| /* |
| * This file is part of the coreboot project. |
| * |
| * Copyright 2009 Vipin Kumar, ST Microelectronics |
| * Copyright 2016 Google Inc. |
| * |
| * 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. |
| */ |
| |
| #include <arch/acpigen.h> |
| #include <arch/io.h> |
| #include <console/console.h> |
| #include <device/device.h> |
| #include <device/i2c.h> |
| #include <device/pci.h> |
| #include <device/pci_def.h> |
| #include <device/pci_ids.h> |
| #include <intelblocks/lpss_i2c.h> |
| #include <string.h> |
| #include <timer.h> |
| #include "lpss_i2c.h" |
| |
| /* Use a ~10ms timeout for various operations */ |
| #define LPSS_I2C_TIMEOUT_US 10000 |
| |
| /* High and low times in different speed modes (in ns) */ |
| enum { |
| /* SDA Hold Time */ |
| DEFAULT_SDA_HOLD_TIME = 300, |
| /* Standard Speed */ |
| MIN_SS_SCL_HIGHTIME = 4000, |
| MIN_SS_SCL_LOWTIME = 4700, |
| /* Fast Speed */ |
| MIN_FS_SCL_HIGHTIME = 600, |
| MIN_FS_SCL_LOWTIME = 1300, |
| /* Fast Plus Speed */ |
| MIN_FP_SCL_HIGHTIME = 260, |
| MIN_FP_SCL_LOWTIME = 500, |
| /* High Speed */ |
| MIN_HS_SCL_HIGHTIME = 60, |
| MIN_HS_SCL_LOWTIME = 160, |
| }; |
| |
| /* Frequency represented as ticks per ns. Can also be used to calculate |
| * the number of ticks to meet a time target or the period. */ |
| struct freq { |
| uint32_t ticks; |
| uint32_t ns; |
| }; |
| |
| /* Control register definitions */ |
| enum { |
| CONTROL_MASTER_MODE = (1 << 0), |
| CONTROL_SPEED_SS = (1 << 1), |
| CONTROL_SPEED_FS = (1 << 2), |
| CONTROL_SPEED_HS = (3 << 1), |
| CONTROL_SPEED_MASK = (3 << 1), |
| CONTROL_10BIT_SLAVE = (1 << 3), |
| CONTROL_10BIT_MASTER = (1 << 4), |
| CONTROL_RESTART_ENABLE = (1 << 5), |
| CONTROL_SLAVE_DISABLE = (1 << 6), |
| }; |
| |
| /* Command/Data register definitions */ |
| enum { |
| CMD_DATA_CMD = (1 << 8), |
| CMD_DATA_STOP = (1 << 9), |
| }; |
| |
| /* Status register definitions */ |
| enum { |
| STATUS_ACTIVITY = (1 << 0), |
| STATUS_TX_FIFO_NOT_FULL = (1 << 1), |
| STATUS_TX_FIFO_EMPTY = (1 << 2), |
| STATUS_RX_FIFO_NOT_EMPTY = (1 << 3), |
| STATUS_RX_FIFO_FULL = (1 << 4), |
| STATUS_MASTER_ACTIVITY = (1 << 5), |
| STATUS_SLAVE_ACTIVITY = (1 << 6), |
| }; |
| |
| /* Enable register definitions */ |
| enum { |
| ENABLE_CONTROLLER = (1 << 0), |
| }; |
| |
| /* Interrupt status register definitions */ |
| enum { |
| INTR_STAT_RX_UNDER = (1 << 0), |
| INTR_STAT_RX_OVER = (1 << 1), |
| INTR_STAT_RX_FULL = (1 << 2), |
| INTR_STAT_TX_OVER = (1 << 3), |
| INTR_STAT_TX_EMPTY = (1 << 4), |
| INTR_STAT_RD_REQ = (1 << 5), |
| INTR_STAT_TX_ABORT = (1 << 6), |
| INTR_STAT_RX_DONE = (1 << 7), |
| INTR_STAT_ACTIVITY = (1 << 8), |
| INTR_STAT_STOP_DET = (1 << 9), |
| INTR_STAT_START_DET = (1 << 10), |
| INTR_STAT_GEN_CALL = (1 << 11), |
| }; |
| |
| static const struct i2c_descriptor { |
| enum i2c_speed speed; |
| struct freq freq; |
| int min_thigh_ns; |
| int min_tlow_ns; |
| } speed_descriptors[] = { |
| { |
| .speed = I2C_SPEED_STANDARD, |
| .freq = { |
| .ticks = 100, |
| .ns = 1000*1000, |
| }, |
