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Laurentiu Palcudb23e502014-11-06 15:48:04 +02001/*
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
44struct 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
55static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
56{
Laurentiu Palcudb23e502014-11-06 15:48:04 +020057 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
Octavian Purdila93316422014-11-18 14:57:58 +020069 return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
Laurentiu Palcudb23e502014-11-06 15:48:04 +020070}
71
72static 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
103static 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
142static 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
178static 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
185static const struct i2c_algorithm dln2_i2c_usb_algorithm = {
186 .master_xfer = dln2_i2c_xfer,
187 .functionality = dln2_i2c_func,
188};
189
190static 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
235out_disable:
236 dln2_i2c_enable(dln2, false);
237
238 return ret;
239}
240
241static 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
251static struct platform_driver dln2_i2c_driver = {
252 .driver.name = "dln2-i2c",
253 .probe = dln2_i2c_probe,
254 .remove = dln2_i2c_remove,
255};
256
257module_platform_driver(dln2_i2c_driver);
258
259MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
260MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C master interface");
261MODULE_LICENSE("GPL v2");
262MODULE_ALIAS("platform:dln2-i2c");