1 files changed, 598 insertions, 0 deletions

diff --git a/drivers/i2c/busses/scx200_acb.c b/drivers/i2c/busses/scx200_acb.c
new file mode 100644
index 0000000000..83c1db610f
--- /dev/null
+++ b/drivers/i2c/busses/scx200_acb.c
@@ -0,0 +1,598 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+    Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
+
+    National Semiconductor SCx200 ACCESS.bus support
+    Also supports the AMD CS5535 and AMD CS5536
+
+    Based on i2c-keywest.c which is:
+        Copyright (c) 2001 Benjamin Herrenschmidt <benh@kernel.crashing.org>
+        Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
+
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+
+#include <linux/scx200.h>
+
+MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
+MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
+MODULE_ALIAS("platform:cs5535-smb");
+MODULE_LICENSE("GPL");
+
+#define MAX_DEVICES 4
+static int base[MAX_DEVICES] = { 0x820, 0x840 };
+module_param_hw_array(base, int, ioport, NULL, 0);
+MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
+
+#define POLL_TIMEOUT	(HZ/5)
+
+enum scx200_acb_state {
+	state_idle,
+	state_address,
+	state_command,
+	state_repeat_start,
+	state_quick,
+	state_read,
+	state_write,
+};
+
+static const char *scx200_acb_state_name[] = {
+	"idle",
+	"address",
+	"command",
+	"repeat_start",
+	"quick",
+	"read",
+	"write",
+};
+
+/* Physical interface */
+struct scx200_acb_iface {
+	struct scx200_acb_iface *next;
+	struct i2c_adapter adapter;
+	unsigned base;
+	struct mutex mutex;
+
+	/* State machine data */
+	enum scx200_acb_state state;
+	int result;
+	u8 address_byte;
+	u8 command;
+	u8 *ptr;
+	char needs_reset;
+	unsigned len;
+};
+
+/* Register Definitions */
+#define ACBSDA		(iface->base + 0)
+#define ACBST		(iface->base + 1)
+#define    ACBST_SDAST		0x40 /* SDA Status */
+#define    ACBST_BER		0x20
+#define    ACBST_NEGACK		0x10 /* Negative Acknowledge */
+#define    ACBST_STASTR		0x08 /* Stall After Start */
+#define    ACBST_MASTER		0x02
+#define ACBCST		(iface->base + 2)
+#define    ACBCST_BB		0x02
+#define ACBCTL1		(iface->base + 3)
+#define    ACBCTL1_STASTRE	0x80
+#define    ACBCTL1_NMINTE	0x40
+#define    ACBCTL1_ACK		0x10
+#define    ACBCTL1_STOP		0x02
+#define    ACBCTL1_START	0x01
+#define ACBADDR		(iface->base + 4)
+#define ACBCTL2		(iface->base + 5)
+#define    ACBCTL2_ENABLE	0x01
+
+/************************************************************************/
+
+static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
+{
+	const char *errmsg;
+
+	dev_dbg(&iface->adapter.dev, "state %s, status = 0x%02x\n",
+		scx200_acb_state_name[iface->state], status);
+
+	if (status & ACBST_BER) {
+		errmsg = "bus error";
+		goto error;
+	}
+	if (!(status & ACBST_MASTER)) {
+		errmsg = "not master";
+		goto error;
+	}
+	if (status & ACBST_NEGACK) {
+		dev_dbg(&iface->adapter.dev, "negative ack in state %s\n",
+			scx200_acb_state_name[iface->state]);
+
+		iface->state = state_idle;
+		iface->result = -ENXIO;
+
+		outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
+		outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
+
+		/* Reset the status register */
+		outb(0, ACBST);
+		return;
+	}
+
+	switch (iface->state) {
+	case state_idle:
+		dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
+		break;
+
+	case state_address:
+		/* Do a pointer write first */
+		outb(iface->address_byte & ~1, ACBSDA);
+
