus]; + ret = i2c_transfer(i2c->regs, I2C_READ, chip << 1, &xaddr[4 - alen], + alen, buf, len); + if (ret) { + printk(BIOS_ERR, "I2c read: failed %d\n", ret); + return 1; + } + return 0; +} + +int i2c_write(unsigned bus, unsigned chip, unsigned addr, + unsigned alen, const uint8_t *buf, unsigned len) +{ + struct s3c24x0_i2c_bus *i2c; + unsigned char xaddr[4]; + int ret; + + if (alen > 4) { + printk(BIOS_ERR, "I2C write: addr len %d not supported\n", + alen); + return 1; + } + + if (alen > 0) { + xaddr[0] = (addr >> 24) & 0xFF; + xaddr[1] = (addr >> 16) & 0xFF; + xaddr[2] = (addr >> 8) & 0xFF; + xaddr[3] = addr & 0xFF; + } + + i2c = &i2c_buses[bus]; + ret = i2c_transfer(i2c->regs, I2C_WRITE, chip << 1, &xaddr[4 - alen], + alen, (void *)buf, len); + + return ret != 0; +} |