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u-boot-brain/drivers/i2c/meson_i2c.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2017 - Beniamino Galvani <b.galvani@gmail.com>
*/
#include <common.h>
#include <asm/arch/i2c.h>
#include <asm/io.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 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);
unsigned int clk_rate = MESON_I2C_CLK_RATE;
unsigned int div;
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 %u, 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);
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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