diff options
Diffstat (limited to 'kernel/drivers/i2c/busses/i2c-isch.c')
| -rw-r--r-- | kernel/drivers/i2c/busses/i2c-isch.c | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/kernel/drivers/i2c/busses/i2c-isch.c b/kernel/drivers/i2c/busses/i2c-isch.c new file mode 100644 index 000000000..c2f25f19d --- /dev/null +++ b/kernel/drivers/i2c/busses/i2c-isch.c @@ -0,0 +1,322 @@ +/* + i2c-isch.c - Linux kernel driver for Intel SCH chipset SMBus + - Based on i2c-piix4.c + Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl> and + Philip Edelbrock <phil@netroedge.com> + - Intel SCH support + Copyright (c) 2007 - 2008 Jacob Jun Pan <jacob.jun.pan@intel.com> + + 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. +*/ + +/* + Supports: + Intel SCH chipsets (AF82US15W, AF82US15L, AF82UL11L) + Note: we assume there can only be one device, with one SMBus interface. +*/ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/kernel.h> +#include <linux/delay.h> +#include <linux/stddef.h> +#include <linux/ioport.h> +#include <linux/i2c.h> +#include <linux/io.h> +#include <linux/acpi.h> + +/* SCH SMBus address offsets */ +#define SMBHSTCNT (0 + sch_smba) +#define SMBHSTSTS (1 + sch_smba) +#define SMBHSTCLK (2 + sch_smba) +#define SMBHSTADD (4 + sch_smba) /* TSA */ +#define SMBHSTCMD (5 + sch_smba) +#define SMBHSTDAT0 (6 + sch_smba) +#define SMBHSTDAT1 (7 + sch_smba) +#define SMBBLKDAT (0x20 + sch_smba) + +/* Other settings */ +#define MAX_RETRIES 5000 + +/* I2C constants */ +#define SCH_QUICK 0x00 +#define SCH_BYTE 0x01 +#define SCH_BYTE_DATA 0x02 +#define SCH_WORD_DATA 0x03 +#define SCH_BLOCK_DATA 0x05 + +static unsigned short sch_smba; +static struct i2c_adapter sch_adapter; +static int backbone_speed = 33000; /* backbone speed in kHz */ +module_param(backbone_speed, int, S_IRUSR | S_IWUSR); +MODULE_PARM_DESC(backbone_speed, "Backbone speed in kHz, (default = 33000)"); + +/* + * Start the i2c transaction -- the i2c_access will prepare the transaction + * and this function will execute it. + * return 0 for success and others for failure. + */ +static int sch_transaction(void) +{ + int temp; + int result = 0; + int retries = 0; + + dev_dbg(&sch_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, " + "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT), + inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0), + inb(SMBHSTDAT1)); + + /* Make sure the SMBus host is ready to start transmitting */ + temp = inb(SMBHSTSTS) & 0x0f; + if (temp) { + /* Can not be busy since we checked it in sch_access */ + if (temp & 0x01) { + dev_dbg(&sch_adapter.dev, "Completion (%02x). " + "Clear...\n", temp); + } + if (temp & 0x06) { + dev_dbg(&sch_adapter.dev, "SMBus error (%02x). " + "Resetting...\n", temp); + } + outb(temp, SMBHSTSTS); + temp = inb(SMBHSTSTS) & 0x0f; + if (temp) { + dev_err(&sch_adapter.dev, + "SMBus is not ready: (%02x)\n", temp); + return -EAGAIN; + } + } + + /* start the transaction by setting bit 4 */ + outb(inb(SMBHSTCNT) | 0x10, SMBHSTCNT); + + do { + usleep_range(100, 200); + temp = inb(SMBHSTSTS) & 0x0f; + } while ((temp & 0x08) && (retries++ < MAX_RETRIES)); + + /* If the SMBus is still busy, we give up */ + if (retries > MAX_RETRIES) { + dev_err(&sch_adapter.dev, "SMBus Timeout!\n"); + result = -ETIMEDOUT; + } + if (temp & 0x04) { + result = -EIO; + dev_dbg(&sch_adapter.dev, "Bus collision! SMBus may be " + "locked until next hard reset. (sorry!)\n"); + /* Clock stops and slave is stuck in mid-transmission */ + } else if (temp & 0x02) { + result = -EIO; + dev_err(&sch_adapter.dev, "Error: no response!\n"); + } else if (temp & 0x01) { + dev_dbg(&sch_adapter.dev, "Post complete!\n"); + outb(temp, SMBHSTSTS); + temp = inb(SMBHSTSTS) & 0x07; + if (temp & 0x06) { + /* Completion clear failed */ + dev_dbg(&sch_adapter.dev, "Failed reset at end of " + "transaction (%02x), Bus error!\n", temp); + } + } else { + result = -ENXIO; + dev_dbg(&sch_adapter.dev, "No such address.