Initial import

1 files changed, 561 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
new file mode 100644
index 000000000..abf5db7e4
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -0,0 +1,561 @@
+/*
+ * i2c-ocores.c: I2C bus driver for OpenCores I2C controller
+ * (http://www.opencores.org/projects.cgi/web/i2c/overview).
+ *
+ * Peter Korsgaard <jacmet@sunsite.dk>
+ *
+ * Support for the GRLIB port of the controller by
+ * Andreas Larsson <andreas@gaisler.com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include <linux/i2c-ocores.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/log2.h>
+
+struct ocores_i2c {
+	void __iomem *base;
+	u32 reg_shift;
+	u32 reg_io_width;
+	wait_queue_head_t wait;
+	struct i2c_adapter adap;
+	struct i2c_msg *msg;
+	int pos;
+	int nmsgs;
+	int state; /* see STATE_ */
+	struct clk *clk;
+	int ip_clock_khz;
+	int bus_clock_khz;
+	void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value);
+	u8 (*getreg)(struct ocores_i2c *i2c, int reg);
+};
+
+/* registers */
+#define OCI2C_PRELOW		0
+#define OCI2C_PREHIGH		1
+#define OCI2C_CONTROL		2
+#define OCI2C_DATA		3
+#define OCI2C_CMD		4 /* write only */
+#define OCI2C_STATUS		4 /* read only, same address as OCI2C_CMD */
+
+#define OCI2C_CTRL_IEN		0x40
+#define OCI2C_CTRL_EN		0x80
+
+#define OCI2C_CMD_START		0x91
+#define OCI2C_CMD_STOP		0x41
+#define OCI2C_CMD_READ		0x21
+#define OCI2C_CMD_WRITE		0x11
+#define OCI2C_CMD_READ_ACK	0x21
+#define OCI2C_CMD_READ_NACK	0x29
+#define OCI2C_CMD_IACK		0x01
+
+#define OCI2C_STAT_IF		0x01
+#define OCI2C_STAT_TIP		0x02
+#define OCI2C_STAT_ARBLOST	0x20
+#define OCI2C_STAT_BUSY		0x40
+#define OCI2C_STAT_NACK		0x80
+
+#define STATE_DONE		0
+#define STATE_START		1
+#define STATE_WRITE		2
+#define STATE_READ		3
+#define STATE_ERROR		4
+
+#define TYPE_OCORES		0
+#define TYPE_GRLIB		1
+
+static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value)
+{
+	iowrite8(value, i2c->base + (reg << i2c->reg_shift));
+}
+
+static void oc_setreg_16(struct ocores_i2c *i2c, int reg, u8 value)
+{
+	iowrite16(value, i2c->base + (reg << i2c->reg_shift));
+}
+
+static void oc_setreg_32(struct ocores_i2c *i2c, int reg, u8 value)
+{
+	iowrite32(value, i2c->base + (reg << i2c->reg_shift));
+}
+
+static inline u8 oc_getreg_8(struct ocores_i2c *i2c, int reg)
+{
+	return ioread8(i2c->base + (reg << i2c->reg_shift));
+}
+
+static inline u8 oc_getreg_16(struct ocores_i2c *i2c, int reg)
+{
+	return ioread16(i2c->base + (reg << i2c->reg_shift));
+}
+
+static inline u8 oc_getreg_32(struct ocores_i2c *i2c, int reg)
+{
+	return ioread32(i2c->base + (reg << i2c->reg_shift));
+}
+
+static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
+{
+	i2c->setreg(i2c, reg, value);
+}
+
+static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
+{
+	return i2c->getreg(i2c, reg);
+}
+
+static void ocores_process(struct ocores_i2c *i2c)
+{
+	struct i2c_msg *msg = i2c->msg;
+	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
+
+	if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
+		/* stop has been sent */
+		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
+		wake_up(&i2c->wait);
+		return;
+	}
+
+	/* error? */
+	if (stat & OCI2C_STAT_ARBLOST) {
+		i2c->state = STATE_ERROR;
+		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
+		return;
+	}
+
+	if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
+		i2c->state =
+			(msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