| .min_thigh_ns = MIN_SS_SCL_HIGHTIME, |
| .min_tlow_ns = MIN_SS_SCL_LOWTIME, |
| }, |
| { |
| .speed = I2C_SPEED_FAST, |
| .freq = { |
| .ticks = 400, |
| .ns = 1000*1000, |
| }, |
| .min_thigh_ns = MIN_FS_SCL_HIGHTIME, |
| .min_tlow_ns = MIN_FS_SCL_LOWTIME, |
| }, |
| { |
| .speed = I2C_SPEED_FAST_PLUS, |
| .freq = { |
| .ticks = 1, |
| .ns = 1000, |
| }, |
| .min_thigh_ns = MIN_FP_SCL_HIGHTIME, |
| .min_tlow_ns = MIN_FP_SCL_LOWTIME, |
| }, |
| { |
| /* 100pF max capacitance */ |
| .speed = I2C_SPEED_HIGH, |
| .freq = { |
| .ticks = 3400, |
| .ns = 1000*1000, |
| }, |
| .min_thigh_ns = MIN_HS_SCL_HIGHTIME, |
| .min_tlow_ns = MIN_HS_SCL_LOWTIME, |
| }, |
| }; |
| |
| static const struct soc_clock { |
| int clk_speed_mhz; |
| struct freq freq; |
| } soc_clocks[] = { |
| { |
| .clk_speed_mhz = 120, |
| .freq = { |
| .ticks = 120, |
| .ns = 1000, |
| }, |
| }, |
| { |
| .clk_speed_mhz = 133, |
| .freq = { |
| .ticks = 400, |
| .ns = 3000, |
| }, |
| }, |
| }; |
| |
| static const struct i2c_descriptor *get_bus_descriptor(enum i2c_speed speed) |
| { |
| size_t i; |
| |
| for (i = 0; i < ARRAY_SIZE(speed_descriptors); i++) |
| if (speed == speed_descriptors[i].speed) |
| return &speed_descriptors[i]; |
| |
| return NULL; |
| } |
| |
| static const struct soc_clock *get_soc_descriptor(int ic_clk) |
| { |
| size_t i; |
| |
| for (i = 0; i < ARRAY_SIZE(soc_clocks); i++) |
| if (ic_clk == soc_clocks[i].clk_speed_mhz) |
| return &soc_clocks[i]; |
| |
| return NULL; |
| } |
| |
| static int counts_from_time(const struct freq *f, int ns) |
| { |
| return DIV_ROUND_UP(f->ticks * ns, f->ns); |
| } |
| |
| static int counts_from_freq(const struct freq *fast, const struct freq *slow) |
| { |
| return DIV_ROUND_UP(fast->ticks * slow->ns, fast->ns * slow->ticks); |
| } |
| |
| /* Enable this I2C controller */ |
| static void lpss_i2c_enable(struct lpss_i2c_regs *regs) |
| { |
| uint32_t enable = read32(®s->enable); |
| |
| if (!(enable & ENABLE_CONTROLLER)) |
| write32(®s->enable, enable | ENABLE_CONTROLLER); |
| } |
| |
| /* Disable this I2C controller */ |
| static int lpss_i2c_disable(struct lpss_i2c_regs *regs) |
| { |
| uint32_t enable = read32(®s->enable); |
| |
| if (enable & ENABLE_CONTROLLER) { |
| struct stopwatch sw; |
| |
| write32(®s->enable, enable & ~ENABLE_CONTROLLER); |
| |
| /* Wait for enable bit to clear */ |
| stopwatch_init_usecs_expire(&sw, LPSS_I2C_TIMEOUT_US); |
| while (read32(®s->enable_status) & ENABLE_CONTROLLER) |
| if (stopwatch_expired(&sw)) |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* Wait for this I2C controller to go idle for transmit */ |
| static int lpss_i2c_wait_for_bus_idle(struct lpss_i2c_regs *regs) |
| { |
| struct stopwatch sw; |
| |
| /* Start timeout for up to 16 bytes in FIFO */ |
| stopwatch_init_usecs_expire(&sw, 16 * LPSS_I2C_TIMEOUT_US); |
| |
| while (!stopwatch_expired(&sw)) { |
| uint32_t status = read32(®s->status); |
| |
| /* Check for master activity and keep waiting */ |
| if (status & STATUS_MASTER_ACTIVITY) |
| continue; |
| |
| /* Check for TX FIFO empty to indicate TX idle */ |
