diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-hisi.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-hisi.c | 532 |
1 files changed, 532 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-hisi.c b/drivers/i2c/busses/i2c-hisi.c new file mode 100644 index 000000000..dfad5bad5 --- /dev/null +++ b/drivers/i2c/busses/i2c-hisi.c @@ -0,0 +1,532 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * HiSilicon I2C Controller Driver for Kunpeng SoC + * + * Copyright (c) 2021 HiSilicon Technologies Co., Ltd. + */ + +#include <linux/bits.h> +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/units.h> + +#define HISI_I2C_FRAME_CTRL 0x0000 +#define HISI_I2C_FRAME_CTRL_SPEED_MODE GENMASK(1, 0) +#define HISI_I2C_FRAME_CTRL_ADDR_TEN BIT(2) +#define HISI_I2C_SLV_ADDR 0x0004 +#define HISI_I2C_SLV_ADDR_VAL GENMASK(9, 0) +#define HISI_I2C_SLV_ADDR_GC_S_MODE BIT(10) +#define HISI_I2C_SLV_ADDR_GC_S_EN BIT(11) +#define HISI_I2C_CMD_TXDATA 0x0008 +#define HISI_I2C_CMD_TXDATA_DATA GENMASK(7, 0) +#define HISI_I2C_CMD_TXDATA_RW BIT(8) +#define HISI_I2C_CMD_TXDATA_P_EN BIT(9) +#define HISI_I2C_CMD_TXDATA_SR_EN BIT(10) +#define HISI_I2C_RXDATA 0x000c +#define HISI_I2C_RXDATA_DATA GENMASK(7, 0) +#define HISI_I2C_SS_SCL_HCNT 0x0010 +#define HISI_I2C_SS_SCL_LCNT 0x0014 +#define HISI_I2C_FS_SCL_HCNT 0x0018 +#define HISI_I2C_FS_SCL_LCNT 0x001c +#define HISI_I2C_HS_SCL_HCNT 0x0020 +#define HISI_I2C_HS_SCL_LCNT 0x0024 +#define HISI_I2C_FIFO_CTRL 0x0028 +#define HISI_I2C_FIFO_RX_CLR BIT(0) +#define HISI_I2C_FIFO_TX_CLR BIT(1) +#define HISI_I2C_FIFO_RX_AF_THRESH GENMASK(7, 2) +#define HISI_I2C_FIFO_TX_AE_THRESH GENMASK(13, 8) +#define HISI_I2C_FIFO_STATE 0x002c +#define HISI_I2C_FIFO_STATE_RX_RERR BIT(0) +#define HISI_I2C_FIFO_STATE_RX_WERR BIT(1) +#define HISI_I2C_FIFO_STATE_RX_EMPTY BIT(3) +#define HISI_I2C_FIFO_STATE_TX_RERR BIT(6) +#define HISI_I2C_FIFO_STATE_TX_WERR BIT(7) +#define HISI_I2C_FIFO_STATE_TX_FULL BIT(11) +#define HISI_I2C_SDA_HOLD 0x0030 +#define HISI_I2C_SDA_HOLD_TX GENMASK(15, 0) +#define HISI_I2C_SDA_HOLD_RX GENMASK(23, 16) +#define HISI_I2C_FS_SPK_LEN 0x0038 +#define HISI_I2C_FS_SPK_LEN_CNT GENMASK(7, 0) +#define HISI_I2C_HS_SPK_LEN 0x003c +#define HISI_I2C_HS_SPK_LEN_CNT GENMASK(7, 0) +#define HISI_I2C_INT_MSTAT 0x0044 +#define HISI_I2C_INT_CLR 0x0048 +#define HISI_I2C_INT_MASK 0x004C +#define HISI_I2C_TRANS_STATE 0x0050 +#define HISI_I2C_TRANS_ERR 0x0054 +#define HISI_I2C_VERSION 0x0058 + +#define HISI_I2C_INT_ALL GENMASK(4, 0) +#define HISI_I2C_INT_TRANS_CPLT BIT(0) +#define HISI_I2C_INT_TRANS_ERR BIT(1) +#define HISI_I2C_INT_FIFO_ERR BIT(2) +#define