1 /*
2  * Copyright (C) 2005-2006 Micronas USA Inc.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License (Version 2) as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  */
13 
14 #include <linux/module.h>
15 #include <linux/delay.h>
16 #include <linux/sched.h>
17 #include <linux/list.h>
18 #include <linux/unistd.h>
19 #include <linux/time.h>
20 #include <linux/device.h>
21 #include <linux/i2c.h>
22 #include <linux/mutex.h>
23 #include <linux/uaccess.h>
24 
25 #include "go7007-priv.h"
26 
27 /********************* Driver for on-board I2C adapter *********************/
28 
29 /* #define GO7007_I2C_DEBUG */
30 
31 #define SPI_I2C_ADDR_BASE		0x1400
32 #define STATUS_REG_ADDR			(SPI_I2C_ADDR_BASE + 0x2)
33 #define I2C_CTRL_REG_ADDR		(SPI_I2C_ADDR_BASE + 0x6)
34 #define I2C_DEV_UP_ADDR_REG_ADDR	(SPI_I2C_ADDR_BASE + 0x7)
35 #define I2C_LO_ADDR_REG_ADDR		(SPI_I2C_ADDR_BASE + 0x8)
36 #define I2C_DATA_REG_ADDR		(SPI_I2C_ADDR_BASE + 0x9)
37 #define I2C_CLKFREQ_REG_ADDR		(SPI_I2C_ADDR_BASE + 0xa)
38 
39 #define I2C_STATE_MASK			0x0007
40 #define I2C_READ_READY_MASK		0x0008
41 
42 /* There is only one I2C port on the TW2804 that feeds all four GO7007 VIPs
43  * on the Adlink PCI-MPG24, so access is shared between all of them. */
44 static DEFINE_MUTEX(adlink_mpg24_i2c_lock);
45 
46 static int go7007_i2c_xfer(struct go7007 *go, u16 addr, int read,
47 		u16 command, int flags, u8 *data)
48 {
49 	int i, ret = -EIO;
50 	u16 val;
51 
52 	if (go->status == STATUS_SHUTDOWN)
53 		return -ENODEV;
54 
55 #ifdef GO7007_I2C_DEBUG
56 	if (read)
57 		dev_dbg(go->dev, "go7007-i2c: reading 0x%02x on 0x%02x\n",
58 			command, addr);
59 	else
60 		dev_dbg(go->dev,
61 			"go7007-i2c: writing 0x%02x to 0x%02x on 0x%02x\n",
62 			*data, command, addr);
63 #endif
64 
65 	mutex_lock(&go->hw_lock);
66 
67 	if (go->board_id == GO7007_BOARDID_ADLINK_MPG24) {
68 		/* Bridge the I2C port on this GO7007 to the shared bus */
69 		mutex_lock(&adlink_mpg24_i2c_lock);
70 		go7007_write_addr(go, 0x3c82, 0x0020);
71 	}
72 
73 	/* Wait for I2C adapter to be ready */
74 	for (i = 0; i < 10; ++i) {
75 		if (go7007_read_addr(go, STATUS_REG_ADDR, &val) < 0)
76 			goto i2c_done;
77 		if (!(val & I2C_STATE_MASK))
78 			break;
79 		msleep(100);
80 	}
81 	if (i == 10) {
82 		dev_err(go->dev, "go7007-i2c: I2C adapter is hung\n");
83 		goto i2c_done;
84 	}
85 
86 	/* Set target register (command) */
87 	go7007_write_addr(go, I2C_CTRL_REG_ADDR, flags);
88 	go7007_write_addr(go, I2C_LO_ADDR_REG_ADDR, command);
89 
90 	/* If we're writing, send the data and target address and we're done */
91 	if (!read) {
92 		go7007_write_addr(go, I2C_DATA_REG_ADDR, *data);
93 		go7007_write_addr(go, I2C_DEV_UP_ADDR_REG_ADDR,
94 					(addr << 9) | (command >> 8));
95 		ret = 0;
96 		goto i2c_done;
97 	}
98 
99 	/* Otherwise, we're reading.  First clear i2c_rx_data_rdy. */
100 	if (go7007_read_addr(go, I2C_DATA_REG_ADDR, &val) < 0)
101 		goto i2c_done;
102 
103 	/* Send the target address plus read flag */
104 	go7007_write_addr(go, I2C_DEV_UP_ADDR_REG_ADDR,
105 			(addr << 9) | 0x0100 | (command >> 8));
106 
107 	/* Wait for i2c_rx_data_rdy */
108 	for (i = 0; i < 10; ++i) {
109 		if (go7007_read_addr(go, STATUS_REG_ADDR, &val) < 0)
110 			goto i2c_done;
111 		if (val & I2C_READ_READY_MASK)
