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linux/drivers/i2c/busses/i2c-mt7621.c
Wolfram Sang 839052d1d3 i2c: mt7621: reword according to newest specification 
Change the wording of this driver wrt. the newest I2C v7 and SMBus 3.2
specifications and replace "master/slave" with more appropriate terms.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
2024-07-11 15:14:15 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* drivers/i2c/busses/i2c-mt7621.c
*
* Copyright (C) 2013 Steven Liu <steven_liu@mediatek.com>
* Copyright (C) 2016 Michael Lee <igvtee@gmail.com>
* Copyright (C) 2018 Jan Breuer <jan.breuer@jaybee.cz>
*
* Improve driver for i2cdetect from i2c-tools to detect i2c devices on the bus.
* (C) 2014 Sittisak <sittisaks@hotmail.com>
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#define REG_SM0CFG2_REG 0x28
#define REG_SM0CTL0_REG 0x40
#define REG_SM0CTL1_REG 0x44
#define REG_SM0D0_REG 0x50
#define REG_SM0D1_REG 0x54
#define REG_PINTEN_REG 0x5c
#define REG_PINTST_REG 0x60
#define REG_PINTCL_REG 0x64
/* REG_SM0CFG2_REG */
#define SM0CFG2_IS_AUTOMODE BIT(0)
/* REG_SM0CTL0_REG */
#define SM0CTL0_ODRAIN BIT(31)
#define SM0CTL0_CLK_DIV_MASK (0x7ff << 16)
#define SM0CTL0_CLK_DIV_MAX 0x7ff
#define SM0CTL0_CS_STATUS BIT(4)
#define SM0CTL0_SCL_STATE BIT(3)
#define SM0CTL0_SDA_STATE BIT(2)
#define SM0CTL0_EN BIT(1)
#define SM0CTL0_SCL_STRETCH BIT(0)
/* REG_SM0CTL1_REG */
#define SM0CTL1_ACK_MASK (0xff << 16)
#define SM0CTL1_PGLEN_MASK (0x7 << 8)
#define SM0CTL1_PGLEN(x) ((((x) - 1) << 8) & SM0CTL1_PGLEN_MASK)
#define SM0CTL1_READ (5 << 4)
#define SM0CTL1_READ_LAST (4 << 4)
#define SM0CTL1_STOP (3 << 4)
#define SM0CTL1_WRITE (2 << 4)
#define SM0CTL1_START (1 << 4)
#define SM0CTL1_MODE_MASK (0x7 << 4)
#define SM0CTL1_TRI BIT(0)
/* timeout waiting for I2C devices to respond */
#define TIMEOUT_MS 1000
struct mtk_i2c {
void __iomem *base;
struct device *dev;
struct i2c_adapter adap;
u32 bus_freq;
u32 clk_div;
u32 flags;
struct clk *clk;
};
static int mtk_i2c_wait_idle(struct mtk_i2c *i2c)
{
int ret;
u32 val;
ret = readl_relaxed_poll_timeout(i2c->base + REG_SM0CTL1_REG,
val, !(val & SM0CTL1_TRI),
10, TIMEOUT_MS * 1000);
if (ret)
dev_dbg(i2c->dev, "idle err(%d)\n", ret);
return ret;
}
static void mtk_i2c_reset(struct mtk_i2c *i2c)
{
int ret;
ret = device_reset(i2c->adap.dev.parent);
if (ret)
dev_err(i2c->dev, "I2C reset failed!\n");
/*
* Don't set SM0CTL0_ODRAIN as its bit meaning is inverted. To
* configure open-drain mode, this bit needs to be cleared.
*/
iowrite32(((i2c->clk_div << 16) & SM0CTL0_CLK_DIV_MASK) | SM0CTL0_EN |
SM0CTL0_SCL_STRETCH, i2c->base + REG_SM0CTL0_REG);
iowrite32(0, i2c->base + REG_SM0CFG2_REG);
}
static void mtk_i2c_dump_reg(struct mtk_i2c *i2c)
{
dev_dbg(i2c->dev,
"SM0CFG2 %08x, SM0CTL0 %08x, SM0CTL1 %08x, SM0D0 %08x, SM0D1 %08x\n",
ioread32(i2c->base + REG_SM0CFG2_REG),
ioread32(i2c->base + REG_SM0CTL0_REG),
ioread32(i2c->base + REG_SM0CTL1_REG),
ioread32(i2c->base + REG_SM0D0_REG),
ioread32(i2c->base + REG_SM0D1_REG));
}
static int mtk_i2c_check_ack(struct mtk_i2c *i2c, u32 expected)
{
u32 ack = readl_relaxed(i2c->base + REG_SM0CTL1_REG);
u32 ack_expected = (expected << 16) & SM0CTL1_ACK_MASK;
return ((ack & ack_expected) == ack_expected) ? 0 : -ENXIO;
}
static int mtk_i2c_start(struct mtk_i2c *i2c)
{
iowrite32(SM0CTL1_START | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG);
return mtk_i2c_wait_idle(i2c);
}
static int mtk_i2c_stop(struct mtk_i2c *i2c)
{
iowrite32(SM0CTL1_STOP | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG);
return mtk_i2c_wait_idle(i2c);
}
static int mtk_i2c_cmd(struct mtk_i2c *i2c, u32 cmd, int page_len)
{
iowrite32(cmd | SM0CTL1_TRI | SM0CTL1_PGLEN(page_len),
i2c->base + REG_SM0CTL1_REG);
return mtk_i2c_wait_idle(i2c);
}
static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
struct mtk_i2c *i2c;
struct i2c_msg *pmsg;
u16 addr;
int i, j, ret, len, page_len;
u32 cmd;
u32 data[2];
i2c = i2c_get_adapdata(adap);
for (i = 0; i < num; i++) {
pmsg = &msgs[i];
/* wait hardware idle */
ret = mtk_i2c_wait_idle(i2c);
if (ret)
goto err_timeout;
/* start sequence */
ret = mtk_i2c_start(i2c);
if (ret)
goto err_timeout;
/* write address */
if (pmsg->flags & I2C_M_TEN) {
/* 10 bits address */
addr = 0xf0 | ((pmsg->addr >> 7) & 0x06);
addr |= (pmsg->addr & 0xff) << 8;
if (pmsg->flags & I2C_M_RD)
addr |= 1;
iowrite32(addr, i2c->base + REG_SM0D0_REG);
ret = mtk_i2c_cmd(i2c, SM0CTL1_WRITE, 2);
if (ret)
goto err_timeout;
} else {
/* 7 bits address */
addr = i2c_8bit_addr_from_msg(pmsg);
iowrite32(addr, i2c->base + REG_SM0D0_REG);
ret = mtk_i2c_cmd(i2c, SM0CTL1_WRITE, 1);
if (ret)
goto err_timeout;
}
/* check address ACK */
if (!(pmsg->flags & I2C_M_IGNORE_NAK)) {
ret = mtk_i2c_check_ack(i2c, BIT(0));
if (ret)
goto err_ack;
}
/* transfer data */
for (len = pmsg->len, j = 0; len > 0; len -= 8, j += 8) {
page_len = (len >= 8) ? 8 : len;
if (pmsg->flags & I2C_M_RD) {
cmd = (len > 8) ?
