1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2006-2007 PA Semi, Inc
4 *
5 * SMBus host driver for PA Semi PWRficient
6 */
7
8 #include <linux/module.h>
9 #include <linux/pci.h>
10 #include <linux/kernel.h>
11 #include <linux/stddef.h>
12 #include <linux/sched.h>
13 #include <linux/i2c.h>
14 #include <linux/delay.h>
15 #include <linux/slab.h>
16 #include <linux/io.h>
17
18 #include "i2c-pasemi-core.h"
19
20 /* Register offsets */
21 #define REG_MTXFIFO 0x00
22 #define REG_MRXFIFO 0x04
23 #define REG_SMSTA 0x14
24 #define REG_CTL 0x1c
25 #define REG_REV 0x28
26
27 /* Register defs */
28 #define MTXFIFO_READ 0x00000400
29 #define MTXFIFO_STOP 0x00000200
30 #define MTXFIFO_START 0x00000100
31 #define MTXFIFO_DATA_M 0x000000ff
32
33 #define MRXFIFO_EMPTY 0x00000100
34 #define MRXFIFO_DATA_M 0x000000ff
35
36 #define SMSTA_XEN 0x08000000
37 #define SMSTA_MTN 0x00200000
38
39 #define CTL_MRR 0x00000400
40 #define CTL_MTR 0x00000200
41 #define CTL_EN 0x00000800
42 #define CTL_CLK_M 0x000000ff
43
reg_write(struct pasemi_smbus * smbus,int reg,int val)44 static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val)
45 {
46 dev_dbg(smbus->dev, "smbus write reg %x val %08x\n", reg, val);
47 iowrite32(val, smbus->ioaddr + reg);
48 }
49
reg_read(struct pasemi_smbus * smbus,int reg)50 static inline int reg_read(struct pasemi_smbus *smbus, int reg)
51 {
52 int ret;
53 ret = ioread32(smbus->ioaddr + reg);
54 dev_dbg(smbus->dev, "smbus read reg %x val %08x\n", reg, ret);
55 return ret;
56 }
57
58 #define TXFIFO_WR(smbus, reg) reg_write((smbus), REG_MTXFIFO, (reg))
59 #define RXFIFO_RD(smbus) reg_read((smbus), REG_MRXFIFO)
60
pasemi_reset(struct pasemi_smbus * smbus)61 static void pasemi_reset(struct pasemi_smbus *smbus)
62 {
63 u32 val = (CTL_MTR | CTL_MRR | (smbus->clk_div & CTL_CLK_M));
64
65 if (smbus->hw_rev >= 6)
66 val |= CTL_EN;
67
68 reg_write(smbus, REG_CTL, val);
69 }
70
pasemi_smb_clear(struct pasemi_smbus * smbus)71 static void pasemi_smb_clear(struct pasemi_smbus *smbus)
72 {
73 unsigned int status;
74
75 status = reg_read(smbus, REG_SMSTA);
76 reg_write(smbus, REG_SMSTA, status);
77 }
78
pasemi_smb_waitready(struct pasemi_smbus * smbus)79 static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
80 {
81 int timeout = 10;
82 unsigned int status;
83
84 status = reg_read(smbus, REG_SMSTA);
85
86 while (!(status & SMSTA_XEN) && timeout--) {
87 msleep(1);
88 status = reg_read(smbus, REG_SMSTA);
89 }
90
91 /* Got NACK? */
92 if (status & SMSTA_MTN)
93 return -ENXIO;
94
95 if (timeout < 0) {
96 dev_warn(smbus->dev, "Timeout, status 0x%08x\n", status);
97 reg_write(smbus, REG_SMSTA, status);
98 return -ETIME;
99 }
100
101 /* Clear XEN */
102 reg_write(smbus, REG_SMSTA, SMSTA_XEN);
103
104 return 0;
105 }
106
pasemi_i2c_xfer_msg(struct i2c_adapter * adapter,struct i2c_msg * msg,int stop)107 static int pasemi_i2c_xfer_msg(struct i2c_adapter *adapter,
108 struct i2c_msg *msg, int stop)
109 {
110 struct pasemi_smbus *smbus = adapter->algo_data;
111 int read, i, err;
112 u32 rd;
113
114 read = msg->flags & I2C_M_RD ? 1 : 0;
115
116 TXFIFO_WR(smbus, MTXFIFO_START | i2c_8bit_addr_from_msg(msg));
117
118 if (read) {
119 TXFIFO_WR(smbus, msg->len | MTXFIFO_READ |
120 (stop ? MTXFIFO_STOP : 0));
121
122 err = pasemi_smb_waitready(smbus);
123 if (err)
124 goto reset_out;
125
