diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-octeon-core.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-octeon-core.c | 827 |
1 files changed, 827 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-octeon-core.c b/drivers/i2c/busses/i2c-octeon-core.c new file mode 100644 index 000000000000..419b54bfc7c7 --- /dev/null +++ b/drivers/i2c/busses/i2c-octeon-core.c @@ -0,0 +1,827 @@ +/* + * (C) Copyright 2009-2010 + * Nokia Siemens Networks, michael.lawnick.ext@nsn.com + * + * Portions Copyright (C) 2010 - 2016 Cavium, Inc. + * + * This file contains the shared part of the driver for the i2c adapter in + * Cavium Networks' OCTEON processors and ThunderX SOCs. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> + +#include "i2c-octeon-core.h" + +/* interrupt service routine */ +irqreturn_t octeon_i2c_isr(int irq, void *dev_id) +{ + struct octeon_i2c *i2c = dev_id; + + i2c->int_disable(i2c); + wake_up(&i2c->queue); + + return IRQ_HANDLED; +} + +static bool octeon_i2c_test_iflg(struct octeon_i2c *i2c) +{ + return (octeon_i2c_ctl_read(i2c) & TWSI_CTL_IFLG); +} + +static bool octeon_i2c_test_ready(struct octeon_i2c *i2c, bool *first) +{ + if (octeon_i2c_test_iflg(i2c)) + return true; + + if (*first) { + *first = false; + return false; + } + + /* + * IRQ has signaled an event but IFLG hasn't changed. + * Sleep and retry once. + */ + usleep_range(I2C_OCTEON_EVENT_WAIT, 2 * I2C_OCTEON_EVENT_WAIT); + return octeon_i2c_test_iflg(i2c); +} + +/** + * octeon_i2c_wait - wait for the IFLG to be set + * @i2c: The struct octeon_i2c + * + * Returns 0 on success, otherwise a negative errno. + */ +static int octeon_i2c_wait(struct octeon_i2c *i2c) +{ + long time_left; + bool first = true; + + /* + * Some chip revisions don't assert the irq in the interrupt + * controller. So we must poll for the IFLG change. + */ + if (i2c->broken_irq_mode) { + u64 end = get_jiffies_64() + i2c->adap.timeout; + + while (!octeon_i2c_test_iflg(i2c) && + time_before64(get_jiffies_64(), end)) + usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT); + + return octeon_i2c_test_iflg(i2c) ? 0 : -ETIMEDOUT; + } + + i2c->int_enable(i2c); + time_left = wait_event_timeout(i2c->queue, octeon_i2c_test_ready(i2c, &first), + i2c->adap.timeout); + i2c->int_disable(i2c); + + if (i2c->broken_irq_check && !time_left && + octeon_i2c_test_iflg(i2c)) { + dev_err(i2c->dev, "broken irq connection detected, switching to polling mode.\n"); + i2c->broken_irq_mode = true; + return 0; + } + + if (!time_left) + return -ETIMEDOUT; + + return 0; +} + +static bool octeon_i2c_hlc_test_valid(struct octeon_i2c *i2c) +{ + return (__raw_readq(i2c->twsi_base + SW_TWSI(i2c)) & SW_TWSI_V) == 0; +} + +static bool octeon_i2c_hlc_test_ready(struct octeon_i2c *i2c, bool *first) +{ + /* check if valid bit is cleared */ + if (octeon_i2c_hlc_test_valid(i2c)) + return true; + + if (*first) { + *first = false; + return false; + } + + /* + * IRQ has signaled an event but valid bit isn't cleared. + * Sleep and retry once. + */ + usleep_range(I2C_OCTEON_EVENT_WAIT, 2 * I2C_OCTEON_EVENT_WAIT); + return octeon_i2c_hlc_test_valid(i2c); +} + +static void octeon_i2c_hlc_int_clear(struct octeon_i2c *i2c) +{ + /* clear ST/TS events, listen for neither */ + octeon_i2c_write_int(i2c, TWSI_INT_ST_INT | TWSI_INT_TS_INT); +} + +/* + * Cleanup low-level state & enable high-level controller. + */ +static void octeon_i2c_hlc_enable(struct octeon_i2c *i2c) +{ + int try = 0; + u64 val; + + if (i2c->hlc_enabled) + return; + i2c->hlc_enabled = true; + + while (1) { + val = octeon_i2c_ctl_read(i2c); + if (!