1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for the Diolan DLN-2 USB-I2C adapter
4 *
5 * Copyright (c) 2014 Intel Corporation
6 *
7 * Derived from:
8 * i2c-diolan-u2c.c
9 * Copyright (c) 2010-2011 Ericsson AB
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/types.h>
15 #include <linux/slab.h>
16 #include <linux/i2c.h>
17 #include <linux/platform_device.h>
18 #include <linux/mfd/dln2.h>
19 #include <linux/acpi.h>
20
21 #define DLN2_I2C_MODULE_ID 0x03
22 #define DLN2_I2C_CMD(cmd) DLN2_CMD(cmd, DLN2_I2C_MODULE_ID)
23
24 /* I2C commands */
25 #define DLN2_I2C_GET_PORT_COUNT DLN2_I2C_CMD(0x00)
26 #define DLN2_I2C_ENABLE DLN2_I2C_CMD(0x01)
27 #define DLN2_I2C_DISABLE DLN2_I2C_CMD(0x02)
28 #define DLN2_I2C_IS_ENABLED DLN2_I2C_CMD(0x03)
29 #define DLN2_I2C_WRITE DLN2_I2C_CMD(0x06)
30 #define DLN2_I2C_READ DLN2_I2C_CMD(0x07)
31 #define DLN2_I2C_SCAN_DEVICES DLN2_I2C_CMD(0x08)
32 #define DLN2_I2C_PULLUP_ENABLE DLN2_I2C_CMD(0x09)
33 #define DLN2_I2C_PULLUP_DISABLE DLN2_I2C_CMD(0x0A)
34 #define DLN2_I2C_PULLUP_IS_ENABLED DLN2_I2C_CMD(0x0B)
35 #define DLN2_I2C_TRANSFER DLN2_I2C_CMD(0x0C)
36 #define DLN2_I2C_SET_MAX_REPLY_COUNT DLN2_I2C_CMD(0x0D)
37 #define DLN2_I2C_GET_MAX_REPLY_COUNT DLN2_I2C_CMD(0x0E)
38
39 #define DLN2_I2C_MAX_XFER_SIZE 256
40 #define DLN2_I2C_BUF_SIZE (DLN2_I2C_MAX_XFER_SIZE + 16)
41
42 struct dln2_i2c {
43 struct platform_device *pdev;
44 struct i2c_adapter adapter;
45 u8 port;
46 /*
47 * Buffer to hold the packet for read or write transfers. One is enough
48 * since we can't have multiple transfers in parallel on the i2c bus.
49 */
50 void *buf;
51 };
52
dln2_i2c_enable(struct dln2_i2c * dln2,bool enable)53 static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
54 {
55 u16 cmd;
56 struct {
57 u8 port;
58 } tx;
59
60 tx.port = dln2->port;
61
62 if (enable)
63 cmd = DLN2_I2C_ENABLE;
64 else
65 cmd = DLN2_I2C_DISABLE;
66
67 return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
68 }
69
dln2_i2c_write(struct dln2_i2c * dln2,u8 addr,u8 * data,u16 data_len)70 static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
71 u8 *data, u16 data_len)
72 {
73 int ret;
74 struct {
75 u8 port;
76 u8 addr;
77 u8 mem_addr_len;
78 __le32 mem_addr;
79 __le16 buf_len;
80 u8 buf[DLN2_I2C_MAX_XFER_SIZE];
81 } __packed *tx = dln2->buf;
82 unsigned len;
83
84 BUILD_BUG_ON(sizeof(*tx) > DLN2_I2C_BUF_SIZE);
85
86 tx->port = dln2->port;
87 tx->addr = addr;
88 tx->mem_addr_len = 0;
89 tx->mem_addr = 0;
90 tx->buf_len = cpu_to_le16(data_len);
91 memcpy(tx->buf, data, data_len);
92
93 len = sizeof(*tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;
94 ret = dln2_transfer_tx(dln2->pdev, DLN2_I2C_WRITE, tx, len);
95 if (ret < 0)
96 return ret;
97
98 return data_len;
99 }
100
dln2_i2c_read(struct dln2_i2c * dln2,u16 addr,u8 * data,u16 data_len)101 static int dln2_i2c_read(struct dln2_i2c *dln2, u16 addr, u8 *data,
102 u16 data_len)
103 {
104 int ret;
105 struct {
106 u8 port;
107 u8 addr;
108 u8 mem_addr_len;
109 __le32 mem_addr;
110 __le16 buf_len;
111 } __packed tx;
112 struct {
113 __le16 buf_len;
114 u8 buf[DLN2_I2C_MAX_XFER_SIZE];
115 } __packed *rx = dln2->buf;
116 unsigned rx_len = sizeof(*rx);
117
118 BUILD_BUG_ON(sizeof(*rx) > DLN2_I2C_BUF_SIZE);
119
120 tx.port = dln2->port;
121 tx.addr = addr;
122 tx.mem_addr_len = 0;
123 tx.mem_addr = 0;
124 tx.buf_len = cpu_to_le16(data_len);
125
126 ret = dln2_transfer(dln2->pdev, DLN2_I2C_READ, &tx, sizeof(tx),