126 for (i = 0; i < msg->len; i++) {
127 rd = RXFIFO_RD(smbus);
128 if (rd & MRXFIFO_EMPTY) {
129 err = -ENODATA;
130 goto reset_out;
131 }
132 msg->buf[i] = rd & MRXFIFO_DATA_M;
133 }
134 } else {
135 for (i = 0; i < msg->len - 1; i++)
136 TXFIFO_WR(smbus, msg->buf[i]);
137
138 TXFIFO_WR(smbus, msg->buf[msg->len-1] |
139 (stop ? MTXFIFO_STOP : 0));
140
141 if (stop) {
142 err = pasemi_smb_waitready(smbus);
143 if (err)
144 goto reset_out;
145 }
146 }
147
148 return 0;
149
150 reset_out:
151 pasemi_reset(smbus);
152 return err;
153 }
154
pasemi_i2c_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int num)155 static int pasemi_i2c_xfer(struct i2c_adapter *adapter,
156 struct i2c_msg *msgs, int num)
157 {
158 struct pasemi_smbus *smbus = adapter->algo_data;
159 int ret, i;
160
161 pasemi_smb_clear(smbus);
162
163 ret = 0;
164
165 for (i = 0; i < num && !ret; i++)
166 ret = pasemi_i2c_xfer_msg(adapter, &msgs[i], (i == (num - 1)));
167
168 return ret ? ret : num;
169 }
170
pasemi_smb_xfer(struct i2c_adapter * adapter,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)171 static int pasemi_smb_xfer(struct i2c_adapter *adapter,
172 u16 addr, unsigned short flags, char read_write, u8 command,
173 int size, union i2c_smbus_data *data)
174 {
175 struct pasemi_smbus *smbus = adapter->algo_data;
176 unsigned int rd;
177 int read_flag, err;
178 int len = 0, i;
179
180 /* All our ops take 8-bit shifted addresses */
181 addr <<= 1;
182 read_flag = read_write == I2C_SMBUS_READ;
183
184 pasemi_smb_clear(smbus);
185
186 switch (size) {
187 case I2C_SMBUS_QUICK:
188 TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START |
189 MTXFIFO_STOP);
190 break;
191 case I2C_SMBUS_BYTE:
192 TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START);
193 if (read_write)
194 TXFIFO_WR(smbus, 1 | MTXFIFO_STOP | MTXFIFO_READ);
195 else
196 TXFIFO_WR(smbus, MTXFIFO_STOP | command);
197 break;
198 case I2C_SMBUS_BYTE_DATA:
199 TXFIFO_WR(smbus, addr | MTXFIFO_START);
200 TXFIFO_WR(smbus, command);
201 if (read_write) {
202 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
203 TXFIFO_WR(smbus, 1 | MTXFIFO_READ | MTXFIFO_STOP);
204 } else {
205 TXFIFO_WR(smbus, MTXFIFO_STOP | data->byte);
206 }
207 break;
208 case I2C_SMBUS_WORD_DATA:
209 TXFIFO_WR(smbus, addr | MTXFIFO_START);
210 TXFIFO_WR(smbus, command);
211 if (read_write) {
212 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
213 TXFIFO_WR(smbus, 2 | MTXFIFO_READ | MTXFIFO_STOP);
214 } else {
215 TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
216 TXFIFO_WR(smbus, MTXFIFO_STOP | (data->word >> 8));
217 }
218 break;
219 case I2C_SMBUS_BLOCK_DATA:
220 TXFIFO_WR(smbus, addr | MTXFIFO_START);
221 TXFIFO_WR(smbus, command);
222 if (read_write) {
223 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
224 TXFIFO_WR(smbus, 1 | MTXFIFO_READ);
225 rd = RXFIFO_RD(smbus);
226 len = min_t(u8, (rd & MRXFIFO_DATA_M),
227 I2C_SMBUS_BLOCK_MAX);
228 TXFIFO_WR(smbus, len | MTXFIFO_READ |
229 MTXFIFO_STOP);
230 } else {
231 len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX);
232 TXFIFO_WR(smbus, len);
233 for (i = 1; i < len; i++)
234 TXFIFO_WR(smbus, data->block[i]);
235 TXFIFO_WR(smbus, data->block[len] | MTXFIFO_STOP);
236 }
237 break;
238 case I2C_SMBUS_PROC_CALL:
239 read_write = I2C_SMBUS_READ;
240 TXFIFO_WR(smbus, addr | MTXFIFO_START);
