1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-via.c b/drivers/i2c/busses/i2c-via.c
new file mode 100644
index 0000000000..ad4f09c7f0
--- /dev/null
+++ b/drivers/i2c/busses/i2c-via.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+    i2c Support for Via Technologies 82C586B South Bridge
+
+    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
+
+*/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/ioport.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+#include <linux/io.h>
+
+/* Power management registers */
+#define PM_CFG_REVID	0x08	/* silicon revision code */
+#define PM_CFG_IOBASE0	0x20
+#define PM_CFG_IOBASE1	0x48
+
+#define I2C_DIR		(pm_io_base+0x40)
+#define I2C_OUT		(pm_io_base+0x42)
+#define I2C_IN		(pm_io_base+0x44)
+#define I2C_SCL		0x02	/* clock bit in DIR/OUT/IN register */
+#define I2C_SDA		0x04
+
+/* io-region reservation */
+#define IOSPACE		0x06
+
+static struct pci_driver vt586b_driver;
+static u16 pm_io_base;
+
+/*
+   It does not appear from the datasheet that the GPIO pins are
+   open drain. So a we set a low value by setting the direction to
+   output and a high value by setting the direction to input and
+   relying on the required I2C pullup. The data value is initialized
+   to 0 in via_init() and never changed.
+*/
+static void bit_via_setscl(void *data, int state)
+{
+	outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
+}
+
+static void bit_via_setsda(void *data, int state)
+{
+	outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
+}
+
+static int bit_via_getscl(void *data)
+{
+	return (0 != (inb(I2C_IN) & I2C_SCL));
+}
+
+static int bit_via_getsda(void *data)
+{
+	return (0 != (inb(I2C_IN) & I2C_SDA));
+}
+
+
+static struct i2c_algo_bit_data bit_data = {
+	.setsda		= bit_via_setsda,
+	.setscl		= bit_via_setscl,
+	.getsda		= bit_via_getsda,
+	.getscl		= bit_via_getscl,
+	.udelay		= 5,
+	.timeout	= HZ
+};
+
+static struct i2c_adapter vt586b_adapter = {
+	.owner		= THIS_MODULE,
+	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
+	.name		= "VIA i2c",
+	.algo_data	= &bit_data,
+};
+
+
+static const struct pci_device_id vt586b_ids[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
+	{ 0, }
+};
+
+MODULE_DEVICE_TABLE (pci, vt586b_ids);
+
+static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
+{
+	u16 base;
+	u8 rev;
+	int res;
+
+	if (pm_io_base) {
+		dev_err(&dev->dev, "i2c-via: Will only support one host\n");
+		return -ENODEV;
+	}
+
+	pci_read_config_byte(dev, PM_CFG_REVID, &rev);
+
+	switch (rev) {
+	case 0x00:
+		base = PM_CFG_IOBASE0;
+		break;
+	case 0x01:
+	case 0x10:
+		base = PM_CFG_IOBASE1;
+		break;
+
+	default:
+		base = PM_CFG_IOBASE1;
+		/* later revision */
+	}
+
+	pci_read_config_word(dev, base, &pm_io_base);
+	pm_io_base &= (0xff << 8);
+
+	if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
+		dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
+		return -ENODEV;
+	}
+
+	outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
+	outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
+
+	/* set up the sysfs linkage to our parent device */
+	vt586b_adapter.dev.parent = &dev->dev;
+
+	res = i2c_bit_add_bus(&vt586b_adapter);
+	if ( res < 0 ) {
+		release_region(I2C_DIR, IOSPACE);
+		pm_io_base = 0;
+		return res;
+	}
+	return 0;
+}
+
+static void vt586b_remove(struct pci_dev *dev)
+{
+	i2c_del_adapter(&vt586b_adapter);
+	release_region(I2C_DIR, IOSPACE);
+	pm_io_base = 0;
+}
+
+
+static struct pci_driver vt586b_driver = {
+	.name		= "vt586b_smbus",
+	.id_table	= vt586b_ids,
+	.probe		= vt586b_probe,
+	.remove		= vt586b_remove,
+};
+
+module_pci_driver(vt586b_driver);
+
+MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
+MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
+MODULE_LICENSE("GPL");