i2c: PA Semi SMBus driver

New driver for the PA Semi SMBus interfaces.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 426 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-pasemi.c b/drivers/i2c/busses/i2c-pasemi.c
new file mode 100644
index 000000000000..f54fb5d65cc4
--- /dev/null
+++ b/drivers/i2c/busses/i2c-pasemi.c
@@ -0,0 +1,426 @@
+/*
+ * Copyright (C) 2006-2007 PA Semi, Inc
+ *
+ * SMBus host driver for PA Semi PWRficient
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/kernel.h>
+#include <linux/stddef.h>
+#include <linux/sched.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <asm/io.h>
+
+static struct pci_driver pasemi_smb_driver;
+
+struct pasemi_smbus {
+	struct pci_dev		*dev;
+	struct i2c_adapter	 adapter;
+	unsigned long		 base;
+	int			 size;
+};
+
+/* Register offsets */
+#define REG_MTXFIFO	0x00
+#define REG_MRXFIFO	0x04
+#define REG_SMSTA	0x14
+#define REG_CTL		0x1c
+
+/* Register defs */
+#define MTXFIFO_READ	0x00000400
+#define MTXFIFO_STOP	0x00000200
+#define MTXFIFO_START	0x00000100
+#define MTXFIFO_DATA_M	0x000000ff
+
+#define MRXFIFO_EMPTY	0x00000100
+#define MRXFIFO_DATA_M	0x000000ff
+
+#define SMSTA_XEN	0x08000000
+
+#define CTL_MRR		0x00000400
+#define CTL_MTR		0x00000200
+#define CTL_CLK_M	0x000000ff
+
+#define CLK_100K_DIV	84
+#define CLK_400K_DIV	21
+
+static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val)
+{
+	dev_dbg(&smbus->dev->dev, "smbus write reg %lx val %08x\n",
+		smbus->base + reg, val);
+	outl(val, smbus->base + reg);
+}
+
+static inline int reg_read(struct pasemi_smbus *smbus, int reg)
+{
+	int ret;
+	ret = inl(smbus->base + reg);
+	dev_dbg(&smbus->dev->dev, "smbus read reg %lx val %08x\n",
+		smbus->base + reg, ret);
+	return ret;
+}
+
+#define TXFIFO_WR(smbus, reg)	reg_write((smbus), REG_MTXFIFO, (reg))
+#define RXFIFO_RD(smbus)	reg_read((smbus), REG_MRXFIFO)
+
+static void pasemi_smb_clear(struct pasemi_smbus *smbus)
+{
+	unsigned int status;
+
+	status = reg_read(smbus, REG_SMSTA);
+	reg_write(smbus, REG_SMSTA, status);
+}
+
+static unsigned int pasemi_smb_waitready(struct pasemi_smbus *smbus)
+{
+	int timeout = 10;
+	unsigned int status;
+
+	status = reg_read(smbus, REG_SMSTA);
+
+	while (!(status & SMSTA_XEN) && timeout--) {
+		msleep(1);
+		status = reg_read(smbus, REG_SMSTA);
+	}
+
+	if (timeout < 0) {
+		dev_warn(&smbus->dev->dev, "Timeout, status 0x%08x\n", status);
+		reg_write(smbus, REG_SMSTA, status);
+		return -ETIME;
+	}
+
+	/* Clear XEN */
+	reg_write(smbus, REG_SMSTA, SMSTA_XEN);
+
+	return 0;
+}
+
+static int pasemi_i2c_xfer_msg(struct i2c_adapter *adapter,
+			       struct i2c_msg *msg, int stop)
+{
+	struct pasemi_smbus *smbus = adapter->algo_data;
+	int read, i, err;
+	u32 rd;
+
+	read = msg->flags & I2C_M_RD ? 1 : 0;
+
+	TXFIFO_WR(smbus, MTXFIFO_START | (msg->addr << 1) | read);
+
+	if (read) {
+		TXFIFO_WR(smbus, msg->len | MTXFIFO_READ |
+				 (stop ? MTXFIFO_STOP : 0));
+
+		err = pasemi_smb_waitready(smbus);
+		if (err)
+			goto reset_out;
+
+		for (i = 0; i < msg->len; i++) {
+			rd = RXFIFO_RD(smbus);
+			if (rd & MRXFIFO_EMPTY) {
+				err = -ENODATA;
+				goto reset_out;
+			}
+			msg->buf[i] = rd & MRXFIFO_DATA_M;
+		}
+	} else {
+		for (i = 0; i < msg->len - 1; i++)
+			TXFIFO_WR(smbus, msg->buf[i]);
+
+		TXFIFO_WR(smbus, msg->buf[msg->len] |
+			  (stop ? MTXFIFO_STOP : 0));
+	}
+
+	return 0;
+
+ reset_out:
+	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
+		  (CLK_100K_DIV & CTL_CLK_M)));
+	return err;
+}
+
+static int pasemi_i2c_xfer(struct i2c_adapter *adapter,
