1 /*
2 * I2C driver for PKUnity-v3 SoC
3 * Code specific to PKUnity SoC and UniCore ISA
4 *
5 * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
6 * Copyright (C) 2001-2010 Guan Xuetao
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/err.h>
16 #include <linux/slab.h>
17 #include <linux/types.h>
18 #include <linux/delay.h>
19 #include <linux/i2c.h>
20 #include <linux/init.h>
21 #include <linux/clk.h>
22 #include <linux/platform_device.h>
23 #include <linux/io.h>
24 #include <mach/hardware.h>
25
26 /*
27 * Poll the i2c status register until the specified bit is set.
28 * Returns 0 if timed out (100 msec).
29 */
poll_status(unsigned long bit)30 static short poll_status(unsigned long bit)
31 {
32 int loop_cntr = 1000;
33
34 if (bit & I2C_STATUS_TFNF) {
35 do {
36 udelay(10);
37 } while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
38 } else {
39 /* RXRDY handler */
40 do {
41 if (readl(I2C_TAR) == I2C_TAR_EEPROM)
42 msleep(20);
43 else
44 udelay(10);
45 } while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
46 }
47
48 return (loop_cntr > 0);
49 }
50
xfer_read(struct i2c_adapter * adap,unsigned char * buf,int length)51 static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
52 {
53 int i2c_reg = *buf;
54
55 /* Read data */
56 while (length--) {
57 if (!poll_status(I2C_STATUS_TFNF)) {
58 dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
59 return -ETIMEDOUT;
60 }
61
62 /* send addr */
63 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
64
65 /* get ready to next write */
66 i2c_reg++;
67
68 /* send read CMD */
69 writel(I2C_DATACMD_READ, I2C_DATACMD);
70
71 /* wait until the Rx FIFO have available */
72 if (!poll_status(I2C_STATUS_RFNE)) {
73 dev_dbg(&adap->dev, "RXRDY timeout\n");
74 return -ETIMEDOUT;
75 }
76
77 /* read the data to buf */
78 *buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
79 buf++;
80 }
81
82 return 0;
83 }
84
xfer_write(struct i2c_adapter * adap,unsigned char * buf,int length)85 static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
86 {
87 int i2c_reg = *buf;
88
89 /* Do nothing but storing the reg_num to a static variable */
90 if (i2c_reg == -1) {
91 printk(KERN_WARNING "Error i2c reg\n");
92 return -ETIMEDOUT;
93 }
94
95 if (length == 1)
96 return 0;
97
98 buf++;
99 length--;
100 while (length--) {
101 /* send addr */
102 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
103
104 /* send write CMD */
105 writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);
106
107 /* wait until the Rx FIFO have available */
108 msleep(20);
109
110 /* read the data to buf */
111 i2c_reg++;
112 buf++;
113 }
114
115 return 0;
116 }
117
118 /*
119 * Generic i2c master transfer entrypoint.
120 *
121 */
puv3_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * pmsg,int num)122 static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
123 int num)
124 {
125 int i, ret;
126 unsigned char swap;
127
128 /* Disable i2c */
129 writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
130
131 /* Set the work mode and speed*/
132 writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);
133
134 writel(pmsg->addr, I2C_TAR);
135
136 /* Enable i2c */
137 writel(I2C_ENABLE_ENABLE, I2C_ENABLE);
138
139 dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);
140
141 for (i = 0; i < num; i++) {
142 dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
143 pmsg->flags & I2C_M_RD ? "read" : "writ",
144 pmsg->len, pmsg->len > 1 ? "s" : "",
145 pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr);
146
147 if (pmsg->len && pmsg->buf) { /* sanity check */
148 if (pmsg->flags & I2C_M_RD)
149 ret = xfer_read(adap, pmsg->buf, pmsg->len);
150 else
151 ret = xfer_write(adap, pmsg->buf, pmsg->len);
152
153 if (ret)
154 return ret;
155
156 }
157 dev_dbg(&adap->dev, "transfer complete\n");
158 pmsg++; /* next message */
159 }
160
161 /* XXX: fixup be16_to_cpu in bq27x00_battery.c */
162 if (pmsg->addr == I2C_TAR_PWIC) {
163 swap = pmsg->buf[0];
164 pmsg->buf[0] = pmsg->buf[1];
165 pmsg->buf[1] = swap;
166 }
167
168 return i;
169 }
170
171 /*
172 * Return list of supported functionality.
