1 files changed, 544 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-iop3xx.c b/drivers/i2c/busses/i2c-iop3xx.c
new file mode 100644
index 000000000..4a6ff54d8
--- /dev/null
+++ b/drivers/i2c/busses/i2c-iop3xx.c
@@ -0,0 +1,544 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* ------------------------------------------------------------------------- */
+/* i2c-iop3xx.c i2c driver algorithms for Intel XScale IOP3xx & IXP46x       */
+/* ------------------------------------------------------------------------- */
+/* Copyright (C) 2003 Peter Milne, D-TACQ Solutions Ltd
+ *                    <Peter dot Milne at D hyphen TACQ dot com>
+ *
+ * With acknowledgements to i2c-algo-ibm_ocp.c by
+ * Ian DaSilva, MontaVista Software, Inc. idasilva@mvista.com
+ *
+ * And i2c-algo-pcf.c, which was created by Simon G. Vogl and Hans Berglund:
+ *
+ * Copyright (C) 1995-1997 Simon G. Vogl, 1998-2000 Hans Berglund
+ *
+ * And which acknowledged Kyösti Mälkki <kmalkki@cc.hut.fi>,
+ * Frodo Looijaard <frodol@dds.nl>, Martin Bailey<mbailey@littlefeet-inc.com>
+ *
+ * Major cleanup by Deepak Saxena <dsaxena@plexity.net>, 01/2005:
+ *
+ * - Use driver model to pass per-chip info instead of hardcoding and #ifdefs
+ * - Use ioremap/__raw_readl/__raw_writel instead of direct dereference
+ * - Make it work with IXP46x chips
+ * - Cleanup function names, coding style, etc
+ *
+ * - writing to slave address causes latchup on iop331.
+ *	fix: driver refuses to address self.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/gpio/consumer.h>
+
+#include "i2c-iop3xx.h"
+
+/* global unit counter */
+static int i2c_id;
+
+static inline unsigned char
+iic_cook_addr(struct i2c_msg *msg)
+{
+	unsigned char addr;
+
+	addr = i2c_8bit_addr_from_msg(msg);
+
+	return addr;
+}
+
+static void
+iop3xx_i2c_reset(struct i2c_algo_iop3xx_data *iop3xx_adap)
+{
+	/* Follows devman 9.3 */
+	__raw_writel(IOP3XX_ICR_UNIT_RESET, iop3xx_adap->ioaddr + CR_OFFSET);
+	__raw_writel(IOP3XX_ISR_CLEARBITS, iop3xx_adap->ioaddr + SR_OFFSET);
+	__raw_writel(0, iop3xx_adap->ioaddr + CR_OFFSET);
+}
+
+static void
+iop3xx_i2c_enable(struct i2c_algo_iop3xx_data *iop3xx_adap)
+{
+	u32 cr = IOP3XX_ICR_GCD | IOP3XX_ICR_SCLEN | IOP3XX_ICR_UE;
+
+	/*
+	 * Every time unit enable is asserted, GPOD needs to be cleared
+	 * on IOP3XX to avoid data corruption on the bus. We use the
+	 * gpiod_set_raw_value() to make sure the 0 hits the hardware
+	 * GPOD register. These descriptors are only passed along to
+	 * the device if this is necessary.
+	 */
+	if (iop3xx_adap->gpio_scl)
+		gpiod_set_raw_value(iop3xx_adap->gpio_scl, 0);
+	if (iop3xx_adap->gpio_sda)
+		gpiod_set_raw_value(iop3xx_adap->gpio_sda, 0);
+
+	/* NB SR bits not same position as CR IE bits :-( */
+	iop3xx_adap->SR_enabled =
+		IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD |
+		IOP3XX_ISR_RXFULL | IOP3XX_ISR_TXEMPTY;
+
+	cr |= IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
+		IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE;
+
+	__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
+}
+
+static void
+iop3xx_i2c_transaction_cleanup(struct i2c_algo_iop3xx_data *iop3xx_adap)
+{
+	unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
+
+	cr &= ~(IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE |
+		IOP3XX_ICR_MSTOP | IOP3XX_ICR_SCLEN);
+
+	__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
+}
+
+/*
+ * NB: the handler has to clear the source of the interrupt!