(val & (TWSI_CTL_STA | TWSI_CTL_STP))) + break; + + /* clear IFLG event */ + if (val & TWSI_CTL_IFLG) + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); + + if (try++ > 100) { + pr_err("%s: giving up\n", __func__); + break; + } + + /* spin until any start/stop has finished */ + udelay(10); + } + octeon_i2c_ctl_write(i2c, TWSI_CTL_CE | TWSI_CTL_AAK | TWSI_CTL_ENAB); +} + +static void octeon_i2c_hlc_disable(struct octeon_i2c *i2c) +{ + if (!i2c->hlc_enabled) + return; + + i2c->hlc_enabled = false; + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); +} + +/** + * octeon_i2c_hlc_wait - wait for an HLC operation to complete + * @i2c: The struct octeon_i2c + * + * Returns 0 on success, otherwise -ETIMEDOUT. + */ +static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c) +{ + bool first = true; + int time_left; + + /* + * Some cn38xx boards don't assert the irq in the interrupt + * controller. So we must poll for the valid bit change. + */ + if (i2c->broken_irq_mode) { + u64 end = get_jiffies_64() + i2c->adap.timeout; + + while (!octeon_i2c_hlc_test_valid(i2c) && + time_before64(get_jiffies_64(), end)) + usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT); + + return octeon_i2c_hlc_test_valid(i2c) ? 0 : -ETIMEDOUT; + } + + i2c->hlc_int_enable(i2c); + time_left = wait_event_timeout(i2c->queue, + octeon_i2c_hlc_test_ready(i2c, &first), + i2c->adap.timeout); + i2c->hlc_int_disable(i2c); + if (!time_left) + octeon_i2c_hlc_int_clear(i2c); + + if (i2c->broken_irq_check && !time_left && + octeon_i2c_hlc_test_valid(i2c)) { + dev_err(i2c->dev, "broken irq connection detected, switching to polling mode.\n"); + i2c->broken_irq_mode = true; + return 0; + } + + if (!time_left) + return -ETIMEDOUT; + return 0; +} + +static int octeon_i2c_check_status(struct octeon_i2c *i2c, int final_read) +{ + u8 stat; + + /* + * This is ugly... in HLC mode the status is not in the status register + * but in the lower 8 bits of SW_TWSI. + */ + if (i2c->hlc_enabled) + stat = __raw_readq(i2c->twsi_base + SW_TWSI(i2c)); + else + stat = octeon_i2c_stat_read(i2c); + + switch (stat) { + /* Everything is fine */ + case STAT_IDLE: + case STAT_AD2W_ACK: + case STAT_RXADDR_ACK: + case STAT_TXADDR_ACK: + case STAT_TXDATA_ACK: + return 0; + + /* ACK allowed on pre-terminal bytes only */ + case STAT_RXDATA_ACK: + if (!final_read) + return 0; + return -EIO; + + /* NAK allowed on terminal byte only */ + case STAT_RXDATA_NAK: + if (final_read) + return 0; + return -EIO; + + /* Arbitration lost */ + case STAT_LOST_ARB_38: + case STAT_LOST_ARB_68: + case STAT_LOST_ARB_78: + case STAT_LOST_ARB_B0: + return -EAGAIN; + + /* Being addressed as slave, should back off & listen */ + case STAT_SLAVE_60: + case STAT_SLAVE_70: + case STAT_GENDATA_ACK: + case STAT_GENDATA_NAK: + return -EOPNOTSUPP; + + /* Core busy as slave */ + case STAT_SLAVE_80: + case STAT_SLAVE_88: + case STAT_SLAVE_A0: + case STAT_SLAVE_A8: + case STAT_SLAVE_LOST: + case STAT_SLAVE_NAK: + case STAT_SLAVE_ACK: + return -EOPNOTSUPP; + + case STAT_TXDATA_NAK: + return -EIO; + case STAT_TXADDR_NAK: + case STAT_RXADDR_NAK: + case STAT_AD2W_NAK: + return -ENXIO; + default: + dev_err(i2c->dev, "unhandled state: %d\n", stat); + return -EIO; + } +} + +static int octeon_i2c_recovery(struct octeon_i2c *i2c) +{ + int ret; + + ret = i2c_recover_bus(&i2c->adap); + if (ret) + /* recover failed, try hardware re-init */ + ret = octeon_i2c_init_lowlevel(i2c); + return ret; +} + +/** + * octeon_i2c_start - send START to the bus + * @i2c: The struct octeon_i2c + * + * Returns 0 on success, otherwise a negative errno. + */ +static int octeon_i2c_start(struct octeon_i2c *i2c) +{ + int ret; + u8 stat; + + octeon_i2c_hlc_disable(i2c); + + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STA); + ret = octeon_i2c_wait(i2c); + if (ret) + goto error; + + stat = octeon_i2c_stat_read(i2c); + if (stat == STAT_START || stat == STAT_REP_START) + /* START successful, bail out */ + return 0; + +error: + /* START failed, try to recover */ + ret = octeon_i2c_recovery(i2c); + return (ret) ? ret : -EAGAIN; +} + +/* send STOP to the bus */ +static void octeon_i2c_stop(struct octeon_i2c *i2c) +{ + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STP); +} + +/** + * octeon_i2c_read - receive data from the bus via low-level controller + * @i2c: The struct octeon_i2c + * @target: Target address + * @data: Pointer to the location to store the data + * @rlength: Length of the data + * @recv_len: flag for length byte + * + * The address is sent over the bus, then the data is read. + * + * Returns 0 on success, otherwise a negative errno. + */ +static int octeon_i2c_read(struct octeon_i2c *i2c, int target, + u8 *data, u16 *rlength, bool recv_len) +{ + int i, result, length = *rlength; + bool final_read = false; + + octeon_i2c_data_write(i2c, (target << 1) | 1); + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); + + result = octeon_i2c_wait(i2c); + if (result) + return result; + + /* address OK ? */ + result = octeon_i2c_check_status(i2c, false); + if (result) + return result; + + for (i = 0; i < length; i++) { + /* + * For the last byte to receive TWSI_CTL_AAK must not be set. + * + * A special case is I2C_M_RECV_LEN where we don't know the + * additional length yet. If recv_len is set we assume we're + * not reading the final byte and therefore need to set + * TWSI_CTL_AAK. + */ + if ((i + 1 == length) && !(recv_len && i == 0)) + final_read = true; + + /* clear iflg to allow next event */ + if (final_read) + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); + else + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_AAK); + + result = octeon_i2c_wait(i2c); + if (result) + return result; + + data[i] = octeon_i2c_data_read(i2c, &result); + if (result) + return result; + if (recv_len && i == 0) { + if (data[i] > I2C_SMBUS_BLOCK_MAX + 1) + return -EPROTO; + length += data[i]; + } + + result = octeon_i2c_check_status(i2c, final_read); + if (result) + return result; + } + *rlength = length; + return 0; +} + +/** + * octeon_i2c_write - send data to the bus via low-level controller + * @i2c: The struct octeon_i2c + * @target: Target address + * @data: Pointer to the data to be sent + * @length: Length of the data + * + * The address is sent over the bus, then the data. + * + * Returns 0 on success, otherwise a negative errno. + */ +static int octeon_i2c_write(struct octeon_i2c *i2c, int target, + const u8 *data, int length) +{ + int i, result; + + octeon_i2c_data_write(i2c, target << 1); + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); + + result = octeon_i2c_wait(i2c); + if (result) + return result; + + for (i = 0; i < length; i++) { + result = octeon_i2c_check_status(i2c, false); + if (result) + return