diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-sis96x.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-sis96x.c | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-sis96x.c b/drivers/i2c/busses/i2c-sis96x.c new file mode 100644 index 0000000000..cde8003985 --- /dev/null +++ b/drivers/i2c/busses/i2c-sis96x.c @@ -0,0 +1,318 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com> + +*/ + +/* + This module must be considered BETA unless and until + the chipset manufacturer releases a datasheet. + The register definitions are based on the SiS630. + + This module relies on quirk_sis_96x_smbus (drivers/pci/quirks.c) + for just about every machine for which users have reported. + If this module isn't detecting your 96x south bridge, have a + look there. + + We assume there can only be one SiS96x with one SMBus interface. +*/ + +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/kernel.h> +#include <linux/delay.h> +#include <linux/stddef.h> +#include <linux/ioport.h> +#include <linux/i2c.h> +#include <linux/acpi.h> +#include <linux/io.h> + +/* base address register in PCI config space */ +#define SIS96x_BAR 0x04 + +/* SiS96x SMBus registers */ +#define SMB_STS 0x00 +#define SMB_EN 0x01 +#define SMB_CNT 0x02 +#define SMB_HOST_CNT 0x03 +#define SMB_ADDR 0x04 +#define SMB_CMD 0x05 +#define SMB_PCOUNT 0x06 +#define SMB_COUNT 0x07 +#define SMB_BYTE 0x08 +#define SMB_DEV_ADDR 0x10 +#define SMB_DB0 0x11 +#define SMB_DB1 0x12 +#define SMB_SAA 0x13 + +/* register count for request_region */ +#define SMB_IOSIZE 0x20 + +/* Other settings */ +#define MAX_TIMEOUT 500 + +/* SiS96x SMBus constants */ +#define SIS96x_QUICK 0x00 +#define SIS96x_BYTE 0x01 +#define SIS96x_BYTE_DATA 0x02 +#define SIS96x_WORD_DATA 0x03 +#define SIS96x_PROC_CALL 0x04 +#define SIS96x_BLOCK_DATA 0x05 + +static struct pci_driver sis96x_driver; +static struct i2c_adapter sis96x_adapter; +static u16 sis96x_smbus_base; + +static inline u8 sis96x_read(u8 reg) +{ + return inb(sis96x_smbus_base + reg) ; +} + +static inline void sis96x_write(u8 reg, u8 data) +{ + outb(data, sis96x_smbus_base + reg) ; +} + +/* Execute a SMBus transaction. + int size is from SIS96x_QUICK to SIS96x_BLOCK_DATA + */ +static int sis96x_transaction(int size) +{ + int temp; + int result = 0; + int timeout = 0; + + dev_dbg(&sis96x_adapter.dev, "SMBus transaction %d\n", size); + + /* Make sure the SMBus host is ready to start transmitting */ + if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) { + + dev_dbg(&sis96x_adapter.dev, "SMBus busy (0x%02x). " + "Resetting...\n", temp); + + /* kill the transaction */ + sis96x_write(SMB_HOST_CNT, 0x20); + + /* check it again */ + if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) { + dev_dbg(&sis96x_adapter.dev, "Failed (0x%02x)\n", temp); + return -EBUSY; + } else { + dev_dbg(&sis96x_adapter.dev, "Successful\n"); + } + } + + /* Turn off timeout interrupts, set fast host clock */ + sis96x_write(SMB_CNT, 0x20); + + /* clear all (sticky) status flags */ + temp = sis96x_read(SMB_STS); + sis96x_write(SMB_STS, temp & 0x1e); + + /* start the transaction by setting bit 4 and size bits */ + sis96x_write(SMB_HOST_CNT, 0x10 | (size & 0x07)); + + /* We will always wait for a fraction of a second! */ + do { + msleep(1); + temp = sis96x_read(SMB_STS); + } while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT)); + + /* If the SMBus is still busy, we give up */ + if (timeout > MAX_TIMEOUT) { + dev_dbg(&sis96x_adapter.dev, "SMBus Timeout! (0x%02x)\n", temp); + result = -ETIMEDOUT; + } + + /* device error - probably missing ACK */ + if (temp & 0x02) { + dev_dbg(&sis96x_adapter.dev, "Failed bus transaction!\n"); + result = -ENXIO; + } + + /* bus collision */ + if (temp & 0x04) { + dev_dbg(&sis96x_adapter.dev, "Bus collision!