kernel/drivers/media/pci/saa7164/saa7164-i2c.c

   1 /*
   2  *  Driver for the NXP SAA7164 PCIe bridge
   3  *
   4  *  Copyright (c) 2010-2015 Steven Toth <stoth@kernellabs.com>
   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  *
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/init.h>
  25 #include <linux/delay.h>
  26 #include <linux/io.h>
  27
  28 #include "saa7164.h"
  29
  30 static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
  31 {
  32         struct saa7164_i2c *bus = i2c_adap->algo_data;
  33         struct saa7164_dev *dev = bus->dev;
  34         int i, retval = 0;
  35
  36         dprintk(DBGLVL_I2C, "%s(num = %d)\n", __func__, num);
  37
  38         for (i = 0 ; i < num; i++) {
  39                 dprintk(DBGLVL_I2C, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
  40                         __func__, num, msgs[i].addr, msgs[i].len);
  41                 if (msgs[i].flags & I2C_M_RD) {
  42                         retval = saa7164_api_i2c_read(bus,
  43                                 msgs[i].addr,
  44                                 0 /* reglen */,
  45                                 NULL /* reg */, msgs[i].len, msgs[i].buf);
  46                 } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
  47                            msgs[i].addr == msgs[i + 1].addr) {
  48                         /* write then read from same address */
  49
  50                         retval = saa7164_api_i2c_read(bus, msgs[i].addr,
  51                                 msgs[i].len, msgs[i].buf,
  52                                 msgs[i+1].len, msgs[i+1].buf
  53                                 );
  54
  55                         i++;
  56
  57                         if (retval < 0)
  58                                 goto err;
  59                 } else {
  60                         /* write */
  61                         retval = saa7164_api_i2c_write(bus, msgs[i].addr,
  62                                 msgs[i].len, msgs[i].buf);
  63                 }
  64                 if (retval < 0)
  65                         goto err;
  66         }
  67         return num;
  68
  69 err:
  70         return retval;
  71 }
  72
  73 static u32 saa7164_functionality(struct i2c_adapter *adap)
  74 {
  75         return I2C_FUNC_I2C;
  76 }
  77
  78 static struct i2c_algorithm saa7164_i2c_algo_template = {
  79         .master_xfer    = i2c_xfer,
  80         .functionality  = saa7164_functionality,
  81 };
  82
  83 /* ----------------------------------------------------------------------- */
  84
  85 static struct i2c_adapter saa7164_i2c_adap_template = {
  86         .name              = "saa7164",
  87         .owner             = THIS_MODULE,
  88         .algo              = &saa7164_i2c_algo_template,
  89 };
  90
  91 static struct i2c_client saa7164_i2c_client_template = {
  92         .name   = "saa7164 internal",
  93 };
  94
  95 int saa7164_i2c_register(struct saa7164_i2c *bus)
  96 {
  97         struct saa7164_dev *dev = bus->dev;
  98
  99         dprintk(DBGLVL_I2C, "%s(bus = %d)\n", __func__, bus->nr);
 100
 101         bus->i2c_adap = saa7164_i2c_adap_template;
 102         bus->i2c_client = saa7164_i2c_client_template;
 103
 104         bus->i2c_adap.dev.parent = &dev->pci->dev;
 105
 106         strlcpy(bus->i2c_adap.name, bus->dev->name,
 107                 sizeof(bus->i2c_adap.name));
 108
 109         bus->i2c_adap.algo_data = bus;
 110         i2c_set_adapdata(&bus->i2c_adap, bus);
 111         i2c_add_adapter(&bus->i2c_adap);
 112
 113         bus->i2c_client.adapter = &bus->i2c_adap;
 114
 115         if (0 != bus->i2c_rc)
 116                 printk(KERN_ERR "%s: i2c bus %d register FAILED\n",
 117                         dev->name, bus->nr);
 118
 119         return bus->i2c_rc;
 120 }
 121
 122 int saa7164_i2c_unregister(struct saa7164_i2c *bus)
 123 {
 124         i2c_del_adapter(&bus->i2c_adap);
 125         return 0;
 126 }