diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-zx2967.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-zx2967.c | 611 |
1 files changed, 611 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-zx2967.c b/drivers/i2c/busses/i2c-zx2967.c new file mode 100644 index 000000000..b8f9e020d --- /dev/null +++ b/drivers/i2c/busses/i2c-zx2967.c @@ -0,0 +1,611 @@ +/* + * Copyright (C) 2017 Sanechips Technology Co., Ltd. + * Copyright 2017 Linaro Ltd. + * + * Author: Baoyou Xie <baoyou.xie@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/clk.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +#define REG_CMD 0x04 +#define REG_DEVADDR_H 0x0C +#define REG_DEVADDR_L 0x10 +#define REG_CLK_DIV_FS 0x14 +#define REG_CLK_DIV_HS 0x18 +#define REG_WRCONF 0x1C +#define REG_RDCONF 0x20 +#define REG_DATA 0x24 +#define REG_STAT 0x28 + +#define I2C_STOP 0 +#define I2C_MASTER BIT(0) +#define I2C_ADDR_MODE_TEN BIT(1) +#define I2C_IRQ_MSK_ENABLE BIT(3) +#define I2C_RW_READ BIT(4) +#define I2C_CMB_RW_EN BIT(5) +#define I2C_START BIT(6) + +#define I2C_ADDR_LOW_MASK GENMASK(6, 0) +#define I2C_ADDR_LOW_SHIFT 0 +#define I2C_ADDR_HI_MASK GENMASK(2, 0) +#define I2C_ADDR_HI_SHIFT 7 + +#define I2C_WFIFO_RESET BIT(7) +#define I2C_RFIFO_RESET BIT(7) + +#define I2C_IRQ_ACK_CLEAR BIT(7) +#define I2C_INT_MASK GENMASK(6, 0) + +#define I2C_TRANS_DONE BIT(0) +#define I2C_SR_EDEVICE BIT(1) +#define I2C_SR_EDATA BIT(2) + +#define I2C_FIFO_MAX 16 + +#define I2C_TIMEOUT msecs_to_jiffies(1000) + +#define DEV(i2c) ((i2c)->adap.dev.parent) + +struct zx2967_i2c { + struct i2c_adapter adap; + struct clk *clk; + struct completion complete; + u32 clk_freq; + void __iomem *reg_base; + size_t residue; + int irq; + int msg_rd; + u8 *cur_trans; + u8 access_cnt; + bool is_suspended; + int error; +}; + +static void zx2967_i2c_writel(struct zx2967_i2c *i2c, + u32 val, unsigned long reg) +{ + writel_relaxed(val, i2c->reg_base + reg); +} + +static u32 zx2967_i2c_readl(struct zx2967_i2c *i2c, unsigned long reg) +{ + return readl_relaxed(i2c->reg_base + reg); +} + +static void zx2967_i2c_writesb(struct zx2967_i2c *i2c, + void *data, unsigned long reg, int len) +{ + writesb(i2c->reg_base + reg, data, len); +} + +static void zx2967_i2c_readsb(struct zx2967_i2c *i2c, + void *data, unsigned long reg, int len) +{ + readsb(i2c->reg_base + reg, data, len); +} + +static void zx2967_i2c_start_ctrl(struct zx2967_i2c *i2c) +{ + u32 status; + u32 ctl; + + status = zx2967_i2c_readl(i2c, REG_STAT); + status |= I2C_IRQ_ACK_CLEAR; + zx2967_i2c_writel(i2c, status, REG_STAT); + + ctl = zx2967_i2c_readl(i2c, REG_CMD); + if (i2c->msg_rd) + ctl |= I2C_RW_READ; + else + ctl &= ~I2C_RW_READ; + ctl &= ~I2C_CMB_RW_EN; + ctl |= I2C_START; + zx2967_i2c_writel(i2c, ctl, REG_CMD); +} + +static void zx2967_i2c_flush_fifos(struct zx2967_i2c *i2c) +{ + u32 offset; + u32 val; + + if (i2c->msg_rd) { + offset = REG_RDCONF; + val = I2C_RFIFO_RESET; + } else { + offset = REG_WRCONF; + val = I2C_WFIFO_RESET; + } + + val |= zx2967_i2c_readl(i2c, offset); + zx2967_i2c_writel(i2c, val, offset); +} + +static int zx2967_i2c_empty_rx_fifo(struct zx2967_i2c *i2c, u32 size) +{ + u8 val[I2C_FIFO_MAX] = {0}; + int i; + + if (size > I2C_FIFO_MAX) { + dev_err(DEV(i2c), "fifo size %d over the max value %d\n", + size, I2C_FIFO_MAX); + return -EINVAL; + } + + zx2967_i2c_readsb(i2c, val, REG_DATA, size); + for (i = 0; i < size; i++) { + *i2c->cur_trans++ = val[i]; + i2c->residue--; + } + + barrier(); + + return 0; +} + +static int zx2967_i2c_fill_tx_fifo(struct zx2967_i2c *i2c) +{ + size_t residue = i2c->residue; + u8 *buf = i2c->cur_trans; + + if (residue == 0) { + dev_err(DEV(i2c), "residue is %d\n", (int)residue); + return -EINVAL; + } + + if (residue <= I2C_FIFO_MAX) { + zx2967_i2c_writesb(i2c, buf, REG_DATA, residue); + + /* Again update before writing to FIFO to make sure isr sees. */ + i2c->residue = 0; + i2c->cur_trans = NULL; + } else { + zx2967_i2c_writesb(i2c, buf, REG_DATA, I2C_FIFO_MAX); + i2c->residue -= I2C_FIFO_MAX; + i2c->cur_trans += I2C_FIFO_MAX; + } + + barrier(); + + return 0; +} + +static int zx2967_i2c_reset_hardware(struct zx2967_i2c *i2c) +{ + u32 val; + u32 clk_div; + + val = I2C_MASTER | I2C_IRQ_MSK_ENABLE; + zx2967_i2c_writel(i2c, val, REG_CMD); + + clk_div = clk_get_rate(i2c->clk) / i2c->clk_freq - 1; + zx2967_i2c_writel(i2c, clk_div, REG_CLK_DIV_FS); + zx2967_i2c_writel(i2c, clk_div, REG_CLK_DIV_HS); + + zx2967_i2c_writel(i2c, I2C_FIFO_MAX - 1, REG_WRCONF); + zx2967_i2c_writel(i2c, I2C_FIFO_MAX - 1, REG_RDCONF); + zx2967_i2c_writel(i2c, 1, REG_RDCONF); + + zx2967_i2c_flush_fifos(i2c); + + return 0; +} + +static void zx2967_i2c_isr_clr(struct zx2967_i2c *i2c) +{ + u32 status; + + status = zx2967_i2c_readl(i2c, REG_STAT); + status |= I2C_IRQ_ACK_CLEAR; + zx2967_i2c_writel(i2c, status, REG_STAT); +} + +static irqreturn_t zx2967_i2c_isr(int irq, void *dev_id) +{ + u32 status; + struct zx2967_i2c *i2c = (struct zx2967_i2c *)dev_id; + + status = zx2967_i2c_readl(i2c, REG_STAT) & I2C_INT_MASK; + zx2967_i2c_isr_clr(i2c); + + if (status & I2C_SR_EDEVICE) + i2c->error = -ENXIO; + else if (status & I2C_SR_EDATA) + i2c->error = -EIO; + else if (status & I2C_TRANS_DONE) + i2c->error = 0; + else + goto done; + + complete(&i2c->complete); +done: + return IRQ_HANDLED; +} + +static void zx2967_set_addr(struct zx2967_i2c *i2c, u16 addr) +{ + u16 val; + + val = (addr >> I2C_ADDR_LOW_SHIFT) & I2C_ADDR_LOW_MASK; + zx2967_i2c_writel(i2c, val, REG_DEVADDR_L); + + val = (addr >> I2C_ADDR_HI_SHIFT) & I2C_ADDR_HI_MASK; + zx2967_i2c_writel(i2c, val, REG_DEVADDR_H); + if (val) + val = zx2967_i2c_readl(i2c, REG_CMD) | I2C_ADDR_MODE_TEN; + else + val = zx2967_i2c_readl(i2c, REG_CMD) & ~I2C_ADDR_MODE_TEN; + zx2967_i2c_writel(i2c, val, REG_CMD); +} + +static int zx2967_i2c_xfer_bytes(struct zx2967_i2c *i2c, u32 bytes) +{ + unsigned long time_left; + int rd = i2c->msg_rd; + int ret; + + reinit_completion(&i2c->complete); + + if (rd) { + zx2967_i2c_writel(i2c, bytes - 1, REG_RDCONF); + } else { + ret = zx2967_i2c_fill_tx_fifo(i2c); + if (ret) + return ret; + } + + zx2967_i2c_start_ctrl(i2c); + + time_left = wait_for_completion_timeout(&i2c->complete, + I2C_TIMEOUT); + if (time_left == 0) + return -ETIMEDOUT; + + if (i2c->error) + return i2c->error; + + return rd ? zx2967_i2c_empty_rx_fifo(i2c, bytes) : 0; +} + +static int zx2967_i2c_xfer_msg(struct zx2967_i2c *i2c, + struct i2c_msg *msg) +{ + int ret; + int i; + + zx2967_i2c_flush_fifos(i2c); + + i2c->cur_trans = msg->buf; + i2c->residue = msg->len; + i2c->access_cnt = msg->len / I2C_FIFO_MAX; + i2c->msg_rd = msg->flags & I2C_M_RD; + + for (i = 0; i < i2c->access_cnt; i++) { + ret = zx2967_i2c_xfer_bytes(i2c, I2C_FIFO_MAX); + if (ret) + return ret; + } + + if (i2c->residue > 0) { + ret = zx2967_i2c_xfer_bytes(i2c, i2c->residue); + if (ret) + return ret; + } + + i2c->residue = 0; + i2c->access_cnt = 