--- /dev/null
+/*
+ * Copyright (C) 2012-2020 ASPEED Technology Inc.
+ * Copyright 2016 IBM Corporation
+ * Copyright 2017 Google, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <i2c.h>
+#include <asm/io.h>
+#include <asm/arch/scu_ast2500.h>
+
+#include "ast_i2c.h"
+
+#define I2C_TIMEOUT_US 100000
+#define I2C_SLEEP_STEP_US 20
+
+#define HIGHSPEED_TTIMEOUT 3
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * Device private data
+ */
+struct ast_i2c_priv {
+ /* This device's clock */
+ struct clk clk;
+ /* Device registers */
+ struct ast_i2c_regs *regs;
+ /* I2C speed in Hz */
+ int speed;
+};
+
+/*
+ * Given desired divider ratio, return the value that needs to be set
+ * in Clock and AC Timing Control register
+ */
+static u32 get_clk_reg_val(ulong divider_ratio)
+{
+ ulong inc = 0, div;
+ ulong scl_low, scl_high, data;
+
+ for (div = 0; divider_ratio >= 16; div++) {
+ inc |= (divider_ratio & 1);
+ divider_ratio >>= 1;
+ }
+ divider_ratio += inc;
+ scl_low = (divider_ratio >> 1) - 1;
+ scl_high = divider_ratio - scl_low - 2;
+ data = I2CD_CACTC_BASE
+ | (scl_high << I2CD_TCKHIGH_SHIFT)
+ | (scl_low << I2CD_TCKLOW_SHIFT)
+ | (div << I2CD_BASE_DIV_SHIFT);
+
+ return data;
+}
+
+static void ast_i2c_clear_interrupts(struct udevice *dev)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+
+ writel(~0, &priv->regs->isr);
+}
+
+static void ast_i2c_init_bus(struct udevice *dev)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+
+ /* Reset device */
+ writel(0, &priv->regs->fcr);
+ /* Enable Master Mode. Assuming single-master */
+ writel(I2CD_MASTER_EN
+ | I2CD_M_SDA_LOCK_EN
+ | I2CD_MULTI_MASTER_DIS | I2CD_M_SCL_DRIVE_EN,
+ &priv->regs->fcr);
+ /* Enable Interrupts */
+ writel(I2CD_INTR_TX_ACK
+ | I2CD_INTR_TX_NAK
+ | I2CD_INTR_RX_DONE
+ | I2CD_INTR_BUS_RECOVER_DONE
+ | I2CD_INTR_NORMAL_STOP
+ | I2CD_INTR_ABNORMAL, &priv->regs->icr);
+}
+
+static int ast_i2c_ofdata_to_platdata(struct udevice *dev)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ priv->regs = dev_get_addr_ptr(dev);
+ if (IS_ERR(priv->regs))
+ return PTR_ERR(priv->regs);
+
+ ret = clk_get_by_index(dev, 0, &priv->clk);
+ if (ret < 0) {
+ debug("%s: Can't get clock for %s: %d\n", __func__, dev->name,
+ ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int ast_i2c_probe(struct udevice *dev)
+{
+ struct ast2500_scu *scu;
+
+ debug("Enabling I2C%u\n", dev->seq);
+
+ /*
+ * Get all I2C devices out of Reset.
+ * Only needs to be done once, but doing it for every
+ * device does not hurt.
