drivers/i2c/busses/i2c-pca-platform.c

   1 /*
   2  *  i2c_pca_platform.c
   3  *
   4  *  Platform driver for the PCA9564 I2C controller.
   5  *
   6  *  Copyright (C) 2008 Pengutronix
   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/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/delay.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/errno.h>
  20 #include <linux/i2c.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/i2c-algo-pca.h>
  24 #include <linux/i2c-pca-platform.h>
  25 #include <linux/gpio.h>
  26
  27 #include <asm/irq.h>
  28 #include <asm/io.h>
  29
  30 #define res_len(r)              ((r)->end - (r)->start + 1)
  31
  32 struct i2c_pca_pf_data {
  33         void __iomem                    *reg_base;
  34         int                             irq;    /* if 0, use polling */
  35         int                             gpio;
  36         wait_queue_head_t               wait;
  37         struct i2c_adapter              adap;
  38         struct i2c_algo_pca_data        algo_data;
  39         unsigned long                   io_base;
  40         unsigned long                   io_size;
  41 };
  42
  43 /* Read/Write functions for different register alignments */
  44
  45 static int i2c_pca_pf_readbyte8(void *pd, int reg)
  46 {
  47         struct i2c_pca_pf_data *i2c = pd;
  48         return ioread8(i2c->reg_base + reg);
  49 }
  50
  51 static int i2c_pca_pf_readbyte16(void *pd, int reg)
  52 {
  53         struct i2c_pca_pf_data *i2c = pd;
  54         return ioread8(i2c->reg_base + reg * 2);
  55 }
  56
  57 static int i2c_pca_pf_readbyte32(void *pd, int reg)
  58 {
  59         struct i2c_pca_pf_data *i2c = pd;
  60         return ioread8(i2c->reg_base + reg * 4);
  61 }
  62
  63 static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
  64 {
  65         struct i2c_pca_pf_data *i2c = pd;
  66         iowrite8(val, i2c->reg_base + reg);
  67 }
  68
  69 static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
  70 {
  71         struct i2c_pca_pf_data *i2c = pd;
  72         iowrite8(val, i2c->reg_base + reg * 2);
  73 }
  74
  75 static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
  76 {
  77         struct i2c_pca_pf_data *i2c = pd;
  78         iowrite8(val, i2c->reg_base + reg * 4);
  79 }
  80
  81
  82 static int i2c_pca_pf_waitforcompletion(void *pd)
  83 {
  84         struct i2c_pca_pf_data *i2c = pd;
  85         long ret = ~0;
  86         unsigned long timeout;
  87
  88         if (i2c->irq) {
  89                 ret = wait_event_interruptible_timeout(i2c->wait,
  90                         i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  91                         & I2C_PCA_CON_SI, i2c->adap.timeout);
  92         } else {
  93                 /* Do polling */
  94                 timeout = jiffies + i2c->adap.timeout;
  95                 while (((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  96                                 & I2C_PCA_CON_SI) == 0)
  97                                 && (ret = time_before(jiffies, timeout)))
  98                         udelay(100);
  99         }
 100
 101         return ret > 0;
 102 }
 103
 104 static void i2c_pca_pf_dummyreset(void *pd)
 105 {
 106         struct i2c_pca_pf_data *i2c = pd;
 107         printk(KERN_WARNING "%s: No reset-pin found. Chip may get stuck!\n",
 108                 i2c->adap.name);
 109 }
 110
 111 static void i2c_pca_pf_resetchip(void *pd)
 112 {
 113         struct i2c_pca_pf_data *i2c = pd;
 114
 115         gpio_set_value(i2c->gpio, 0);
 116         ndelay(100);
 117         gpio_set_value(i2c->gpio, 1);
 118 }
 119
 120 static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
 121 {
 122         struct i2c_pca_pf_data *i2c = dev_id;
 123
 124         if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
 125                 return IRQ_NONE;
 126
 127         wake_up_interruptible(&i2c->wait);
 128
 129         return IRQ_HANDLED;
 130 }
 131
 132
 133 static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
 134 {
 135         struct i2c_pca_pf_data *i2c;
 136         struct resource *res;
 137         struct i2c_pca9564_pf_platform_data *platform_data =
 138                                 pdev->dev.platform_data;
 139         int ret = 0;
 140         int irq;
 141
 142         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 143         irq = platform_get_irq(pdev, 0);
 144         /* If irq is 0, we do polling. */
 145
 146         if (res == NULL) {
