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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     You should have received a copy of the GNU General Public License
 17     along with this program; if not, write to the Free Software
 18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 19 */
 20 
 21 #include <linux/kernel.h>
 22 #include <linux/module.h>
 23 #include <linux/pci.h>
 24 #include <linux/ioport.h>
 25 #include <linux/i2c.h>
 26 #include <linux/i2c-algo-bit.h>
 27 #include <linux/io.h>
 28 
 29 /* Power management registers */
 30 #define PM_CFG_REVID    0x08    /* silicon revision code */
 31 #define PM_CFG_IOBASE0  0x20
 32 #define PM_CFG_IOBASE1  0x48
 33 
 34 #define I2C_DIR         (pm_io_base+0x40)
 35 #define I2C_OUT         (pm_io_base+0x42)
 36 #define I2C_IN          (pm_io_base+0x44)
 37 #define I2C_SCL         0x02    /* clock bit in DIR/OUT/IN register */
 38 #define I2C_SDA         0x04
 39 
 40 /* io-region reservation */
 41 #define IOSPACE         0x06
 42 
 43 static struct pci_driver vt586b_driver;
 44 static u16 pm_io_base;
 45 
 46 /*
 47    It does not appear from the datasheet that the GPIO pins are
 48    open drain. So a we set a low value by setting the direction to
 49    output and a high value by setting the direction to input and
 50    relying on the required I2C pullup. The data value is initialized
 51    to 0 in via_init() and never changed.
 52 */
 53 static void bit_via_setscl(void *data, int state)
 54 {
 55         outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
 56 }
 57 
 58 static void bit_via_setsda(void *data, int state)
 59 {
 60         outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
 61 }
 62 
 63 static int bit_via_getscl(void *data)
 64 {
 65         return (0 != (inb(I2C_IN) & I2C_SCL));
 66 }
 67 
 68 static int bit_via_getsda(void *data)
 69 {
 70         return (0 != (inb(I2C_IN) & I2C_SDA));
 71 }
 72 
 73 
 74 static struct i2c_algo_bit_data bit_data = {
 75         .setsda         = bit_via_setsda,
 76         .setscl         = bit_via_setscl,
 77         .getsda         = bit_via_getsda,
 78         .getscl         = bit_via_getscl,
 79         .udelay         = 5,
 80         .timeout        = HZ
 81 };
 82 
 83 static struct i2c_adapter vt586b_adapter = {
 84         .owner          = THIS_MODULE,
 85         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 86         .name           = "VIA i2c",
 87         .algo_data      = &bit_data,
 88 };
 89 
 90 
 91 static const struct pci_device_id vt586b_ids[] = {
 92         { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
 93         { 0, }
 94 };
 95 
 96 MODULE_DEVICE_TABLE (pci, vt586b_ids);
 97 
 98 static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
 99 {
100         u16 base;
101         u8 rev;
102         int res;
103 
104         if (pm_io_base) {
105                 dev_err(&dev->dev, "i2c-via: Will only support one host\n");
106                 return -ENODEV;
107         }
108 
109         pci_read_config_byte(dev, PM_CFG_REVID, &rev);
110 
111         switch (rev) {
112         case 0x00:
113                 base = PM_CFG_IOBASE0;
114                 break;
115         case 0x01:
116         case 0x10:
117                 base = PM_CFG_IOBASE1;
118                 break;
119 
120         default:
121                 base = PM_CFG_IOBASE1;
122                 /* later revision */
123         }
124 
125         pci_read_config_word(dev, base, &pm_io_base);
126         pm_io_base &= (0xff << 8);
127 
128         if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
129                 dev_err(&dev->dev, "IO 0x%x-0x%x already in use\n", I2C_DIR, I2C_DIR + IOSPACE);
130                 return -ENODEV;
131         }
132 
133         outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
134         outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
135 
136         /* set up the sysfs linkage to our parent device */
137         vt586b_adapter.dev.parent = &dev->dev;
138 
139         res = i2c_bit_add_bus(&vt586b_adapter);
140         if ( res < 0 ) {
141                 release_region(I2C_DIR, IOSPACE);
142                 pm_io_base = 0;
143                 return res;
144         }
145         return 0;
146 }
147 
148 static void vt586b_remove(struct pci_dev *dev)
149 {
150         i2c_del_adapter(&vt586b_adapter);
151         release_region(I2C_DIR, IOSPACE);
152         pm_io_base = 0;
153 }
154 
155 
156 static struct pci_driver vt586b_driver = {
157         .name           = "vt586b_smbus",
158         .id_table       = vt586b_ids,
159         .probe          = vt586b_probe,
160         .remove         = vt586b_remove,
161 };
162 
163 module_pci_driver(vt586b_driver);
164 
165 MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
166 MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
167 MODULE_LICENSE("GPL");
168 

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