HISI_I2C_INT_RX_FULL BIT(3) +#define HISI_I2C_INT_TX_EMPTY BIT(4) +#define HISI_I2C_INT_ERR \ + (HISI_I2C_INT_TRANS_ERR | HISI_I2C_INT_FIFO_ERR) + +#define HISI_I2C_STD_SPEED_MODE 0 +#define HISI_I2C_FAST_SPEED_MODE 1 +#define HISI_I2C_HIGH_SPEED_MODE 2 + +#define HISI_I2C_TX_FIFO_DEPTH 64 +#define HISI_I2C_RX_FIFO_DEPTH 64 +#define HISI_I2C_TX_F_AE_THRESH 1 +#define HISI_I2C_RX_F_AF_THRESH 60 + +#define NSEC_TO_CYCLES(ns, clk_rate_khz) \ + DIV_ROUND_UP_ULL((clk_rate_khz) * (ns), NSEC_PER_MSEC) + +struct hisi_i2c_controller { + struct i2c_adapter adapter; + void __iomem *iobase; + struct device *dev; + struct clk *clk; + int irq; + + /* Intermediates for recording the transfer process */ + struct completion *completion; + struct i2c_msg *msgs; + int msg_num; + int msg_tx_idx; + int buf_tx_idx; + int msg_rx_idx; + int buf_rx_idx; + u16 tar_addr; + u32 xfer_err; + + /* I2C bus configuration */ + struct i2c_timings t; + u32 clk_rate_khz; + u32 spk_len; +}; + +static void hisi_i2c_enable_int(struct hisi_i2c_controller *ctlr, u32 mask) +{ + writel_relaxed(mask, ctlr->iobase + HISI_I2C_INT_MASK); +} + +static void hisi_i2c_disable_int(struct hisi_i2c_controller *ctlr, u32 mask) +{ + writel_relaxed((~mask) & HISI_I2C_INT_ALL, ctlr->iobase + HISI_I2C_INT_MASK); +} + +static void hisi_i2c_clear_int(struct hisi_i2c_controller *ctlr, u32 mask) +{ + writel_relaxed(mask, ctlr->iobase + HISI_I2C_INT_CLR); +} + +static void hisi_i2c_handle_errors(struct hisi_i2c_controller *ctlr) +{ + u32 int_err = ctlr->xfer_err, reg; + + if (int_err & HISI_I2C_INT_FIFO_ERR) { + reg = readl(ctlr->iobase + HISI_I2C_FIFO_STATE); + + if (reg & HISI_I2C_FIFO_STATE_RX_RERR) + dev_err(ctlr->dev, "rx fifo error read\n"); + + if (reg & HISI_I2C_FIFO_STATE_RX_WERR) + dev_err(ctlr->dev, "rx fifo error write\n"); + + if (reg & HISI_I2C_FIFO_STATE_TX_RERR) + dev_err(ctlr->dev, "tx fifo error read\n"); + + if (reg & HISI_I2C_FIFO_STATE_TX_WERR) + dev_err(ctlr->dev, "tx fifo error write\n"); + } +} + +static int hisi_i2c_start_xfer(struct hisi_i2c_controller *ctlr) +{ + struct i2c_msg *msg = ctlr->msgs; + u32 reg; + + reg = readl(ctlr->iobase + HISI_I2C_FRAME_CTRL); + reg &= ~HISI_I2C_FRAME_CTRL_ADDR_TEN; + if (msg->flags & I2C_M_TEN) + reg |= HISI_I2C_FRAME_CTRL_ADDR_TEN; + writel(reg, ctlr->iobase + HISI_I2C_FRAME_CTRL); + + reg = readl(ctlr->iobase + HISI_I2C_SLV_ADDR); + reg &= ~HISI_I2C_SLV_ADDR_VAL; + reg |= FIELD_PREP(HISI_I2C_SLV_ADDR_VAL, msg->addr); + writel(reg, ctlr->iobase + HISI_I2C_SLV_ADDR); + + reg = readl(ctlr->iobase + HISI_I2C_FIFO_CTRL); + reg |= HISI_I2C_FIFO_RX_CLR | HISI_I2C_FIFO_TX_CLR; + writel(reg, ctlr->iobase + HISI_I2C_FIFO_CTRL); + reg &= ~(HISI_I2C_FIFO_RX_CLR | HISI_I2C_FIFO_TX_CLR); + writel(reg, ctlr->iobase + HISI_I2C_FIFO_CTRL); + + hisi_i2c_clear_int(ctlr, HISI_I2C_INT_ALL); + hisi_i2c_enable_int(ctlr, HISI_I2C_INT_ALL); + + return 0; +} + +static void hisi_i2c_reset_xfer(struct hisi_i2c_controller *ctlr) +{ + ctlr->msg_num = 0; + ctlr->xfer_err = 0; + ctlr->msg_tx_idx = 0; + ctlr->msg_rx_idx = 0; + ctlr->buf_tx_idx = 0; + ctlr->buf_rx_idx = 0; +} + +/* + * Initialize the transfer information and start the I2C bus transfer. + * We only configure the transfer and do some pre/post works here, and + * wait for the transfer done. The major transfer process is performed + * in the IRQ handler. + */ +static int hisi_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + struct hisi_i2c_controller *ctlr = i2c_get_adapdata(adap); + DECLARE_COMPLETION_ONSTACK(done); + int ret = num; + + hisi_i2c_reset_xfer(ctlr); + ctlr->completion = &done; + ctlr->msg_num = num; + ctlr->msgs = msgs; + + hisi_i2c_start_xfer(ctlr); + + if (!wait_for_completion_timeout(ctlr->completion, adap->timeout)) { + hisi_i2c_disable_int(ctlr, HISI_I2C_INT_ALL); + synchronize_irq(ctlr->irq); + i2c_recover_bus(&ctlr->adapter); + dev_err(ctlr->dev, "bus transfer timeout\n"); + ret = -EIO; + } + + if (ctlr->xfer_err) { + hisi_i2c_handle_errors(ctlr); + ret = -EIO; + } + + hisi_i2c_reset_xfer(ctlr); + ctlr->completion = NULL; + + return ret; +} + +static u32 hisi_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm hisi_i2c_algo = { + .master_xfer = hisi_i2c_master_xfer, + .functionality = hisi_i2c_functionality, +}; + +static int hisi_i2c_read_rx_fifo(struct hisi_i2c_controller *ctlr) +{ + struct i2c_msg *cur_msg; + u32 fifo_state; + + while (ctlr->msg_rx_idx < ctlr->msg_num) { + cur_msg = ctlr->msgs + ctlr->msg_rx_idx; + + if (!(cur_msg->flags & I2C_M_RD)) { + ctlr->msg_rx_idx++; + continue; + } + + fifo_state = readl(ctlr->iobase + HISI_I2C_FIFO_STATE); + while (!(fifo_state & HISI_I2C_FIFO_STATE_RX_EMPTY) && + ctlr->buf_rx_idx < cur_msg->len) { + cur_msg->buf[ctlr->buf_rx_idx++] = readl(ctlr->iobase + HISI_I2C_RXDATA); + fifo_state = readl(ctlr->iobase + HISI_I2C_FIFO_STATE); + } + + if (ctlr->buf_rx_idx == cur_msg->len) { + ctlr->buf_rx_idx = 0; + ctlr->msg_rx_idx++; + } + + if (fifo_state & HISI_I2C_FIFO_STATE_RX_EMPTY) + break; + } + + return 0; +} + +static void hisi_i2c_xfer_msg(struct hisi_i2c_controller *ctlr) +{ + int max_write = HISI_I2C_TX_FIFO_DEPTH; + bool need_restart = false, last_msg; + struct i2c_msg *cur_msg; + u32 cmd, fifo_state; + + while (ctlr->msg_tx_idx < ctlr->msg_num) { + cur_msg = ctlr->msgs + ctlr->msg_tx_idx; + last_msg = (ctlr->msg_tx_idx == ctlr->msg_num - 1); + + /* Signal the SR bit when we start transferring a new message */ + if (ctlr->msg_tx_idx && !ctlr->buf_tx_idx) + need_restart = true; + + fifo_state = readl(ctlr->iobase + HISI_I2C_FIFO_STATE); + while (!