+
+		if (stat & OCI2C_STAT_NACK) {
+			i2c->state = STATE_ERROR;
+			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
+			return;
+		}
+	} else
+		msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
+
+	/* end of msg? */
+	if (i2c->pos == msg->len) {
+		i2c->nmsgs--;
+		i2c->msg++;
+		i2c->pos = 0;
+		msg = i2c->msg;
+
+		if (i2c->nmsgs) {	/* end? */
+			/* send start? */
+			if (!(msg->flags & I2C_M_NOSTART)) {
+				u8 addr = (msg->addr << 1);
+
+				if (msg->flags & I2C_M_RD)
+					addr |= 1;
+
+				i2c->state = STATE_START;
+
+				oc_setreg(i2c, OCI2C_DATA, addr);
+				oc_setreg(i2c, OCI2C_CMD,  OCI2C_CMD_START);
+				return;
+			} else
+				i2c->state = (msg->flags & I2C_M_RD)
+					? STATE_READ : STATE_WRITE;
+		} else {
+			i2c->state = STATE_DONE;
+			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
+			return;
+		}
+	}
+
+	if (i2c->state == STATE_READ) {
+		oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
+			  OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
+	} else {
+		oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
+		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
+	}
+}
+
+static irqreturn_t ocores_isr(int irq, void *dev_id)
+{
+	struct ocores_i2c *i2c = dev_id;
+
+	ocores_process(i2c);
+
+	return IRQ_HANDLED;
+}
+
+static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct ocores_i2c *i2c = i2c_get_adapdata(adap);
+
+	i2c->msg = msgs;
+	i2c->pos = 0;
+	i2c->nmsgs = num;
+	i2c->state = STATE_START;
+
+	oc_setreg(i2c, OCI2C_DATA,
+			(i2c->msg->addr << 1) |
+			((i2c->msg->flags & I2C_M_RD) ? 1:0));
+
+	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
+
+	if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
+			       (i2c->state == STATE_DONE), HZ))
+		return (i2c->state == STATE_DONE) ? num : -EIO;
+	else
+		return -ETIMEDOUT;
+}
+
+static int ocores_init(struct device *dev, struct ocores_i2c *i2c)
+{
+	int prescale;
+	int diff;
+	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
+
+	/* make sure the device is disabled */
+	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
+
+	prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;
+	prescale = clamp(prescale, 0, 0xffff);
+
+	diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz;
+	if (abs(diff) > i2c->bus_clock_khz / 10) {
+		dev_err(dev,
+			"Unsupported clock settings: core: %d KHz, bus: %d KHz\n",
+			i2c->ip_clock_khz, i2c->bus_clock_khz);
+		return -EINVAL;
+	}
+
+	oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
+	oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);
+
+	/* Init the device */
+	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
+	oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);
+
+	return 0;
+}
+
+
+static u32 ocores_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm ocores_algorithm = {
+	.master_xfer = ocores_xfer,
+	.functionality = ocores_func,
+};
+
+static struct i2c_adapter ocores_adapter = {
+	.owner = THIS_MODULE,
+	.name = "i2c-ocores",
+	.class = I2C_CLASS_DEPRECATED,
+	.algo = &ocores_algorithm,
+};
+
+static const struct of_device_id ocores_i2c_match[] = {
+	{
+		.compatible = "opencores,i2c-ocores",
+		.data = (void *)TYPE_OCORES,
+	},
+	{
+		.compatible = "aeroflexgaisler,i2cmst",
+		.data = (void *)TYPE_GRLIB,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, ocores_i2c_match);
+
+#ifdef CONFIG_OF
+/* Read and write functions for the GRLIB port of the controller. Registers are