+		iface->state = state_command;
+		break;
+
+	case state_command:
+		outb(iface->command, ACBSDA);
+
+		if (iface->address_byte & 1)
+			iface->state = state_repeat_start;
+		else
+			iface->state = state_write;
+		break;
+
+	case state_repeat_start:
+		outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
+		fallthrough;
+
+	case state_quick:
+		if (iface->address_byte & 1) {
+			if (iface->len == 1)
+				outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
+			else
+				outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
+			outb(iface->address_byte, ACBSDA);
+
+			iface->state = state_read;
+		} else {
+			outb(iface->address_byte, ACBSDA);
+
+			iface->state = state_write;
+		}
+		break;
+
+	case state_read:
+		/* Set ACK if _next_ byte will be the last one */
+		if (iface->len == 2)
+			outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
+		else
+			outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
+
+		if (iface->len == 1) {
+			iface->result = 0;
+			iface->state = state_idle;
+			outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
+		}
+
+		*iface->ptr++ = inb(ACBSDA);
+		--iface->len;
+
+		break;
+
+	case state_write:
+		if (iface->len == 0) {
+			iface->result = 0;
+			iface->state = state_idle;
+			outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
+			break;
+		}
+
+		outb(*iface->ptr++, ACBSDA);
+		--iface->len;
+
+		break;
+	}
+
+	return;
+
+ error:
+	dev_err(&iface->adapter.dev,
+		"%s in state %s (addr=0x%02x, len=%d, status=0x%02x)\n", errmsg,
+		scx200_acb_state_name[iface->state], iface->address_byte,
+		iface->len, status);
+
+	iface->state = state_idle;
+	iface->result = -EIO;
+	iface->needs_reset = 1;
+}
+
+static void scx200_acb_poll(struct scx200_acb_iface *iface)
+{
+	u8 status;
+	unsigned long timeout;
+
+	timeout = jiffies + POLL_TIMEOUT;
+	while (1) {
+		status = inb(ACBST);
+
+		/* Reset the status register to avoid the hang */
+		outb(0, ACBST);
+
+		if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
+			scx200_acb_machine(iface, status);
+			return;
+		}
+		if (time_after(jiffies, timeout))
+			break;
+		cpu_relax();
+		cond_resched();
+	}
+
+	dev_err(&iface->adapter.dev, "timeout in state %s\n",
+		scx200_acb_state_name[iface->state]);
+
+	iface->state = state_idle;
+	iface->result = -EIO;
+	iface->needs_reset = 1;
+}
+
+static void scx200_acb_reset(struct scx200_acb_iface *iface)
+{
+	/* Disable the ACCESS.bus device and Configure the SCL
+	   frequency: 16 clock cycles */
+	outb(0x70, ACBCTL2);
+	/* Polling mode */
+	outb(0, ACBCTL1);
+	/* Disable slave address */
+	outb(0, ACBADDR);
+	/* Enable the ACCESS.bus device */
+	outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
+	/* Free STALL after START */
+	outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
+	/* Send a STOP */
+	outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
+	/* Clear BER, NEGACK and STASTR bits */
+	outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
+	/* Clear BB bit */
+	outb(inb(ACBCST) | ACBCST_BB, ACBCST);
+}
+
+static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
+				 u16 address, unsigned short flags,
+				 char rw, u8 command, int size,
+				 union i2c_smbus_data *data)
+{
+	struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
+	int len;
+	u8 *buffer;
+	u16 cur_word;
+	int rc;
+
+	switch (size) {
+	case I2C_SMBUS_QUICK:
+		len = 0;
+		buffer = NULL;
+		break;
+
+	case I2C_SMBUS_BYTE:
+		len = 1;