+ */
+ scu = ast_get_scu();
+ ast_scu_unlock(scu);
+ clrbits_le32(&scu->sysreset_ctrl1, SCU_SYSRESET_I2C);
+ ast_scu_lock(scu);
+
+ ast_i2c_init_bus(dev);
+
+ return 0;
+}
+
+static int ast_i2c_wait_isr(struct udevice *dev, u32 flag)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+ int timeout = I2C_TIMEOUT_US;
+
+ while (!(readl(&priv->regs->isr) & flag) && timeout > 0) {
+ udelay(I2C_SLEEP_STEP_US);
+ timeout -= I2C_SLEEP_STEP_US;
+ }
+
+ ast_i2c_clear_interrupts(dev);
+ if (timeout <= 0)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int ast_i2c_send_stop(struct udevice *dev)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+
+ writel(I2CD_M_STOP_CMD, &priv->regs->csr);
+
+ return ast_i2c_wait_isr(dev, I2CD_INTR_NORMAL_STOP);
+}
+
+static int ast_i2c_wait_tx(struct udevice *dev)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+ int timeout = I2C_TIMEOUT_US;
+ u32 flag = I2CD_INTR_TX_ACK | I2CD_INTR_TX_NAK;
+ u32 status = readl(&priv->regs->isr) & flag;
+ int ret = 0;
+
+ while (!status && timeout > 0) {
+ status = readl(&priv->regs->isr) & flag;
+ udelay(I2C_SLEEP_STEP_US);
+ timeout -= I2C_SLEEP_STEP_US;
+ }
+
+ if (status == I2CD_INTR_TX_NAK)
+ ret = -EREMOTEIO;
+
+ if (timeout <= 0)
+ ret = -ETIMEDOUT;
+
+ ast_i2c_clear_interrupts(dev);
+
+ return ret;
+}
+
+static int ast_i2c_start_txn(struct udevice *dev, uint devaddr)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+
+ /* Start and Send Device Address */
+ writel(devaddr, &priv->regs->trbbr);
+ writel(I2CD_M_START_CMD | I2CD_M_TX_CMD, &priv->regs->csr);
+
+ return ast_i2c_wait_tx(dev);
+}
+
+static int ast_i2c_read_data(struct udevice *dev, u8 chip_addr, u8 *buffer,
+ size_t len, bool send_stop)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+ u32 i2c_cmd = I2CD_M_RX_CMD;
+ int ret;
+
+ ret = ast_i2c_start_txn(dev, (chip_addr << 1) | I2C_M_RD);
+ if (ret < 0)
+ return ret;
+
+ for (; len > 0; len--, buffer++) {
+ if (len == 1)
+ i2c_cmd |= I2CD_M_S_RX_CMD_LAST;
+ writel(i2c_cmd, &priv->regs->csr);
+ ret = ast_i2c_wait_isr(dev, I2CD_INTR_RX_DONE);
+ if (ret < 0)
+ return ret;
+ *buffer = (readl(&priv->regs->trbbr) & I2CD_RX_DATA_MASK)
+ >> I2CD_RX_DATA_SHIFT;
+ }
+ ast_i2c_clear_interrupts(dev);
+
+ if (send_stop)
+ return ast_i2c_send_stop(dev);
+
+ return 0;
+}
+
+static int ast_i2c_write_data(struct udevice *dev, u8 chip_addr, u8
+ *buffer, size_t len, bool send_stop)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ ret = ast_i2c_start_txn(dev, (chip_addr << 1));
+ if (ret < 0)
+ return ret;
+
+ for (; len > 0; len--, buffer++) {
+ writel(*buffer, &priv->regs->trbbr);
+ writel(I2CD_M_TX_CMD, &priv->regs->csr);
+ ret = ast_i2c_wait_tx(dev);
+ if (ret < 0)
+ return ret;
+ }
+
+ if (send_stop)
+ return ast_i2c_send_stop(dev);
+
+ return 0;
+}
+
+static int ast_i2c_deblock(struct udevice *dev)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+ struct ast_i2c_regs *regs = priv->regs;
+ u32 csr = readl(®s->csr);
+ bool sda_high = csr & I2CD_SDA_LINE_STS;
+ bool scl_high = csr & I2CD_SCL_LINE_STS;
+ int ret = 0;
+
+ if (sda_high && scl_high) {
+ /* Bus is idle, no deblocking needed. */
+ return 0;
+ } else if (sda_high) {
+ /* Send stop command */
+ debug("Unterminated TXN in (%x), sending stop\n", csr);
+ ret = ast_i2c_send_stop(dev);
+ } else if (scl_high) {
+ /* Possibly stuck slave */
+ debug("Bus stuck (%x), attempting recovery\n", csr);
+ writel(I2CD_BUS_RECOVER_CMD, ®s->csr);
+ ret = ast_i2c_wait_isr(dev, I2CD_INTR_BUS_RECOVER_DONE);
+ } else {
+ /* Just try to reinit the device. */
+ ast_i2c_init_bus(dev);
+ }
+
+ return ret;
+}
+
+static int ast_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
+{
+ int ret;
+
+ ret = ast_i2c_deblock(dev);