SM0CTL1_READ : SM0CTL1_READ_LAST;
} else {
memcpy(data, &pmsg->buf[j], page_len);
iowrite32(data[0], i2c->base + REG_SM0D0_REG);
iowrite32(data[1], i2c->base + REG_SM0D1_REG);
cmd = SM0CTL1_WRITE;
}
ret = mtk_i2c_cmd(i2c, cmd, page_len);
if (ret)
goto err_timeout;
if (pmsg->flags & I2C_M_RD) {
data[0] = ioread32(i2c->base + REG_SM0D0_REG);
data[1] = ioread32(i2c->base + REG_SM0D1_REG);
memcpy(&pmsg->buf[j], data, page_len);
} else {
if (!(pmsg->flags & I2C_M_IGNORE_NAK)) {
ret = mtk_i2c_check_ack(i2c,
(1 << page_len)
- 1);
if (ret)
goto err_ack;
}
}
}
}
ret = mtk_i2c_stop(i2c);
if (ret)
goto err_timeout;
/* the return value is number of executed messages */
return i;
err_ack:
ret = mtk_i2c_stop(i2c);
if (ret)
goto err_timeout;
return -ENXIO;
err_timeout:
mtk_i2c_dump_reg(i2c);
mtk_i2c_reset(i2c);
return ret;
}
static u32 mtk_i2c_func(struct i2c_adapter *a)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
}
static const struct i2c_algorithm mtk_i2c_algo = {
.xfer = mtk_i2c_xfer,
.functionality = mtk_i2c_func,
};
static const struct of_device_id i2c_mtk_dt_ids[] = {
{ .compatible = "mediatek,mt7621-i2c" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, i2c_mtk_dt_ids);
static void mtk_i2c_init(struct mtk_i2c *i2c)
{
i2c->clk_div = clk_get_rate(i2c->clk) / i2c->bus_freq - 1;
if (i2c->clk_div < 99)
i2c->clk_div = 99;
if (i2c->clk_div > SM0CTL0_CLK_DIV_MAX)
i2c->clk_div = SM0CTL0_CLK_DIV_MAX;
mtk_i2c_reset(i2c);
}
static int mtk_i2c_probe(struct platform_device *pdev)
{
struct mtk_i2c *i2c;
struct i2c_adapter *adap;
int ret;
i2c = devm_kzalloc(&pdev->dev, sizeof(struct mtk_i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
i2c->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
if (IS_ERR(i2c->base))
return PTR_ERR(i2c->base);
i2c->clk = devm_clk_get_enabled(&pdev->dev, NULL);
if (IS_ERR(i2c->clk)) {
dev_err(&pdev->dev, "Failed to enable clock\n");
return PTR_ERR(i2c->clk);
}
i2c->dev = &pdev->dev;
if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
&i2c->bus_freq))
i2c->bus_freq = I2C_MAX_STANDARD_MODE_FREQ;
if (i2c->bus_freq == 0) {
dev_warn(i2c->dev, "clock-frequency 0 not supported\n");
return -EINVAL;
}
adap = &i2c->adap;
adap->owner = THIS_MODULE;
adap->algo = &mtk_i2c_algo;
adap->retries = 3;
adap->dev.parent = &pdev->dev;
i2c_set_adapdata(adap, i2c);
adap->dev.of_node = pdev->dev.of_node;
strscpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name));
platform_set_drvdata(pdev, i2c);
mtk_i2c_init(i2c);
ret = i2c_add_adapter(adap);
if (ret < 0)
return ret;
dev_info(&pdev->dev, "clock %u kHz\n", i2c->bus_freq / 1000);
return 0;
}
static void mtk_i2c_remove(struct platform_device *pdev)
{
struct mtk_i2c *i2c = platform_get_drvdata(pdev);
i2c_del_adapter(&i2c->adap);
}
static struct platform_driver mtk_i2c_driver = {
.probe = mtk_i2c_probe,
.remove_new = mtk_i2c_remove,
.driver = {
.name = "i2c-mt7621",
.of_match_table = i2c_mtk_dt_ids,
},
};
module_platform_driver(mtk_i2c_driver);
MODULE_AUTHOR("Steven Liu");
MODULE_DESCRIPTION("MT7621 I2C host driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:MT7621-I2C");
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