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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2017 - Beniamino Galvani <b.galvani@gmail.com>
*/
#include <common.h>
#include <asm/io.h>
#include <clk.h>
#include <dm.h>
#include <i2c.h>
#define I2C_TIMEOUT_MS 100
/* Control register fields */
#define REG_CTRL_START BIT(0)
#define REG_CTRL_ACK_IGNORE BIT(1)
#define REG_CTRL_STATUS BIT(2)
#define REG_CTRL_ERROR BIT(3)
#define REG_CTRL_CLKDIV_SHIFT 12
#define REG_CTRL_CLKDIV_MASK GENMASK(21, 12)
#define REG_CTRL_CLKDIVEXT_SHIFT 28
#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28)
enum {
TOKEN_END = 0,
TOKEN_START,
TOKEN_SLAVE_ADDR_WRITE,
TOKEN_SLAVE_ADDR_READ,
TOKEN_DATA,
TOKEN_DATA_LAST,
TOKEN_STOP,
};
struct i2c_regs {
u32 ctrl;
u32 slave_addr;
u32 tok_list0;
u32 tok_list1;
u32 tok_wdata0;
u32 tok_wdata1;
u32 tok_rdata0;
u32 tok_rdata1;
};
struct meson_i2c {
struct clk clk;
struct i2c_regs *regs;
struct i2c_msg *msg; /* Current I2C message */
bool last; /* Whether the message is the last */
uint count; /* Number of bytes in the current transfer */
uint pos; /* Position of current transfer in message */
u32 tokens[2]; /* Sequence of tokens to be written */
uint num_tokens; /* Number of tokens to be written */
};
static void meson_i2c_reset_tokens(struct meson_i2c *i2c)
{
i2c->tokens[0] = 0;
i2c->tokens[1] = 0;
i2c->num_tokens = 0;
}
static void meson_i2c_add_token(struct meson_i2c *i2c, int token)
{
if (i2c->num_tokens < 8)
i2c->tokens[0] |= (token & 0xf) << (i2c->num_tokens * 4);
else
i2c->tokens[1] |= (token & 0xf) << ((i2c->num_tokens % 8) * 4);
i2c->num_tokens++;
}
/*
* Retrieve data for the current transfer (which can be at most 8
* bytes) from the device internal buffer.
*/
static void meson_i2c_get_data(struct meson_i2c *i2c, u8 *buf, int len)
{
u32 rdata0, rdata1;
int i;
rdata0 = readl(&i2c->regs->tok_rdata0);
rdata1 = readl(&i2c->regs->tok_rdata1);
debug("meson i2c: read data %08x %08x len %d\n", rdata0, rdata1, len);
for (i = 0; i < min(4, len); i++)
*buf++ = (rdata0 >> i * 8) & 0xff;
for (i = 4; i < min(8, len); i++)
*buf++ = (rdata1 >> (i - 4) * 8) & 0xff;
}
/*
* Write data for the current transfer (which can be at most 8 bytes)
* to the device internal buffer.
*/
static void meson_i2c_put_data(struct meson_i2c *i2c, u8 *buf, int len)
{
u32 wdata0 = 0, wdata1 = 0;
int i;
for (i = 0; i < min(4, len); i++)
wdata0 |= *buf++ << (i * 8);
for (i = 4; i < min(8, len); i++)
wdata1 |= *buf++ << ((i - 4) * 8);
writel(wdata0, &i2c->regs->tok_wdata0);
writel(wdata1, &i2c->regs->tok_wdata1);
debug("meson i2c: write data %08x %08x len %d\n", wdata0, wdata1, len);
}
/*
* Prepare the next transfer: pick the next 8 bytes in the remaining
* part of message and write tokens and data (if needed) to the
* device.