+ if (ret < 0)
+ return ret;
+
+ debug("i2c_xfer: %d messages\n", nmsgs);
+ for (; nmsgs > 0; nmsgs--, msg++) {
+ if (msg->flags & I2C_M_RD) {
+ debug("i2c_read: chip=0x%x, len=0x%x, flags=0x%x\n",
+ msg->addr, msg->len, msg->flags);
+ ret = ast_i2c_read_data(dev, msg->addr, msg->buf,
+ msg->len, (nmsgs == 1));
+ } else {
+ debug("i2c_write: chip=0x%x, len=0x%x, flags=0x%x\n",
+ msg->addr, msg->len, msg->flags);
+ ret = ast_i2c_write_data(dev, msg->addr, msg->buf,
+ msg->len, (nmsgs == 1));
+ }
+ if (ret) {
+ debug("%s: error (%d)\n", __func__, ret);
+ return -EREMOTEIO;
+ }
+ }
+
+ return 0;
+}
+
+static int ast_i2c_set_speed(struct udevice *dev, unsigned int speed)
+{
+ struct ast_i2c_priv *priv = dev_get_priv(dev);
+ struct ast_i2c_regs *regs = priv->regs;
+ ulong i2c_rate, divider;
+
+ debug("Setting speed for I2C%d to <%u>\n", dev->seq, speed);
+ if (!speed) {
+ debug("No valid speed specified\n");
+ return -EINVAL;
+ }
+
+ i2c_rate = clk_get_rate(&priv->clk);
+ divider = i2c_rate / speed;
+
+ priv->speed = speed;
+ if (speed > I2C_HIGHSPEED_RATE) {
+ debug("Enable High Speed\n");
+ setbits_le32(®s->fcr, I2CD_M_HIGH_SPEED_EN
+ | I2CD_M_SDA_DRIVE_1T_EN
+ | I2CD_SDA_DRIVE_1T_EN);
+ writel(HIGHSPEED_TTIMEOUT, ®s->cactcr2);
+ } else {
+ debug("Enabling Normal Speed\n");
+ writel(I2CD_NO_TIMEOUT_CTRL, ®s->cactcr2);
+ }
+
+ writel(get_clk_reg_val(divider), ®s->cactcr1);
+ ast_i2c_clear_interrupts(dev);
+
+ return 0;
+}
+
+static const struct dm_i2c_ops ast_i2c_ops = {
+ .xfer = ast_i2c_xfer,
+ .set_bus_speed = ast_i2c_set_speed,
+ .deblock = ast_i2c_deblock,
+};
+
+static const struct udevice_id ast_i2c_ids[] = {
+ { .compatible = "aspeed,ast2400-i2c-bus" },
+ { .compatible = "aspeed,ast2500-i2c-bus" },
+ { },
+};
+
+U_BOOT_DRIVER(ast_i2c) = {
+ .name = "ast_i2c",
+ .id = UCLASS_I2C,
+ .of_match = ast_i2c_ids,
+ .probe = ast_i2c_probe,
+ .ofdata_to_platdata = ast_i2c_ofdata_to_platdata,
+ .priv_auto_alloc_size = sizeof(struct ast_i2c_priv),
+ .ops = &ast_i2c_ops,
+};
--- /dev/null
+/*
+ * Copyright (C) 2012-2020 ASPEED Technology Inc.
+ * Copyright 2016 IBM Corporation
+ * Copyright 2017 Google, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+#ifndef __AST_I2C_H_
+#define __AST_I2C_H_
+
+struct ast_i2c_regs {
+ u32 fcr;
+ u32 cactcr1;
+ u32 cactcr2;
+ u32 icr;
+ u32 isr;
+ u32 csr;
+ u32 sdar;
+ u32 pbcr;
+ u32 trbbr;
+#ifdef CONFIG_ASPEED_AST2500
+ u32 dma_mbar;
+ u32 dma_tlr;
+#endif
+};
+
+/* Device Register Definition */
+/* 0x00 : I2CD Function Control Register */
+#define I2CD_BUFF_SEL_MASK (0x7 << 20)
+#define I2CD_BUFF_SEL(x) (x << 20)
+#define I2CD_M_SDA_LOCK_EN (0x1 << 16)
+#define I2CD_MULTI_MASTER_DIS (0x1 << 15)
+#define I2CD_M_SCL_DRIVE_EN (0x1 << 14)
+#define I2CD_MSB_STS (0x1 << 9)
+#define I2CD_SDA_DRIVE_1T_EN (0x1 << 8)
+#define I2CD_M_SDA_DRIVE_1T_EN (0x1 << 7)
+#define I2CD_M_HIGH_SPEED_EN (0x1 << 6)
+#define I2CD_DEF_ADDR_EN (0x1 << 5)
+#define I2CD_DEF_ALERT_EN (0x1 << 4)
+#define I2CD_DEF_ARP_EN (0x1 << 3)
+#define I2CD_DEF_GCALL_EN (0x1 << 2)
+#define I2CD_SLAVE_EN (0x1 << 1)
+#define I2CD_MASTER_EN (0x1)
+
+/* 0x04 : I2CD Clock and AC Timing Control Register #1 */
+/* Base register value. These bits are always set by the driver. */
+#define I2CD_CACTC_BASE 0xfff00300
+#define I2CD_TCKHIGH_SHIFT 16
+#define I2CD_TCKLOW_SHIFT 12
+#define I2CD_THDDAT_SHIFT 10
+#define I2CD_TO_DIV_SHIFT 8
+#define I2CD_BASE_DIV_SHIFT 0
+
+/* 0x08 : I2CD Clock and AC Timing Control Register #2 */
+#define I2CD_tTIMEOUT 1
+#define I2CD_NO_TIMEOUT_CTRL 0
+
+/* 0x0c : I2CD Interrupt Control Register &
+ * 0x10 : I2CD Interrupt Status Register
+ *
+ * These share bit definitions, so use the same values for the enable &
+ * status bits.
