diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-mt7621.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-mt7621.c | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-mt7621.c b/drivers/i2c/busses/i2c-mt7621.c new file mode 100644 index 000000000..901f0fb04 --- /dev/null +++ b/drivers/i2c/busses/i2c-mt7621.c @@ -0,0 +1,362 @@ +// 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 resource *res; + struct mtk_i2c *i2c; + struct i2c_adapter *adap; + int ret; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + i2c = devm_kzalloc(&pdev->dev, sizeof(struct mtk_i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + i2c->base = devm_ioremap_resource(&pdev->dev, res); + 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; + strlcpy(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"); |