drivers/i2c/busses/i2c-dln2.c

   1 /*
   2  * Driver for the Diolan DLN-2 USB-I2C adapter
   3  *
   4  * Copyright (c) 2014 Intel Corporation
   5  *
   6  * Derived from:
   7  *  i2c-diolan-u2c.c
   8  *  Copyright (c) 2010-2011 Ericsson AB
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation, version 2.
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/types.h>
  18 #include <linux/slab.h>
  19 #include <linux/i2c.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mfd/dln2.h>
  22
  23 #define DLN2_I2C_MODULE_ID              0x03
  24 #define DLN2_I2C_CMD(cmd)               DLN2_CMD(cmd, DLN2_I2C_MODULE_ID)
  25
  26 /* I2C commands */
  27 #define DLN2_I2C_GET_PORT_COUNT         DLN2_I2C_CMD(0x00)
  28 #define DLN2_I2C_ENABLE                 DLN2_I2C_CMD(0x01)
  29 #define DLN2_I2C_DISABLE                DLN2_I2C_CMD(0x02)
  30 #define DLN2_I2C_IS_ENABLED             DLN2_I2C_CMD(0x03)
  31 #define DLN2_I2C_WRITE                  DLN2_I2C_CMD(0x06)
  32 #define DLN2_I2C_READ                   DLN2_I2C_CMD(0x07)
  33 #define DLN2_I2C_SCAN_DEVICES           DLN2_I2C_CMD(0x08)
  34 #define DLN2_I2C_PULLUP_ENABLE          DLN2_I2C_CMD(0x09)
  35 #define DLN2_I2C_PULLUP_DISABLE         DLN2_I2C_CMD(0x0A)
  36 #define DLN2_I2C_PULLUP_IS_ENABLED      DLN2_I2C_CMD(0x0B)
  37 #define DLN2_I2C_TRANSFER               DLN2_I2C_CMD(0x0C)
  38 #define DLN2_I2C_SET_MAX_REPLY_COUNT    DLN2_I2C_CMD(0x0D)
  39 #define DLN2_I2C_GET_MAX_REPLY_COUNT    DLN2_I2C_CMD(0x0E)
  40
  41 #define DLN2_I2C_MAX_XFER_SIZE          256
  42 #define DLN2_I2C_BUF_SIZE               (DLN2_I2C_MAX_XFER_SIZE + 16)
  43
  44 struct dln2_i2c {
  45         struct platform_device *pdev;
  46         struct i2c_adapter adapter;
  47         u8 port;
  48         /*
  49          * Buffer to hold the packet for read or write transfers. One is enough
  50          * since we can't have multiple transfers in parallel on the i2c bus.
  51          */
  52         void *buf;
  53 };
  54
  55 static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
  56 {
  57         int ret;
  58         u16 cmd;
  59         struct {
  60                 u8 port;
  61         } tx;
  62
  63         tx.port = dln2->port;
  64
  65         if (enable)
  66                 cmd = DLN2_I2C_ENABLE;
  67         else
  68                 cmd = DLN2_I2C_DISABLE;
  69
  70         ret = dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
  71         if (ret < 0)
  72                 return ret;
  73
  74         return 0;
  75 }
  76
  77 static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
  78                           u8 *data, u16 data_len)
  79 {
  80         int ret;
  81         struct {
  82                 u8 port;
  83                 u8 addr;
  84                 u8 mem_addr_len;
  85                 __le32 mem_addr;
  86                 __le16 buf_len;
  87                 u8 buf[DLN2_I2C_MAX_XFER_SIZE];
  88         } __packed *tx = dln2->buf;
  89         unsigned len;
  90
  91         BUILD_BUG_ON(sizeof(*tx) > DLN2_I2C_BUF_SIZE);
  92
  93         tx->port = dln2->port;
  94         tx->addr = addr;
  95         tx->mem_addr_len = 0;
  96         tx->mem_addr = 0;
  97         tx->buf_len = cpu_to_le16(data_len);
  98         memcpy(tx->buf, data, data_len);
  99
 100         len = sizeof(*tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;
 101         ret = dln2_transfer_tx(dln2->pdev, DLN2_I2C_WRITE, tx, len);
 102         if (ret < 0)
 103                 return ret;
 104
 105         return data_len;
 106 }
 107
 108 static int dln2_i2c_read(struct dln2_i2c *dln2, u16 addr, u8 *data,
 109                          u16 data_len)
 110 {
 111         int ret;
 112         struct {
 113                 u8 port;
 114                 u8 addr;
 115                 u8 mem_addr_len;
 116                 __le32 mem_addr;
 117                 __le16 buf_len;
 118         } __packed tx;
 119         struct {
 120                 __le16 buf_len;
 121                 u8 buf[DLN2_I2C_MAX_XFER_SIZE];
 122         } __packed *rx = dln2->buf;
 123         unsigned rx_len = sizeof(*rx);
 124
 125         BUILD_BUG_ON(sizeof(*rx) > DLN2_I2C_BUF_SIZE);
 126
 127         tx.port = dln2->port;
 128         tx.addr = addr;
 129         tx.mem_addr_len = 0;
 130         tx.mem_addr = 0;
 131         tx.buf_len = cpu_to_le16(data_len);
 132
 133         ret = dln2_transfer(dln2->pdev, DLN2_I2C_READ, &tx, sizeof(tx),
 134                             rx, &rx_len);
 135         if (ret < 0)
 136                 return ret;
