From 5af1734d9fc79c2d08853c703d1edfef2a4cae16 Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Sun, 5 Sep 2010 03:19:10 +0200
Subject: [PATCH 10/23] i2c: Add i2c driver for JZ47XX SoCs

This patch adds a driver for the i2c controller found in Ingenic JZ47XX based
SoCs.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 drivers/i2c/busses/Kconfig      |   10 +
 drivers/i2c/busses/Makefile     |    1 +
 drivers/i2c/busses/i2c-jz47xx.c |  424 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 435 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-jz47xx.c

--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -431,6 +431,16 @@ config I2C_IXP2000
 	  This driver is deprecated and will be dropped soon. Use i2c-gpio
 	  instead.
 
+config I2C_JZ47XX
+	tristate "JZ4740 I2C Interface"
+	depends on ARCH_JZ4740
+	help
+	  Say Y here if you want support for the I2C controller found on Ingenic
+	  JZ47XX based SoCs.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called i2c-jz47xx.
+
 config I2C_MPC
 	tristate "MPC107/824x/85xx/512x/52xx/83xx/86xx"
 	depends on PPC32
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -41,6 +41,7 @@ obj-$(CONFIG_I2C_IMX)		+= i2c-imx.o
 obj-$(CONFIG_I2C_INTEL_MID)	+= i2c-intel-mid.o
 obj-$(CONFIG_I2C_IOP3XX)	+= i2c-iop3xx.o
 obj-$(CONFIG_I2C_IXP2000)	+= i2c-ixp2000.o
+obj-$(CONFIG_I2C_JZ47XX)	+= i2c-jz47xx.o
 obj-$(CONFIG_I2C_MPC)		+= i2c-mpc.o
 obj-$(CONFIG_I2C_MV64XXX)	+= i2c-mv64xxx.o
 obj-$(CONFIG_I2C_NOMADIK)	+= i2c-nomadik.o
--- /dev/null
+++ b/drivers/i2c/busses/i2c-jz47xx.c
@@ -0,0 +1,424 @@
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+
+#include <linux/gpio.h>
+#include <linux/delay.h>
+
+#define JZ47XX_REG_I2C_DATA	0x00
+#define JZ47XX_REG_I2C_CTRL	0x04
+#define JZ47XX_REG_I2C_STATUS	0x08
+#define JZ47XX_REG_I2C_CLOCK	0x0C
+
+#define JZ47XX_I2C_STATUS_FIFO_FULL	BIT(4)
+#define JZ47XX_I2C_STATUS_BUSY		BIT(3)
+#define JZ47XX_I2C_STATUS_TEND		BIT(2)
+#define JZ47XX_I2C_STATUS_DATA_VALID	BIT(1)
+#define JZ47XX_I2C_STATUS_NACK		BIT(0)
+
+#define JZ47XX_I2C_CTRL_IRQ_ENABLE	BIT(4)
+#define JZ47XX_I2C_CTRL_START		BIT(3)
+#define JZ47XX_I2C_CTRL_STOP		BIT(2)
+#define JZ47XX_I2C_CTRL_NACK		BIT(1)
+#define JZ47XX_I2C_CTRL_ENABLE		BIT(0)
+
+struct jz47xx_i2c {
+	struct resource *mem;
+	void __iomem *base;
+	int irq;
+	struct clk *clk;
+
+	struct i2c_adapter adapter;
+
+	wait_queue_head_t wait_queue;
+};
+
+static inline struct jz47xx_i2c *adapter_to_jz47xx_i2c(struct i2c_adapter *adap)
+{
+	return container_of(adap, struct jz47xx_i2c, adapter);
+}
+
+static inline void jz47xx_i2c_set_ctrl(struct jz47xx_i2c *jz47xx_i2c,
+	uint8_t mask, uint8_t value)
+{
+	uint8_t ctrl;
+	ctrl = readb(jz47xx_i2c->base + JZ47XX_REG_I2C_CTRL);
+	ctrl &= ~mask;
+	ctrl |= value;
+	printk("ctrl: %x\n", ctrl);
+	writeb(ctrl, jz47xx_i2c->base + JZ47XX_REG_I2C_CTRL);
+}
+
+static irqreturn_t jz47xx_i2c_irq_handler(int irq, void *devid)
+{
