drivers/i2c/busses/i2c-savage4.c

   1 /*
   2     i2c-savage4.c - Part of lm_sensors, Linux kernel modules for hardware
   3               monitoring
   4     Copyright (C) 1998-2003  The LM Sensors Team
   5     Alexander Wold <awold@bigfoot.com>
   6     Mark D. Studebaker <mdsxyz123@yahoo.com>
   7
   8     Based on i2c-voodoo3.c.
   9
  10     This program is free software; you can redistribute it and/or modify
  11     it under the terms of the GNU General Public License as published by
  12     the Free Software Foundation; either version 2 of the License, or
  13     (at your option) any later version.
  14
  15     This program is distributed in the hope that it will be useful,
  16     but WITHOUT ANY WARRANTY; without even the implied warranty of
  17     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18     GNU General Public License for more details.
  19
  20     You should have received a copy of the GNU General Public License
  21     along with this program; if not, write to the Free Software
  22     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 /* This interfaces to the I2C bus of the Savage4 to gain access to
  26    the BT869 and possibly other I2C devices. The DDC bus is not
  27    yet supported because its register is not memory-mapped.
  28 */
  29
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/init.h>
  33 #include <linux/pci.h>
  34 #include <linux/i2c.h>
  35 #include <linux/i2c-algo-bit.h>
  36 #include <asm/io.h>
  37
  38 /* device IDs */
  39 #define PCI_CHIP_SAVAGE4        0x8A22
  40 #define PCI_CHIP_SAVAGE2000     0x9102
  41
  42 #define REG                     0xff20  /* Serial Port 1 Register */
  43
  44 /* bit locations in the register */
  45 #define I2C_ENAB                0x00000020
  46 #define I2C_SCL_OUT             0x00000001
  47 #define I2C_SDA_OUT             0x00000002
  48 #define I2C_SCL_IN              0x00000008
  49 #define I2C_SDA_IN              0x00000010
  50
  51 /* delays */
  52 #define CYCLE_DELAY             10
  53 #define TIMEOUT                 (HZ / 2)
  54
  55
  56 static void __iomem *ioaddr;
  57
  58 /* The sav GPIO registers don't have individual masks for each bit
  59    so we always have to read before writing. */
  60
  61 static void bit_savi2c_setscl(void *data, int val)
  62 {
  63         unsigned int r;
  64         r = readl(ioaddr + REG);
  65         if(val)
  66                 r |= I2C_SCL_OUT;
  67         else
  68                 r &= ~I2C_SCL_OUT;
  69         writel(r, ioaddr + REG);
  70         readl(ioaddr + REG);    /* flush posted write */
  71 }
  72
  73 static void bit_savi2c_setsda(void *data, int val)
  74 {
  75         unsigned int r;
  76         r = readl(ioaddr + REG);
  77         if(val)
  78                 r |= I2C_SDA_OUT;
  79         else
  80                 r &= ~I2C_SDA_OUT;
  81         writel(r, ioaddr + REG);
  82         readl(ioaddr + REG);    /* flush posted write */
  83 }
  84
  85 /* The GPIO pins are open drain, so the pins always remain outputs.
  86    We rely on the i2c-algo-bit routines to set the pins high before
  87    reading the input from other chips. */
  88
  89 static int bit_savi2c_getscl(void *data)
  90 {
  91         return (0 != (readl(ioaddr + REG) & I2C_SCL_IN));
  92 }
  93
  94 static int bit_savi2c_getsda(void *data)
  95 {
  96         return (0 != (readl(ioaddr + REG) & I2C_SDA_IN));
  97 }
  98
  99 /* Configures the chip */
 100
 101 static int config_s4(struct pci_dev *dev)
 102 {
 103         unsigned long cadr;
 104
 105         /* map memory */
 106         cadr = dev->resource[0].start;
 107         cadr &= PCI_BASE_ADDRESS_MEM_MASK;
 108         ioaddr = ioremap_nocache(cadr, 0x0080000);
 109         if (ioaddr) {
 110                 /* writel(0x8160, ioaddr + REG2); */
 111                 writel(0x00000020, ioaddr + REG);
 112                 dev_info(&dev->dev, "Using Savage4 at %p\n", ioaddr);
 113                 return 0;
 114         }
 115         return -ENODEV;
 116 }
 117
 118 static struct i2c_algo_bit_data sav_i2c_bit_data = {
 119         .setsda         = bit_savi2c_setsda,
 120         .setscl         = bit_savi2c_setscl,
 121         .getsda         = bit_savi2c_getsda,
 122         .getscl         = bit_savi2c_getscl,
 123         .udelay         = CYCLE_DELAY,
 124         .timeout        = TIMEOUT
 125 };
 126
 127 static struct i2c_adapter savage4_i2c_adapter = {
 128         .owner          = THIS_MODULE,
 129         .id             = I2C_HW_B_SAVAGE,
 130         .name           = "I2C Savage4 adapter",
 131         .algo_data      = &sav_i2c_bit_data,
 132 };
 133
 134 static struct pci_device_id savage4_ids[] __devinitdata = {
 135         { PCI_DEVICE(PCI_VENDOR_ID_S3, PCI_CHIP_SAVAGE4) },
 136         { PCI_DEVICE(PCI_VENDOR_ID_S3, PCI_CHIP_SAVAGE2000) },
 137         { 0, }
 138 };
 139
 140 MODULE_DEVICE_TABLE (pci, savage4_ids);
 141
 142 static int __devinit savage4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 143 {
 144         int retval;
 145
 146         retval = config_s4(dev);
 147         if (retval)
 148                 return retval;
 149
 150         /* set up the sysfs linkage to our parent device */
 151         savage4_i2c_adapter.dev.parent = &dev->dev;
 152
 153         return i2c_bit_add_bus(&savage4_i2c_adapter);
 154 }
 155
 156 static void __devexit savage4_remove(struct pci_dev *dev)
 157 {
 158         i2c_del_adapter(&savage4_i2c_adapter);
 159         iounmap(ioaddr);
 160 }
 161
 162 static struct pci_driver savage4_driver = {
 163         .name           = "savage4_smbus",
 164         .id_table       = savage4_ids,
 165         .probe          = savage4_probe,
 166         .remove         = __devexit_p(savage4_remove),
 167 };
 168
 169 static int __init i2c_savage4_init(void)
 170 {
 171         return pci_register_driver(&savage4_driver);
 172 }
 173
 174 static void __exit i2c_savage4_exit(void)
 175 {
 176         pci_unregister_driver(&savage4_driver);
 177 }
 178
 179 MODULE_AUTHOR("Alexander Wold <awold@bigfoot.com> "
 180                 "and Mark D. Studebaker <mdsxyz123@yahoo.com>");
 181 MODULE_DESCRIPTION("Savage4 I2C/SMBus driver");
 182 MODULE_LICENSE("GPL");
 183
 184 module_init(i2c_savage4_init);
 185 module_exit(i2c_savage4_exit);