173 */
puv3_i2c_func(struct i2c_adapter * adapter)174 static u32 puv3_i2c_func(struct i2c_adapter *adapter)
175 {
176 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
177 }
178
179 static struct i2c_algorithm puv3_i2c_algorithm = {
180 .master_xfer = puv3_i2c_xfer,
181 .functionality = puv3_i2c_func,
182 };
183
184 /*
185 * Main initialization routine.
186 */
puv3_i2c_probe(struct platform_device * pdev)187 static int __devinit puv3_i2c_probe(struct platform_device *pdev)
188 {
189 struct i2c_adapter *adapter;
190 struct resource *mem;
191 int rc;
192
193 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
194 if (!mem)
195 return -ENODEV;
196
197 if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
198 return -EBUSY;
199
200 adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
201 if (adapter == NULL) {
202 dev_err(&pdev->dev, "can't allocate inteface!\n");
203 rc = -ENOMEM;
204 goto fail_nomem;
205 }
206 snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
207 mem->start);
208 adapter->algo = &puv3_i2c_algorithm;
209 adapter->class = I2C_CLASS_HWMON;
210 adapter->dev.parent = &pdev->dev;
211
212 platform_set_drvdata(pdev, adapter);
213
214 adapter->nr = pdev->id;
215 rc = i2c_add_numbered_adapter(adapter);
216 if (rc) {
217 dev_err(&pdev->dev, "Adapter '%s' registration failed\n",
218 adapter->name);
219 goto fail_add_adapter;
220 }
221
222 dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
223 return 0;
224
225 fail_add_adapter:
226 platform_set_drvdata(pdev, NULL);
227 kfree(adapter);
228 fail_nomem:
229 release_mem_region(mem->start, resource_size(mem));
230
231 return rc;
232 }
233
puv3_i2c_remove(struct platform_device * pdev)234 static int __devexit puv3_i2c_remove(struct platform_device *pdev)
235 {
236 struct i2c_adapter *adapter = platform_get_drvdata(pdev);
237 struct resource *mem;
238 int rc;
239
240 rc = i2c_del_adapter(adapter);
241 if (rc) {
242 dev_err(&pdev->dev, "Adapter '%s' delete fail\n",
243 adapter->name);
244 return rc;
245 }
246
247 put_device(&pdev->dev);
248 platform_set_drvdata(pdev, NULL);
249
250 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
251 release_mem_region(mem->start, resource_size(mem));
252
253 return rc;
254 }
255
256 #ifdef CONFIG_PM
puv3_i2c_suspend(struct platform_device * dev,pm_message_t state)257 static int puv3_i2c_suspend(struct platform_device *dev, pm_message_t state)
258 {
259 int poll_count;
260 /* Disable the IIC */
261 writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
262 for (poll_count = 0; poll_count < 50; poll_count++) {
263 if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
264 udelay(25);
265 }
266
267 return 0;
268 }
269
puv3_i2c_resume(struct platform_device * dev)270 static int puv3_i2c_resume(struct platform_device *dev)
271 {
272 return 0 ;
273 }
274 #else
275 #define puv3_i2c_suspend NULL
276 #define puv3_i2c_resume NULL
277 #endif
278
279 static struct platform_driver puv3_i2c_driver = {
280 .probe = puv3_i2c_probe,
281 .remove = __devexit_p(puv3_i2c_remove),
282 .suspend = puv3_i2c_suspend,
283 .resume = puv3_i2c_resume,
284 .driver = {
285 .name = "PKUnity-v3-I2C",
286 .owner = THIS_MODULE,
287 }
288 };
289
290 module_platform_driver(puv3_i2c_driver);
291
292 MODULE_DESCRIPTION("PKUnity v3 I2C driver");
293 MODULE_LICENSE("GPL v2");
294 MODULE_ALIAS("platform:puv3_i2c");
295