+ */
+#define I2CD_INTR_SDA_DL_TIMEOUT (0x1 << 14)
+#define I2CD_INTR_BUS_RECOVER_DONE (0x1 << 13)
+#define I2CD_INTR_SMBUS_ALERT (0x1 << 12)
+#define I2CD_INTR_SMBUS_ARP_ADDR (0x1 << 11)
+#define I2CD_INTR_SMBUS_DEV_ALERT_ADDR (0x1 << 10)
+#define I2CD_INTR_SMBUS_DEF_ADDR (0x1 << 9)
+#define I2CD_INTR_GCALL_ADDR (0x1 << 8)
+#define I2CD_INTR_SLAVE_MATCH (0x1 << 7)
+#define I2CD_INTR_SCL_TIMEOUT (0x1 << 6)
+#define I2CD_INTR_ABNORMAL (0x1 << 5)
+#define I2CD_INTR_NORMAL_STOP (0x1 << 4)
+#define I2CD_INTR_ARBIT_LOSS (0x1 << 3)
+#define I2CD_INTR_RX_DONE (0x1 << 2)
+#define I2CD_INTR_TX_NAK (0x1 << 1)
+#define I2CD_INTR_TX_ACK (0x1 << 0)
+
+/* 0x14 : I2CD Command/Status Register */
+#define I2CD_SDA_OE (0x1 << 28)
+#define I2CD_SDA_O (0x1 << 27)
+#define I2CD_SCL_OE (0x1 << 26)
+#define I2CD_SCL_O (0x1 << 25)
+#define I2CD_TX_TIMING (0x1 << 24)
+#define I2CD_TX_STATUS (0x1 << 23)
+
+/* Tx State Machine */
+#define I2CD_IDLE 0x0
+#define I2CD_MACTIVE 0x8
+#define I2CD_MSTART 0x9
+#define I2CD_MSTARTR 0xa
+#define I2CD_MSTOP 0xb
+#define I2CD_MTXD 0xc
+#define I2CD_MRXACK 0xd
+#define I2CD_MRXD 0xe
+#define I2CD_MTXACK 0xf
+#define I2CD_SWAIT 0x1
+#define I2CD_SRXD 0x4
+#define I2CD_STXACK 0x5
+#define I2CD_STXD 0x6
+#define I2CD_SRXACK 0x7
+#define I2CD_RECOVER 0x3
+
+#define I2CD_SCL_LINE_STS (0x1 << 18)
+#define I2CD_SDA_LINE_STS (0x1 << 17)
+#define I2CD_BUS_BUSY_STS (0x1 << 16)
+#define I2CD_SDA_OE_OUT_DIR (0x1 << 15)
+#define I2CD_SDA_O_OUT_DIR (0x1 << 14)
+#define I2CD_SCL_OE_OUT_DIR (0x1 << 13)
+#define I2CD_SCL_O_OUT_DIR (0x1 << 12)
+#define I2CD_BUS_RECOVER_CMD (0x1 << 11)
+#define I2CD_S_ALT_EN (0x1 << 10)
+#define I2CD_RX_DMA_ENABLE (0x1 << 9)
+#define I2CD_TX_DMA_ENABLE (0x1 << 8)
+
+/* Command Bit */
+#define I2CD_RX_BUFF_ENABLE (0x1 << 7)
+#define I2CD_TX_BUFF_ENABLE (0x1 << 6)
+#define I2CD_M_STOP_CMD (0x1 << 5)
+#define I2CD_M_S_RX_CMD_LAST (0x1 << 4)
+#define I2CD_M_RX_CMD (0x1 << 3)
+#define I2CD_S_TX_CMD (0x1 << 2)
+#define I2CD_M_TX_CMD (0x1 << 1)
+#define I2CD_M_START_CMD 0x1
+
+#define I2CD_RX_DATA_SHIFT 8
+#define I2CD_RX_DATA_MASK (0xff << I2CD_RX_DATA_SHIFT)
+
+#define I2C_HIGHSPEED_RATE 400000
+
+#endif /* __AST_I2C_H_ */
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