1 files changed, 385 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-digicolor.c b/drivers/i2c/busses/i2c-digicolor.c
new file mode 100644
index 000000000000..03f1e5549896
--- /dev/null
+++ b/drivers/i2c/busses/i2c-digicolor.c
@@ -0,0 +1,385 @@
+/*
+ * I2C bus driver for Conexant Digicolor SoCs
+ *
+ * Author: Baruch Siach <baruch@tkos.co.il>
+ *
+ * Copyright (C) 2015 Paradox Innovation Ltd.
+ *
+ * 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/completion.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#define DEFAULT_FREQ		100000
+#define TIMEOUT_MS		100
+
+#define II_CONTROL		0x0
+#define II_CONTROL_LOCAL_RESET	BIT(0)
+
+#define II_CLOCKTIME		0x1
+
+#define II_COMMAND		0x2
+#define II_CMD_START		1
+#define II_CMD_RESTART		2
+#define II_CMD_SEND_ACK		3
+#define II_CMD_GET_ACK		6
+#define II_CMD_GET_NOACK	7
+#define II_CMD_STOP		10
+#define II_COMMAND_GO		BIT(7)
+#define II_COMMAND_COMPLETION_STATUS(r)	(((r) >> 5) & 3)
+#define II_CMD_STATUS_NORMAL	0
+#define II_CMD_STATUS_ACK_GOOD	1
+#define II_CMD_STATUS_ACK_BAD	2
+#define II_CMD_STATUS_ABORT	3
+
+#define II_DATA			0x3
+#define II_INTFLAG_CLEAR	0x8
+#define II_INTENABLE		0xa
+
+struct dc_i2c {
+	struct i2c_adapter	adap;
+	struct device		*dev;
+	void __iomem		*regs;
+	struct clk		*clk;
+	unsigned int		frequency;
+
+	struct i2c_msg		*msg;
+	unsigned int		msgbuf_ptr;
+	int			last;
+	spinlock_t		lock;
+	struct completion	done;
+	int			state;
+	int			error;
+};
+
+enum {
+	STATE_IDLE,
+	STATE_START,
+	STATE_ADDR,
+	STATE_WRITE,
+	STATE_READ,
+	STATE_STOP,
+};
+
+static void dc_i2c_cmd(struct dc_i2c *i2c, u8 cmd)
+{
+	writeb_relaxed(cmd | II_COMMAND_GO, i2c->regs + II_COMMAND);
+}
+
+static u8 dc_i2c_addr_cmd(struct i2c_msg *msg)
+{
+	u8 addr = (msg->addr & 0x7f) << 1;
+
+	if (msg->flags & I2C_M_RD)
+		addr |= 1;
+
+	return addr;
+}
+
+static void dc_i2c_data(struct dc_i2c *i2c, u8 data)
+{
+	writeb_relaxed(data, i2c->regs + II_DATA);
+}
+
+static void dc_i2c_write_byte(struct dc_i2c *i2c, u8 byte)
+{
+	dc_i2c_data(i2c, byte);
+	dc_i2c_cmd(i2c, II_CMD_SEND_ACK);
+}
+
+static void dc_i2c_write_buf(struct dc_i2c *i2c)
+{
+	dc_i2c_write_byte(i2c, i2c->msg->buf[i2c->msgbuf_ptr++]);
+}
+
+static void dc_i2c_next_read(struct dc_i2c *i2c)
+{
+	bool last = (i2c->msgbuf_ptr + 1 == i2c->msg->len);
+
+	dc_i2c_cmd(i2c, last ? II_CMD_GET_NOACK : II_CMD_GET_ACK);
+}
+
+static void dc_i2c_stop(struct dc_i2c *i2c)
+{
+	i2c->state = STATE_STOP;
+	if (i2c->last)
+		dc_i2c_cmd(i2c, II_CMD_STOP);
+	else
+		complete(&i2c->done);
+}
+
+static u8 dc_i2c_read_byte(struct dc_i2c *i2c)
+{
+	return readb_relaxed(i2c->regs + II_DATA);
+}
+
+static void dc_i2c_read_buf(struct dc_i2c *i2c)
+{
+	i2c->msg->buf[i2c->msgbuf_ptr++] = dc_i2c_read_byte(i2c);
+	dc_i2c_next_read(i2c);
+}
+
+static void dc_i2c_set_irq(struct dc_i2c *i2c, int enable)