241 TXFIFO_WR(smbus, command);
242 TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
243 TXFIFO_WR(smbus, (data->word >> 8) & MTXFIFO_DATA_M);
244 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
245 TXFIFO_WR(smbus, 2 | MTXFIFO_STOP | MTXFIFO_READ);
246 break;
247 case I2C_SMBUS_BLOCK_PROC_CALL:
248 len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX - 1);
249 read_write = I2C_SMBUS_READ;
250 TXFIFO_WR(smbus, addr | MTXFIFO_START);
251 TXFIFO_WR(smbus, command);
252 TXFIFO_WR(smbus, len);
253 for (i = 1; i <= len; i++)
254 TXFIFO_WR(smbus, data->block[i]);
255 TXFIFO_WR(smbus, addr | I2C_SMBUS_READ);
256 TXFIFO_WR(smbus, MTXFIFO_READ | 1);
257 rd = RXFIFO_RD(smbus);
258 len = min_t(u8, (rd & MRXFIFO_DATA_M),
259 I2C_SMBUS_BLOCK_MAX - len);
260 TXFIFO_WR(smbus, len | MTXFIFO_READ | MTXFIFO_STOP);
261 break;
262
263 default:
264 dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
265 return -EINVAL;
266 }
267
268 err = pasemi_smb_waitready(smbus);
269 if (err)
270 goto reset_out;
271
272 if (read_write == I2C_SMBUS_WRITE)
273 return 0;
274
275 switch (size) {
276 case I2C_SMBUS_BYTE:
277 case I2C_SMBUS_BYTE_DATA:
278 rd = RXFIFO_RD(smbus);
279 if (rd & MRXFIFO_EMPTY) {
280 err = -ENODATA;
281 goto reset_out;
282 }
283 data->byte = rd & MRXFIFO_DATA_M;
284 break;
285 case I2C_SMBUS_WORD_DATA:
286 case I2C_SMBUS_PROC_CALL:
287 rd = RXFIFO_RD(smbus);
288 if (rd & MRXFIFO_EMPTY) {
289 err = -ENODATA;
290 goto reset_out;
291 }
292 data->word = rd & MRXFIFO_DATA_M;
293 rd = RXFIFO_RD(smbus);
294 if (rd & MRXFIFO_EMPTY) {
295 err = -ENODATA;
296 goto reset_out;
297 }
298 data->word |= (rd & MRXFIFO_DATA_M) << 8;
299 break;
300 case I2C_SMBUS_BLOCK_DATA:
301 case I2C_SMBUS_BLOCK_PROC_CALL:
302 data->block[0] = len;
303 for (i = 1; i <= len; i ++) {
304 rd = RXFIFO_RD(smbus);
305 if (rd & MRXFIFO_EMPTY) {
306 err = -ENODATA;
307 goto reset_out;
308 }
309 data->block[i] = rd & MRXFIFO_DATA_M;
310 }
311 break;
312 }
313
314 return 0;
315
316 reset_out:
317 pasemi_reset(smbus);
318 return err;
319 }
320
pasemi_smb_func(struct i2c_adapter * adapter)321 static u32 pasemi_smb_func(struct i2c_adapter *adapter)
322 {
323 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
324 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
325 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL |
326 I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_I2C;
327 }
328
329 static const struct i2c_algorithm smbus_algorithm = {
330 .master_xfer = pasemi_i2c_xfer,
331 .smbus_xfer = pasemi_smb_xfer,
332 .functionality = pasemi_smb_func,
333 };
334
pasemi_i2c_common_probe(struct pasemi_smbus * smbus)335 int pasemi_i2c_common_probe(struct pasemi_smbus *smbus)
336 {
337 int error;
338
339 smbus->adapter.owner = THIS_MODULE;
340 snprintf(smbus->adapter.name, sizeof(smbus->adapter.name),
341 "PA Semi SMBus adapter (%s)", dev_name(smbus->dev));
342 smbus->adapter.algo = &smbus_algorithm;
343 smbus->adapter.algo_data = smbus;
344
345 /* set up the sysfs linkage to our parent device */
346 smbus->adapter.dev.parent = smbus->dev;
347
348 if (smbus->hw_rev != PASEMI_HW_REV_PCI)
349 smbus->hw_rev = reg_read(smbus, REG_REV);
350
351 pasemi_reset(smbus);
352
353 error = devm_i2c_add_adapter(smbus->dev, &smbus->adapter);
354 if (error)
355 return error;
356
357 return 0;
358 }
359