(fifo_state & HISI_I2C_FIFO_STATE_TX_FULL) && + ctlr->buf_tx_idx < cur_msg->len && max_write) { + cmd = 0; + + if (need_restart) { + cmd |= HISI_I2C_CMD_TXDATA_SR_EN; + need_restart = false; + } + + /* Signal the STOP bit at the last frame of the last message */ + if (ctlr->buf_tx_idx == cur_msg->len - 1 && last_msg) + cmd |= HISI_I2C_CMD_TXDATA_P_EN; + + if (cur_msg->flags & I2C_M_RD) + cmd |= HISI_I2C_CMD_TXDATA_RW; + else + cmd |= FIELD_PREP(HISI_I2C_CMD_TXDATA_DATA, + cur_msg->buf[ctlr->buf_tx_idx]); + + writel(cmd, ctlr->iobase + HISI_I2C_CMD_TXDATA); + ctlr->buf_tx_idx++; + max_write--; + + fifo_state = readl(ctlr->iobase + HISI_I2C_FIFO_STATE); + } + + /* Update the transfer index after per message transfer is done. */ + if (ctlr->buf_tx_idx == cur_msg->len) { + ctlr->buf_tx_idx = 0; + ctlr->msg_tx_idx++; + } + + if ((fifo_state & HISI_I2C_FIFO_STATE_TX_FULL) || + max_write == 0) + break; + } + + /* + * Disable the TX_EMPTY interrupt after finishing all the messages to + * avoid overwhelming the CPU. + */ + if (ctlr->msg_tx_idx == ctlr->msg_num) + hisi_i2c_disable_int(ctlr, HISI_I2C_INT_TX_EMPTY); +} + +static irqreturn_t hisi_i2c_irq(int irq, void *context) +{ + struct hisi_i2c_controller *ctlr = context; + u32 int_stat; + + /* + * Don't handle the interrupt if cltr->completion is NULL. We may + * reach here because the interrupt is spurious or the transfer is + * started by another port (e.g. firmware) rather than us. + */ + if (!ctlr->completion) + return IRQ_NONE; + + int_stat = readl(ctlr->iobase + HISI_I2C_INT_MSTAT); + hisi_i2c_clear_int(ctlr, int_stat); + if (!(int_stat & HISI_I2C_INT_ALL)) + return IRQ_NONE; + + if (int_stat & HISI_I2C_INT_TX_EMPTY) + hisi_i2c_xfer_msg(ctlr); + + if (int_stat & HISI_I2C_INT_ERR) { + ctlr->xfer_err = int_stat; + goto out; + } + + /* Drain the rx fifo before finish the transfer */ + if (int_stat & (HISI_I2C_INT_TRANS_CPLT | HISI_I2C_INT_RX_FULL)) + hisi_i2c_read_rx_fifo(ctlr); + +out: + /* + * Only use TRANS_CPLT to indicate the completion. On error cases we'll + * get two interrupts, INT_ERR first then TRANS_CPLT. + */ + if (int_stat & HISI_I2C_INT_TRANS_CPLT) { + hisi_i2c_disable_int(ctlr, HISI_I2C_INT_ALL); + hisi_i2c_clear_int(ctlr, HISI_I2C_INT_ALL); + complete(ctlr->completion); + } + + return