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"); 266