+ * 32-bit big endian and the PRELOW and PREHIGH registers are merged into one
+ * register. The subsequent registers has their offset decreased accordingly. */
+static u8 oc_getreg_grlib(struct ocores_i2c *i2c, int reg)
+{
+	u32 rd;
+	int rreg = reg;
+	if (reg != OCI2C_PRELOW)
+		rreg--;
+	rd = ioread32be(i2c->base + (rreg << i2c->reg_shift));
+	if (reg == OCI2C_PREHIGH)
+		return (u8)(rd >> 8);
+	else
+		return (u8)rd;
+}
+
+static void oc_setreg_grlib(struct ocores_i2c *i2c, int reg, u8 value)
+{
+	u32 curr, wr;
+	int rreg = reg;
+	if (reg != OCI2C_PRELOW)
+		rreg--;
+	if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) {
+		curr = ioread32be(i2c->base + (rreg << i2c->reg_shift));
+		if (reg == OCI2C_PRELOW)
+			wr = (curr & 0xff00) | value;
+		else
+			wr = (((u32)value) << 8) | (curr & 0xff);
+	} else {
+		wr = value;
+	}
+	iowrite32be(wr, i2c->base + (rreg << i2c->reg_shift));
+}
+
+static int ocores_i2c_of_probe(struct platform_device *pdev,
+				struct ocores_i2c *i2c)
+{
+	struct device_node *np = pdev->dev.of_node;
+	const struct of_device_id *match;
+	u32 val;
+	u32 clock_frequency;
+	bool clock_frequency_present;
+
+	if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {
+		/* no 'reg-shift', check for deprecated 'regstep' */
+		if (!of_property_read_u32(np, "regstep", &val)) {
+			if (!is_power_of_2(val)) {
+				dev_err(&pdev->dev, "invalid regstep %d\n",
+					val);
+				return -EINVAL;
+			}
+			i2c->reg_shift = ilog2(val);
+			dev_warn(&pdev->dev,
+				"regstep property deprecated, use reg-shift\n");
+		}
+	}
+
+	clock_frequency_present = !of_property_read_u32(np, "clock-frequency",
+							&clock_frequency);
+	i2c->bus_clock_khz = 100;
+
+	i2c->clk = devm_clk_get(&pdev->dev, NULL);
+
+	if (!IS_ERR(i2c->clk)) {
+		int ret = clk_prepare_enable(i2c->clk);
+
+		if (ret) {
+			dev_err(&pdev->dev,
+				"clk_prepare_enable failed: %d\n", ret);
+			return ret;
+		}
+		i2c->ip_clock_khz = clk_get_rate(i2c->clk) / 1000;
+		if (clock_frequency_present)
+			i2c->bus_clock_khz = clock_frequency / 1000;
+	}
+
+	if (i2c->ip_clock_khz == 0) {
+		if (of_property_read_u32(np, "opencores,ip-clock-frequency",
+						&val)) {
+			if (!clock_frequency_present) {
+				dev_err(&pdev->dev,
+					"Missing required parameter 'opencores,ip-clock-frequency'\n");
+				return -ENODEV;
+			}
+			i2c->ip_clock_khz = clock_frequency / 1000;
+			dev_warn(&pdev->dev,
+				 "Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n");
+		} else {
+			i2c->ip_clock_khz = val / 1000;
+			if (clock_frequency_present)
+				i2c->bus_clock_khz = clock_frequency / 1000;
+		}
+	}
+
+	of_property_read_u32(pdev->dev.of_node, "reg-io-width",
+				&i2c->reg_io_width);
+
+	match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
+	if (match && (long)match->data == TYPE_GRLIB) {
+		dev_dbg(&pdev->dev, "GRLIB variant of i2c-ocores\n");
+		i2c->setreg = oc_setreg_grlib;
+		i2c->getreg = oc_getreg_grlib;
+	}
+
+	return 0;
+}
+#else
+#define ocores_i2c_of_probe(pdev,i2c) -ENODEV
+#endif
+
+static int ocores_i2c_probe(struct platform_device *pdev)
+{
+	struct ocores_i2c *i2c;
+	struct ocores_i2c_platform_data *pdata;
+	struct resource *res;
+	int irq;
+	int ret;
+	int i;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
+	if (!i2c)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	i2c->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(i2c->base))
+		return PTR_ERR(i2c->base);