127 rx, &rx_len);
128 if (ret < 0)
129 return ret;
130 if (rx_len < sizeof(rx->buf_len) + data_len)
131 return -EPROTO;
132 if (le16_to_cpu(rx->buf_len) != data_len)
133 return -EPROTO;
134
135 memcpy(data, rx->buf, data_len);
136
137 return data_len;
138 }
139
dln2_i2c_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int num)140 static int dln2_i2c_xfer(struct i2c_adapter *adapter,
141 struct i2c_msg *msgs, int num)
142 {
143 struct dln2_i2c *dln2 = i2c_get_adapdata(adapter);
144 struct i2c_msg *pmsg;
145 int i;
146
147 for (i = 0; i < num; i++) {
148 int ret;
149
150 pmsg = &msgs[i];
151
152 if (pmsg->flags & I2C_M_RD) {
153 ret = dln2_i2c_read(dln2, pmsg->addr, pmsg->buf,
154 pmsg->len);
155 if (ret < 0)
156 return ret;
157
158 pmsg->len = ret;
159 } else {
160 ret = dln2_i2c_write(dln2, pmsg->addr, pmsg->buf,
161 pmsg->len);
162 if (ret != pmsg->len)
163 return -EPROTO;
164 }
165 }
166
167 return num;
168 }
169
dln2_i2c_func(struct i2c_adapter * a)170 static u32 dln2_i2c_func(struct i2c_adapter *a)
171 {
172 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
173 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
174 I2C_FUNC_SMBUS_I2C_BLOCK;
175 }
176
177 static const struct i2c_algorithm dln2_i2c_usb_algorithm = {
178 .xfer = dln2_i2c_xfer,
179 .functionality = dln2_i2c_func,
180 };
181
182 static const struct i2c_adapter_quirks dln2_i2c_quirks = {
183 .max_read_len = DLN2_I2C_MAX_XFER_SIZE,
184 .max_write_len = DLN2_I2C_MAX_XFER_SIZE,
185 };
186
dln2_i2c_probe(struct platform_device * pdev)187 static int dln2_i2c_probe(struct platform_device *pdev)
188 {
189 int ret;
190 struct dln2_i2c *dln2;
191 struct device *dev = &pdev->dev;
192 struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
193
194 dln2 = devm_kzalloc(dev, sizeof(*dln2), GFP_KERNEL);
195 if (!dln2)
196 return -ENOMEM;
197
198 dln2->buf = devm_kmalloc(dev, DLN2_I2C_BUF_SIZE, GFP_KERNEL);
199 if (!dln2->buf)
200 return -ENOMEM;
201
202 dln2->pdev = pdev;
203 dln2->port = pdata->port;
204
205 /* setup i2c adapter description */
206 dln2->adapter.owner = THIS_MODULE;
207 dln2->adapter.class = I2C_CLASS_HWMON;
208 dln2->adapter.algo = &dln2_i2c_usb_algorithm;
209 dln2->adapter.quirks = &dln2_i2c_quirks;
210 dln2->adapter.dev.parent = dev;
211 ACPI_COMPANION_SET(&dln2->adapter.dev, ACPI_COMPANION(&pdev->dev));
212 dln2->adapter.dev.of_node = dev->of_node;
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 return dev_err_probe(dev, ret, "failed to initialize adapter\n");
223
224 /* and finally attach to i2c layer */
225 ret = i2c_add_adapter(&dln2->adapter);
226 if (ret < 0)
227 goto out_disable;
228
229 return 0;
230
231 out_disable:
232 dln2_i2c_enable(dln2, false);
233
234 return ret;
235 }
236
dln2_i2c_remove(struct platform_device * pdev)237 static void dln2_i2c_remove(struct platform_device *pdev)
238 {
239 struct dln2_i2c *dln2 = platform_get_drvdata(pdev);
240
241 i2c_del_adapter(&dln2->adapter);
242 dln2_i2c_enable(dln2, false);
243 }
244
245 static struct platform_driver dln2_i2c_driver = {
246 .driver.name = "dln2-i2c",
247 .probe = dln2_i2c_probe,
248 .remove_new = dln2_i2c_remove,
249 };
250
251 module_platform_driver(dln2_i2c_driver);
252
253 MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
254 MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C controller interface");
255 MODULE_LICENSE("GPL v2");
256 MODULE_ALIAS("platform:dln2-i2c");
257