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kernel/linux-imx6_3.14.28/drivers/i2c/busses/i2c-via.c 4.12 KB
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  /*
      i2c Support for Via Technologies 82C586B South Bridge
  
      Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
  
      This program is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published by
      the Free Software Foundation; either version 2 of the License, or
      (at your option) any later version.
  
      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.
  
      You should have received a copy of the GNU General Public License
      along with this program; if not, write to the Free Software
      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  #include <linux/ioport.h>
  #include <linux/i2c.h>
  #include <linux/i2c-algo-bit.h>
  #include <linux/io.h>
  
  /* Power management registers */
  #define PM_CFG_REVID	0x08	/* silicon revision code */
  #define PM_CFG_IOBASE0	0x20
  #define PM_CFG_IOBASE1	0x48
  
  #define I2C_DIR		(pm_io_base+0x40)
  #define I2C_OUT		(pm_io_base+0x42)
  #define I2C_IN		(pm_io_base+0x44)
  #define I2C_SCL		0x02	/* clock bit in DIR/OUT/IN register */
  #define I2C_SDA		0x04
  
  /* io-region reservation */
  #define IOSPACE		0x06
  
  static struct pci_driver vt586b_driver;
  static u16 pm_io_base;
  
  /*
     It does not appear from the datasheet that the GPIO pins are
     open drain. So a we set a low value by setting the direction to
     output and a high value by setting the direction to input and
     relying on the required I2C pullup. The data value is initialized
     to 0 in via_init() and never changed.
  */
  static void bit_via_setscl(void *data, int state)
  {
  	outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL, I2C_DIR);
  }
  
  static void bit_via_setsda(void *data, int state)
  {
  	outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA, I2C_DIR);
  }
  
  static int bit_via_getscl(void *data)
  {
  	return (0 != (inb(I2C_IN) & I2C_SCL));
  }
  
  static int bit_via_getsda(void *data)
  {
  	return (0 != (inb(I2C_IN) & I2C_SDA));
  }
  
  
  static struct i2c_algo_bit_data bit_data = {
  	.setsda		= bit_via_setsda,
  	.setscl		= bit_via_setscl,
  	.getsda		= bit_via_getsda,
  	.getscl		= bit_via_getscl,
  	.udelay		= 5,
  	.timeout	= HZ
  };
  
  static struct i2c_adapter vt586b_adapter = {
  	.owner		= THIS_MODULE,
  	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
  	.name		= "VIA i2c",
  	.algo_data	= &bit_data,
  };
  
  
  static DEFINE_PCI_DEVICE_TABLE(vt586b_ids) = {
  	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3) },
  	{ 0, }
  };
  
  MODULE_DEVICE_TABLE (pci, vt586b_ids);
  
  static int vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
  {
  	u16 base;
  	u8 rev;
  	int res;
  
  	if (pm_io_base) {
  		dev_err(&dev->dev, "i2c-via: Will only support one host
  ");
  		return -ENODEV;
  	}
  
  	pci_read_config_byte(dev, PM_CFG_REVID, &rev);
  
  	switch (rev) {
  	case 0x00:
  		base = PM_CFG_IOBASE0;
  		break;
  	case 0x01:
  	case 0x10:
  		base = PM_CFG_IOBASE1;
  		break;
  
  	default:
  		base = PM_CFG_IOBASE1;
  		/* later revision */
  	}
  
  	pci_read_config_word(dev, base, &pm_io_base);
  	pm_io_base &= (0xff << 8);
  
  	if (!request_region(I2C_DIR, IOSPACE, vt586b_driver.name)) {
  		dev_err(&dev->dev, "IO 0x%x-0x%x already in use
  ", I2C_DIR, I2C_DIR + IOSPACE);
  		return -ENODEV;
  	}
  
  	outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
  	outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);
  
  	/* set up the sysfs linkage to our parent device */
  	vt586b_adapter.dev.parent = &dev->dev;
  
  	res = i2c_bit_add_bus(&vt586b_adapter);
  	if ( res < 0 ) {
  		release_region(I2C_DIR, IOSPACE);
  		pm_io_base = 0;
  		return res;
  	}
  	return 0;
  }
  
  static void vt586b_remove(struct pci_dev *dev)
  {
  	i2c_del_adapter(&vt586b_adapter);
  	release_region(I2C_DIR, IOSPACE);
  	pm_io_base = 0;
  }
  
  
  static struct pci_driver vt586b_driver = {
  	.name		= "vt586b_smbus",
  	.id_table	= vt586b_ids,
  	.probe		= vt586b_probe,
  	.remove		= vt586b_remove,
  };
  
  module_pci_driver(vt586b_driver);
  
  MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
  MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");
  MODULE_LICENSE("GPL");