| if (status & STATUS_TX_FIFO_EMPTY) |
| return 0; |
| } |
| |
| /* Timed out while waiting for bus to go idle */ |
| return -1; |
| } |
| |
| /* Transfer one byte of one segment, sending stop bit if requested */ |
| static int lpss_i2c_transfer_byte(struct lpss_i2c_regs *regs, |
| struct i2c_seg *segment, |
| size_t byte, int send_stop) |
| { |
| struct stopwatch sw; |
| uint32_t cmd = CMD_DATA_CMD; /* Read op */ |
| |
| stopwatch_init_usecs_expire(&sw, LPSS_I2C_TIMEOUT_US); |
| |
| if (!segment->read) { |
| /* Write op only: Wait for FIFO not full */ |
| while (!(read32(®s->status) & STATUS_TX_FIFO_NOT_FULL)) { |
| if (stopwatch_expired(&sw)) { |
| printk(BIOS_ERR, "I2C transmit timeout\n"); |
| return -1; |
| } |
| } |
| cmd = segment->buf[byte]; |
| } |
| |
| /* Send stop on last byte, if desired */ |
| if (send_stop && byte == segment->len - 1) |
| cmd |= CMD_DATA_STOP; |
| |
| write32(®s->cmd_data, cmd); |
| |
| if (segment->read) { |
| /* Read op only: Wait for FIFO data and store it */ |
| while (!(read32(®s->status) & STATUS_RX_FIFO_NOT_EMPTY)) { |
| if (stopwatch_expired(&sw)) { |
| printk(BIOS_ERR, "I2C receive timeout\n"); |
| return -1; |
| } |
| } |
| segment->buf[byte] = read32(®s->cmd_data); |
| } |
| |
| return 0; |
| } |
| |
| /* Global I2C bus handler, defined in include/i2c.h */ |
| int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segments, int count) |
| { |
| struct stopwatch sw; |
| struct lpss_i2c_regs *regs; |
| size_t byte; |
| int ret = -1; |
| |
| if (count <= 0 || !segments) |
| return -1; |
| |
| regs = (struct lpss_i2c_regs *)lpss_i2c_base_address(bus); |
| if (!regs) { |
| printk(BIOS_ERR, "I2C bus %u base address not found\n", bus); |
| return -1; |
| } |
| |
| lpss_i2c_enable(regs); |
| |
| if (lpss_i2c_wait_for_bus_idle(regs)) { |
| printk(BIOS_ERR, "I2C timeout waiting for bus %u idle\n", bus); |
| goto out; |
| } |
| |
| /* Process each segment */ |
| while (count--) { |
| if (CONFIG_SOC_INTEL_COMMON_LPSS_I2C_DEBUG) |
| printk(BIOS_DEBUG, "i2c %u:%02x %s %d bytes : ", |
| bus, segments->chip, segments->read ? "R" : "W", |
| segments->len); |
| |
| /* Set target slave address */ |
| write32(®s->target_addr, segments->chip); |
| |
| /* Read or write each byte in segment */ |
| for (byte = 0; byte < segments->len; byte++) { |
| /* |
| * Set stop condition on final segment only. |
| * Repeated start will be automatically generated |
| * by the controller on R->W or W->R switch. |
| */ |
| if (lpss_i2c_transfer_byte(regs, segments, byte, |
| count == 0) < 0) { |
| printk(BIOS_ERR, "I2C %s failed: bus %u " |
| "addr 0x%02x\n", segments->read ? |
| "read" : "write", bus, segments->chip); |
| goto out; |
| } |
| } |
| |
| if (CONFIG_SOC_INTEL_COMMON_LPSS_I2C_DEBUG) { |
| int j; |
| for (j = 0; j < segments->len; j++) |
| printk(BIOS_DEBUG, "%02x ", segments->buf[j]); |
| printk(BIOS_DEBUG, "\n"); |
| } |
| |
| segments++; |
| } |
| |
| /* Wait for interrupt status to indicate transfer is complete */ |
| stopwatch_init_usecs_expire(&sw, LPSS_I2C_TIMEOUT_US); |