\n"); + } + dev_dbg(&sch_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, " + "ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb(SMBHSTCNT), + inb(SMBHSTCMD), inb(SMBHSTADD), inb(SMBHSTDAT0), + inb(SMBHSTDAT1)); + return result; +} + +/* + * This is the main access entry for i2c-sch access + * adap is i2c_adapter pointer, addr is the i2c device bus address, read_write + * (0 for read and 1 for write), size is i2c transaction type and data is the + * union of transaction for data to be transferred or data read from bus. + * return 0 for success and others for failure. + */ +static s32 sch_access(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, union i2c_smbus_data *data) +{ + int i, len, temp, rc; + + /* Make sure the SMBus host is not busy */ + temp = inb(SMBHSTSTS) & 0x0f; + if (temp & 0x08) { + dev_dbg(&sch_adapter.dev, "SMBus busy (%02x)\n", temp); + return -EAGAIN; + } + temp = inw(SMBHSTCLK); + if (!temp) { + /* + * We can't determine if we have 33 or 25 MHz clock for + * SMBus, so expect 33 MHz and calculate a bus clock of + * 100 kHz. If we actually run at 25 MHz the bus will be + * run ~75 kHz instead which should do no harm. + */ + dev_notice(&sch_adapter.dev, + "Clock divider unitialized. Setting defaults\n"); + outw(backbone_speed / (4 * 100), SMBHSTCLK); + } + + dev_dbg(&sch_adapter.dev, "access size: %d %s\n", size, + (read_write)?"READ":"WRITE"); + switch (size) { + case I2C_SMBUS_QUICK: + outb((addr << 1) | read_write, SMBHSTADD); + size = SCH_QUICK; + break; + case I2C_SMBUS_BYTE: + outb((addr << 1) | read_write, SMBHSTADD); + if (read_write == I2C_SMBUS_WRITE) + outb(command, SMBHSTCMD); + size = SCH_BYTE; + break; + case I2C_SMBUS_BYTE_DATA: + outb((addr << 1) | read_write, SMBHSTADD); + outb(command, SMBHSTCMD); + if (read_write == I2C_SMBUS_WRITE) + outb(data->byte, SMBHSTDAT0); + size = SCH_BYTE_DATA; + break; + case I2C_SMBUS_WORD_DATA: + outb((addr << 1) | read_write, SMBHSTADD); + outb(command, SMBHSTCMD); + if (read_write == I2C_SMBUS_WRITE) { + outb(data->word & 0xff, SMBHSTDAT0); + outb((data->word & 0xff00) >> 8, SMBHSTDAT1); + } + size = SCH_WORD_DATA; + break; + case I2C_SMBUS_BLOCK_DATA: + outb((addr << 1) | read_write, SMBHSTADD); + outb(command, SMBHSTCMD); + if (read_write == I2C_SMBUS_WRITE) { + len = data->block[0]; + if (len == 0 || len > I2C_SMBUS_BLOCK_MAX) + return -EINVAL; + outb(len, SMBHSTDAT0); + for (i = 1; i <= len; i++) + outb(data->block[i], SMBBLKDAT+i-1); + } + size = SCH_BLOCK_DATA; + break; + default: + dev_warn(&adap->dev, "Unsupported transaction %d\n", size); + return -EOPNOTSUPP; + } + dev_dbg(&sch_adapter.dev, "write size %d to 0x%04x\n", size, SMBHSTCNT); + outb((inb(SMBHSTCNT) & 0xb0) | (size & 0x7), SMBHSTCNT); + + rc = sch_transaction(); + if (rc) /* Error in transaction */ + return rc; + + if ((read_write == I2C_SMBUS_WRITE) || (size == SCH_QUICK)) + return 0; + + switch (size) { + case SCH_BYTE: + case SCH_BYTE_DATA: + data->byte = inb(SMBHSTDAT0); + break; + case SCH_WORD_DATA: + data->word = inb(SMBHSTDAT0) + (inb(SMBHSTDAT1) << 8); + break; + case SCH_BLOCK_DATA: + data->block[0] = inb(SMBHSTDAT0); + if (data->block[0] == 0 || data->block[0] > I2C_SMBUS_BLOCK_MAX) + return -EPROTO; + for (i = 1; i <= data->block[0]; i++) + data->block[i] = inb(SMBBLKDAT+i-1); + break; + } + return 0; +} + +static u32 sch_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; +} + +static const struct i2c_algorithm smbus_algorithm = { + .smbus_xfer = sch_access, + .functionality = sch_func, +}; + +static struct i2c_adapter sch_adapter = { + .owner = THIS_MODULE, + .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, + .algo = &smbus_algorithm, +}; + +static int smbus_sch_probe(struct platform_device *dev) +{ + struct resource *res; + int retval; + + res = platform_get_resource(dev, IORESOURCE_IO, 0); + if (!res) + return -EBUSY; + + if (!devm_request_region(&dev->dev, res->start, resource_size(res), + dev->name)) { + dev_err(&dev->dev, "SMBus region 0x%x already in use!\n", + sch_smba); + return -EBUSY; + } + + sch_smba = res->start; + + dev_dbg(&dev->dev, "SMBA = 0x%X\n", sch_smba); + + /* set up the sysfs linkage to our parent device */ + sch_adapter.dev.parent = &dev->dev; + + snprintf(sch_adapter.name, sizeof(sch_adapter.name), + "SMBus SCH adapter at %04x", sch_smba); + + retval = i2c_add_adapter(&sch_adapter); + if (retval) { + dev_err(&dev->dev, "Couldn't register adapter!\n"); + sch_smba = 0; + } + + return retval; +} + +static int smbus_sch_remove(struct platform_device *pdev) +{ + if (sch_smba) { + i2c_del_adapter(&sch_adapter); + sch_smba = 0; + } + + return 0; +} + +static struct platform_driver smbus_sch_driver = { + .driver = { + .name = "isch_smbus", + }, + .probe = smbus_sch_probe, + .remove = smbus_sch_remove, +}; + +module_platform_driver(smbus_sch_driver); + +MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@intel.com>"); +MODULE_DESCRIPTION("Intel SCH SMBus driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:isch_smbus"); |