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/clk.h>
21 #include <linux/platform_device.h>
22 #include <linux/io.h>
23 #include <mach/hardware.h>
24
25 /*
26 * Poll the i2c status register until the specified bit is set.
27 * Returns 0 if timed out (100 msec).
28 */
poll_status(unsigned long bit)29 static short poll_status(unsigned long bit)
30 {
31 int loop_cntr = 1000;
32
33 if (bit & I2C_STATUS_TFNF) {
34 do {
35 udelay(10);
36 } while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
37 } else {
38 /* RXRDY handler */
39 do {
40 if (readl(I2C_TAR) == I2C_TAR_EEPROM)
41 msleep(20);
42 else
43 udelay(10);
44 } while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
45 }
46
47 return (loop_cntr > 0);
48 }
49
xfer_read(struct i2c_adapter * adap,unsigned char * buf,int length)50 static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
51 {
52 int i2c_reg = *buf;
53
54 /* Read data */
55 while (length--) {
56 if (!poll_status(I2C_STATUS_TFNF)) {
57 dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
58 return -ETIMEDOUT;
59 }
60
61 /* send addr */
62 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
63
64 /* get ready to next write */
65 i2c_reg++;
66
67 /* send read CMD */
68 writel(I2C_DATACMD_READ, I2C_DATACMD);
69
70 /* wait until the Rx FIFO have available */
71 if (!poll_status(I2C_STATUS_RFNE)) {
72 dev_dbg(&adap->dev, "RXRDY timeout\n");
73 return -ETIMEDOUT;
74 }
75
76 /* read the data to buf */
77 *buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
78 buf++;
79 }
80
81 return 0;
82 }
83
xfer_write(struct i2c_adapter * adap,unsigned char * buf,int length)84 static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
85 {
86 int i2c_reg = *buf;
87
88 /* Do nothing but storing the reg_num to a static variable */
89 if (i2c_reg == -1) {
90 printk(KERN_WARNING "Error i2c reg\n");
91 return -ETIMEDOUT;
92 }
93
94 if (length == 1)
95 return 0;
96
97 buf++;
98 length--;
99 while (length--) {
100 /* send addr */
101 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
102
103 /* send write CMD */
104 writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);
105
106 /* wait until the Rx FIFO have available */
107 msleep(20);
108
109 /* read the data to buf */
110 i2c_reg++;
111 buf++;
112 }
113
114 return 0;
115 }
116
117 /*
118 * Generic i2c master transfer entrypoint.
119 *
120 */
puv3_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * pmsg,int num)121 static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
122 int num)
123 {
124 int i, ret;
125 unsigned char swap;
126
127 /* Disable i2c */
128 writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
129
130 /* Set the work mode and speed*/
131 writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);
132
133 writel(pmsg->addr, I2C_TAR);
134
135 /* Enable i2c */
136 writel(I2C_ENABLE_ENABLE, I2C_ENABLE);
137
138 dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);
139
140 for (i = 0; i < num; i++) {
141 dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
142 pmsg->flags & I2C_M_RD ? "read" : "writ",
143 pmsg->len, pmsg->len > 1 ? "s" : "",
144 pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr);
145
146 if (pmsg->len && pmsg->buf) { /* sanity check */
147 if (pmsg->flags & I2C_M_RD)
148 ret = xfer_read(adap, pmsg->buf, pmsg->len);
149 else
150 ret = xfer_write(adap, pmsg->buf, pmsg->len);
151
152 if (ret)
153 return ret;
154
155 }
156 dev_dbg(&adap->dev, "transfer complete\n");
157 pmsg++; /* next message */
158 }
159
160 /* XXX: fixup be16_to_cpu in bq27x00_battery.c */
161 if (pmsg->addr == I2C_TAR_PWIC) {
162 swap = pmsg->buf[0];
163 pmsg->buf[0] = pmsg->buf[1];
164 pmsg->buf[1] = swap;
165 }
166
167 return i;
168 }
169
170 /*
171 * Return list of supported functionality.
172 */
puv3_i2c_func(struct i2c_adapter * adapter)173 static u32 puv3_i2c_func(struct i2c_adapter *adapter)
174 {
175 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
176 }
177
178 static struct i2c_algorithm puv3_i2c_algorithm = {
179 .master_xfer = puv3_i2c_xfer,
180 .functionality = puv3_i2c_func,
181 };
182
183 /*
184 * Main initialization routine.
185 */
puv3_i2c_probe(struct platform_device * pdev)186 static int puv3_i2c_probe(struct platform_device *pdev)
187 {
188 struct i2c_adapter *adapter;
189 struct resource *mem;
190 int rc;
191
192 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
193 if (!mem)
194 return -ENODEV;
195
196 if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
197 return -EBUSY;
198
199 adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
200 if (adapter == NULL) {
201 dev_err(&pdev->dev, "can't allocate interface!\n");
202 rc = -ENOMEM;
203 goto fail_nomem;
204 }
205 snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
206 mem->start);
207 adapter->algo = &puv3_i2c_algorithm;
208 adapter->class = I2C_CLASS_HWMON;
209 adapter->dev.parent = &pdev->dev;
210
211 platform_set_drvdata(pdev, adapter);
212
213 adapter->nr = pdev->id;
214 rc = i2c_add_numbered_adapter(adapter);
215 if (rc) {
216 dev_err(&pdev->dev, "Adapter '%s' registration failed\n",
217 adapter->name);
218 goto fail_add_adapter;
219 }
220
221 dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
222 return 0;
223
224 fail_add_adapter:
225 kfree(adapter);
226 fail_nomem:
227 release_mem_region(mem->start, resource_size(mem));
228
229 return rc;
230 }
231
puv3_i2c_remove(struct platform_device * pdev)232 static int puv3_i2c_remove(struct platform_device *pdev)
233 {
234 struct i2c_adapter *adapter = platform_get_drvdata(pdev);
235 struct resource *mem;
236
237 i2c_del_adapter(adapter);
238
239 put_device(&pdev->dev);
240
241 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
242 release_mem_region(mem->start, resource_size(mem));
243
244 return 0;
245 }
246
247 #ifdef CONFIG_PM_SLEEP
puv3_i2c_suspend(struct device * dev)248 static int puv3_i2c_suspend(struct device *dev)
249 {
250 int poll_count;
251 /* Disable the IIC */
252 writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
253 for (poll_count = 0; poll_count < 50; poll_count++) {
254 if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
255 udelay(25);
256 }
257
258 return 0;
259 }
260
261 static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL);
262 #define PUV3_I2C_PM (&puv3_i2c_pm)
263
264 #else
265 #define PUV3_I2C_PM NULL
266 #endif
267
268 static struct platform_driver puv3_i2c_driver = {
269 .probe = puv3_i2c_probe,
270 .remove = puv3_i2c_remove,
271 .driver = {
272 .name = "PKUnity-v3-I2C",
273 .pm = PUV3_I2C_PM,
274 }
275 };
276
277 module_platform_driver(puv3_i2c_driver);
278
279 MODULE_DESCRIPTION("PKUnity v3 I2C driver");
280 MODULE_LICENSE("GPL v2");
281 MODULE_ALIAS("platform:puv3_i2c");
282