| while (!(read32(®s->raw_intr_stat) & INTR_STAT_STOP_DET)) { |
| if (stopwatch_expired(&sw)) { |
| printk(BIOS_ERR, "I2C stop bit not received\n"); |
| goto out; |
| } |
| } |
| |
| /* Read to clear INTR_STAT_STOP_DET */ |
| read32(®s->clear_stop_det_intr); |
| |
| /* Wait for the bus to go idle */ |
| if (lpss_i2c_wait_for_bus_idle(regs)) { |
| printk(BIOS_ERR, "I2C timeout waiting for bus %u idle\n", bus); |
| goto out; |
| } |
| |
| /* Flush the RX FIFO in case it is not empty */ |
| stopwatch_init_usecs_expire(&sw, 16 * LPSS_I2C_TIMEOUT_US); |
| while (read32(®s->status) & STATUS_RX_FIFO_NOT_EMPTY) { |
| if (stopwatch_expired(&sw)) { |
| printk(BIOS_ERR, "I2C timeout flushing RX FIFO\n"); |
| goto out; |
| } |
| read32(®s->cmd_data); |
| } |
| |
| ret = 0; |
| |
| out: |
| read32(®s->clear_intr); |
| lpss_i2c_disable(regs); |
| return ret; |
| } |
| |
| static int lpss_i2c_set_speed_config(unsigned int bus, |
| const struct lpss_i2c_speed_config *config) |
| { |
| struct lpss_i2c_regs *regs; |
| void *hcnt_reg, *lcnt_reg; |
| |
| regs = (struct lpss_i2c_regs *)lpss_i2c_base_address(bus); |
| if (!regs || !config) |
| return -1; |
| |
| /* Nothing to do if no values are set */ |
| if (!config->scl_lcnt && !config->scl_hcnt && !config->sda_hold) |
| return 0; |
| |
| if (config->speed >= I2C_SPEED_HIGH) { |
| /* High and Fast Ultra speed */ |
| hcnt_reg = ®s->hs_scl_hcnt; |
| lcnt_reg = ®s->hs_scl_lcnt; |
| } else if (config->speed >= I2C_SPEED_FAST) { |
| /* Fast and Fast-Plus speed */ |
| hcnt_reg = ®s->fs_scl_hcnt; |
| lcnt_reg = ®s->fs_scl_lcnt; |
| } else { |
| /* Standard speed */ |
| hcnt_reg = ®s->ss_scl_hcnt; |
| lcnt_reg = ®s->ss_scl_lcnt; |
| } |
| |
| /* SCL count must be set after the speed is selected */ |
| if (config->scl_hcnt) |
| write32(hcnt_reg, config->scl_hcnt); |
| if (config->scl_lcnt) |
| write32(lcnt_reg, config->scl_lcnt); |
| |
| /* Set SDA Hold Time register */ |
| if (config->sda_hold) |
| write32(®s->sda_hold, config->sda_hold); |
| |
| return 0; |
| } |
| |
| static int lpss_i2c_gen_config_rise_fall_time(struct lpss_i2c_regs *regs, |
| enum i2c_speed speed, |
| const struct lpss_i2c_bus_config *bcfg, |
| int ic_clk, |
| struct lpss_i2c_speed_config *config) |
| { |
| const struct i2c_descriptor *bus; |
| const struct soc_clock *soc; |
| int fall_cnt, rise_cnt, min_tlow_cnt, min_thigh_cnt, spk_cnt; |
| int hcnt, lcnt, period_cnt, diff, tot; |
| int data_hold_time_ns; |
| |
| bus = get_bus_descriptor(speed); |
| soc = get_soc_descriptor(ic_clk); |
| |
| if (bus == NULL) { |
| printk(BIOS_ERR, "lpss_i2c: invalid bus speed %d\n", speed); |
| return -1; |
| } |
| |
| if (soc == NULL) { |
| printk(BIOS_ERR, "lpss_i2c: invalid SoC clock speed %d MHz\n", |
| ic_clk); |
| return -1; |
| } |
| |
| /* Get the proper spike suppression count based on target speed. */ |
| if (speed >= I2C_SPEED_HIGH) |
| spk_cnt = read32(®s->hs_spklen); |
| else |
| spk_cnt = read32(®s->fs_spklen); |
| |
| /* Find the period, rise, fall, min tlow, and min thigh in terms of |
