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linux/drivers/i2c/busses/i2c-mt7621.c
Wolfram Sang ea1558ce14 i2c: move drivers from strlcpy to strscpy 
Follow the advice of the below link and prefer 'strscpy'. Conversion is
easy because no driver used the return value and has been done with a
simple sed invocation.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2022-08-11 23:02:51 +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_platform.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_master_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_master_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_master_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_master_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_master_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_master_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_master_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_master_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_master_stop(i2c);
if (ret)
goto err_timeout;
/* the return value is number of executed messages */
return i;
err_ack:
ret = mtk_i2c_master_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 = {
.master_xfer = mtk_i2c_master_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(&pdev->dev, NULL);
if (IS_ERR(i2c->clk)) {
dev_err(&pdev->dev, "no clock defined\n");
return PTR_ERR(i2c->clk);
}
ret = clk_prepare_enable(i2c->clk);
if (ret) {
dev_err(&pdev->dev, "Unable to enable clock\n");
return ret;
}
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");
ret = -EINVAL;
goto err_disable_clk;
}
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)
goto err_disable_clk;
dev_info(&pdev->dev, "clock %u kHz\n", i2c->bus_freq / 1000);
return 0;
err_disable_clk:
clk_disable_unprepare(i2c->clk);
return ret;
}
static int mtk_i2c_remove(struct platform_device *pdev)
{
struct mtk_i2c *i2c = platform_get_drvdata(pdev);
clk_disable_unprepare(i2c->clk);
i2c_del_adapter(&i2c->adap);
return 0;
}
static struct platform_driver mtk_i2c_driver = {
.probe = mtk_i2c_probe,
.remove = 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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