result; + + octeon_i2c_data_write(i2c, data[i]); + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); + + result = octeon_i2c_wait(i2c); + if (result) + return result; + } + + return 0; +} + +/* high-level-controller pure read of up to 8 bytes */ +static int octeon_i2c_hlc_read(struct octeon_i2c *i2c, struct i2c_msg *msgs) +{ + int i, j, ret = 0; + u64 cmd; + + octeon_i2c_hlc_enable(i2c); + octeon_i2c_hlc_int_clear(i2c); + + cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR; + /* SIZE */ + cmd |= (u64)(msgs[0].len - 1) << SW_TWSI_SIZE_SHIFT; + /* A */ + cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT; + + if (msgs[0].flags & I2C_M_TEN) + cmd |= SW_TWSI_OP_10; + else + cmd |= SW_TWSI_OP_7; + + octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI(i2c)); + ret = octeon_i2c_hlc_wait(i2c); + if (ret) + goto err; + + cmd = __raw_readq(i2c->twsi_base + SW_TWSI(i2c)); + if ((cmd & SW_TWSI_R) == 0) + return octeon_i2c_check_status(i2c, false); + + for (i = 0, j = msgs[0].len - 1; i < msgs[0].len && i < 4; i++, j--) + msgs[0].buf[j] = (cmd >> (8 * i)) & 0xff; + + if (msgs[0].len > 4) { + cmd = __raw_readq(i2c->twsi_base + SW_TWSI_EXT(i2c)); + for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--) + msgs[0].buf[j] = (cmd >> (8 * i)) & 0xff; + } + +err: + return ret; +} + +/* high-level-controller pure write of up to 8 bytes */ +static int octeon_i2c_hlc_write(struct octeon_i2c *i2c, struct i2c_msg *msgs) +{ + int i, j, ret = 0; + u64 cmd; + + octeon_i2c_hlc_enable(i2c); + octeon_i2c_hlc_int_clear(i2c); + + cmd = SW_TWSI_V | SW_TWSI_SOVR; + /* SIZE */ + cmd |= (u64)(msgs[0].len - 1) << SW_TWSI_SIZE_SHIFT; + /* A */ + cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT; + + if (msgs[0].flags & I2C_M_TEN) + cmd |= SW_TWSI_OP_10; + else + cmd |= SW_TWSI_OP_7; + + for (i = 0, j = msgs[0].len - 1; i < msgs[0].len && i < 4; i++, j--) + cmd |= (u64)msgs[0].buf[j] << (8 * i); + + if (msgs[0].len > 4) { + u64 ext = 0; + + for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--) + ext |= (u64)msgs[0].buf[j] << (8 * i); + octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT(i2c)); + } + + octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI(i2c)); + ret = octeon_i2c_hlc_wait(i2c); + if (ret) + goto err; + + cmd = __raw_readq(i2c->twsi_base + SW_TWSI(i2c)); + if ((cmd & SW_TWSI_R) == 0) + return octeon_i2c_check_status(i2c, false); + +err: + return ret; +} + +/* high-level-controller composite write+read, msg0=addr, msg1=data */ +static int octeon_i2c_hlc_comp_read(struct octeon_i2c *i2c, struct i2c_msg *msgs) +{ + int i, j, ret = 0; + u64 cmd; + + octeon_i2c_hlc_enable(i2c); + + cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR; + /* SIZE */ + cmd |= (u64)(msgs[1].len - 1) << SW_TWSI_SIZE_SHIFT; + /* A */ + cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT; + + if (msgs[0].flags & I2C_M_TEN) + cmd |= SW_TWSI_OP_10_IA; + else + cmd |= SW_TWSI_OP_7_IA; + + if (msgs[0].len == 2) { + u64 ext = 0; + + cmd |= SW_TWSI_EIA; + ext = (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT; + cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT; + octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT(i2c)); + } else { + cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT; + } + + octeon_i2c_hlc_int_clear(i2c); + octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI(i2c)); + + ret = octeon_i2c_hlc_wait(i2c); + if (ret) + goto