text: /*
      i2c Support for Apple SMU Controller
  
      Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
                         <benh@kernel.crashing.org>
  
      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/module.h>
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/i2c.h>
  #include <linux/init.h>
  #include <linux/device.h>
  #include <linux/platform_device.h>
  #include <asm/prom.h>
  #include <asm/pmac_low_i2c.h>
  
  MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
  MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
  MODULE_LICENSE("GPL");
  
  /*
   * SMBUS-type transfer entrypoint
   */
  static s32 i2c_powermac_smbus_xfer(	struct i2c_adapter*	adap,
  					u16			addr,
  					unsigned short		flags,
  					char			read_write,
  					u8			command,
  					int			size,
  					union i2c_smbus_data*	data)
  {
  	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adap);
  	int			rc = 0;
  	int			read = (read_write == I2C_SMBUS_READ);
  	int			addrdir = (addr << 1) | read;
  	u8			local[2];
  
  	rc = pmac_i2c_open(bus, 0);
  	if (rc)
  		return rc;
  
  	switch (size) {
          case I2C_SMBUS_QUICK:
  		rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
  		if (rc)
  			goto bail;
  		rc = pmac_i2c_xfer(bus, addrdir, 0, 0, NULL, 0);
  	    	break;
          case I2C_SMBUS_BYTE:
  		rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
  		if (rc)
  			goto bail;
  		rc = pmac_i2c_xfer(bus, addrdir, 0, 0, &data->byte, 1);
  	    	break;
          case I2C_SMBUS_BYTE_DATA:
  		rc = pmac_i2c_setmode(bus, read ?
  				      pmac_i2c_mode_combined :
  				      pmac_i2c_mode_stdsub);
  		if (rc)
  			goto bail;
  		rc = pmac_i2c_xfer(bus, addrdir, 1, command, &data->byte, 1);
  	    	break;
          case I2C_SMBUS_WORD_DATA:
  		rc = pmac_i2c_setmode(bus, read ?
  				      pmac_i2c_mode_combined :
  				      pmac_i2c_mode_stdsub);
  		if (rc)
  			goto bail;
  		if (!read) {
  			local[0] = data->word & 0xff;
  			local[1] = (data->word >> 8) & 0xff;
  		}
  		rc = pmac_i2c_xfer(bus, addrdir, 1, command, local, 2);
  		if (rc == 0 && read) {
  			data->word = ((u16)local[1]) << 8;
  			data->word |= local[0];
  		}
  	    	break;
  
  	/* Note that these are broken vs. the expected smbus API where
  	 * on reads, the length is actually returned from the function,
  	 * but I think the current API makes no sense and I don't want
  	 * any driver that I haven't verified for correctness to go
  	 * anywhere near a pmac i2c bus anyway ...
  	 *
  	 * I'm also not completely sure what kind of phases to do between
  	 * the actual command and the data (what I am _supposed_ to do that
  	 * is). For now, I assume writes are a single stream and reads have
  	 * a repeat start/addr phase (but not stop in between)
  	 */
          case I2C_SMBUS_BLOCK_DATA:
  		rc = pmac_i2c_setmode(bus, read ?
  				      pmac_i2c_mode_combined :
  				      pmac_i2c_mode_stdsub);
  		if (rc)
  			goto bail;
  		rc = pmac_i2c_xfer(bus, addrdir, 1, command, data->block,
  				   data->block[0] + 1);
  
  		break;
  	case I2C_SMBUS_I2C_BLOCK_DATA:
  		rc = pmac_i2c_setmode(bus, read ?
  				      pmac_i2c_mode_combined :
  				      pmac_i2c_mode_stdsub);
  		if (rc)
  			goto bail;
  		rc = pmac_i2c_xfer(bus, addrdir, 1, command,
  				   &data->block[1], data->block[0]);
  		break;
  
          default:
  	    	rc = -EINVAL;
  	}
   bail:
  	pmac_i2c_close(bus);
  	return rc;
  }
  