\n"); + result = -EIO; + } + + /* Finish up by resetting the bus */ + sis96x_write(SMB_STS, temp); + if ((temp = sis96x_read(SMB_STS))) { + dev_dbg(&sis96x_adapter.dev, "Failed reset at " + "end of transaction! (0x%02x)\n", temp); + } + + return result; +} + +/* Return negative errno on error. */ +static s32 sis96x_access(struct i2c_adapter * adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, union i2c_smbus_data * data) +{ + int status; + + switch (size) { + case I2C_SMBUS_QUICK: + sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01)); + size = SIS96x_QUICK; + break; + + case I2C_SMBUS_BYTE: + sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01)); + if (read_write == I2C_SMBUS_WRITE) + sis96x_write(SMB_CMD, command); + size = SIS96x_BYTE; + break; + + case I2C_SMBUS_BYTE_DATA: + sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01)); + sis96x_write(SMB_CMD, command); + if (read_write == I2C_SMBUS_WRITE) + sis96x_write(SMB_BYTE, data->byte); + size = SIS96x_BYTE_DATA; + break; + + case I2C_SMBUS_PROC_CALL: + case I2C_SMBUS_WORD_DATA: + sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01)); + sis96x_write(SMB_CMD, command); + if (read_write == I2C_SMBUS_WRITE) { + sis96x_write(SMB_BYTE, data->word & 0xff); + sis96x_write(SMB_BYTE + 1, (data->word & 0xff00) >> 8); + } + size = (size == I2C_SMBUS_PROC_CALL ? + SIS96x_PROC_CALL : SIS96x_WORD_DATA); + break; + + default: + dev_warn(&adap->dev, "Unsupported transaction %d\n", size); + return -EOPNOTSUPP; + } + + status = sis96x_transaction(size); + if (status) + return status; + + if ((size != SIS96x_PROC_CALL) && + ((read_write == I2C_SMBUS_WRITE) || (size == SIS96x_QUICK))) + return 0; + + switch (size) { + case SIS96x_BYTE: + case SIS96x_BYTE_DATA: + data->byte = sis96x_read(SMB_BYTE); + break; + + case SIS96x_WORD_DATA: + case SIS96x_PROC_CALL: + data->word = sis96x_read(SMB_BYTE) + + (sis96x_read(SMB_BYTE + 1) << 8); + break; + } + return 0; +} + +static u32 sis96x_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_PROC_CALL; +} + +static const struct i2c_algorithm smbus_algorithm = { + .smbus_xfer = sis96x_access, + .functionality = sis96x_func, +}; + +static struct i2c_adapter sis96x_adapter = { + .owner = THIS_MODULE, + .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, + .algo = &smbus_algorithm, +}; + +static const struct pci_device_id sis96x_ids[] = { + { PCI_DEVICE(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_SMBUS) }, + { 0, } +}; + +MODULE_DEVICE_TABLE (pci, sis96x_ids); + +static int sis96x_probe(struct pci_dev *dev, + const struct pci_device_id *id) +{ + u16 ww = 0; + int retval; + + if (sis96x_smbus_base) { + dev_err(&dev->dev, "Only one device supported.\n"); + return -EBUSY; + } + + pci_read_config_word(dev, PCI_CLASS_DEVICE, &ww); + if (PCI_CLASS_SERIAL_SMBUS != ww) { + dev_err(&dev->dev, "Unsupported device class 0x%04x!\n", ww); + return -ENODEV; + } + + sis96x_smbus_base = pci_resource_start(dev, SIS96x_BAR); + if (!sis96x_smbus_base) { + dev_err(&dev->dev, "SiS96x SMBus base address " + "not initialized!\n"); + return -EINVAL; + } + dev_info(&dev->dev, "SiS96x SMBus base address: 0x%04x\n", + sis96x_smbus_base); + + retval = acpi_check_resource_conflict(&dev->resource[SIS96x_BAR]); + if (retval) + return -ENODEV; + + /* Everything is happy, let's grab the memory and set things up. */ + if (!request_region(sis96x_smbus_base, SMB_IOSIZE, + sis96x_driver.name)) { + dev_err(&dev->dev, "SMBus registers 0x%04x-0x%04x " + "already in use!\n", sis96x_smbus_base, + sis96x_smbus_base + SMB_IOSIZE - 1); + + sis96x_smbus_base = 0; + return -EINVAL; + } + + /* set up the sysfs linkage to our parent device */ + sis96x_adapter.dev.parent = &dev->dev; + + snprintf(sis96x_adapter.name, sizeof(sis96x_adapter.name), + "SiS96x SMBus adapter at 0x%04x", sis96x_smbus_base); + + if ((retval = i2c_add_adapter(&sis96x_adapter))) { + dev_err(&dev->dev, "Couldn't register adapter!\n"); + release_region(sis96x_smbus_base, SMB_IOSIZE); + sis96x_smbus_base = 0; + } + + return retval; +} + +static void sis96x_remove(struct pci_dev *dev) +{ + if (sis96x_smbus_base) { + i2c_del_adapter(&sis96x_adapter); + release_region(sis96x_smbus_base, SMB_IOSIZE); + sis96x_smbus_base = 0; + } +} + +static struct pci_driver sis96x_driver = { + .name = "sis96x_smbus", + .id_table = sis96x_ids, + .probe = sis96x_probe, + .remove = sis96x_remove, +}; + +module_pci_driver(sis96x_driver); + +MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>"); +MODULE_DESCRIPTION("SiS96x SMBus driver"); +MODULE_LICENSE("GPL"); |