+	struct jz47xx_i2c *jz47xx_i2c = devid;
+
+	printk("IRQ\n");
+
+	wake_up(&jz47xx_i2c->wait_queue);
+
+	jz47xx_i2c_set_ctrl(jz47xx_i2c, JZ47XX_I2C_CTRL_IRQ_ENABLE, 0);
+
+	return IRQ_HANDLED;
+}
+
+static inline void jz47xx_i2c_set_data_valid(struct jz47xx_i2c *jz47xx_i2c,
+	bool valid)
+{
+	uint8_t val;
+	val = readb(jz47xx_i2c->base + JZ47XX_REG_I2C_STATUS);
+	if (valid)
+		val |= JZ47XX_I2C_STATUS_DATA_VALID;
+	else
+		val &= ~JZ47XX_I2C_STATUS_DATA_VALID;
+	writeb(val, jz47xx_i2c->base + JZ47XX_REG_I2C_STATUS);
+}
+
+static int jz47xx_i2c_test_event(struct jz47xx_i2c *jz47xx_i2c, uint8_t mask, uint8_t value)
+{
+	uint8_t status;
+
+	mask |= JZ47XX_I2C_STATUS_NACK;
+	value |= JZ47XX_I2C_STATUS_NACK;
+
+	status = readb(jz47xx_i2c->base + JZ47XX_REG_I2C_STATUS);
+	printk("status: %x %x %x %x\n", status, mask, value, (status & mask) ^
+	value);
+	if (((status & mask) ^ value) == mask) {
+		jz47xx_i2c_set_ctrl(jz47xx_i2c, JZ47XX_I2C_CTRL_IRQ_ENABLE,
+			JZ47XX_I2C_CTRL_IRQ_ENABLE);
+		return 0;
+	}
+	return 1;
+}
+
+static int jz47xx_i2c_wait_event_or_nack(struct jz47xx_i2c *jz47xx_i2c, uint8_t
+mask, uint8_t value)
+{
+	int ret;
+
+	ret = wait_event_interruptible_timeout(jz47xx_i2c->wait_queue,
+		jz47xx_i2c_test_event(jz47xx_i2c, mask, value), 30 * HZ);
+
+/*	while (!jz47xx_i2c_test_event(jz47xx_i2c, mask, value));
+
+	ret = 1;*/
+
+	printk("wait event or nack: %d %x\n", ret, readb(jz47xx_i2c->base +
+	JZ47XX_REG_I2C_STATUS));
+
+	if (ret == 0)
+		ret = -ETIMEDOUT;
+	else if(ret > 0) {
+		if (readb(jz47xx_i2c->base + JZ47XX_REG_I2C_STATUS) & JZ47XX_I2C_STATUS_NACK)
+			ret = -EIO;
+		else
+			ret = 0;
+	}
+
+	return ret;
+}
+
+static int jz47xx_i2c_wait_event(struct jz47xx_i2c *jz47xx_i2c, uint8_t event)
+{
+	int ret;
+
+	ret = wait_event_interruptible_timeout(jz47xx_i2c->wait_queue,
+		jz47xx_i2c_test_event(jz47xx_i2c, event, event), 30 * HZ);
+
+	if (ret == 0)
+		ret = -ETIMEDOUT;
+	else if(ret > 0)
+		ret = 0;
+
+	return ret;
+}
+
+
+static int jz47xx_i2c_write_msg(struct jz47xx_i2c *jz47xx_i2c,
+	struct i2c_msg *msg)
+{
+	int ret;
+	int i;
+
+	printk("%s:%s[%d]\n", __FILE__, __func__, __LINE__);
+	for (i = 0; i < msg->len; ++i) {
+		writeb(msg->buf[i], jz47xx_i2c->base + JZ47XX_REG_I2C_DATA);
+		jz47xx_i2c_set_data_valid(jz47xx_i2c, true);
+		ret = jz47xx_i2c_wait_event_or_nack(jz47xx_i2c,
+			JZ47XX_I2C_STATUS_DATA_VALID, 0);
+		if (ret)
+			break;
+	}
+	jz47xx_i2c_set_ctrl(jz47xx_i2c, JZ47XX_I2C_CTRL_STOP,
+		JZ47XX_I2C_CTRL_STOP);
+
+	if (!ret)
+		ret = jz47xx_i2c_wait_event_or_nack(jz47xx_i2c, JZ47XX_I2C_STATUS_TEND,
+			JZ47XX_I2C_STATUS_TEND);
+
+	return ret;
+}
+
+static int jz47xx_i2c_read_msg(struct jz47xx_i2c *jz47xx_i2c,
+	struct i2c_msg *msg)
+{
+	int i;
+	int ret;
+	printk("%s:%s[%d]\n", __FILE__, __func__, __LINE__);
+
+	jz47xx_i2c_set_ctrl(jz47xx_i2c, JZ47XX_I2C_CTRL_NACK,
+		msg->len == 1 ? JZ47XX_I2C_CTRL_NACK : 0);
+
+	for (i = 0; i < msg->len; ++i) {