+		buffer = rw ? &data->byte : &command;
+		break;
+
+	case I2C_SMBUS_BYTE_DATA:
+		len = 1;
+		buffer = &data->byte;
+		break;
+
+	case I2C_SMBUS_WORD_DATA:
+		len = 2;
+		cur_word = cpu_to_le16(data->word);
+		buffer = (u8 *)&cur_word;
+		break;
+
+	case I2C_SMBUS_I2C_BLOCK_DATA:
+		len = data->block[0];
+		if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
+			return -EINVAL;
+		buffer = &data->block[1];
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(&adapter->dev,
+		"size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
+		size, address, command, len, rw);
+
+	if (!len && rw == I2C_SMBUS_READ) {
+		dev_dbg(&adapter->dev, "zero length read\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&iface->mutex);
+
+	iface->address_byte = (address << 1) | rw;
+	iface->command = command;
+	iface->ptr = buffer;
+	iface->len = len;
+	iface->result = -EINVAL;
+	iface->needs_reset = 0;
+
+	outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
+
+	if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
+		iface->state = state_quick;
+	else
+		iface->state = state_address;
+
+	while (iface->state != state_idle)
+		scx200_acb_poll(iface);
+
+	if (iface->needs_reset)
+		scx200_acb_reset(iface);
+
+	rc = iface->result;
+
+	mutex_unlock(&iface->mutex);
+
+	if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
+		data->word = le16_to_cpu(cur_word);
+
+#ifdef DEBUG
+	dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
+	if (buffer) {
+		int i;
+		printk(" data:");
+		for (i = 0; i < len; ++i)
+			printk(" %02x", buffer[i]);
+	}
+	printk("\n");
+#endif
+
+	return rc;
+}
+
+static u32 scx200_acb_func(struct i2c_adapter *adapter)
+{
+	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+	       I2C_FUNC_SMBUS_I2C_BLOCK;
+}
+
+/* For now, we only handle combined mode (smbus) */
+static const struct i2c_algorithm scx200_acb_algorithm = {
+	.smbus_xfer	= scx200_acb_smbus_xfer,
+	.functionality	= scx200_acb_func,
+};
+
+static struct scx200_acb_iface *scx200_acb_list;
+static DEFINE_MUTEX(scx200_acb_list_mutex);
+
+static int scx200_acb_probe(struct scx200_acb_iface *iface)
+{
+	u8 val;
+
+	/* Disable the ACCESS.bus device and Configure the SCL
+	   frequency: 16 clock cycles */
+	outb(0x70, ACBCTL2);
+
+	if (inb(ACBCTL2) != 0x70) {
+		pr_debug("ACBCTL2 readback failed\n");
+		return -ENXIO;
+	}
+
+	outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
+
+	val = inb(ACBCTL1);
+	if (val) {
+		pr_debug("disabled, but ACBCTL1=0x%02x\n", val);
+		return -ENXIO;
+	}
+
+	outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
+
+	outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
+
+	val = inb(ACBCTL1);
+	if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
+		pr_debug("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n",
+			 val);
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static struct scx200_acb_iface *scx200_create_iface(const char *text,
+		struct device *dev, int index)
+{
+	struct scx200_acb_iface *iface;
+	struct i2c_adapter *adapter;
+
+	iface = kzalloc(sizeof(*iface), GFP_KERNEL);
+	if (!iface)
+		return NULL;
+
+	adapter = &iface->adapter;
+	i2c_set_adapdata(adapter, iface);
+	snprintf(adapter->name, sizeof(adapter->name), "%s ACB%d", text, index);
+	adapter->owner = THIS_MODULE;
+	adapter->algo = &scx200_acb_algorithm;
+	adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	adapter->dev.parent = dev;
+
+	mutex_init(&iface->mutex);
+
+	return iface;
+}
+
