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Linux/drivers/i2c/busses/i2c-via.c

  1 /*
  2     i2c Support for Via Technologies 82C586B South Bridge
  3 
  4     Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
  5 
  6     This program is free software; you can redistribute it and/or modify
  7     it under the terms of the GNU General Public License as published by
  8     the Free Software Foundation; either version 2 of the License, or
  9     (at your option) any later version.
 10 
 11     This program is distributed in the hope that it will be useful,
 12     but WITHOUT ANY WARRANTY; without even the implied warranty of
 13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14     GNU General Public License for more details.
 15 */
 16 
 17 #include <linux/kernel.h>
 18 #include <linux/module.h>
 19 #include <linux/pci.h>
 20 #include <linux/ioport.h>
 21 #include <linux/i2c.h>
 22 #include <linux/i2c-algo-bit.h>
 23 #include <linux/io.h>
 24 
 25 /* Power management registers */
 26 #define PM_CFG_REVID    0x08    /* silicon revision code */
 27 #define PM_CFG_IOBASE0  0x20
 28 #define PM_CFG_IOBASE1  0x48
 29 
 30 #define I2C_DIR         (pm_io_base+0x40)
 31 #define I2C_OUT         (pm_io_base+0x42)
 32 #define I2C_IN          (pm_io_base+0x44)
 33 #define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */
 34 #define I2C_SDA         0x04
 35 
 36 /* io-region reservation */
 37 #define IOSPACE         0x06
 38 
 39 static struct pci_driver vt586b_driver;
 40 static u16 pm_io_base;
 41 
 42 /*
 43    It does not appear from the datasheet that the GPIO pins are
 44    open drain. So a we set a low value by setting the direction to
 45    output and a high value by setting the direction to input and
 46    relying on the required I2C pullup. The data value is initialized
 47    to 0 in via_init() and never changed.
 48 */
 49 static void bit_via_setscl(void *data, int state)
 50 {
 51         outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
 52 }
 53 
 54 static void bit_via_setsda(void *data, int state)
 55 {
 56         outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
 57 }
 58 
 59 static int bit_via_getscl(void *data)
 60 {
 61         return (0 != (inb(I2C_IN) & I2C_SCL));
 62 }
 63 
 64 static int bit_via_getsda(void *data)
 65 {
 66         return (0 != (inb(I2C_IN) & I2C_SDA));
 67 }
 68 
 69 
 70 static struct i2c_algo_bit_data bit_data = {
 71         .setsda         = bit_via_setsda,
 72         .setscl         = bit_via_setscl,
 73         .getsda         = bit_via_getsda,
 74         .getscl         = bit_via_getscl,
 75         .udelay         = 5,
 76         .timeout        = HZ
 77 };
 78 
 79 static struct i2c_adapter vt586b_adapter = {
 80         .owner          = THIS_MODULE,
 81         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 82         .name           = "VIA i2c",
 83         .algo_data      = &bit_data,
 84 };
 85 
 86 
 87 static const struct pci_device_id vt586b_ids[] = {
 88         { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
 89         { 0, }
 90 };
 91 
 92 MODULE_DEVICE_TABLE (pci, vt586b_ids);
 93 
 94 static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
 95 {
 96         u16 base;
 97         u8 rev;
 98         int res;
 99 
100         if (pm_io_base) {
101                 dev_err(&dev->dev, "i2c-via: Will only support one host\n");
102                 return -ENODEV;
103         }
104 
105         pci_read_config_byte(dev, PM_CFG_REVID, &rev);
106 
107         switch (rev) {
108         case 0x00:
109                 base = PM_CFG_IOBASE0;
110                 break;
111         case 0x01:
112         case 0x10:
113                 base = PM_CFG_IOBASE1;
114                 break;
115 
116         default:
117                 base = PM_CFG_IOBASE1;
118                 /* later revision */
119         }
120 
121         pci_read_config_word(dev, base, &pm_io_base);
122         pm_io_base &= (0xff << 8);
123 
124         if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
125                 dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
126                 return -ENODEV;
127         }
128 
129         outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
130         outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
131 
132         /* set up the sysfs linkage to our parent device */
133         vt586b_adapter.dev.parent = &dev->dev;
134 
135         res = i2c_bit_add_bus(&vt586b_adapter);
136         if ( res < 0 ) {
137                 release_region(I2C_DIR, IOSPACE);
138                 pm_io_base = 0;
139                 return res;
140         }
141         return 0;
142 }
143 
144 static void vt586b_remove(struct pci_dev *dev)
145 {
146         i2c_del_adapter(&vt586b_adapter);
147         release_region(I2C_DIR, IOSPACE);
148         pm_io_base = 0;
149 }
150 
151 
152 static struct pci_driver vt586b_driver = {
153         .name           = "vt586b_smbus",
154         .id_table       = vt586b_ids,
155         .probe          = vt586b_probe,
156         .remove         = vt586b_remove,
157 };
158 
159 module_pci_driver(vt586b_driver);
160 
161 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
162 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
163 MODULE_LICENSE("GPL");
164 

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