+		ret = jz47xx_i2c_wait_event(jz47xx_i2c, JZ47XX_I2C_STATUS_DATA_VALID);
+		if (ret) {
+			jz47xx_i2c_set_ctrl(jz47xx_i2c, JZ47XX_I2C_CTRL_NACK,
+				JZ47XX_I2C_CTRL_NACK);
+			break;
+		}
+
+		if (i == msg->len - 2) {
+			jz47xx_i2c_set_ctrl(jz47xx_i2c, JZ47XX_I2C_CTRL_NACK,
+				JZ47XX_I2C_CTRL_NACK);
+		}
+
+		msg->buf[i] = readb(jz47xx_i2c->base + JZ47XX_REG_I2C_DATA);
+		printk("read: %x\n", msg->buf[i]);
+		jz47xx_i2c_set_data_valid(jz47xx_i2c, false);
+	}
+
+	jz47xx_i2c_set_ctrl(jz47xx_i2c, JZ47XX_I2C_CTRL_STOP,
+		JZ47XX_I2C_CTRL_STOP);
+
+	return ret;
+}
+
+static int jz47xx_i2c_xfer_msg(struct jz47xx_i2c *jz47xx_i2c,
+	struct i2c_msg *msg)
+{
+	uint8_t addr;
+	int ret;
+
+	addr = msg->addr << 1;
+	if (msg->flags & I2C_M_RD)
+		addr |= 1;
+
+	jz47xx_i2c_set_ctrl(jz47xx_i2c, JZ47XX_I2C_CTRL_START,
+		JZ47XX_I2C_CTRL_START);
+	writeb(addr, jz47xx_i2c->base + JZ47XX_REG_I2C_DATA);
+	jz47xx_i2c_set_data_valid(jz47xx_i2c, true);
+
+	if (msg->flags & I2C_M_RD) {
+		printk("%s:%s[%d]\n", __FILE__, __func__, __LINE__);
+		ret = jz47xx_i2c_wait_event_or_nack(jz47xx_i2c,
+		JZ47XX_I2C_STATUS_TEND, JZ47XX_I2C_STATUS_TEND);
+		if (!ret)
+			ret = jz47xx_i2c_read_msg(jz47xx_i2c, msg);
+	} else {
+		printk("%s:%s[%d]\n", __FILE__, __func__, __LINE__);
+		ret = jz47xx_i2c_wait_event_or_nack(jz47xx_i2c,
+		    JZ47XX_I2C_STATUS_DATA_VALID, 0);
+		if (!ret)
+			ret = jz47xx_i2c_write_msg(jz47xx_i2c, msg);
+	}
+
+	return ret;
+}
+
+static int jz47xx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int
+num)
+{
+	struct jz47xx_i2c *jz47xx_i2c = adapter_to_jz47xx_i2c(adap);
+	int ret = 0;
+	int i;
+	int mask = JZ47XX_I2C_CTRL_ENABLE;
+
+	printk("xfer: %d %x\n", num, readb(jz47xx_i2c->base +
+	JZ47XX_REG_I2C_STATUS));
+
+	clk_enable(jz47xx_i2c->clk);
+	jz47xx_i2c_set_ctrl(jz47xx_i2c, mask, mask);
+
+	for (i = 0; i < num; ++i) {
+		ret = jz47xx_i2c_xfer_msg(jz47xx_i2c, &msgs[i]);
+		if (ret)
+			break;
+	}
+
+	jz47xx_i2c_set_ctrl(jz47xx_i2c, mask, 0);
+	clk_disable(jz47xx_i2c->clk);
+
+	printk("xfer ret: %d\n", ret);
+
+	return ret;
+}
+
+static u32 jz47xx_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm jz47xx_i2c_algorithm = {
+	.master_xfer = jz47xx_i2c_xfer,
+	.functionality = jz47xx_i2c_functionality,
+};
+
+const static struct jz_gpio_bulk_request jz47xx_i2c_pins[] = {
+	JZ_GPIO_BULK_PIN(I2C_SDA),
+	JZ_GPIO_BULK_PIN(I2C_SCK),
+};
+
+static int __devinit jz47xx_i2c_probe(struct platform_device *pdev)
+{
+	struct jz47xx_i2c *jz47xx_i2c;
+	struct resource *mem;
+	void __iomem *base;
+	struct clk *clk;
+	int irq;
+	int ret;
+
+	irq = platform_get_irq(pdev, 0);
+	if (!irq) {
+		dev_err(&pdev->dev, "Failed to get IRQ: %d\n", irq);
+		return irq;
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem) {
+		dev_err(&pdev->dev, "Failed to get iomem region\n");
+		return -ENXIO;
+	}
+
+	mem = request_mem_region(mem->start, resource_size(mem), pdev->name);
+	if (!mem) {