0; + + return 0; +} + +static int zx2967_i2c_xfer(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + struct zx2967_i2c *i2c = i2c_get_adapdata(adap); + int ret; + int i; + + if (i2c->is_suspended) + return -EBUSY; + + zx2967_set_addr(i2c, msgs->addr); + + for (i = 0; i < num; i++) { + ret = zx2967_i2c_xfer_msg(i2c, &msgs[i]); + if (ret) + return ret; + } + + return num; +} + +static void +zx2967_smbus_xfer_prepare(struct zx2967_i2c *i2c, u16 addr, + char read_write, u8 command, int size, + union i2c_smbus_data *data) +{ + u32 val; + + val = zx2967_i2c_readl(i2c, REG_RDCONF); + val |= I2C_RFIFO_RESET; + zx2967_i2c_writel(i2c, val, REG_RDCONF); + zx2967_set_addr(i2c, addr); + val = zx2967_i2c_readl(i2c, REG_CMD); + val &= ~I2C_RW_READ; + zx2967_i2c_writel(i2c, val, REG_CMD); + + switch (size) { + case I2C_SMBUS_BYTE: + zx2967_i2c_writel(i2c, command, REG_DATA); + break; + case I2C_SMBUS_BYTE_DATA: + zx2967_i2c_writel(i2c, command, REG_DATA); + if (read_write == I2C_SMBUS_WRITE) + zx2967_i2c_writel(i2c, data->byte, REG_DATA); + break; + case I2C_SMBUS_WORD_DATA: + zx2967_i2c_writel(i2c, command, REG_DATA); + if (read_write == I2C_SMBUS_WRITE) { + zx2967_i2c_writel(i2c, (data->word >> 8), REG_DATA); + zx2967_i2c_writel(i2c, (data->word & 0xff), + REG_DATA); + } + break; + } +} + +static int zx2967_smbus_xfer_read(struct zx2967_i2c *i2c, int size, + union i2c_smbus_data *data) +{ + unsigned long time_left; + u8 buf[2]; + u32 val; + + reinit_completion(&i2c->complete); + + val = zx2967_i2c_readl(i2c, REG_CMD); + val |= I2C_CMB_RW_EN; + zx2967_i2c_writel(i2c, val, REG_CMD); + + val = zx2967_i2c_readl(i2c, REG_CMD); + val |= I2C_START; + zx2967_i2c_writel(i2c, val, REG_CMD); + + time_left = wait_for_completion_timeout(&i2c->complete, + I2C_TIMEOUT); + if (time_left == 0) + return -ETIMEDOUT; + + if (i2c->error) + return i2c->error; + + switch (size) { + case I2C_SMBUS_BYTE: + case I2C_SMBUS_BYTE_DATA: + val = zx2967_i2c_readl(i2c, REG_DATA); + data->byte = val; + break; + case I2C_SMBUS_WORD_DATA: + case I2C_SMBUS_PROC_CALL: + buf[0] = zx2967_i2c_readl(i2c, REG_DATA); + buf[1] = zx2967_i2c_readl(i2c, REG_DATA); + data->word = (buf[0] << 8) | buf[1]; + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static int zx2967_smbus_xfer_write(struct zx2967_i2c *i2c) +{ + unsigned long time_left; + u32 val; + + reinit_completion(&i2c->complete); + val = zx2967_i2c_readl(i2c, REG_CMD); + val |= I2C_START; + zx2967_i2c_writel(i2c, val, REG_CMD); + + time_left = wait_for_completion_timeout(&i2c->complete, + I2C_TIMEOUT); + if (time_left == 0) + return -ETIMEDOUT; + + if (i2c->error) + return i2c->error; + + return 0; +} + +static int zx2967_smbus_xfer(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, union i2c_smbus_data *data) +{ + struct zx2967_i2c *i2c = i2c_get_adapdata(adap); + + if (size == I2C_SMBUS_QUICK) + read_write = I2C_SMBUS_WRITE; + + switch (size) { + case I2C_SMBUS_QUICK: + case I2C_SMBUS_BYTE: + case I2C_SMBUS_BYTE_DATA: + case I2C_SMBUS_WORD_DATA: + zx2967_smbus_xfer_prepare(i2c, addr, read_write, + command, size, data); + break; + default: + return -EOPNOTSUPP; + } + + if (read_write == I2C_SMBUS_READ) + return zx2967_smbus_xfer_read(i2c, size, data); + + return zx2967_smbus_xfer_write(i2c); +} + +static u32 zx2967_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | + I2C_FUNC_SMBUS_QUICK | + I2C_FUNC_SMBUS_BYTE | + I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_WORD_DATA | + I2C_FUNC_SMBUS_BLOCK_DATA | + I2C_FUNC_SMBUS_PROC_CALL | + I2C_FUNC_SMBUS_I2C_BLOCK; +} + +static int __maybe_unused zx2967_i2c_suspend(struct device *dev) +{ + struct zx2967_i2c *i2c = dev_get_drvdata(dev); + + i2c->is_suspended = true; + clk_disable_unprepare(i2c->clk); + + return 0; +} + +static int __maybe_unused zx2967_i2c_resume(struct device *dev) +{ + struct zx2967_i2c *i2c = dev_get_drvdata(dev); + + i2c->is_suspended = false; + clk_prepare_enable(i2c->clk); + + return 0; +} + +static SIMPLE_DEV_PM_OPS(zx2967_i2c_dev_pm_ops, + zx2967_i2c_suspend, zx2967_i2c_resume); + +static const struct i2c_algorithm zx2967_i2c_algo = { + .master_xfer = zx2967_i2c_xfer, + .smbus_xfer = zx2967_smbus_xfer, + .functionality = zx2967_i2c_func, +}; + +static const struct i2c_adapter_quirks zx2967_i2c_quirks = { + .flags = I2C_AQ_NO_ZERO_LEN, +}; + +static const struct of_device_id zx2967_i2c_of_match[] = { + { .compatible = "zte,zx296718-i2c", }, + { }, +}; +MODULE_DEVICE_TABLE(of, zx2967_i2c_of_match); + +static int zx2967_i2c_probe(struct platform_device *pdev) +{ + struct zx2967_i2c *i2c; + void __iomem *reg_base; + struct resource *res; + struct clk *clk; + int ret; + + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + reg_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(reg_base)) + return PTR_ERR(reg_base); + + clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(clk)) { + dev_err(&pdev->dev, "missing controller clock"); + return PTR_ERR(clk); + } + + ret = clk_prepare_enable(clk); + if (ret) { + dev_err(&pdev->dev, "failed to enable i2c_clk\n"); + return ret; + } + + ret = device_property_read_u32(&pdev->dev, "clock-frequency", + &i2c->clk_freq); + if (ret) { + dev_err(&pdev->dev, "missing clock-frequency"); + return ret; + } + + ret = platform_get_irq(pdev, 0); + if (ret < 0) + return ret; + + i2c->irq = ret; + i2c->reg_base = reg_base; + i2c->clk = clk; + + init_completion(&i2c->complete); + platform_set_drvdata(pdev, i2c); + + ret = zx2967_i2c_reset_hardware(i2c); + if (ret) { + dev_err(&pdev->dev, "failed to initialize i2c controller\n"); + goto err_clk_unprepare; + } + + ret = devm_request_irq(&pdev->dev, i2c->irq, + zx2967_i2c_isr, 0, dev_name(&pdev->dev), i2c); + if (ret) { + dev_err(&pdev->dev, "failed to request irq %i\n", i2c->irq); + goto err_clk_unprepare; + } + + i2c_set_adapdata(&i2c->adap, i2c); + strlcpy(i2c->adap.name, "zx2967 i2c adapter", + sizeof(i2c->adap.name)); + i2c->adap.algo = &zx2967_i2c_algo; + i2c->adap.quirks = &zx2967_i2c_quirks; + i2c->adap.nr = pdev->id; + i2c->adap.dev.parent = &pdev->dev; + i2c->adap.dev.of_node = pdev->dev.of_node; + + ret = i2c_add_numbered_adapter(&i2c->adap); + if (ret) + goto err_clk_unprepare; + + return 0; + +err_clk_unprepare: + clk_disable_unprepare(i2c->clk); + return ret; +} + +static int zx2967_i2c_remove(struct platform_device *pdev) +{ + struct zx2967_i2c *i2c = platform_get_drvdata(pdev); + + i2c_del_adapter(&i2c->adap); + clk_disable_unprepare(i2c->clk); + + return 0; +} + +static struct platform_driver zx2967_i2c_driver = { + .probe = zx2967_i2c_probe, + .remove = zx2967_i2c_remove, + .driver = { + .name = "zx2967_i2c", + .of_match_table = zx2967_i2c_of_match, + .pm = &zx2967_i2c_dev_pm_ops, + }, +}; +module_platform_driver(zx2967_i2c_driver); + +MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>"); +MODULE_DESCRIPTION("ZTE ZX2967 I2C Bus Controller driver"); +MODULE_LICENSE("GPL v2"); |