 137         if (rx_len < sizeof(rx->buf_len) + data_len)
 138                 return -EPROTO;
 139         if (le16_to_cpu(rx->buf_len) != data_len)
 140                 return -EPROTO;
 141
 142         memcpy(data, rx->buf, data_len);
 143
 144         return data_len;
 145 }
 146
 147 static int dln2_i2c_xfer(struct i2c_adapter *adapter,
 148                          struct i2c_msg *msgs, int num)
 149 {
 150         struct dln2_i2c *dln2 = i2c_get_adapdata(adapter);
 151         struct i2c_msg *pmsg;
 152         struct device *dev = &dln2->adapter.dev;
 153         int i;
 154
 155         for (i = 0; i < num; i++) {
 156                 int ret;
 157
 158                 pmsg = &msgs[i];
 159
 160                 if (pmsg->len > DLN2_I2C_MAX_XFER_SIZE) {
 161                         dev_warn(dev, "maximum transfer size exceeded\n");
 162                         return -EOPNOTSUPP;
 163                 }
 164
 165                 if (pmsg->flags & I2C_M_RD) {
 166                         ret = dln2_i2c_read(dln2, pmsg->addr, pmsg->buf,
 167                                             pmsg->len);
 168                         if (ret < 0)
 169                                 return ret;
 170
 171                         pmsg->len = ret;
 172                 } else {
 173                         ret = dln2_i2c_write(dln2, pmsg->addr, pmsg->buf,
 174                                              pmsg->len);
 175                         if (ret != pmsg->len)
 176                                 return -EPROTO;
 177                 }
 178         }
 179
 180         return num;
 181 }
 182
 183 static u32 dln2_i2c_func(struct i2c_adapter *a)
 184 {
 185         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
 186                 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
 187                 I2C_FUNC_SMBUS_I2C_BLOCK;
 188 }
 189
 190 static const struct i2c_algorithm dln2_i2c_usb_algorithm = {
 191         .master_xfer = dln2_i2c_xfer,
 192         .functionality = dln2_i2c_func,
 193 };
 194
 195 static int dln2_i2c_probe(struct platform_device *pdev)
 196 {
 197         int ret;
 198         struct dln2_i2c *dln2;
 199         struct device *dev = &pdev->dev;
 200         struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
 201
 202         dln2 = devm_kzalloc(dev, sizeof(*dln2), GFP_KERNEL);
 203         if (!dln2)
 204                 return -ENOMEM;
 205
 206         dln2->buf = devm_kmalloc(dev, DLN2_I2C_BUF_SIZE, GFP_KERNEL);
 207         if (!dln2->buf)
 208                 return -ENOMEM;
 209
 210         dln2->pdev = pdev;
 211         dln2->port = pdata->port;
 212
 213         /* setup i2c adapter description */
 214         dln2->adapter.owner = THIS_MODULE;
 215         dln2->adapter.class = I2C_CLASS_HWMON;
 216         dln2->adapter.algo = &dln2_i2c_usb_algorithm;
 217         dln2->adapter.dev.parent = dev;
 218         i2c_set_adapdata(&dln2->adapter, dln2);
 219         snprintf(dln2->adapter.name, sizeof(dln2->adapter.name), "%s-%s-%d",
 220                  "dln2-i2c", dev_name(pdev->dev.parent), dln2->port);
 221
 222         platform_set_drvdata(pdev, dln2);
 223
 224         /* initialize the i2c interface */
 225         ret = dln2_i2c_enable(dln2, true);
 226         if (ret < 0) {
 227                 dev_err(dev, "failed to initialize adapter: %d\n", ret);
 228                 return ret;
 229         }
 230
 231         /* and finally attach to i2c layer */
 232         ret = i2c_add_adapter(&dln2->adapter);
 233         if (ret < 0) {
 234                 dev_err(dev, "failed to add I2C adapter: %d\n", ret);
 235                 goto out_disable;
 236         }
 237
 238         return 0;
 239
 240 out_disable:
 241         dln2_i2c_enable(dln2, false);
 242
 243         return ret;
 244 }
 245
 246 static int dln2_i2c_remove(struct platform_device *pdev)
 247 {
 248         struct dln2_i2c *dln2 = platform_get_drvdata(pdev);
 249
 250         i2c_del_adapter(&dln2->adapter);
 251         dln2_i2c_enable(dln2, false);
 252
 253         return 0;
 254 }
 255
 256 static struct platform_driver dln2_i2c_driver = {
 257         .driver.name    = "dln2-i2c",
 258         .probe          = dln2_i2c_probe,
 259         .remove         = dln2_i2c_remove,
 260 };
 261
 262 module_platform_driver(dln2_i2c_driver);
 263
 264 MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
 265 MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C master interface");
 266 MODULE_LICENSE("GPL v2");
 267 MODULE_ALIAS("platform:dln2-i2c");