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 #include <linux/acpi.h>
  23
  24 #define DLN2_I2C_MODULE_ID              0x03
  25 #define DLN2_I2C_CMD(cmd)               DLN2_CMD(cmd, DLN2_I2C_MODULE_ID)
  26
  27 /* I2C commands */
  28 #define DLN2_I2C_GET_PORT_COUNT         DLN2_I2C_CMD(0x00)
  29 #define DLN2_I2C_ENABLE                 DLN2_I2C_CMD(0x01)
  30 #define DLN2_I2C_DISABLE                DLN2_I2C_CMD(0x02)
  31 #define DLN2_I2C_IS_ENABLED             DLN2_I2C_CMD(0x03)
  32 #define DLN2_I2C_WRITE                  DLN2_I2C_CMD(0x06)
  33 #define DLN2_I2C_READ                   DLN2_I2C_CMD(0x07)
  34 #define DLN2_I2C_SCAN_DEVICES           DLN2_I2C_CMD(0x08)
  35 #define DLN2_I2C_PULLUP_ENABLE          DLN2_I2C_CMD(0x09)
  36 #define DLN2_I2C_PULLUP_DISABLE         DLN2_I2C_CMD(0x0A)
  37 #define DLN2_I2C_PULLUP_IS_ENABLED      DLN2_I2C_CMD(0x0B)
  38 #define DLN2_I2C_TRANSFER               DLN2_I2C_CMD(0x0C)
  39 #define DLN2_I2C_SET_MAX_REPLY_COUNT    DLN2_I2C_CMD(0x0D)
  40 #define DLN2_I2C_GET_MAX_REPLY_COUNT    DLN2_I2C_CMD(0x0E)
  41
  42 #define DLN2_I2C_MAX_XFER_SIZE          256
  43 #define DLN2_I2C_BUF_SIZE               (DLN2_I2C_MAX_XFER_SIZE + 16)
  44
  45 struct dln2_i2c {
  46         struct platform_device *pdev;
  47         struct i2c_adapter adapter;
  48         u8 port;
  49         /*
  50          * Buffer to hold the packet for read or write transfers. One is enough
  51          * since we can't have multiple transfers in parallel on the i2c bus.
  52          */
  53         void *buf;
  54 };
  55
  56 static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
  57 {
  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         return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
  71 }
  72
  73 static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
  74                           u8 *data, u16 data_len)
  75 {
  76         int ret;
  77         struct {
  78                 u8 port;
  79                 u8 addr;
  80                 u8 mem_addr_len;
  81                 __le32 mem_addr;
  82                 __le16 buf_len;
  83                 u8 buf[DLN2_I2C_MAX_XFER_SIZE];
  84         } __packed *tx = dln2->buf;
  85         unsigned len;
  86
  87         BUILD_BUG_ON(sizeof(*tx) > DLN2_I2C_BUF_SIZE);
  88
  89         tx->port = dln2->port;
  90         tx->addr = addr;
  91         tx->mem_addr_len = 0;
  92         tx->mem_addr = 0;
  93         tx->buf_len = cpu_to_le16(data_len);
  94         memcpy(tx->buf, data, data_len);
  95
  96         len = sizeof(*tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;
  97         ret = dln2_transfer_tx(dln2->pdev, DLN2_I2C_WRITE, tx, len);
  98         if (ret < 0)
  99                 return ret;
 100
 101         return data_len;
 102 }
 103
 104 static int dln2_i2c_read(struct dln2_i2c *dln2, u16 addr, u8 *data,
 105                          u16 data_len)
 106 {
 107         int ret;
 108         struct {
 109                 u8 port;
 110                 u8 addr;
 111                 u8 mem_addr_len;
 112                 __le32 mem_addr;
 113                 __le16 buf_len;
 114         } __packed tx;
 115         struct {
 116                 __le16 buf_len;
 117                 u8 buf[DLN2_I2C_MAX_XFER_SIZE];
 118         } __packed *rx = dln2->buf;
 119         unsigned rx_len = sizeof(*rx);
 120
 121         BUILD_BUG_ON(sizeof(*rx) > DLN2_I2C_BUF_SIZE);
 122
 123         tx.port = dln2->port;
 124         tx.addr = addr;
 125         tx.mem_addr_len = 0;
 126         tx.mem_addr = 0;
 127         tx.buf_len = cpu_to_le16(data_len);
 128
 129         ret = dln2_transfer(dln2->pdev, DLN2_I2C_READ, &tx, sizeof(tx),
 130                             rx, &rx_len);
 131         if (ret < 0)
 132                 return ret;
 133         if (rx_len < sizeof(rx->buf_len) + data_len)
 134                 return -EPROTO;
 135         if (le16_to_cpu(rx->buf_len) != data_len)
 136                 return -EPROTO;
 137
 138         memcpy(data, rx->buf, data_len);
 139
 140         return data_len;
 141 }
 142
 143 static int dln2_i2c_xfer(struct i2c_adapter *adapter,
 144                          struct i2c_msg *msgs, int num)
 145 {
