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 struct device *dev = &dln2->adapter.dev; 148 int i; 149 150 for (i = 0; i < num; i++) { 151 int ret; 152 153 pmsg = &msgs[i]; 154 155 if (pmsg->len > DLN2_I2C_MAX_XFER_SIZE) { 156 dev_warn(dev, "maximum transfer size exceeded\n"); 157 return -EOPNOTSUPP; 158 } 159 160 if (pmsg->flags & I2C_M_RD) { 161 ret = dln2_i2c_read(dln2, pmsg->addr, pmsg->buf, 162 pmsg->len); 163 if (ret < 0) 164 return ret; 165 166 pmsg->len = ret; 167 } else { 168 ret = dln2_i2c_write(dln2, pmsg->addr, pmsg->buf, 169 pmsg->len); 170 if (ret != pmsg->len) 171 return -EPROTO; 172 } 173 } 174 175 return num; 176 } 177 178 static u32 dln2_i2c_func(struct i2c_adapter *a) 179 { 180 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA | 181 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | 182 I2C_FUNC_SMBUS_I2C_BLOCK; 183 } 184 185 static const struct i2c_algorithm dln2_i2c_usb_algorithm = { 186 .master_xfer = dln2_i2c_xfer, 187 .functionality = dln2_i2c_func, 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.dev.parent = dev; 213 i2c_set_adapdata(&dln2->adapter, dln2); 214 snprintf(dln2->adapter.name, sizeof(dln2->adapter.name), "%s-%s-%d", 215 "dln2-i2c", dev_name(pdev->dev.parent), dln2->port); 216 217 platform_set_drvdata(pdev, dln2); 218 219 /* initialize the i2c interface */ 220 ret = dln2_i2c_enable(dln2, true); 221 if (ret < 0) { 222 dev_err(dev, "failed to initialize adapter: %d\n", ret); 223 return ret; 224 } 225 226 /* and finally attach to i2c layer */ 227 ret = i2c_add_adapter(&dln2->adapter); 228 if (ret < 0) { 229 dev_err(dev, "failed to add I2C adapter: %d\n", ret); 230 goto out_disable; 231 } 232 233 return 0; 234 235 out_disable: 236 dln2_i2c_enable(dln2, false); 237 238 return ret; 239 } 240 241 static int dln2_i2c_remove(struct platform_device *pdev) 242 { 243 struct dln2_i2c *dln2 = platform_get_drvdata(pdev); 244 245 i2c_del_adapter(&dln2->adapter); 246 dln2_i2c_enable(dln2, false); 247 248 return 0; 249 } 250 251 static struct platform_driver dln2_i2c_driver = { 252 .driver.name = "dln2-i2c", 253 .probe = dln2_i2c_probe, 254 .remove = dln2_i2c_remove, 255 }; 256 257 module_platform_driver(dln2_i2c_driver); 258 259 MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>"); 260 MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C master interface"); 261 MODULE_LICENSE("GPL v2"); 262 MODULE_ALIAS("platform:dln2-i2c"); 263