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aspeed: Add I2C Driver

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Add Device Model based I2C driver for ast2500/ast2400 SoCs.
The driver is very limited, it only supports master mode and
synchronous byte-by-byte reads/writes, no DMA or Pool Buffers.

Signed-off-by: Maxim Sloyko <maxims@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>
master
maxims@google.com 8 years ago committed by Tom Rini
parent 4999bb06cc
commit 4dc038f3a1
4 changed files with 499 additions and 0 deletions
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  1. 9
      drivers/i2c/Kconfig
  2. 1
      drivers/i2c/Makefile
  3. 357
      drivers/i2c/ast_i2c.c
  4. 132
      drivers/i2c/ast_i2c.h

9
drivers/i2c/Kconfig
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@ -114,6 +114,15 @@ config SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED
enable status register. This config option can be enabled in such
cases.
config SYS_I2C_ASPEED
bool "Aspeed I2C Controller"
depends on DM_I2C && ARCH_ASPEED
help
Say yes here to select Aspeed I2C Host Controller. The driver
supports AST2500 and AST2400 controllers, but is very limited.
Only single master mode is supported and only byte-by-byte
synchronous reads and writes are supported, no Pool Buffers or DMA.
config SYS_I2C_INTEL
bool "Intel I2C/SMBUS driver"
depends on DM_I2C

1
drivers/i2c/Makefile
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@ -15,6 +15,7 @@ obj-$(CONFIG_I2C_MV) += mv_i2c.o
obj-$(CONFIG_TSI108_I2C) += tsi108_i2c.o
obj-$(CONFIG_SH_SH7734_I2C) += sh_sh7734_i2c.o
obj-$(CONFIG_SYS_I2C) += i2c_core.o
obj-$(CONFIG_SYS_I2C_ASPEED) += ast_i2c.o
obj-$(CONFIG_SYS_I2C_AT91) += at91_i2c.o
obj-$(CONFIG_SYS_I2C_CADENCE) += i2c-cdns.o
obj-$(CONFIG_SYS_I2C_DAVINCI) += davinci_i2c.o

357
drivers/i2c/ast_i2c.c
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@ -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(&regs->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, &regs->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(&regs->fcr, I2CD_M_HIGH_SPEED_EN
| I2CD_M_SDA_DRIVE_1T_EN
| I2CD_SDA_DRIVE_1T_EN);
writel(HIGHSPEED_TTIMEOUT, &regs->cactcr2);
} else {
debug("Enabling Normal Speed\n");
writel(I2CD_NO_TIMEOUT_CTRL, &regs->cactcr2);
}
writel(get_clk_reg_val(divider), &regs->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,
};

132
drivers/i2c/ast_i2c.h
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@ -0,0 +1,132 @@
/*
* 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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