// SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2012-2020 ASPEED Technology Inc. * Copyright 2016 IBM Corporation * Copyright 2017 Google, Inc. */ #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 /* * 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 = devfdt_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, };