  /*
   * Generic i2c master transfer entrypoint. This driver only support single
   * messages (for "lame i2c" transfers). Anything else should use the smbus
   * entry point
   */
  static int i2c_powermac_master_xfer(	struct i2c_adapter *adap,
  					struct i2c_msg *msgs,
  					int num)
  {
  	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adap);
  	int			rc = 0;
  	int			read;
  	int			addrdir;
  
  	if (msgs->flags & I2C_M_TEN)
  		return -EINVAL;
  	read = (msgs->flags & I2C_M_RD) != 0;
  	addrdir = (msgs->addr << 1) | read;
  	if (msgs->flags & I2C_M_REV_DIR_ADDR)
  		addrdir ^= 1;
  
  	rc = pmac_i2c_open(bus, 0);
  	if (rc)
  		return rc;
  	rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
  	if (rc)
  		goto bail;
  	rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
   bail:
  	pmac_i2c_close(bus);
  	return rc < 0 ? rc : 1;
  }
  
  static u32 i2c_powermac_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_BLOCK_DATA | I2C_FUNC_I2C;
  }
  
  /* For now, we only handle smbus */
  static const struct i2c_algorithm i2c_powermac_algorithm = {
  	.smbus_xfer	= i2c_powermac_smbus_xfer,
  	.master_xfer	= i2c_powermac_master_xfer,
  	.functionality	= i2c_powermac_func,
  };
  
  
  static int i2c_powermac_remove(struct platform_device *dev)
  {
  	struct i2c_adapter	*adapter = platform_get_drvdata(dev);
  	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adapter);
  	int			rc;
  
  	rc = i2c_del_adapter(adapter);
  	pmac_i2c_detach_adapter(bus, adapter);
  	i2c_set_adapdata(adapter, NULL);
  	/* We aren't that prepared to deal with this... */
  	if (rc)
  		printk("i2c-powermac.c: Failed to remove bus %s !\n",
  		       adapter->name);
  	platform_set_drvdata(dev, NULL);
  	kfree(adapter);
  
  	return 0;
  }
  
  
  static int __devexit i2c_powermac_probe(struct platform_device *dev)
  {
  	struct pmac_i2c_bus *bus = dev->dev.platform_data;
  	struct device_node *parent = NULL;
  	struct i2c_adapter *adapter;
  	char name[32];
  	const char *basename;
  	int rc;
  
  	if (bus == NULL)
  		return -EINVAL;
  
  	/* Ok, now we need to make up a name for the interface that will
  	 * match what we used to do in the past, that is basically the
  	 * controller's parent device node for keywest. PMU didn't have a
  	 * naming convention and SMU has a different one
  	 */
  	switch(pmac_i2c_get_type(bus)) {
  	case pmac_i2c_bus_keywest:
  		parent = of_get_parent(pmac_i2c_get_controller(bus));
  		if (parent == NULL)
  			return -EINVAL;
  		basename = parent->name;
  		break;
  	case pmac_i2c_bus_pmu:
  		basename = "pmu";
  		break;
  	case pmac_i2c_bus_smu:
  		/* This is not what we used to do but I'm fixing drivers at
  		 * the same time as this change
  		 */
  		basename = "smu";
  		break;
  	default:
  		return -EINVAL;
  	}
  	snprintf(name, 32, "%s %d", basename, pmac_i2c_get_channel(bus));
  	of_node_put(parent);
  
  	adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
  	if (adapter == NULL) {
  		printk(KERN_ERR "i2c-powermac: can't allocate inteface !\n");
  		return -ENOMEM;
  	}
  	platform_set_drvdata(dev, adapter);
  	strcpy(adapter->name, name);
  	adapter->algo = &i2c_powermac_algorithm;
  	i2c_set_adapdata(adapter, bus);
  	adapter->dev.parent = &dev->dev;
  	pmac_i2c_attach_adapter(bus, adapter);
  	rc = i2c_add_adapter(adapter);
  	if (rc) {
  		printk(KERN_ERR "i2c-powermac: Adapter %s registration "
  		       "failed\n", name);
  		i2c_set_adapdata(adapter, NULL);
  		pmac_i2c_detach_adapter(bus, adapter);
  	}
  
  	printk(KERN_INFO "PowerMac i2c bus %s registered\n", name);
  	return rc;
  }
  
  
  static struct platform_driver i2c_powermac_driver = {
  	.probe = i2c_powermac_probe,
  	.remove = __devexit_p(i2c_powermac_remove),
  	.driver = {
  		.name = "i2c-powermac",
  		.bus = &platform_bus_type,
  	},
  };
  
  static int __init i2c_powermac_init(void)
  {
  	platform_driver_register(&i2c_powermac_driver);
  	return 0;
  }
  
  
  static void __exit i2c_powermac_cleanup(void)
  {
  	platform_driver_unregister(&i2c_powermac_driver);
  }
  
  module_init(i2c_powermac_init);
  module_exit(i2c_powermac_cleanup);
  