+			   struct i2c_msg *msgs, int num)
+{
+	struct pasemi_smbus *smbus = adapter->algo_data;
+	int ret, i;
+
+	pasemi_smb_clear(smbus);
+
+	ret = 0;
+
+	for (i = 0; i < num && !ret; i++)
+		ret = pasemi_i2c_xfer_msg(adapter, &msgs[i], (i == (num - 1)));
+
+	return ret ? ret : num;
+}
+
+static int pasemi_smb_xfer(struct i2c_adapter *adapter,
+		u16 addr, unsigned short flags, char read_write, u8 command,
+		int size, union i2c_smbus_data *data)
+{
+	struct pasemi_smbus *smbus = adapter->algo_data;
+	unsigned int rd;
+	int read_flag, err;
+	int len = 0, i;
+
+	/* All our ops take 8-bit shifted addresses */
+	addr <<= 1;
+	read_flag = read_write == I2C_SMBUS_READ;
+
+	pasemi_smb_clear(smbus);
+
+	switch (size) {
+	case I2C_SMBUS_QUICK:
+		TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START |
+			  MTXFIFO_STOP);
+		break;
+	case I2C_SMBUS_BYTE:
+		TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START);
+		if (read_write)
+			TXFIFO_WR(smbus, 1 | MTXFIFO_STOP | MTXFIFO_READ);
+		else
+			TXFIFO_WR(smbus, MTXFIFO_STOP | command);
+		break;
+	case I2C_SMBUS_BYTE_DATA:
+		TXFIFO_WR(smbus, addr | MTXFIFO_START);
+		TXFIFO_WR(smbus, command);
+		if (read_write) {
+			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
+			TXFIFO_WR(smbus, 1 | MTXFIFO_READ | MTXFIFO_STOP);
+		} else {
+			TXFIFO_WR(smbus, MTXFIFO_STOP | data->byte);
+		}
+		break;
+	case I2C_SMBUS_WORD_DATA:
+		TXFIFO_WR(smbus, addr | MTXFIFO_START);
+		TXFIFO_WR(smbus, command);
+		if (read_write) {
+			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
+			TXFIFO_WR(smbus, 2 | MTXFIFO_READ | MTXFIFO_STOP);
+		} else {
+			TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
+			TXFIFO_WR(smbus, MTXFIFO_STOP | (data->word >> 8));
+		}
+		break;
+	case I2C_SMBUS_BLOCK_DATA:
+		TXFIFO_WR(smbus, addr | MTXFIFO_START);
+		TXFIFO_WR(smbus, command);
+		if (read_write) {
+			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
+			TXFIFO_WR(smbus, 1 | MTXFIFO_READ);
+			rd = RXFIFO_RD(smbus);
+			len = min_t(u8, (rd & MRXFIFO_DATA_M),
+				    I2C_SMBUS_BLOCK_MAX);
+			TXFIFO_WR(smbus, (len + 1) | MTXFIFO_READ |
+					 MTXFIFO_STOP);
+		} else {
+			len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX);
+			TXFIFO_WR(smbus, len);
+			for (i = 1; i < len; i++)
+				TXFIFO_WR(smbus, data->block[i]);
+			TXFIFO_WR(smbus, data->block[len] | MTXFIFO_STOP);
+		}
+		break;
+	case I2C_SMBUS_PROC_CALL:
+		read_write = I2C_SMBUS_READ;
+		TXFIFO_WR(smbus, addr | MTXFIFO_START);
+		TXFIFO_WR(smbus, command);
+		TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
+		TXFIFO_WR(smbus, (data->word >> 8) & MTXFIFO_DATA_M);
+		TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
+		TXFIFO_WR(smbus, 2 | MTXFIFO_STOP | MTXFIFO_READ);
+		break;
+	case I2C_SMBUS_BLOCK_PROC_CALL:
+		len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX - 1);
+		read_write = I2C_SMBUS_READ;
+		TXFIFO_WR(smbus, addr | MTXFIFO_START);
+		TXFIFO_WR(smbus, command);
+		TXFIFO_WR(smbus, len);
+		for (i = 1; i <= len; i++)
+			TXFIFO_WR(smbus, data->block[i]);
+		TXFIFO_WR(smbus, addr | I2C_SMBUS_READ);
+		TXFIFO_WR(smbus, MTXFIFO_READ | 1);
+		rd = RXFIFO_RD(smbus);
+		len = min_t(u8, (rd & MRXFIFO_DATA_M),
+			    I2C_SMBUS_BLOCK_MAX - len);
+		TXFIFO_WR(smbus, (len + 1) | MTXFIFO_READ | MTXFIFO_STOP);
+		break;
+
+	default:
+		dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
+		return -EINVAL;
+	}
+
+	err = pasemi_smb_waitready(smbus);
+	if (err)
+		goto reset_out;
+
+	if (read_write == I2C_SMBUS_WRITE)
+		return 0;
+
+	switch (size) {