+		dev_err(&pdev->dev, "Failed to request iomem region\n");
+		return -EBUSY;
+	}
+
+	base = ioremap(mem->start, resource_size(mem));
+	if (!base) {
+		dev_err(&pdev->dev, "Failed to ioremap iomem\n");
+		ret = -EBUSY;
+		goto err_release_mem_region;
+	}
+
+	clk = clk_get(&pdev->dev, "i2c");
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
+		goto err_iounmap;
+	}
+
+	jz47xx_i2c = kzalloc(sizeof(*jz47xx_i2c), GFP_KERNEL);
+	if (!jz47xx_i2c) {
+		ret = -ENOMEM;
+		goto err_clk_put;
+	}
+
+	jz47xx_i2c->adapter.owner = THIS_MODULE;
+	jz47xx_i2c->adapter.algo = &jz47xx_i2c_algorithm;
+	jz47xx_i2c->adapter.dev.parent = &pdev->dev;
+	jz47xx_i2c->adapter.nr = pdev->id < 0 ?: 0;
+	strcpy(jz47xx_i2c->adapter.name, pdev->name);
+
+	jz47xx_i2c->mem = mem;
+	jz47xx_i2c->base = base;
+	jz47xx_i2c->clk = clk;
+	jz47xx_i2c->irq = irq;
+
+	init_waitqueue_head(&jz47xx_i2c->wait_queue);
+
+	ret = request_irq(irq, jz47xx_i2c_irq_handler, 0, pdev->name, jz47xx_i2c);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
+		goto err_free;
+	}
+
+    ret = jz_gpio_bulk_request(jz47xx_i2c_pins, ARRAY_SIZE(jz47xx_i2c_pins));
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request i2c pins: %d\n", ret);
+		goto err_free_irq;
+	}
+
+	writew(0x10, jz47xx_i2c->base + JZ47XX_REG_I2C_CLOCK);
+
+	ret = i2c_add_numbered_adapter(&jz47xx_i2c->adapter);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to add i2c adapter: %d\n", ret);
+		goto err_free_gpios;
+	}
+
+	platform_set_drvdata(pdev, jz47xx_i2c);
+
+	printk("JZ4740 I2C\n");
+
+	return 0;
+
+err_free_gpios:
+	jz_gpio_bulk_free(jz47xx_i2c_pins, ARRAY_SIZE(jz47xx_i2c_pins));
+err_free_irq:
+	free_irq(irq, jz47xx_i2c);
+err_free:
+	kfree(jz47xx_i2c);
+err_clk_put:
+	clk_put(clk);
+err_iounmap:
+	iounmap(base);
+err_release_mem_region:
+	release_mem_region(mem->start, resource_size(mem));
+	return ret;
+}
+
+static int __devexit jz47xx_i2c_remove(struct platform_device *pdev)
+{
+	struct jz47xx_i2c *jz47xx_i2c = platform_get_drvdata(pdev);
+
+	platform_set_drvdata(pdev, NULL);
+	i2c_del_adapter(&jz47xx_i2c->adapter);
+
+	jz_gpio_bulk_free(jz47xx_i2c_pins, ARRAY_SIZE(jz47xx_i2c_pins));
+
+	free_irq(jz47xx_i2c->irq, jz47xx_i2c);
+	clk_put(jz47xx_i2c->clk);
+
+	iounmap(jz47xx_i2c->base);
+	release_mem_region(jz47xx_i2c->mem->start, resource_size(jz47xx_i2c->mem));
+
+	kfree(jz47xx_i2c);
+
+	return 0;
+}
+
+static struct platform_driver jz47xx_i2c_driver = {
+	.probe = jz47xx_i2c_probe,
+	.remove = jz47xx_i2c_remove,
+	.driver = {
+		.name = "jz47xx-i2c",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init jz47xx_i2c_init(void)
+{
+	return platform_driver_register(&jz47xx_i2c_driver);
+}
+module_init(jz47xx_i2c_init);
+
+static void jz47xx_i2c_exit(void)
+{
+	platform_driver_unregister(&jz47xx_i2c_driver);
+}
+module_exit(jz47xx_i2c_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("I2C adapter driver for JZ47XX SoCs");
+MODULE_ALIAS("platform:jz47xx-i2c");
+