| * counts of SoC clock. */ |
| period_cnt = counts_from_freq(&soc->freq, &bus->freq); |
| rise_cnt = counts_from_time(&soc->freq, bcfg->rise_time_ns); |
| fall_cnt = counts_from_time(&soc->freq, bcfg->fall_time_ns); |
| min_tlow_cnt = counts_from_time(&soc->freq, bus->min_tlow_ns); |
| min_thigh_cnt = counts_from_time(&soc->freq, bus->min_thigh_ns); |
| |
| printk(LPSS_DEBUG, "lpss_i2c: SoC %d/%d ns Bus: %d/%d ns\n", |
| soc->freq.ticks, soc->freq.ns, bus->freq.ticks, bus->freq.ns); |
| printk(LPSS_DEBUG, "lpss_i2c: period %d rise %d fall %d tlow %d thigh %d spk %d\n", |
| period_cnt, rise_cnt, fall_cnt, min_tlow_cnt, min_thigh_cnt, |
| spk_cnt); |
| |
| /* |
| * Back solve for hcnt and lcnt according to the following equations. |
| * SCL_High_time = [(HCNT + IC_*_SPKLEN + 7) * ic_clk] + SCL_Fall_time |
| * SCL_Low_time = [(LCNT + 1) * ic_clk] - SCL_Fall_time + SCL_Rise_time |
| */ |
| hcnt = min_thigh_cnt - fall_cnt - 7 - spk_cnt; |
| lcnt = min_tlow_cnt - rise_cnt + fall_cnt - 1; |
| |
| if (hcnt < 0 || lcnt < 0) { |
| printk(BIOS_ERR, "lpss_i2c: bad counts. hcnt = %d lcnt = %d\n", |
| hcnt, lcnt); |
| return -1; |
| } |
| |
| /* Now add things back up to ensure the period is hit. If off, |
| * split the difference and bias to lcnt for remainder. */ |
| tot = hcnt + lcnt + 7 + spk_cnt + rise_cnt + 1; |
| |
| if (tot < period_cnt) { |
| diff = (period_cnt - tot) / 2; |
| hcnt += diff; |
| lcnt += diff; |
| tot = hcnt + lcnt + 7 + spk_cnt + rise_cnt + 1; |
| lcnt += period_cnt - tot; |
| } |
| |
| config->speed = speed; |
| config->scl_lcnt = lcnt; |
| config->scl_hcnt = hcnt; |
| |
| /* Use internal default unless other value is specified. */ |
| data_hold_time_ns = DEFAULT_SDA_HOLD_TIME; |
| if (bcfg->data_hold_time_ns) |
| data_hold_time_ns = bcfg->data_hold_time_ns; |
| |
| config->sda_hold = counts_from_time(&soc->freq, data_hold_time_ns); |
| |
| printk(LPSS_DEBUG, "lpss_i2c: hcnt = %d lcnt = %d sda hold = %d\n", |
| hcnt, lcnt, config->sda_hold); |
| |
| return 0; |
| } |
| |
| int lpss_i2c_gen_speed_config(struct lpss_i2c_regs *regs, |
| enum i2c_speed speed, |
| const struct lpss_i2c_bus_config *bcfg, |
| struct lpss_i2c_speed_config *config) |
| { |
| const int ic_clk = CONFIG_SOC_INTEL_COMMON_LPSS_CLOCK_MHZ; |
| uint16_t hcnt_min, lcnt_min; |
| int i; |
| |
| /* Clock must be provided by Kconfig */ |
| if (!ic_clk) |
| return -1; |
| |
| /* Apply board specific override for this speed if found */ |
| for (i = 0; i < LPSS_I2C_SPEED_CONFIG_COUNT; i++) { |
| if (bcfg->speed_config[i].speed != speed) |
| continue; |
| memcpy(config, &bcfg->speed_config[i], sizeof(*config)); |
| return 0; |
| } |
| |
| /* If rise time is set use the time calculation. */ |
| if (bcfg->rise_time_ns) |
| return lpss_i2c_gen_config_rise_fall_time(regs, speed, bcfg, |
| ic_clk, config); |
| |
| if (speed >= I2C_SPEED_HIGH) { |
| /* High speed */ |
| hcnt_min = MIN_HS_SCL_HIGHTIME; |
| lcnt_min = MIN_HS_SCL_LOWTIME; |
| } else if (speed >= I2C_SPEED_FAST_PLUS) { |
| /* Fast-Plus speed */ |
| hcnt_min = MIN_FP_SCL_HIGHTIME; |