err; + + cmd = __raw_readq(i2c->twsi_base + SW_TWSI(i2c)); + if ((cmd & SW_TWSI_R) == 0) + return octeon_i2c_check_status(i2c, false); + + for (i = 0, j = msgs[1].len - 1; i < msgs[1].len && i < 4; i++, j--) + msgs[1].buf[j] = (cmd >> (8 * i)) & 0xff; + + if (msgs[1].len > 4) { + cmd = __raw_readq(i2c->twsi_base + SW_TWSI_EXT(i2c)); + for (i = 0; i < msgs[1].len - 4 && i < 4; i++, j--) + msgs[1].buf[j] = (cmd >> (8 * i)) & 0xff; + } + +err: + return ret; +} + +/* high-level-controller composite write+write, m[0]len<=2, m[1]len<=8 */ +static int octeon_i2c_hlc_comp_write(struct octeon_i2c *i2c, struct i2c_msg *msgs) +{ + bool set_ext = false; + int i, j, ret = 0; + u64 cmd, ext = 0; + + octeon_i2c_hlc_enable(i2c); + + cmd = SW_TWSI_V | SW_TWSI_SOVR; + /* SIZE */ + cmd |= (u64)(msgs[1].len - 1) << SW_TWSI_SIZE_SHIFT; + /* A */ + cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT; + + if (msgs[0].flags & I2C_M_TEN) + cmd |= SW_TWSI_OP_10_IA; + else + cmd |= SW_TWSI_OP_7_IA; + + if (msgs[0].len == 2) { + cmd |= SW_TWSI_EIA; + ext |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT; + set_ext = true; + cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT; + } else { + cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT; + } + + for (i = 0, j = msgs[1].len - 1; i < msgs[1].len && i < 4; i++, j--) + cmd |= (u64)msgs[1].buf[j] << (8 * i); + + if (msgs[1].len > 4) { + for (i = 0; i < msgs[1].len - 4 && i < 4; i++, j--) + ext |= (u64)msgs[1].buf[j] << (8 * i); + set_ext = true; + } + if (set_ext) + octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT(i2c)); + + octeon_i2c_hlc_int_clear(i2c); + octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI(i2c)); + + ret = octeon_i2c_hlc_wait(i2c); + if (ret) + goto err; + + cmd = __raw_readq(i2c->twsi_base + SW_TWSI(i2c)); + if ((cmd & SW_TWSI_R) == 0) + return octeon_i2c_check_status(i2c, false); + +err: + return ret; +} + +/** + * octeon_i2c_xfer - The driver's master_xfer function + * @adap: Pointer to the i2c_adapter structure + * @msgs: Pointer to the messages to be processed + * @num: Length of the MSGS array + * + * Returns the number of messages processed, or a negative errno on failure. + */ +int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + int i, ret = 0; + + if (num == 1) { + if (msgs[0].len > 0 && msgs[0].len <= 8) { + if (msgs[0].flags & I2C_M_RD) + ret = octeon_i2c_hlc_read(i2c, msgs); + else + ret = octeon_i2c_hlc_write(i2c, msgs); + goto out; + } + } else if (num == 2) { + if ((msgs[0].flags & I2C_M_RD) == 0 && + (msgs[1].flags & I2C_M_RECV_LEN) == 0 && + msgs[0].len > 0 && msgs[0].len <= 2 && + msgs[1].len > 0 && msgs[1].len <= 8 && + msgs[0].addr == msgs[1].addr) { + if (msgs[1].flags & I2C_M_RD) + ret = octeon_i2c_hlc_comp_read(i2c, msgs); + else + ret = octeon_i2c_hlc_comp_write(i2c, msgs); + goto out; + } + } + + for (i = 0; ret == 0 && i < num; i++) { + struct i2c_msg *pmsg = &msgs[i]; + + /* zero-length messages are not supported */ + if (!pmsg->len) { + ret = -EOPNOTSUPP; + break; + } + + ret = octeon_i2c_start(i2c); + if (ret) + return ret; + + if (pmsg->flags & I2C_M_RD) + ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf, + &pmsg->len, pmsg->flags & I2C_M_RECV_LEN); + else + ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf, + pmsg->len); + } + octeon_i2c_stop(i2c); +out: + return (ret != 0) ? ret : num; +} + +/* calculate and set clock divisors */ +void octeon_i2c_set_clock(struct