diff options
Diffstat (limited to 'drivers/i2c/ast_i2c.c')
| -rw-r--r-- | drivers/i2c/ast_i2c.c | 357 |
1 files changed, 357 insertions, 0 deletions
diff --git a/drivers/i2c/ast_i2c.c b/drivers/i2c/ast_i2c.c new file mode 100644 index 0000000..16dfb57 --- /dev/null +++ b/drivers/i2c/ast_i2c.c @@ -0,0 +1,357 @@ +/* + * 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, +}; |