1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * I2C driver for PKUnity-v3 SoC
4 * Code specific to PKUnity SoC and UniCore ISA
5 *
6 * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
7 * Copyright (C) 2001-2010 Guan Xuetao
8 */
9
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/err.h>
13 #include <linux/slab.h>
14 #include <linux/types.h>
15 #include <linux/delay.h>
16 #include <linux/i2c.h>
17 #include <linux/clk.h>
18 #include <linux/platform_device.h>
19 #include <linux/io.h>
20 #include <mach/hardware.h>
21
22 /*
23 * Poll the i2c status register until the specified bit is set.
24 * Returns 0 if timed out (100 msec).
25 */
poll_status(unsigned long bit)26 static short poll_status(unsigned long bit)
27 {
28 int loop_cntr = 1000;
29
30 if (bit & I2C_STATUS_TFNF) {
31 do {
32 udelay(10);
33 } while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
34 } else {
35 /* RXRDY handler */
36 do {
37 if (readl(I2C_TAR) == I2C_TAR_EEPROM)
38 msleep(20);
39 else
40 udelay(10);
41 } while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
42 }
43
44 return (loop_cntr > 0);
45 }
46
xfer_read(struct i2c_adapter * adap,unsigned char * buf,int length)47 static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
48 {
49 int i2c_reg = *buf;
50
51 /* Read data */
52 while (length--) {
53 if (!poll_status(I2C_STATUS_TFNF)) {
54 dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
55 return -ETIMEDOUT;
56 }
57
58 /* send addr */
59 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
60
61 /* get ready to next write */
62 i2c_reg++;
63
64 /* send read CMD */
65 writel(I2C_DATACMD_READ, I2C_DATACMD);
66
67 /* wait until the Rx FIFO have available */
68 if (!poll_status(I2C_STATUS_RFNE)) {
69 dev_dbg(&adap->dev, "RXRDY timeout\n");
70 return -ETIMEDOUT;
71 }
72
73 /* read the data to buf */
74 *buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
75 buf++;
76 }
77
78 return 0;
79 }
80
xfer_write(struct i2c_adapter * adap,unsigned char * buf,int length)81 static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
82 {
83 int i2c_reg = *buf;
84
85 /* Do nothing but storing the reg_num to a static variable */
86 if (i2c_reg == -1) {
87 printk(KERN_WARNING "Error i2c reg\n");
88 return -ETIMEDOUT;
89 }
90
91 if (length == 1)
92 return 0;
93
94 buf++;
95 length--;
96 while (length--) {
97 /* send addr */
98 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
99
100 /* send write CMD */
101 writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);
102
103 /* wait until the Rx FIFO have available */
104 msleep(20);
105
106 /* read the data to buf */
107 i2c_reg++;
108 buf++;
109 }
110
111 return 0;
112 }
113
114 /*
115 * Generic i2c master transfer entrypoint.
116 *
117 */
puv3_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * pmsg,int num)118 static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
119 int num)
120 {
121 int i, ret;
122 unsigned char swap;
123
124 /* Disable i2c */
125 writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
126
127 /* Set the work mode and speed*/
128 writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);
129
130 writel(pmsg->addr, I2C_TAR);
131
132 /* Enable i2c */
133 writel(I2C_ENABLE_ENABLE, I2C_ENABLE);
134
135 dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);
136
137 for (i = 0; i < num; i++) {
138 dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
139 pmsg->flags & I2C_M_RD ? "read" : "writ",
140 pmsg->len, pmsg->len > 1 ? "s" : "",
141 pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr);
142
143 if (pmsg->len && pmsg->buf) { /* sanity check */
144 if (pmsg->flags & I2C_M_RD)
145 ret = xfer_read(adap, pmsg->buf, pmsg->len);
146 else
147 ret = xfer_write(adap, pmsg->buf, pmsg->len);
148
149 if (ret)
150 return ret;
151
152 }
153 dev_dbg(&adap->dev, "transfer complete\n");
154 pmsg++; /* next message */
155 }
156
157 /* XXX: fixup be16_to_cpu in bq27x00_battery.c */
158 if (pmsg->addr == I2C_TAR_PWIC) {
159 swap = pmsg->buf[0];
160 pmsg->buf[0] = pmsg->buf[1];
161 pmsg->buf[1] = swap;
162 }
163
164 return i;
165 }
166
167 /*
168 * Return list of supported functionality.
169 */
puv3_i2c_func(struct i2c_adapter * adapter)170 static u32 puv3_i2c_func(struct i2c_adapter *adapter)
171 {
172 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
173 }
174
175 static const struct i2c_algorithm puv3_i2c_algorithm = {
176 .master_xfer = puv3_i2c_xfer,
177 .functionality = puv3_i2c_func,
178 };
179
180 /*
181 * Main initialization routine.
182 */
puv3_i2c_probe(struct platform_device * pdev)183 static int puv3_i2c_probe(struct platform_device *pdev)
184 {
185 struct i2c_adapter *adapter;
186 struct resource *mem;
187 int rc;
188
189 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
190 if (!mem)
191 return -ENODEV;
192
193 if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
194 return -EBUSY;
195
196 adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
197 if (adapter == NULL) {
198 dev_err(&pdev->dev, "can't allocate interface!\n");
199 rc = -ENOMEM;
200 goto fail_nomem;
201 }
202 snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
203 mem->start);
204 adapter->algo = &puv3_i2c_algorithm;
205 adapter->class = I2C_CLASS_HWMON;
206 adapter->dev.parent = &pdev->dev;
207
208 platform_set_drvdata(pdev, adapter);
209
210 adapter->nr = pdev->id;
211 rc = i2c_add_numbered_adapter(adapter);
212 if (rc)
213 goto fail_add_adapter;
214
215 dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
216 return 0;
217
218 fail_add_adapter:
219 kfree(adapter);
220 fail_nomem:
221 release_mem_region(mem->start, resource_size(mem));
222
223 return rc;
224 }
225
puv3_i2c_remove(struct platform_device * pdev)226 static int puv3_i2c_remove(struct platform_device *pdev)
227 {
228 struct i2c_adapter *adapter = platform_get_drvdata(pdev);
229 struct resource *mem;
230
231 i2c_del_adapter(adapter);
232
233 put_device(&pdev->dev);
234
235 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
236 release_mem_region(mem->start, resource_size(mem));
237
238 return 0;
239 }
240
241 #ifdef CONFIG_PM_SLEEP
puv3_i2c_suspend(struct device * dev)242 static int puv3_i2c_suspend(struct device *dev)
243 {
244 int poll_count;
245 /* Disable the IIC */
246 writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
247 for (poll_count = 0; poll_count < 50; poll_count++) {
248 if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
249 udelay(25);
250 }
251
252 return 0;
253 }
254
255 static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL);
256 #define PUV3_I2C_PM (&puv3_i2c_pm)
257
258 #else
259 #define PUV3_I2C_PM NULL
260 #endif
261
262 static struct platform_driver puv3_i2c_driver = {
263 .probe = puv3_i2c_probe,
264 .remove = puv3_i2c_remove,
265 .driver = {
266 .name = "PKUnity-v3-I2C",
267 .pm = PUV3_I2C_PM,
268 }
269 };
270
271 module_platform_driver(puv3_i2c_driver);
272
273 MODULE_DESCRIPTION("PKUnity v3 I2C driver");
274 MODULE_LICENSE("GPL v2");
275 MODULE_ALIAS("platform:puv3_i2c");
276