+static int scx200_acb_create(struct scx200_acb_iface *iface)
+{
+	struct i2c_adapter *adapter;
+	int rc;
+
+	adapter = &iface->adapter;
+
+	rc = scx200_acb_probe(iface);
+	if (rc) {
+		pr_warn("probe failed\n");
+		return rc;
+	}
+
+	scx200_acb_reset(iface);
+
+	if (i2c_add_adapter(adapter) < 0) {
+		pr_err("failed to register\n");
+		return -ENODEV;
+	}
+
+	if (!adapter->dev.parent) {
+		/* If there's no dev, we're tracking (ISA) ifaces manually */
+		mutex_lock(&scx200_acb_list_mutex);
+		iface->next = scx200_acb_list;
+		scx200_acb_list = iface;
+		mutex_unlock(&scx200_acb_list_mutex);
+	}
+
+	return 0;
+}
+
+static struct scx200_acb_iface *scx200_create_dev(const char *text,
+		unsigned long base, int index, struct device *dev)
+{
+	struct scx200_acb_iface *iface;
+	int rc;
+
+	iface = scx200_create_iface(text, dev, index);
+
+	if (iface == NULL)
+		return NULL;
+
+	if (!request_region(base, 8, iface->adapter.name)) {
+		pr_err("can't allocate io 0x%lx-0x%lx\n", base, base + 8 - 1);
+		goto errout_free;
+	}
+
+	iface->base = base;
+	rc = scx200_acb_create(iface);
+
+	if (rc == 0)
+		return iface;
+
+	release_region(base, 8);
+ errout_free:
+	kfree(iface);
+	return NULL;
+}
+
+static int scx200_probe(struct platform_device *pdev)
+{
+	struct scx200_acb_iface *iface;
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "can't fetch device resource info\n");
+		return -ENODEV;
+	}
+
+	iface = scx200_create_dev("CS5535", res->start, 0, &pdev->dev);
+	if (!iface)
+		return -EIO;
+
+	dev_info(&pdev->dev, "SCx200 device '%s' registered\n",
+			iface->adapter.name);
+	platform_set_drvdata(pdev, iface);
+
+	return 0;
+}
+
+static void scx200_cleanup_iface(struct scx200_acb_iface *iface)
+{
+	i2c_del_adapter(&iface->adapter);
+	release_region(iface->base, 8);
+	kfree(iface);
+}
+
+static void scx200_remove(struct platform_device *pdev)
+{
+	struct scx200_acb_iface *iface;
+
+	iface = platform_get_drvdata(pdev);
+	scx200_cleanup_iface(iface);
+}
+
+static struct platform_driver scx200_pci_driver = {
+	.driver = {
+		.name = "cs5535-smb",
+	},
+	.probe = scx200_probe,
+	.remove_new = scx200_remove,
+};
+
+static const struct pci_device_id scx200_isa[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
+	{ 0, }
+};
+
+static __init void scx200_scan_isa(void)
+{
+	int i;
+
+	if (!pci_dev_present(scx200_isa))
+		return;
+
+	for (i = 0; i < MAX_DEVICES; ++i) {
+		if (base[i] == 0)
+			continue;
+
+		/* XXX: should we care about failures? */
+		scx200_create_dev("SCx200", base[i], i, NULL);
+	}
+}
+
+static int __init scx200_acb_init(void)
+{
+	pr_debug("NatSemi SCx200 ACCESS.bus Driver\n");
+
+	/* First scan for ISA-based devices */
+	scx200_scan_isa();	/* XXX: should we care about errors? */
+
+	/* If at least one bus was created, init must succeed */
+	if (scx200_acb_list)
+		return 0;
+
+	/* No ISA devices; register the platform driver for PCI-based devices */
+	return platform_driver_register(&scx200_pci_driver);
+}
+
+static void __exit scx200_acb_cleanup(void)
+{
+	struct scx200_acb_iface *iface;
+
+	platform_driver_unregister(&scx200_pci_driver);
+
+	mutex_lock(&scx200_acb_list_mutex);
+	while ((iface = scx200_acb_list) != NULL) {
+		scx200_acb_list = iface->next;
+		mutex_unlock(&scx200_acb_list_mutex);
+
+		scx200_cleanup_iface(iface);
+
+		mutex_lock(&scx200_acb_list_mutex);
+	}
+	mutex_unlock(&scx200_acb_list_mutex);
+}
+
+module_init(scx200_acb_init);
+module_exit(scx200_acb_cleanup);