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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 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 interface!\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 	kfree(adapter);
227 fail_nomem:
228 	release_mem_region(mem->start, resource_size(mem));
229 
230 	return rc;
231 }
232 
puv3_i2c_remove(struct platform_device * pdev)233 static int puv3_i2c_remove(struct platform_device *pdev)
234 {
235 	struct i2c_adapter *adapter = platform_get_drvdata(pdev);
236 	struct resource *mem;
237 
238 	i2c_del_adapter(adapter);
239 
240 	put_device(&pdev->dev);
241 
242 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
243 	release_mem_region(mem->start, resource_size(mem));
244 
245 	return 0;
246 }
247 
248 #ifdef CONFIG_PM
puv3_i2c_suspend(struct device * dev)249 static int puv3_i2c_suspend(struct device *dev)
250 {
251 	int poll_count;
252 	/* Disable the IIC */
253 	writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
254 	for (poll_count = 0; poll_count < 50; poll_count++) {
255 		if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
256 			udelay(25);
257 	}
258 
259 	return 0;
260 }
261 
262 static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL);
263 #define PUV3_I2C_PM	(&puv3_i2c_pm)
264 
265 #else
266 #define PUV3_I2C_PM	NULL
267 #endif
268 
269 static struct platform_driver puv3_i2c_driver = {
270 	.probe		= puv3_i2c_probe,
271 	.remove		= puv3_i2c_remove,
272 	.driver		= {
273 		.name	= "PKUnity-v3-I2C",
274 		.owner	= THIS_MODULE,
275 		.pm	= PUV3_I2C_PM,
276 	}
277 };
278 
279 module_platform_driver(puv3_i2c_driver);
280 
281 MODULE_DESCRIPTION("PKUnity v3 I2C driver");
282 MODULE_LICENSE("GPL v2");
283 MODULE_ALIAS("platform:puv3_i2c");
284