drivers/i2c/busses/i2c-puv3.c

   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  */
  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
  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
  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  */
 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  */
 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  */
 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
 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
 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");