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (pdata) {
+		i2c->reg_shift = pdata->reg_shift;
+		i2c->reg_io_width = pdata->reg_io_width;
+		i2c->ip_clock_khz = pdata->clock_khz;
+		i2c->bus_clock_khz = 100;
+	} else {
+		ret = ocores_i2c_of_probe(pdev, i2c);
+		if (ret)
+			return ret;
+	}
+
+	if (i2c->reg_io_width == 0)
+		i2c->reg_io_width = 1; /* Set to default value */
+
+	if (!i2c->setreg || !i2c->getreg) {
+		switch (i2c->reg_io_width) {
+		case 1:
+			i2c->setreg = oc_setreg_8;
+			i2c->getreg = oc_getreg_8;
+			break;
+
+		case 2:
+			i2c->setreg = oc_setreg_16;
+			i2c->getreg = oc_getreg_16;
+			break;
+
+		case 4:
+			i2c->setreg = oc_setreg_32;
+			i2c->getreg = oc_getreg_32;
+			break;
+
+		default:
+			dev_err(&pdev->dev, "Unsupported I/O width (%d)\n",
+				i2c->reg_io_width);
+			return -EINVAL;
+		}
+	}
+
+	ret = ocores_init(&pdev->dev, i2c);
+	if (ret)
+		return ret;
+
+	init_waitqueue_head(&i2c->wait);
+	ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
+			       pdev->name, i2c);
+	if (ret) {
+		dev_err(&pdev->dev, "Cannot claim IRQ\n");
+		return ret;
+	}
+
+	/* hook up driver to tree */
+	platform_set_drvdata(pdev, i2c);
+	i2c->adap = ocores_adapter;
+	i2c_set_adapdata(&i2c->adap, i2c);
+	i2c->adap.dev.parent = &pdev->dev;
+	i2c->adap.dev.of_node = pdev->dev.of_node;
+
+	/* add i2c adapter to i2c tree */
+	ret = i2c_add_adapter(&i2c->adap);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to add adapter\n");
+		return ret;
+	}
+
+	/* add in known devices to the bus */
+	if (pdata) {
+		for (i = 0; i < pdata->num_devices; i++)
+			i2c_new_device(&i2c->adap, pdata->devices + i);
+	}
+
+	return 0;
+}
+
+static int ocores_i2c_remove(struct platform_device *pdev)
+{
+	struct ocores_i2c *i2c = platform_get_drvdata(pdev);
+
+	/* disable i2c logic */
+	oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
+		  & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
+
+	/* remove adapter & data */
+	i2c_del_adapter(&i2c->adap);
+
+	if (!IS_ERR(i2c->clk))
+		clk_disable_unprepare(i2c->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int ocores_i2c_suspend(struct device *dev)
+{
+	struct ocores_i2c *i2c = dev_get_drvdata(dev);
+	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
+
+	/* make sure the device is disabled */
+	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
+
+	if (!IS_ERR(i2c->clk))
+		clk_disable_unprepare(i2c->clk);
+	return 0;
+}
+
+static int ocores_i2c_resume(struct device *dev)
+{
+	struct ocores_i2c *i2c = dev_get_drvdata(dev);
+
+	if (!IS_ERR(i2c->clk)) {
+		unsigned long rate;
+		int ret = clk_prepare_enable(i2c->clk);
+
+		if (ret) {
+			dev_err(dev,
+				"clk_prepare_enable failed: %d\n", ret);
+			return ret;
+		}
+		rate = clk_get_rate(i2c->clk) / 1000;
+		if (rate)
+			i2c->ip_clock_khz = rate;
+	}
+	return ocores_init(dev, i2c);
+}
+
+static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume);
+#define OCORES_I2C_PM	(&ocores_i2c_pm)
+#else
+#define OCORES_I2C_PM	NULL
+#endif
+
+static struct platform_driver ocores_i2c_driver = {
+	.probe   = ocores_i2c_probe,
+	.remove  = ocores_i2c_remove,
+	.driver  = {
+		.name = "ocores-i2c",
+		.of_match_table = ocores_i2c_match,
+		.pm = OCORES_I2C_PM,
+	},
+};
+
+module_platform_driver(ocores_i2c_driver);
+
+MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
+MODULE_DESCRIPTION("OpenCores I2C bus driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ocores-i2c");