+{
+	if (enable)
+		writeb_relaxed(1, i2c->regs + II_INTFLAG_CLEAR);
+	writeb_relaxed(!!enable, i2c->regs + II_INTENABLE);
+}
+
+static int dc_i2c_cmd_status(struct dc_i2c *i2c)
+{
+	u8 cmd = readb_relaxed(i2c->regs + II_COMMAND);
+
+	return II_COMMAND_COMPLETION_STATUS(cmd);
+}
+
+static void dc_i2c_start_msg(struct dc_i2c *i2c, int first)
+{
+	struct i2c_msg *msg = i2c->msg;
+
+	if (!(msg->flags & I2C_M_NOSTART)) {
+		i2c->state = STATE_START;
+		dc_i2c_cmd(i2c, first ? II_CMD_START : II_CMD_RESTART);
+	} else if (msg->flags & I2C_M_RD) {
+		i2c->state = STATE_READ;
+		dc_i2c_next_read(i2c);
+	} else {
+		i2c->state = STATE_WRITE;
+		dc_i2c_write_buf(i2c);
+	}
+}
+
+static irqreturn_t dc_i2c_irq(int irq, void *dev_id)
+{
+	struct dc_i2c *i2c = dev_id;
+	int cmd_status = dc_i2c_cmd_status(i2c);
+	unsigned long flags;
+	u8 addr_cmd;
+
+	writeb_relaxed(1, i2c->regs + II_INTFLAG_CLEAR);
+
+	spin_lock_irqsave(&i2c->lock, flags);
+
+	if (cmd_status == II_CMD_STATUS_ACK_BAD
+	    || cmd_status == II_CMD_STATUS_ABORT) {
+		i2c->error = -EIO;
+		complete(&i2c->done);
+		goto out;
+	}
+
+	switch (i2c->state) {
+	case STATE_START:
+		addr_cmd = dc_i2c_addr_cmd(i2c->msg);
+		dc_i2c_write_byte(i2c, addr_cmd);
+		i2c->state = STATE_ADDR;
+		break;
+	case STATE_ADDR:
+		if (i2c->msg->flags & I2C_M_RD) {
+			dc_i2c_next_read(i2c);
+			i2c->state = STATE_READ;
+			break;
+		}
+		i2c->state = STATE_WRITE;
+		/* fall through */
+	case STATE_WRITE:
+		if (i2c->msgbuf_ptr < i2c->msg->len)
+			dc_i2c_write_buf(i2c);
+		else
+			dc_i2c_stop(i2c);
+		break;
+	case STATE_READ:
+		if (i2c->msgbuf_ptr < i2c->msg->len)
+			dc_i2c_read_buf(i2c);
+		else
+			dc_i2c_stop(i2c);
+		break;
+	case STATE_STOP:
+		i2c->state = STATE_IDLE;
+		complete(&i2c->done);
+		break;
+	}
+
+out:
+	spin_unlock_irqrestore(&i2c->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static int dc_i2c_xfer_msg(struct dc_i2c *i2c, struct i2c_msg *msg, int first,
+			   int last)
+{
+	unsigned long timeout = msecs_to_jiffies(TIMEOUT_MS);
+	unsigned long flags;
+
+	spin_lock_irqsave(&i2c->lock, flags);
+	i2c->msg = msg;
+	i2c->msgbuf_ptr = 0;
+	i2c->last = last;
+	i2c->error = 0;
+
+	reinit_completion(&i2c->done);
+	dc_i2c_set_irq(i2c, 1);
+	dc_i2c_start_msg(i2c, first);
+	spin_unlock_irqrestore(&i2c->lock, flags);
+
+	timeout = wait_for_completion_timeout(&i2c->done, timeout);
+	dc_i2c_set_irq(i2c, 0);
+	if (timeout == 0) {
+		i2c->state = STATE_IDLE;
+		return -ETIMEDOUT;
+	}
+
+	if (i2c->error)
+		return i2c->error;
+
+	return 0;
+}
+
+static int dc_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct dc_i2c *i2c = adap->algo_data;
+	int i, ret;
+
+	for (i = 0; i < num; i++) {
+		ret = dc_i2c_xfer_msg(i2c, &msgs[i], i == 0, i == num - 1);
+		if (ret)
+			return ret;
+	}
+
+	return num;
+}
+
+static int dc_i2c_init_hw(struct dc_i2c *i2c)