IRQ_HANDLED; +} + +/* + * Helper function for calculating and configuring the HIGH and LOW + * periods of SCL clock. The caller will pass the ratio of the + * counts (divide / divisor) according to the target speed mode, + * and the target registers. + */ +static void hisi_i2c_set_scl(struct hisi_i2c_controller *ctlr, + u32 divide, u32 divisor, + u32 reg_hcnt, u32 reg_lcnt) +{ + u32 total_cnt, t_scl_hcnt, t_scl_lcnt, scl_fall_cnt, scl_rise_cnt; + u32 scl_hcnt, scl_lcnt; + + /* Total SCL clock cycles per speed period */ + total_cnt = DIV_ROUND_UP_ULL(ctlr->clk_rate_khz * HZ_PER_KHZ, ctlr->t.bus_freq_hz); + /* Total HIGH level SCL clock cycles including edges */ + t_scl_hcnt = DIV_ROUND_UP_ULL(total_cnt * divide, divisor); + /* Total LOW level SCL clock cycles including edges */ + t_scl_lcnt = total_cnt - t_scl_hcnt; + /* Fall edge SCL clock cycles */ + scl_fall_cnt = NSEC_TO_CYCLES(ctlr->t.scl_fall_ns, ctlr->clk_rate_khz); + /* Rise edge SCL clock cycles */ + scl_rise_cnt = NSEC_TO_CYCLES(ctlr->t.scl_rise_ns, ctlr->clk_rate_khz); + + /* Calculated HIGH and LOW periods of SCL clock */ + scl_hcnt = t_scl_hcnt - ctlr->spk_len - 7 - scl_fall_cnt; + scl_lcnt = t_scl_lcnt - 1 - scl_rise_cnt; + + writel(scl_hcnt, ctlr->iobase + reg_hcnt); + writel(scl_lcnt, ctlr->iobase + reg_lcnt); +} + +static void hisi_i2c_configure_bus(struct hisi_i2c_controller *ctlr) +{ + u32 reg, sda_hold_cnt, speed_mode; + + i2c_parse_fw_timings(ctlr->dev, &ctlr->t, true); + ctlr->spk_len = NSEC_TO_CYCLES(ctlr->t.digital_filter_width_ns, ctlr->clk_rate_khz); + + switch (ctlr->t.bus_freq_hz) { + case I2C_MAX_FAST_MODE_FREQ: + speed_mode = HISI_I2C_FAST_SPEED_MODE; + hisi_i2c_set_scl(ctlr, 26, 76, HISI_I2C_FS_SCL_HCNT, HISI_I2C_FS_SCL_LCNT); + break; + case I2C_MAX_HIGH_SPEED_MODE_FREQ: + speed_mode = HISI_I2C_HIGH_SPEED_MODE; + hisi_i2c_set_scl(ctlr, 6, 22, HISI_I2C_HS_SCL_HCNT, HISI_I2C_HS_SCL_LCNT); + break; + case I2C_MAX_STANDARD_MODE_FREQ: + default: + speed_mode = HISI_I2C_STD_SPEED_MODE; + + /* For default condition force the bus speed to standard mode. */ + ctlr->t.bus_freq_hz = I2C_MAX_STANDARD_MODE_FREQ; + hisi_i2c_set_scl(ctlr, 40, 87, HISI_I2C_SS_SCL_HCNT, HISI_I2C_SS_SCL_LCNT); + break; + } + + reg = readl(ctlr->iobase + HISI_I2C_FRAME_CTRL); + reg &= ~HISI_I2C_FRAME_CTRL_SPEED_MODE; + reg |= FIELD_PREP(HISI_I2C_FRAME_CTRL_SPEED_MODE, speed_mode); + writel(reg, ctlr->iobase + HISI_I2C_FRAME_CTRL); + + sda_hold_cnt = NSEC_TO_CYCLES(ctlr->t.sda_hold_ns, ctlr->clk_rate_khz); + + reg = FIELD_PREP(HISI_I2C_SDA_HOLD_TX, sda_hold_cnt); + writel(reg, ctlr->iobase + HISI_I2C_SDA_HOLD); + + writel(ctlr->spk_len, ctlr->iobase + HISI_I2C_FS_SPK_LEN); + + reg = FIELD_PREP(HISI_I2C_FIFO_RX_AF_THRESH, HISI_I2C_RX_F_AF_THRESH); + reg |= FIELD_PREP(HISI_I2C_FIFO_TX_AE_THRESH, HISI_I2C_TX_F_AE_THRESH); + writel(reg, ctlr->iobase + HISI_I2C_FIFO_CTRL); +} + +static int hisi_i2c_probe(struct platform_device *pdev) +{ + struct hisi_i2c_controller *ctlr; + struct device *dev = &pdev->dev; + struct i2c_adapter *adapter; + u64 clk_rate_hz; + u32 hw_version; + int ret; + + ctlr = devm_kzalloc(dev, sizeof(*ctlr), GFP_KERNEL); + if (!ctlr) + return -ENOMEM; + + ctlr->iobase = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(ctlr->iobase)) + return PTR_ERR(ctlr->iobase); + + ctlr->irq = platform_get_irq(pdev, 0); + if (ctlr->irq < 0) + return ctlr->irq; + + ctlr->dev = dev; + + hisi_i2c_disable_int(ctlr, HISI_I2C_INT_ALL); + + ret = devm_request_irq(dev, ctlr->irq, hisi_i2c_irq, 0, "hisi-i2c", ctlr); + if (ret) + return dev_err_probe(dev, ret, "failed to request irq handler\n"); + + ctlr->clk = devm_clk_get_optional_enabled(&pdev->dev, NULL); + if (IS_ERR_OR_NULL(ctlr->clk)) { + ret = device_property_read_u64(dev, "clk_rate", &clk_rate_hz); + if (ret) + return dev_err_probe(dev, ret, "failed to get clock frequency\n"); + } else { + clk_rate_hz = clk_get_rate(ctlr->clk); + } + + ctlr->clk_rate_khz = DIV_ROUND_UP_ULL(clk_rate_hz, HZ_PER_KHZ); + + hisi_i2c_configure_bus(ctlr); + + adapter = &ctlr->adapter; + snprintf(adapter->name, sizeof(adapter->name), + "HiSilicon I2C Controller %s", dev_name(dev)); + adapter->owner = THIS_MODULE; + adapter->algo = &hisi_i2c_algo; + adapter->dev.parent = dev; + i2c_set_adapdata(adapter, ctlr); + + ret = devm_i2c_add_adapter(dev, adapter); + if (ret) + return ret; + + hw_version = readl(ctlr->iobase + HISI_I2C_VERSION); + dev_info(ctlr->dev, "speed mode is %s. hw version 0x%x\n", + i2c_freq_mode_string(ctlr->t.bus_freq_hz), hw_version); + + return 0; +} + +static const struct acpi_device_id hisi_i2c_acpi_ids[] = { + { "HISI03D1", 0 }, + { } +}; +MODULE_DEVICE_TABLE(acpi, hisi_i2c_acpi_ids); + +static const struct of_device_id hisi_i2c_dts_ids[] = { + { .compatible = "hisilicon,ascend910-i2c", }, + { } +}; +MODULE_DEVICE_TABLE(of, hisi_i2c_dts_ids); + +static struct platform_driver hisi_i2c_driver = { + .probe = hisi_i2c_probe, + .driver = { + .name = "hisi-i2c", + .acpi_match_table = hisi_i2c_acpi_ids, + .of_match_table = hisi_i2c_dts_ids, + }, +}; +module_platform_driver(hisi_i2c_driver); + +MODULE_AUTHOR("Yicong Yang <yangyicong@hisilicon.com>"); +MODULE_DESCRIPTION("HiSilicon I2C Controller Driver"); +MODULE_LICENSE("GPL"); |