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/clk.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/io.h>
  23 #include <mach/hardware.h>
  24
  25 /*
  26  * Poll the i2c status register until the specified bit is set.
  27  * Returns 0 if timed out (100 msec).
  28  */
  29 static short poll_status(unsigned long bit)
  30 {
  31         int loop_cntr = 1000;
  32
  33         if (bit & I2C_STATUS_TFNF) {
  34                 do {
  35                         udelay(10);
  36                 } while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
  37         } else {
  38                 /* RXRDY handler */
  39                 do {
  40                         if (readl(I2C_TAR) == I2C_TAR_EEPROM)
  41                                 msleep(20);
  42                         else
  43                                 udelay(10);
  44                 } while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
  45         }
  46
  47         return (loop_cntr > 0);
  48 }
  49
  50 static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
  51 {
  52         int i2c_reg = *buf;
  53
  54         /* Read data */
  55         while (length--) {
  56                 if (!poll_status(I2C_STATUS_TFNF)) {
  57                         dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
  58                         return -ETIMEDOUT;
  59                 }
  60
  61                 /* send addr */
  62                 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
  63
  64                 /* get ready to next write */
  65                 i2c_reg++;
  66
  67                 /* send read CMD */
  68                 writel(I2C_DATACMD_READ, I2C_DATACMD);
  69
  70                 /* wait until the Rx FIFO have available */
  71                 if (!poll_status(I2C_STATUS_RFNE)) {
  72                         dev_dbg(&adap->dev, "RXRDY timeout\n");
  73                         return -ETIMEDOUT;
  74                 }
  75
  76                 /* read the data to buf */
  77                 *buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
  78                 buf++;
  79         }
  80
  81         return 0;
  82 }
  83
  84 static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
  85 {
  86         int i2c_reg = *buf;
  87
  88         /* Do nothing but storing the reg_num to a static variable */
  89         if (i2c_reg == -1) {
  90                 printk(KERN_WARNING "Error i2c reg\n");
  91                 return -ETIMEDOUT;
  92         }
  93
  94         if (length == 1)
  95                 return 0;
  96
  97         buf++;
  98         length--;
  99         while (length--) {
 100                 /* send addr */
 101                 writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
 102
 103                 /* send write CMD */
 104                 writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);
 105
 106                 /* wait until the Rx FIFO have available */
 107                 msleep(20);
 108
 109                 /* read the data to buf */
 110                 i2c_reg++;
 111                 buf++;
 112         }
 113
 114         return 0;
 115 }
 116
 117 /*
 118  * Generic i2c master transfer entrypoint.
 119  *
 120  */
 121 static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
 122                 int num)
 123 {
 124         int i, ret;
 125         unsigned char swap;
 126
 127         /* Disable i2c */
 128         writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
 129
 130         /* Set the work mode and speed*/
 131         writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);
 132
 133         writel(pmsg->addr, I2C_TAR);
 134
 135         /* Enable i2c */
 136         writel(I2C_ENABLE_ENABLE, I2C_ENABLE);
 137
 138         dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);
 139
 140         for (i = 0; i < num; i++) {
 141                 dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
 142                         pmsg->flags & I2C_M_RD ? "read" : "writ",
 143                         pmsg->len, pmsg->len > 1 ? "s" : "",
 144                         pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr);
 145
 146                 if (pmsg->len && pmsg->buf) {   /* sanity check */
 147                         if (pmsg->flags & I2C_M_RD)
 148                                 ret = xfer_read(adap, pmsg->buf, pmsg->len);
 149                         else
 150                                 ret = xfer_write(adap, pmsg->buf, pmsg->len);
 151
 152                         if (ret)
 153                                 return ret;
 154
 155                 }
 156                 dev_dbg(&adap->dev, "transfer complete\n");
 157                 pmsg++;         /* next message */
 158         }
 159
 160         /* XXX: fixup be16_to_cpu in bq27x00_battery.c */
 161         if (pmsg->addr == I2C_TAR_PWIC) {
 162                 swap = pmsg->buf[0];
 163                 pmsg->buf[0] = pmsg->buf[1];
 164                 pmsg->buf[1] = swap;
 165         }
 166
 167         return i;
 168 }
 169
 170 /*
 171  * Return list of supported functionality.
 172  */
 173 static u32 puv3_i2c_func(struct i2c_adapter *adapter)
 174 {
 175         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 176 }
 177
 178 static struct i2c_algorithm puv3_i2c_algorithm = {
 179         .master_xfer    = puv3_i2c_xfer,
 180         .functionality  = puv3_i2c_func,
 181 };
 182
 183 /*
 184  * Main initialization routine.
 185  */
 186 static int puv3_i2c_probe(struct platform_device *pdev)
 187 {
 188         struct i2c_adapter *adapter;
 189         struct resource *mem;
 190         int rc;
 191
 192         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 193         if (!mem)
 194                 return -ENODEV;
 195
 196         if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
 197                 return -EBUSY;
 198
 199         adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
 200         if (adapter == NULL) {
 201                 dev_err(&pdev->dev, "can't allocate interface!\n");
 202                 rc = -ENOMEM;
 203                 goto fail_nomem;
 204         }
 205         snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
 206                         mem->start);
 207         adapter->algo = &puv3_i2c_algorithm;
 208         adapter->class = I2C_CLASS_HWMON;
 209         adapter->dev.parent = &pdev->dev;
 210
 211         platform_set_drvdata(pdev, adapter);
 212
 213         adapter->nr = pdev->id;
 214         rc = i2c_add_numbered_adapter(adapter);
 215         if (rc) {
 216                 dev_err(&pdev->dev, "Adapter '%s' registration failed\n",
 217                                 adapter->name);
 218                 goto fail_add_adapter;
 219         }
 220
 221         dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
 222         return 0;
 223
 224 fail_add_adapter:
 225         kfree(adapter);
 226 fail_nomem:
 227         release_mem_region(mem->start, resource_size(mem));
 228
 229         return rc;
 230 }
 231
 232 static int puv3_i2c_remove(struct platform_device *pdev)
 233 {
 234         struct i2c_adapter *adapter = platform_get_drvdata(pdev);
 235         struct resource *mem;
 236
 237         i2c_del_adapter(adapter);
 238
 239         put_device(&pdev->dev);
 240
 241         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 242         release_mem_region(mem->start, resource_size(mem));
 243
 244         return 0;
 245 }
 246
 247 #ifdef CONFIG_PM_SLEEP
 248 static int puv3_i2c_suspend(struct device *dev)
 249 {
 250         int poll_count;
 251         /* Disable the IIC */
 252         writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
 253         for (poll_count = 0; poll_count < 50; poll_count++) {
 254                 if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
 255                         udelay(25);
 256         }
 257
 258         return 0;
 259 }
 260
 261 static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL);
 262 #define PUV3_I2C_PM     (&puv3_i2c_pm)
 263
 264 #else
 265 #define PUV3_I2C_PM     NULL
 266 #endif
 267
 268 static struct platform_driver puv3_i2c_driver = {
 269         .probe          = puv3_i2c_probe,
 270         .remove         = puv3_i2c_remove,
 271         .driver         = {
 272                 .name   = "PKUnity-v3-I2C",
 273                 .pm     = PUV3_I2C_PM,
 274         }
 275 };
 276
 277 module_platform_driver(puv3_i2c_driver);
 278
 279 MODULE_DESCRIPTION("PKUnity v3 I2C driver");
 280 MODULE_LICENSE("GPL v2");
 281 MODULE_ALIAS("platform:puv3_i2c");