112 			break;
113 		msleep(100);
114 	}
115 	if (i == 10) {
116 		dev_err(go->dev, "go7007-i2c: I2C adapter is hung\n");
117 		goto i2c_done;
118 	}
119 
120 	/* Retrieve the read byte */
121 	if (go7007_read_addr(go, I2C_DATA_REG_ADDR, &val) < 0)
122 		goto i2c_done;
123 	*data = val;
124 	ret = 0;
125 
126 i2c_done:
127 	if (go->board_id == GO7007_BOARDID_ADLINK_MPG24) {
128 		/* Isolate the I2C port on this GO7007 from the shared bus */
129 		go7007_write_addr(go, 0x3c82, 0x0000);
130 		mutex_unlock(&adlink_mpg24_i2c_lock);
131 	}
132 	mutex_unlock(&go->hw_lock);
133 	return ret;
134 }
135 
136 static int go7007_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
137 		unsigned short flags, char read_write,
138 		u8 command, int size, union i2c_smbus_data *data)
139 {
140 	struct go7007 *go = i2c_get_adapdata(adapter);
141 
142 	if (size != I2C_SMBUS_BYTE_DATA)
143 		return -EIO;
144 	return go7007_i2c_xfer(go, addr, read_write == I2C_SMBUS_READ, command,
145 			flags & I2C_CLIENT_SCCB ? 0x10 : 0x00, &data->byte);
146 }
147 
148 /* VERY LIMITED I2C master xfer function -- only needed because the
149  * SMBus functions only support 8-bit commands and the SAA7135 uses
150  * 16-bit commands.  The I2C interface on the GO7007, as limited as
151  * it is, does support this mode. */
152 
153 static int go7007_i2c_master_xfer(struct i2c_adapter *adapter,
154 					struct i2c_msg msgs[], int num)
155 {
156 	struct go7007 *go = i2c_get_adapdata(adapter);
157 	int i;
158 
159 	for (i = 0; i < num; ++i) {
160 		/* We can only do two things here -- write three bytes, or
161 		 * write two bytes and read one byte. */
162 		if (msgs[i].len == 2) {
163 			if (i + 1 == num || msgs[i].addr != msgs[i + 1].addr ||
164 					(msgs[i].flags & I2C_M_RD) ||
165 					!(msgs[i + 1].flags & I2C_M_RD) ||
166 					msgs[i + 1].len != 1)
167 				return -EIO;
168 			if (go7007_i2c_xfer(go, msgs[i].addr, 1,
169 					(msgs[i].buf[0] << 8) | msgs[i].buf[1],
170 					0x01, &msgs[i + 1].buf[0]) < 0)
171 				return -EIO;
172 			++i;
173 		} else if (msgs[i].len == 3) {
174 			if (msgs[i].flags & I2C_M_RD)
175 				return -EIO;
176 			if (msgs[i].len != 3)
177 				return -EIO;
178 			if (go7007_i2c_xfer(go, msgs[i].addr, 0,
179 					(msgs[i].buf[0] << 8) | msgs[i].buf[1],
180 					0x01, &msgs[i].buf[2]) < 0)
181 				return -EIO;
182 		} else
183 			return -EIO;
184 	}
185 
186 	return num;
187 }
188 
189 static u32 go7007_functionality(struct i2c_adapter *adapter)
190 {
191 	return I2C_FUNC_SMBUS_BYTE_DATA;
192 }
193 
194 static const struct i2c_algorithm go7007_algo = {
195 	.smbus_xfer	= go7007_smbus_xfer,
196 	.master_xfer	= go7007_i2c_master_xfer,
197 	.functionality	= go7007_functionality,
198 };
199 
200 static struct i2c_adapter go7007_adap_templ = {
201 	.owner			= THIS_MODULE,
202 	.name			= "WIS GO7007SB",
203 	.algo			= &go7007_algo,
204 };
205 
206 int go7007_i2c_init(struct go7007 *go)
207 {
208 	memcpy(&go->i2c_adapter, &go7007_adap_templ,
209 			sizeof(go7007_adap_templ));
210 	go->i2c_adapter.dev.parent = go->dev;
211 	i2c_set_adapdata(&go->i2c_adapter, go);
212 	if (i2c_add_adapter(&go->i2c_adapter) < 0) {
213 		dev_err(go->dev,
214 			"go7007-i2c: error: i2c_add_adapter failed\n");
215 		return -1;
216 	}
217 	return 0;
218 }
219