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         u16 cmd;
  58         struct {
  59                 u8 port;
  60         } tx;
  61
  62         tx.port = dln2->port;
  63
  64         if (enable)
  65                 cmd = DLN2_I2C_ENABLE;
  66         else
  67                 cmd = DLN2_I2C_DISABLE;
  68
  69         return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
  70 }
  71
  72 static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
  73                           u8 *data, u16 data_len)
  74 {
  75         int ret;
  76         struct {
  77                 u8 port;
  78                 u8 addr;
  79                 u8 mem_addr_len;
  80                 __le32 mem_addr;
  81                 __le16 buf_len;
  82                 u8 buf[DLN2_I2C_MAX_XFER_SIZE];
  83         } __packed *tx = dln2->buf;
  84         unsigned len;
  85
  86         BUILD_BUG_ON(sizeof(*tx) > DLN2_I2C_BUF_SIZE);
  87
  88         tx->port = dln2->port;
  89         tx->addr = addr;
  90         tx->mem_addr_len = 0;
  91         tx->mem_addr = 0;
  92         tx->buf_len = cpu_to_le16(data_len);
  93         memcpy(tx->buf, data, data_len);
  94
  95         len = sizeof(*tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;
  96         ret = dln2_transfer_tx(dln2->pdev, DLN2_I2C_WRITE, tx, len);
  97         if (ret < 0)
  98                 return ret;
  99
 100         return data_len;
 101 }
 102
 103 static int dln2_i2c_read(struct dln2_i2c *dln2, u16 addr, u8 *data,
 104                          u16 data_len)
 105 {
 106         int ret;
 107         struct {
 108                 u8 port;
 109                 u8 addr;
 110                 u8 mem_addr_len;
 111                 __le32 mem_addr;
 112                 __le16 buf_len;
 113         } __packed tx;
 114         struct {
 115                 __le16 buf_len;
 116                 u8 buf[DLN2_I2C_MAX_XFER_SIZE];
 117         } __packed *rx = dln2->buf;
 118         unsigned rx_len = sizeof(*rx);
 119
 120         BUILD_BUG_ON(sizeof(*rx) > DLN2_I2C_BUF_SIZE);
 121
 122         tx.port = dln2->port;
 123         tx.addr = addr;
 124         tx.mem_addr_len = 0;
 125         tx.mem_addr = 0;
 126         tx.buf_len = cpu_to_le16(data_len);
 127
 128         ret = dln2_transfer(dln2->pdev, DLN2_I2C_READ, &tx, sizeof(tx),
 129                             rx, &rx_len);
 130         if (ret < 0)
 131                 return ret;
 132         if (rx_len < sizeof(rx->buf_len) + data_len)
 133                 return -EPROTO;
 134         if (le16_to_cpu(rx->buf_len) != data_len)
 135                 return -EPROTO;
 136
 137         memcpy(data, rx->buf, data_len);
 138
 139         return data_len;
 140 }
 141
 142 static int dln2_i2c_xfer(struct i2c_adapter *adapter,
 143                          struct i2c_msg *msgs, int num)
 144 {
 145         struct dln2_i2c *dln2 = i2c_get_adapdata(adapter);
 146         struct i2c_msg *pmsg;
 147         int i;
 148
 149         for (i = 0; i < num; i++) {
 150                 int ret;
 151
 152                 pmsg = &msgs[i];
 153
 154                 if (pmsg->flags & I2C_M_RD) {
 155                         ret = dln2_i2c_read(dln2, pmsg->addr, pmsg->buf,
 156                                             pmsg->len);
 157                         if (ret < 0)
 158                                 return ret;
 159
 160                         pmsg->len = ret;
 161                 } else {
 162                         ret = dln2_i2c_write(dln2, pmsg->addr, pmsg->buf,
 163                                              pmsg->len);
 164                         if (ret != pmsg->len)
 165                                 return -EPROTO;
 166                 }
 167         }
 168
 169         return num;
 170 }
 171
 172 static u32 dln2_i2c_func(struct i2c_adapter *a)
 173 {
 174         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
 175                 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
 176                 I2C_FUNC_SMBUS_I2C_BLOCK;
 177 }
 178
 179 static const struct i2c_algorithm dln2_i2c_usb_algorithm = {
 180         .master_xfer = dln2_i2c_xfer,
 181         .functionality = dln2_i2c_func,
 182 };
 183
 184 static struct i2c_adapter_quirks dln2_i2c_quirks = {
 185         .max_read_len = DLN2_I2C_MAX_XFER_SIZE,
 186         .max_write_len = DLN2_I2C_MAX_XFER_SIZE,
 187 };
 188
 189 static int dln2_i2c_probe(struct platform_device *pdev)
 190 {
 191         int ret;
 192         struct dln2_i2c *dln2;
 193         struct device *dev = &pdev->dev;
 194         struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
 195
 196         dln2 = devm_kzalloc(dev, sizeof(*dln2), GFP_KERNEL);
 197         if (!dln2)
 198                 return -ENOMEM;
 199
 200         dln2->buf = devm_kmalloc(dev, DLN2_I2C_BUF_SIZE, GFP_KERNEL);
 201         if (!dln2->buf)
 202                 return -ENOMEM;
 203
 204         dln2->pdev = pdev;
 205         dln2->port = pdata->port;
 206
 207         /* setup i2c adapter description */
 208         dln2->adapter.owner = THIS_MODULE;
 209         dln2->adapter.class = I2C_CLASS_HWMON;
 210         dln2->adapter.algo = &dln2_i2c_usb_algorithm;
 211         dln2->adapter.quirks = &dln2_i2c_quirks;
 212         dln2->adapter.dev.parent = dev;
 213         dln2->adapter.dev.of_node = dev->of_node;
 214         i2c_set_adapdata(&dln2->adapter, dln2);
 215         snprintf(dln2->adapter.name, sizeof(dln2->adapter.name), "%s-%s-%d",
 216                  "dln2-i2c", dev_name(pdev->dev.parent), dln2->port);
 217
 218         platform_set_drvdata(pdev, dln2);
 219
 220         /* initialize the i2c interface */
 221         ret = dln2_i2c_enable(dln2, true);
 222         if (ret < 0) {
 223                 dev_err(dev, "failed to initialize adapter: %d\n", ret);
 224                 return ret;
 225         }
 226
 227         /* and finally attach to i2c layer */
 228         ret = i2c_add_adapter(&dln2->adapter);
 229         if (ret < 0) {
 230                 dev_err(dev, "failed to add I2C adapter: %d\n", ret);
 231                 goto out_disable;
 232         }
 233
 234         return 0;
 235
 236 out_disable:
 237         dln2_i2c_enable(dln2, false);
 238
 239         return ret;
 240 }
 241
 242 static int dln2_i2c_remove(struct platform_device *pdev)
 243 {
 244         struct dln2_i2c *dln2 = platform_get_drvdata(pdev);
 245
 246         i2c_del_adapter(&dln2->adapter);
 247         dln2_i2c_enable(dln2, false);
 248
 249         return 0;
 250 }
 251
 252 static struct platform_driver dln2_i2c_driver = {
 253         .driver.name    = "dln2-i2c",
 254         .probe          = dln2_i2c_probe,
 255         .remove         = dln2_i2c_remove,
 256 };
 257
 258 module_platform_driver(dln2_i2c_driver);
 259
 260 MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
 261 MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C master interface");
 262 MODULE_LICENSE("GPL v2");
 263 MODULE_ALIAS("platform:dln2-i2c");