 146         struct dln2_i2c *dln2 = i2c_get_adapdata(adapter);
 147         struct i2c_msg *pmsg;
 148         int i;
 149
 150         for (i = 0; i < num; i++) {
 151                 int ret;
 152
 153                 pmsg = &msgs[i];
 154
 155                 if (pmsg->flags & I2C_M_RD) {
 156                         ret = dln2_i2c_read(dln2, pmsg->addr, pmsg->buf,
 157                                             pmsg->len);
 158                         if (ret < 0)
 159                                 return ret;
 160
 161                         pmsg->len = ret;
 162                 } else {
 163                         ret = dln2_i2c_write(dln2, pmsg->addr, pmsg->buf,
 164                                              pmsg->len);
 165                         if (ret != pmsg->len)
 166                                 return -EPROTO;
 167                 }
 168         }
 169
 170         return num;
 171 }
 172
 173 static u32 dln2_i2c_func(struct i2c_adapter *a)
 174 {
 175         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
 176                 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
 177                 I2C_FUNC_SMBUS_I2C_BLOCK;
 178 }
 179
 180 static const struct i2c_algorithm dln2_i2c_usb_algorithm = {
 181         .master_xfer = dln2_i2c_xfer,
 182         .functionality = dln2_i2c_func,
 183 };
 184
 185 static struct i2c_adapter_quirks dln2_i2c_quirks = {
 186         .max_read_len = DLN2_I2C_MAX_XFER_SIZE,
 187         .max_write_len = DLN2_I2C_MAX_XFER_SIZE,
 188 };
 189
 190 static int dln2_i2c_probe(struct platform_device *pdev)
 191 {
 192         int ret;
 193         struct dln2_i2c *dln2;
 194         struct device *dev = &pdev->dev;
 195         struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
 196
 197         dln2 = devm_kzalloc(dev, sizeof(*dln2), GFP_KERNEL);
 198         if (!dln2)
 199                 return -ENOMEM;
 200
 201         dln2->buf = devm_kmalloc(dev, DLN2_I2C_BUF_SIZE, GFP_KERNEL);
 202         if (!dln2->buf)
 203                 return -ENOMEM;
 204
 205         dln2->pdev = pdev;
 206         dln2->port = pdata->port;
 207
 208         /* setup i2c adapter description */
 209         dln2->adapter.owner = THIS_MODULE;
 210         dln2->adapter.class = I2C_CLASS_HWMON;
 211         dln2->adapter.algo = &dln2_i2c_usb_algorithm;
 212         dln2->adapter.quirks = &dln2_i2c_quirks;
 213         dln2->adapter.dev.parent = dev;
 214         ACPI_COMPANION_SET(&dln2->adapter.dev, ACPI_COMPANION(&pdev->dev));
 215         dln2->adapter.dev.of_node = dev->of_node;
 216         i2c_set_adapdata(&dln2->adapter, dln2);
 217         snprintf(dln2->adapter.name, sizeof(dln2->adapter.name), "%s-%s-%d",
 218                  "dln2-i2c", dev_name(pdev->dev.parent), dln2->port);
 219
 220         platform_set_drvdata(pdev, dln2);
 221
 222         /* initialize the i2c interface */
 223         ret = dln2_i2c_enable(dln2, true);
 224         if (ret < 0) {
 225                 dev_err(dev, "failed to initialize adapter: %d\n", ret);
 226                 return ret;
 227         }
 228
 229         /* and finally attach to i2c layer */
 230         ret = i2c_add_adapter(&dln2->adapter);
 231         if (ret < 0) {
 232                 dev_err(dev, "failed to add I2C adapter: %d\n", ret);
 233                 goto out_disable;
 234         }
 235
 236         return 0;
 237
 238 out_disable:
 239         dln2_i2c_enable(dln2, false);
 240
 241         return ret;
 242 }
 243
 244 static int dln2_i2c_remove(struct platform_device *pdev)
 245 {
 246         struct dln2_i2c *dln2 = platform_get_drvdata(pdev);
 247
 248         i2c_del_adapter(&dln2->adapter);
 249         dln2_i2c_enable(dln2, false);
 250
 251         return 0;
 252 }
 253
 254 static struct platform_driver dln2_i2c_driver = {
 255         .driver.name    = "dln2-i2c",
 256         .probe          = dln2_i2c_probe,
 257         .remove         = dln2_i2c_remove,
 258 };
 259
 260 module_platform_driver(dln2_i2c_driver);
 261
 262 MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
 263 MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C master interface");
 264 MODULE_LICENSE("GPL v2");
 265 MODULE_ALIAS("platform:dln2-i2c");