2 * I2C driver for PKUnity-v3 SoC
3 * Code specific to PKUnity SoC and UniCore ISA
5 * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
6 * Copyright (C) 2001-2010 Guan Xuetao
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.
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>
24 #include <mach/hardware.h>
27 * Poll the i2c status register until the specified bit is set.
28 * Returns 0 if timed out (100 msec).
30 static short poll_status(unsigned long bit)
34 if (bit & I2C_STATUS_TFNF) {
37 } while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
41 if (readl(I2C_TAR) == I2C_TAR_EEPROM)
45 } while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
48 return (loop_cntr > 0);
51 static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
57 if (!poll_status(I2C_STATUS_TFNF)) {
58 dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
63 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
65 /* get ready to next write */
69 writel(I2C_DATACMD_READ, I2C_DATACMD);
71 /* wait until the Rx FIFO have available */
72 if (!poll_status(I2C_STATUS_RFNE)) {
73 dev_dbg(&adap->dev, "RXRDY timeout\n");
77 /* read the data to buf */
78 *buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
85 static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
89 /* Do nothing but storing the reg_num to a static variable */
91 printk(KERN_WARNING "Error i2c reg\n");
102 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
105 writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);
107 /* wait until the Rx FIFO have available */
110 /* read the data to buf */
119 * Generic i2c master transfer entrypoint.
122 static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
129 writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
131 /* Set the work mode and speed*/
132 writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);
134 writel(pmsg->addr, I2C_TAR);
137 writel(I2C_ENABLE_ENABLE, I2C_ENABLE);
139 dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);
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);
147 if (pmsg->len && pmsg->buf) { /* sanity check */
148 if (pmsg->flags & I2C_M_RD)
149 ret = xfer_read(adap, pmsg->buf, pmsg->len);
151 ret = xfer_write(adap, pmsg->buf, pmsg->len);
157 dev_dbg(&adap->dev, "transfer complete\n");
158 pmsg++; /* next message */
161 /* XXX: fixup be16_to_cpu in bq27x00_battery.c */
162 if (pmsg->addr == I2C_TAR_PWIC) {
164 pmsg->buf[0] = pmsg->buf[1];
172 * Return list of supported functionality.
174 static u32 puv3_i2c_func(struct i2c_adapter *adapter)
176 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
179 static struct i2c_algorithm puv3_i2c_algorithm = {
180 .master_xfer = puv3_i2c_xfer,
181 .functionality = puv3_i2c_func,
185 * Main initialization routine.
187 static int puv3_i2c_probe(struct platform_device *pdev)
189 struct i2c_adapter *adapter;
190 struct resource *mem;
193 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
197 if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
200 adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
201 if (adapter == NULL) {
202 dev_err(&pdev->dev, "can't allocate inteface!\n");
206 snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
208 adapter->algo = &puv3_i2c_algorithm;
209 adapter->class = I2C_CLASS_HWMON;
210 adapter->dev.parent = &pdev->dev;
212 platform_set_drvdata(pdev, adapter);
214 adapter->nr = pdev->id;
215 rc = i2c_add_numbered_adapter(adapter);
217 dev_err(&pdev->dev, "Adapter '%s' registration failed\n",
219 goto fail_add_adapter;
222 dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
228 release_mem_region(mem->start, resource_size(mem));
233 static int puv3_i2c_remove(struct platform_device *pdev)
235 struct i2c_adapter *adapter = platform_get_drvdata(pdev);
236 struct resource *mem;
238 i2c_del_adapter(adapter);
240 put_device(&pdev->dev);
242 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
243 release_mem_region(mem->start, resource_size(mem));
249 static int puv3_i2c_suspend(struct device *dev)
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)
262 static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL);
263 #define PUV3_I2C_PM (&puv3_i2c_pm)
266 #define PUV3_I2C_PM NULL
269 static struct platform_driver puv3_i2c_driver = {
270 .probe = puv3_i2c_probe,
271 .remove = puv3_i2c_remove,
273 .name = "PKUnity-v3-I2C",
274 .owner = THIS_MODULE,
279 module_platform_driver(puv3_i2c_driver);
281 MODULE_DESCRIPTION("PKUnity v3 I2C driver");
282 MODULE_LICENSE("GPL v2");
283 MODULE_ALIAS("platform:puv3_i2c");