octeon_i2c *i2c) +{ + int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff; + int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000; + + for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) { + /* + * An mdiv value of less than 2 seems to not work well + * with ds1337 RTCs, so we constrain it to larger values. + */ + for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) { + /* + * For given ndiv and mdiv values check the + * two closest thp values. + */ + tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10; + tclk *= (1 << ndiv_idx); + thp_base = (i2c->sys_freq / (tclk * 2)) - 1; + + for (inc = 0; inc <= 1; inc++) { + thp_idx = thp_base + inc; + if (thp_idx < 5 || thp_idx > 0xff) + continue; + + foscl = i2c->sys_freq / (2 * (thp_idx + 1)); + foscl = foscl / (1 << ndiv_idx); + foscl = foscl / (mdiv_idx + 1) / 10; + diff = abs(foscl - i2c->twsi_freq); + if (diff < delta_hz) { + delta_hz = diff; + thp = thp_idx; + mdiv = mdiv_idx; + ndiv = ndiv_idx; + } + } + } + } + octeon_i2c_reg_write(i2c, SW_TWSI_OP_TWSI_CLK, thp); + octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv); +} + +int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c) +{ + u8 status = 0; + int tries; + + /* reset controller */ + octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_RST, 0); + + for (tries = 10; tries && status != STAT_IDLE; tries--) { + udelay(1); + status = octeon_i2c_stat_read(i2c); + if (status == STAT_IDLE) + break; + } + + if (status != STAT_IDLE) { + dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n", + __func__, status); + return -EIO; + } + + /* toggle twice to force both teardowns */ + octeon_i2c_hlc_enable(i2c); + octeon_i2c_hlc_disable(i2c); + return 0; +} + +static int octeon_i2c_get_scl(struct i2c_adapter *adap) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + u64 state; + + state = octeon_i2c_read_int(i2c); + return state & TWSI_INT_SCL; +} + +static void octeon_i2c_set_scl(struct i2c_adapter *adap, int val) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + + octeon_i2c_write_int(i2c, val ? 0 : TWSI_INT_SCL_OVR); +} + +static int octeon_i2c_get_sda(struct i2c_adapter *adap) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + u64 state; + + state = octeon_i2c_read_int(i2c); + return state & TWSI_INT_SDA; +} + +static void octeon_i2c_prepare_recovery(struct i2c_adapter *adap) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + + octeon_i2c_hlc_disable(i2c); + + /* + * Bring control register to a good state regardless + * of HLC state. + */ + octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); + + octeon_i2c_write_int(i2c, 0); +} + +static void octeon_i2c_unprepare_recovery(struct i2c_adapter *adap) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + + /* + * Generate STOP to finish the unfinished transaction. + * Can't generate STOP via the TWSI CTL register + * since it could bring the TWSI controller into an inoperable state. + */ + octeon_i2c_write_int(i2c, TWSI_INT_SDA_OVR | TWSI_INT_SCL_OVR); + udelay(5); + octeon_i2c_write_int(i2c, TWSI_INT_SDA_OVR); + udelay(5); + octeon_i2c_write_int(i2c, 0); +} + +struct i2c_bus_recovery_info octeon_i2c_recovery_info = { + .recover_bus = i2c_generic_scl_recovery, + .get_scl = octeon_i2c_get_scl, + .set_scl = octeon_i2c_set_scl, + .get_sda = octeon_i2c_get_sda, + .prepare_recovery = octeon_i2c_prepare_recovery, + .unprepare_recovery = octeon_i2c_unprepare_recovery, +}; |