| lcnt_min = MIN_FP_SCL_LOWTIME; |
| } else if (speed >= I2C_SPEED_FAST) { |
| /* Fast speed */ |
| hcnt_min = MIN_FS_SCL_HIGHTIME; |
| lcnt_min = MIN_FS_SCL_LOWTIME; |
| } else { |
| /* Standard speed */ |
| hcnt_min = MIN_SS_SCL_HIGHTIME; |
| lcnt_min = MIN_SS_SCL_LOWTIME; |
| } |
| |
| config->speed = speed; |
| config->scl_hcnt = ic_clk * hcnt_min / KHz; |
| config->scl_lcnt = ic_clk * lcnt_min / KHz; |
| config->sda_hold = ic_clk * DEFAULT_SDA_HOLD_TIME / KHz; |
| |
| return 0; |
| } |
| |
| static int lpss_i2c_set_speed(unsigned int bus, enum i2c_speed speed, |
| const struct lpss_i2c_bus_config *bcfg) |
| { |
| struct lpss_i2c_regs *regs; |
| struct lpss_i2c_speed_config config; |
| uint32_t control; |
| |
| /* Clock must be provided by Kconfig */ |
| regs = (struct lpss_i2c_regs *)lpss_i2c_base_address(bus); |
| if (!regs || !speed) |
| return -1; |
| |
| control = read32(®s->control); |
| control &= ~CONTROL_SPEED_MASK; |
| |
| if (speed >= I2C_SPEED_HIGH) { |
| /* High and Fast-Ultra speed share config registers */ |
| control |= CONTROL_SPEED_HS; |
| } else if (speed >= I2C_SPEED_FAST) { |
| /* Fast speed and Fast-Plus */ |
| control |= CONTROL_SPEED_FS; |
| } else { |
| /* Standard speed */ |
| control |= CONTROL_SPEED_SS; |
| } |
| |
| /* Generate speed config based on clock */ |
| if (lpss_i2c_gen_speed_config(regs, speed, bcfg, &config) < 0) |
| return -1; |
| |
| /* Select this speed in the control register */ |
| write32(®s->control, control); |
| |
| /* Write the speed config that was generated earlier */ |
| lpss_i2c_set_speed_config(bus, &config); |
| |
| return 0; |
| } |
| |
| |
| /* |
| * Initialize this bus controller and set the speed. |
| * |
| * The bus speed can be passed in Hz or using values from device/i2c.h and |
| * will default to I2C_SPEED_FAST if it is not provided. |
| */ |
| int lpss_i2c_init(unsigned int bus, const struct lpss_i2c_bus_config *bcfg) |
| { |
| struct lpss_i2c_regs *regs; |
| enum i2c_speed speed; |
| |
| if (!bcfg) |
| return -1; |
| |
| speed = bcfg->speed ? : I2C_SPEED_FAST; |
| |
| regs = (struct lpss_i2c_regs *)lpss_i2c_base_address(bus); |
| if (!regs) { |
| printk(BIOS_ERR, "I2C bus %u base address not found\n", bus); |
| return -1; |
| } |
| |
| if (lpss_i2c_disable(regs) < 0) { |
| printk(BIOS_ERR, "I2C timeout disabling bus %u\n", bus); |
| return -1; |
| } |
| |
| /* Put controller in master mode with restart enabled */ |
| write32(®s->control, CONTROL_MASTER_MODE | CONTROL_SLAVE_DISABLE | |
| CONTROL_RESTART_ENABLE); |
| |
| /* Set bus speed to FAST by default */ |
| if (lpss_i2c_set_speed(bus, speed, bcfg) < 0) { |
| printk(BIOS_ERR, "I2C failed to set speed for bus %u\n", bus); |
| return -1; |
| } |
| |
| /* Set RX/TX thresholds to smallest values */ |
| write32(®s->rx_thresh, 0); |
| write32(®s->tx_thresh, 0); |
| |
| /* Enable stop detection interrupt */ |
| write32(®s->intr_mask, INTR_STAT_STOP_DET); |
| |
| printk(BIOS_INFO, "LPSS I2C bus %u at 0x%p (%u KHz)\n", |
| bus, regs, speed / KHz); |
| |
| return 0; |
| } |