+ * Then it passes the SR flags of interest to BH via adap data
+ */
+static irqreturn_t
+iop3xx_i2c_irq_handler(int this_irq, void *dev_id)
+{
+	struct i2c_algo_iop3xx_data *iop3xx_adap = dev_id;
+	u32 sr = __raw_readl(iop3xx_adap->ioaddr + SR_OFFSET);
+
+	if ((sr &= iop3xx_adap->SR_enabled)) {
+		__raw_writel(sr, iop3xx_adap->ioaddr + SR_OFFSET);
+		iop3xx_adap->SR_received |= sr;
+		wake_up_interruptible(&iop3xx_adap->waitq);
+	}
+	return IRQ_HANDLED;
+}
+
+/* check all error conditions, clear them , report most important */
+static int
+iop3xx_i2c_error(u32 sr)
+{
+	int rc = 0;
+
+	if ((sr & IOP3XX_ISR_BERRD)) {
+		if (!rc)
+			rc = -I2C_ERR_BERR;
+	}
+	if ((sr & IOP3XX_ISR_ALD)) {
+		if (!rc)
+			rc = -I2C_ERR_ALD;
+	}
+	return rc;
+}
+
+static inline u32
+iop3xx_i2c_get_srstat(struct i2c_algo_iop3xx_data *iop3xx_adap)
+{
+	unsigned long flags;
+	u32 sr;
+
+	spin_lock_irqsave(&iop3xx_adap->lock, flags);
+	sr = iop3xx_adap->SR_received;
+	iop3xx_adap->SR_received = 0;
+	spin_unlock_irqrestore(&iop3xx_adap->lock, flags);
+
+	return sr;
+}
+
+/*
+ * sleep until interrupted, then recover and analyse the SR
+ * saved by handler
+ */
+typedef int (*compare_func)(unsigned test, unsigned mask);
+/* returns 1 on correct comparison */
+
+static int
+iop3xx_i2c_wait_event(struct i2c_algo_iop3xx_data *iop3xx_adap,
+			  unsigned flags, unsigned *status,
+			  compare_func compare)
+{
+	unsigned sr = 0;
+	int interrupted;
+	int done;
+	int rc = 0;
+
+	do {
+		interrupted = wait_event_interruptible_timeout (
+			iop3xx_adap->waitq,
+			(done = compare(sr = iop3xx_i2c_get_srstat(iop3xx_adap), flags)),
+			1 * HZ
+			);
+		if ((rc = iop3xx_i2c_error(sr)) < 0) {
+			*status = sr;
+			return rc;
+		} else if (!interrupted) {
+			*status = sr;
+			return -ETIMEDOUT;
+		}
+	} while (!done);
+
+	*status = sr;
+
+	return 0;
+}
+
+/*
+ * Concrete compare_funcs
+ */
+static int
+all_bits_clear(unsigned test, unsigned mask)
+{
+	return (test & mask) == 0;
+}
+
+static int
+any_bits_set(unsigned test, unsigned mask)
+{
+	return (test & mask) != 0;
+}
+
+static int
+iop3xx_i2c_wait_tx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
+{
+	return iop3xx_i2c_wait_event(
+		iop3xx_adap,
+		IOP3XX_ISR_TXEMPTY | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
+		status, any_bits_set);
+}
+
+static int
+iop3xx_i2c_wait_rx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
+{
+	return iop3xx_i2c_wait_event(
+		iop3xx_adap,
+		IOP3XX_ISR_RXFULL | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
+		status,	any_bits_set);
+}
+
+static int
+iop3xx_i2c_wait_idle(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
+{
+	return iop3xx_i2c_wait_event(
+		iop3xx_adap, IOP3XX_ISR_UNITBUSY, status, all_bits_clear);
+}
+
+static int
+iop3xx_i2c_send_target_addr(struct i2c_algo_iop3xx_data *iop3xx_adap,
+				struct i2c_msg *msg)
+{
+	unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
+	int status;
+	int rc;
+
+	/* avoid writing to my slave address (hangs on 80331),
+	 * forbidden in Intel developer manual
+	 */
+	if (msg->addr == MYSAR) {
+		return -EBUSY;
+	}
+
+	__raw_writel(iic_cook_addr(msg), iop3xx_adap->ioaddr + DBR_OFFSET);
+
+	cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
+	cr |= IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE;
+
+	__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
+	rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
+
+	return rc;
+}
+
+static int