+	case I2C_SMBUS_BYTE:
+	case I2C_SMBUS_BYTE_DATA:
+		rd = RXFIFO_RD(smbus);
+		if (rd & MRXFIFO_EMPTY) {
+			err = -ENODATA;
+			goto reset_out;
+		}
+		data->byte = rd & MRXFIFO_DATA_M;
+		break;
+	case I2C_SMBUS_WORD_DATA:
+	case I2C_SMBUS_PROC_CALL:
+		rd = RXFIFO_RD(smbus);
+		if (rd & MRXFIFO_EMPTY) {
+			err = -ENODATA;
+			goto reset_out;
+		}
+		data->word = rd & MRXFIFO_DATA_M;
+		rd = RXFIFO_RD(smbus);
+		if (rd & MRXFIFO_EMPTY) {
+			err = -ENODATA;
+			goto reset_out;
+		}
+		data->word |= (rd & MRXFIFO_DATA_M) << 8;
+		break;
+	case I2C_SMBUS_BLOCK_DATA:
+	case I2C_SMBUS_BLOCK_PROC_CALL:
+		data->block[0] = len;
+		for (i = 1; i <= len; i ++) {
+			rd = RXFIFO_RD(smbus);
+			if (rd & MRXFIFO_EMPTY) {
+				err = -ENODATA;
+				goto reset_out;
+			}
+			data->block[i] = rd & MRXFIFO_DATA_M;
+		}
+		break;
+	}
+
+	return 0;
+
+ reset_out:
+	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
+		  (CLK_100K_DIV & CTL_CLK_M)));
+	return err;
+}
+
+static u32 pasemi_smb_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_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL |
+	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_I2C;
+}
+
+static const struct i2c_algorithm smbus_algorithm = {
+	.master_xfer	= pasemi_i2c_xfer,
+	.smbus_xfer	= pasemi_smb_xfer,
+	.functionality	= pasemi_smb_func,
+};
+
+static int __devinit pasemi_smb_probe(struct pci_dev *dev,
+				      const struct pci_device_id *id)
+{
+	struct pasemi_smbus *smbus;
+	int error;
+
+	if (!(pci_resource_flags(dev, 0) & IORESOURCE_IO))
+		return -ENODEV;
+
+	smbus = kzalloc(sizeof(struct pasemi_smbus), GFP_KERNEL);
+	if (!smbus)
+		return -ENOMEM;
+
+	smbus->dev = dev;
+	smbus->base = pci_resource_start(dev, 0);
+	smbus->size = pci_resource_len(dev, 0);
+
+	if (!request_region(smbus->base, smbus->size,
+			    pasemi_smb_driver.name)) {
+		error = -EBUSY;
+		goto out_kfree;
+	}
+
+	smbus->adapter.owner = THIS_MODULE;
+	snprintf(smbus->adapter.name, I2C_NAME_SIZE,
+		 "PA Semi SMBus adapter at 0x%lx", smbus->base);
+	smbus->adapter.class = I2C_CLASS_HWMON;
+	smbus->adapter.algo = &smbus_algorithm;
+	smbus->adapter.algo_data = smbus;
+
+	/* set up the driverfs linkage to our parent device */
+	smbus->adapter.dev.parent = &dev->dev;
+
+	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
+		  (CLK_100K_DIV & CTL_CLK_M)));
+
+	error = i2c_add_adapter(&smbus->adapter);
+	if (error)
+		goto out_release_region;
+
+	pci_set_drvdata(dev, smbus);
+
+	return 0;
+
+ out_release_region:
+	release_region(smbus->base, smbus->size);
+ out_kfree:
+	kfree(smbus);
+	return error;
+}
+
+static void __devexit pasemi_smb_remove(struct pci_dev *dev)
+{
+	struct pasemi_smbus *smbus = pci_get_drvdata(dev);
+
+	i2c_del_adapter(&smbus->adapter);
+	release_region(smbus->base, smbus->size);
+	kfree(smbus);
+}
+
+static struct pci_device_id pasemi_smb_ids[] = {
+	{ PCI_DEVICE(0x1959, 0xa003) },
+	{ 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, pasemi_smb_ids);
+
+static struct pci_driver pasemi_smb_driver = {
+	.name		= "i2c-pasemi",
+	.id_table	= pasemi_smb_ids,
+	.probe		= pasemi_smb_probe,
+	.remove		= __devexit_p(pasemi_smb_remove),
+};
+
+static int __init pasemi_smb_init(void)
+{
+	return pci_register_driver(&pasemi_smb_driver);
+}
+
+static void __exit pasemi_smb_exit(void)
+{
+	pci_unregister_driver(&pasemi_smb_driver);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR ("Olof Johansson <olof@lixom.net>");
+MODULE_DESCRIPTION("PA Semi PWRficient SMBus driver");
+
+module_init(pasemi_smb_init);
+module_exit(pasemi_smb_exit);