+{
+	unsigned long clk_rate = clk_get_rate(i2c->clk);
+	unsigned int clocktime;
+
+	writeb_relaxed(II_CONTROL_LOCAL_RESET, i2c->regs + II_CONTROL);
+	udelay(100);
+	writeb_relaxed(0, i2c->regs + II_CONTROL);
+	udelay(100);
+
+	clocktime = DIV_ROUND_UP(clk_rate, 64 * i2c->frequency);
+	if (clocktime < 1 || clocktime > 0xff) {
+		dev_err(i2c->dev, "can't set bus speed of %u Hz\n",
+			i2c->frequency);
+		return -EINVAL;
+	}
+	writeb_relaxed(clocktime - 1, i2c->regs + II_CLOCKTIME);
+
+	return 0;
+}
+
+static u32 dc_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART;
+}
+
+static const struct i2c_algorithm dc_i2c_algorithm = {
+	.master_xfer	= dc_i2c_xfer,
+	.functionality	= dc_i2c_func,
+};
+
+static int dc_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct dc_i2c *i2c;
+	struct resource *r;
+	int ret = 0, irq;
+
+	i2c = devm_kzalloc(&pdev->dev, sizeof(struct dc_i2c), GFP_KERNEL);
+	if (!i2c)
+		return -ENOMEM;
+
+	if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+				 &i2c->frequency))
+		i2c->frequency = DEFAULT_FREQ;
+
+	i2c->dev = &pdev->dev;
+	platform_set_drvdata(pdev, i2c);
+
+	spin_lock_init(&i2c->lock);
+	init_completion(&i2c->done);
+
+	i2c->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(i2c->clk))
+		return PTR_ERR(i2c->clk);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	i2c->regs = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(i2c->regs))
+		return PTR_ERR(i2c->regs);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_irq(&pdev->dev, irq, dc_i2c_irq, 0,
+			       dev_name(&pdev->dev), i2c);
+	if (ret < 0)
+		return ret;
+
+	strlcpy(i2c->adap.name, "Conexant Digicolor I2C adapter",
+		sizeof(i2c->adap.name));
+	i2c->adap.owner = THIS_MODULE;
+	i2c->adap.algo = &dc_i2c_algorithm;
+	i2c->adap.dev.parent = &pdev->dev;
+	i2c->adap.dev.of_node = np;
+	i2c->adap.algo_data = i2c;
+
+	ret = dc_i2c_init_hw(i2c);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(i2c->clk);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_add_adapter(&i2c->adap);
+	if (ret < 0) {
+		clk_unprepare(i2c->clk);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int dc_i2c_remove(struct platform_device *pdev)
+{
+	struct dc_i2c *i2c = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&i2c->adap);
+	clk_disable_unprepare(i2c->clk);
+
+	return 0;
+}
+
+static const struct of_device_id dc_i2c_match[] = {
+	{ .compatible = "cnxt,cx92755-i2c" },
+	{ },
+};
+
+static struct platform_driver dc_i2c_driver = {
+	.probe   = dc_i2c_probe,
+	.remove  = dc_i2c_remove,
+	.driver  = {
+		.name  = "digicolor-i2c",
+		.of_match_table = dc_i2c_match,
+	},
+};
+module_platform_driver(dc_i2c_driver);
+
+MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
+MODULE_DESCRIPTION("Conexant Digicolor I2C master driver");
+MODULE_LICENSE("GPL v2");