--- /dev/null
+/*
+ * 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)
+
+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;
+
+ if (msg->len == 0)
+ return -EINVAL;
+
+ 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 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.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");
projects / karo-tx-linux.git / commitdiff