+iop3xx_i2c_write_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char byte,
+				int stop)
+{
+	unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
+	int status;
+	int rc = 0;
+
+	__raw_writel(byte, iop3xx_adap->ioaddr + DBR_OFFSET);
+	cr &= ~IOP3XX_ICR_MSTART;
+	if (stop) {
+		cr |= IOP3XX_ICR_MSTOP;
+	} else {
+		cr &= ~IOP3XX_ICR_MSTOP;
+	}
+	cr |= IOP3XX_ICR_TBYTE;
+	__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
+	rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
+
+	return rc;
+}
+
+static int
+iop3xx_i2c_read_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char *byte,
+				int stop)
+{
+	unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
+	int status;
+	int rc = 0;
+
+	cr &= ~IOP3XX_ICR_MSTART;
+
+	if (stop) {
+		cr |= IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK;
+	} else {
+		cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
+	}
+	cr |= IOP3XX_ICR_TBYTE;
+	__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
+
+	rc = iop3xx_i2c_wait_rx_done(iop3xx_adap, &status);
+
+	*byte = __raw_readl(iop3xx_adap->ioaddr + DBR_OFFSET);
+
+	return rc;
+}
+
+static int
+iop3xx_i2c_writebytes(struct i2c_adapter *i2c_adap, const char *buf, int count)
+{
+	struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
+	int ii;
+	int rc = 0;
+
+	for (ii = 0; rc == 0 && ii != count; ++ii)
+		rc = iop3xx_i2c_write_byte(iop3xx_adap, buf[ii], ii == count-1);
+	return rc;
+}
+
+static int
+iop3xx_i2c_readbytes(struct i2c_adapter *i2c_adap, char *buf, int count)
+{
+	struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
+	int ii;
+	int rc = 0;
+
+	for (ii = 0; rc == 0 && ii != count; ++ii)
+		rc = iop3xx_i2c_read_byte(iop3xx_adap, &buf[ii], ii == count-1);
+
+	return rc;
+}
+
+/*
+ * Description:  This function implements combined transactions.  Combined
+ * transactions consist of combinations of reading and writing blocks of data.
+ * FROM THE SAME ADDRESS
+ * Each transfer (i.e. a read or a write) is separated by a repeated start
+ * condition.
+ */
+static int
+iop3xx_i2c_handle_msg(struct i2c_adapter *i2c_adap, struct i2c_msg *pmsg)
+{
+	struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
+	int rc;
+
+	rc = iop3xx_i2c_send_target_addr(iop3xx_adap, pmsg);
+	if (rc < 0) {
+		return rc;
+	}
+
+	if ((pmsg->flags&I2C_M_RD)) {
+		return iop3xx_i2c_readbytes(i2c_adap, pmsg->buf, pmsg->len);
+	} else {
+		return iop3xx_i2c_writebytes(i2c_adap, pmsg->buf, pmsg->len);
+	}
+}
+
+/*
+ * master_xfer() - main read/write entry
+ */
+static int
+iop3xx_i2c_master_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
+				int num)
+{
+	struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
+	int im = 0;
+	int ret = 0;
+	int status;
+
+	iop3xx_i2c_wait_idle(iop3xx_adap, &status);
+	iop3xx_i2c_reset(iop3xx_adap);
+	iop3xx_i2c_enable(iop3xx_adap);
+
+	for (im = 0; ret == 0 && im != num; im++) {
+		ret = iop3xx_i2c_handle_msg(i2c_adap, &msgs[im]);
+	}
+
+	iop3xx_i2c_transaction_cleanup(iop3xx_adap);
+
+	if (ret)
+		return ret;
+
+	return im;
+}
+
+static u32
+iop3xx_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm iop3xx_i2c_algo = {
+	.master_xfer	= iop3xx_i2c_master_xfer,
+	.functionality	= iop3xx_i2c_func,
+};
+
+static int
+iop3xx_i2c_remove(struct platform_device *pdev)
+{
+	struct i2c_adapter *padapter = platform_get_drvdata(pdev);
+	struct i2c_algo_iop3xx_data *adapter_data =
+		(struct i2c_algo_iop3xx_data *)padapter->algo_data;
+	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	unsigned long cr = __raw_readl(adapter_data->ioaddr + CR_OFFSET);