*/
static void meson_i2c_prepare_xfer(struct meson_i2c *i2c)
{
bool write = !(i2c->msg->flags & I2C_M_RD);
int i;
i2c->count = min(i2c->msg->len - i2c->pos, 8u);
for (i = 0; i + 1 < i2c->count; i++)
meson_i2c_add_token(i2c, TOKEN_DATA);
if (i2c->count) {
if (write || i2c->pos + i2c->count < i2c->msg->len)
meson_i2c_add_token(i2c, TOKEN_DATA);
else
meson_i2c_add_token(i2c, TOKEN_DATA_LAST);
}
if (write)
meson_i2c_put_data(i2c, i2c->msg->buf + i2c->pos, i2c->count);
if (i2c->last && i2c->pos + i2c->count >= i2c->msg->len)
meson_i2c_add_token(i2c, TOKEN_STOP);
writel(i2c->tokens[0], &i2c->regs->tok_list0);
writel(i2c->tokens[1], &i2c->regs->tok_list1);
}
static void meson_i2c_do_start(struct meson_i2c *i2c, struct i2c_msg *msg)
{
int token;
token = (msg->flags & I2C_M_RD) ? TOKEN_SLAVE_ADDR_READ :
TOKEN_SLAVE_ADDR_WRITE;
writel(msg->addr << 1, &i2c->regs->slave_addr);
meson_i2c_add_token(i2c, TOKEN_START);
meson_i2c_add_token(i2c, token);
}
static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
int last)
{
ulong start;
debug("meson i2c: %s addr %u len %u\n",
(msg->flags & I2C_M_RD) ? "read" : "write",
msg->addr, msg->len);
i2c->msg = msg;
i2c->last = last;
i2c->pos = 0;
i2c->count = 0;
meson_i2c_reset_tokens(i2c);
meson_i2c_do_start(i2c, msg);
do {
meson_i2c_prepare_xfer(i2c);
/* start the transfer */
setbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
start = get_timer(0);
while (readl(&i2c->regs->ctrl) & REG_CTRL_STATUS) {
if (get_timer(start) > I2C_TIMEOUT_MS) {
clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
debug("meson i2c: timeout\n");
return -ETIMEDOUT;
}
udelay(1);
}
meson_i2c_reset_tokens(i2c);
clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
if (readl(&i2c->regs->ctrl) & REG_CTRL_ERROR) {
debug("meson i2c: error\n");
return -EREMOTEIO;
}
if ((msg->flags & I2C_M_RD) && i2c->count) {
meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos,
i2c->count);
}
i2c->pos += i2c->count;
} while (i2c->pos < msg->len);
return 0;
}
static int meson_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
int nmsgs)
{
struct meson_i2c *i2c = dev_get_priv(bus);
int i, ret = 0;
for (i = 0; i < nmsgs; i++) {
ret = meson_i2c_xfer_msg(i2c, msg + i, i == nmsgs - 1);
if (ret)
return ret;
}
return 0;
}
static int meson_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
struct meson_i2c *i2c = dev_get_priv(bus);
ulong clk_rate;
unsigned int div;
clk_rate = clk_get_rate(&i2c->clk);
if (IS_ERR_VALUE(clk_rate))
return -EINVAL;
div = DIV_ROUND_UP(clk_rate, speed * 4);
/* clock divider has 12 bits */
if (div >= (1 << 12)) {
debug("meson i2c: requested bus frequency too low\n");
div = (1 << 12) - 1;
}
clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIV_MASK,
(div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT);
clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIVEXT_MASK,
(div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
debug("meson i2c: set clk %u, src %lu, div %u\n", speed, clk_rate, div);
return 0;
}
static int meson_i2c_probe(struct udevice *bus)
{
struct meson_i2c *i2c = dev_get_priv(bus);
int ret;
ret = clk_get_by_index(bus, 0, &i2c->clk);
if (ret < 0)
return ret;
ret = clk_enable(&i2c->clk);
if (ret)
return ret;
i2c->regs = dev_read_addr_ptr(bus);
clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
return 0;
}
static const struct dm_i2c_ops meson_i2c_ops = {
.xfer = meson_i2c_xfer,
.set_bus_speed = meson_i2c_set_bus_speed,
};
static const struct udevice_id meson_i2c_ids[] = {
{ .compatible = "amlogic,meson6-i2c" },
{ .compatible = "amlogic,meson-gx-i2c" },
{ .compatible = "amlogic,meson-gxbb-i2c" },
{ }
};
U_BOOT_DRIVER(i2c_meson) = {
.name = "i2c_meson",
.id = UCLASS_I2C,
.of_match = meson_i2c_ids,
.probe = meson_i2c_probe,
.priv_auto_alloc_size = sizeof(struct meson_i2c),
.ops = &meson_i2c_ops,
};
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