+
+	/*
+	 * Disable the actual HW unit
+	 */
+	cr &= ~(IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
+		IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE);
+	__raw_writel(cr, adapter_data->ioaddr + CR_OFFSET);
+
+	iounmap(adapter_data->ioaddr);
+	release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
+	kfree(adapter_data);
+	kfree(padapter);
+
+	return 0;
+}
+
+static int
+iop3xx_i2c_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	int ret, irq;
+	struct i2c_adapter *new_adapter;
+	struct i2c_algo_iop3xx_data *adapter_data;
+
+	new_adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
+	if (!new_adapter) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	adapter_data = kzalloc(sizeof(struct i2c_algo_iop3xx_data), GFP_KERNEL);
+	if (!adapter_data) {
+		ret = -ENOMEM;
+		goto free_adapter;
+	}
+
+	adapter_data->gpio_scl = devm_gpiod_get_optional(&pdev->dev,
+							 "scl",
+							 GPIOD_ASIS);
+	if (IS_ERR(adapter_data->gpio_scl)) {
+		ret = PTR_ERR(adapter_data->gpio_scl);
+		goto free_both;
+	}
+	adapter_data->gpio_sda = devm_gpiod_get_optional(&pdev->dev,
+							 "sda",
+							 GPIOD_ASIS);
+	if (IS_ERR(adapter_data->gpio_sda)) {
+		ret = PTR_ERR(adapter_data->gpio_sda);
+		goto free_both;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV;
+		goto free_both;
+	}
+
+	if (!request_mem_region(res->start, IOP3XX_I2C_IO_SIZE, pdev->name)) {
+		ret = -EBUSY;
+		goto free_both;
+	}
+
+	/* set the adapter enumeration # */
+	adapter_data->id = i2c_id++;
+
+	adapter_data->ioaddr = ioremap(res->start, IOP3XX_I2C_IO_SIZE);
+	if (!adapter_data->ioaddr) {
+		ret = -ENOMEM;
+		goto release_region;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		ret = irq;
+		goto unmap;
+	}
+	ret = request_irq(irq, iop3xx_i2c_irq_handler, 0,
+				pdev->name, adapter_data);
+
+	if (ret)
+		goto unmap;
+
+	memcpy(new_adapter->name, pdev->name, strlen(pdev->name));
+	new_adapter->owner = THIS_MODULE;
+	new_adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	new_adapter->dev.parent = &pdev->dev;
+	new_adapter->dev.of_node = pdev->dev.of_node;
+	new_adapter->nr = pdev->id;
+
+	/*
+	 * Default values...should these come in from board code?
+	 */
+	new_adapter->timeout = HZ;
+	new_adapter->algo = &iop3xx_i2c_algo;
+
+	init_waitqueue_head(&adapter_data->waitq);
+	spin_lock_init(&adapter_data->lock);
+
+	iop3xx_i2c_reset(adapter_data);
+	iop3xx_i2c_enable(adapter_data);
+
+	platform_set_drvdata(pdev, new_adapter);
+	new_adapter->algo_data = adapter_data;
+
+	i2c_add_numbered_adapter(new_adapter);
+
+	return 0;
+
+unmap:
+	iounmap(adapter_data->ioaddr);
+
+release_region:
+	release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
+
+free_both:
+	kfree(adapter_data);
+
+free_adapter:
+	kfree(new_adapter);
+
+out:
+	return ret;
+}
+
+static const struct of_device_id i2c_iop3xx_match[] = {
+	{ .compatible = "intel,iop3xx-i2c", },
+	{ .compatible = "intel,ixp4xx-i2c", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, i2c_iop3xx_match);
+
+static struct platform_driver iop3xx_i2c_driver = {
+	.probe		= iop3xx_i2c_probe,
+	.remove		= iop3xx_i2c_remove,
+	.driver		= {
+		.name	= "IOP3xx-I2C",
+		.of_match_table = i2c_iop3xx_match,
+	},
+};
+
+module_platform_driver(iop3xx_i2c_driver);
+
+MODULE_AUTHOR("D-TACQ Solutions Ltd <www.d-tacq.com>");
+MODULE_DESCRIPTION("IOP3xx iic algorithm and driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:IOP3xx-I2C");