 147                 ret = -ENODEV;
 148                 goto e_print;
 149         }
 150
 151         if (!request_mem_region(res->start, res_len(res), res->name)) {
 152                 ret = -ENOMEM;
 153                 goto e_print;
 154         }
 155
 156         i2c = kzalloc(sizeof(struct i2c_pca_pf_data), GFP_KERNEL);
 157         if (!i2c) {
 158                 ret = -ENOMEM;
 159                 goto e_alloc;
 160         }
 161
 162         init_waitqueue_head(&i2c->wait);
 163
 164         i2c->reg_base = ioremap(res->start, res_len(res));
 165         if (!i2c->reg_base) {
 166                 ret = -ENOMEM;
 167                 goto e_remap;
 168         }
 169         i2c->io_base = res->start;
 170         i2c->io_size = res_len(res);
 171         i2c->irq = irq;
 172
 173         i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0;
 174         i2c->adap.owner = THIS_MODULE;
 175         snprintf(i2c->adap.name, sizeof(i2c->adap.name),
 176                  "PCA9564/PCA9665 at 0x%08lx",
 177                  (unsigned long) res->start);
 178         i2c->adap.algo_data = &i2c->algo_data;
 179         i2c->adap.dev.parent = &pdev->dev;
 180
 181         if (platform_data) {
 182                 i2c->adap.timeout = platform_data->timeout;
 183                 i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
 184                 i2c->gpio = platform_data->gpio;
 185         } else {
 186                 i2c->adap.timeout = HZ;
 187                 i2c->algo_data.i2c_clock = 59000;
 188                 i2c->gpio = -1;
 189         }
 190
 191         i2c->algo_data.data = i2c;
 192         i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
 193         i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
 194
 195         switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
 196         case IORESOURCE_MEM_32BIT:
 197                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
 198                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
 199                 break;
 200         case IORESOURCE_MEM_16BIT:
 201                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
 202                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
 203                 break;
 204         case IORESOURCE_MEM_8BIT:
 205         default:
 206                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
 207                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
 208                 break;
 209         }
 210
 211         /* Use gpio_is_valid() when in mainline */
 212         if (i2c->gpio > -1) {
 213                 ret = gpio_request(i2c->gpio, i2c->adap.name);
 214                 if (ret == 0) {
 215                         gpio_direction_output(i2c->gpio, 1);
 216                         i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
 217                 } else {
 218                         printk(KERN_WARNING "%s: Registering gpio failed!\n",
 219                                 i2c->adap.name);
 220                         i2c->gpio = ret;
 221                 }
 222         }
 223
 224         if (irq) {
 225                 ret = request_irq(irq, i2c_pca_pf_handler,
 226                         IRQF_TRIGGER_FALLING, i2c->adap.name, i2c);
 227                 if (ret)
 228                         goto e_reqirq;
 229         }
 230
 231         if (i2c_pca_add_numbered_bus(&i2c->adap) < 0) {
 232                 ret = -ENODEV;
 233                 goto e_adapt;
 234         }
 235
 236         platform_set_drvdata(pdev, i2c);
 237
 238         printk(KERN_INFO "%s registered.\n", i2c->adap.name);
 239
 240         return 0;
 241
 242 e_adapt:
 243         if (irq)
 244                 free_irq(irq, i2c);
 245 e_reqirq:
 246         if (i2c->gpio > -1)
 247                 gpio_free(i2c->gpio);
 248
 249         iounmap(i2c->reg_base);
 250 e_remap:
 251         kfree(i2c);
 252 e_alloc:
 253         release_mem_region(res->start, res_len(res));
 254 e_print:
 255         printk(KERN_ERR "Registering PCA9564/PCA9665 FAILED! (%d)\n", ret);
 256         return ret;
 257 }
 258
 259 static int __devexit i2c_pca_pf_remove(struct platform_device *pdev)
 260 {
 261         struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
 262         platform_set_drvdata(pdev, NULL);
 263
 264         i2c_del_adapter(&i2c->adap);
 265
 266         if (i2c->irq)
 267                 free_irq(i2c->irq, i2c);
 268
 269         if (i2c->gpio > -1)
 270                 gpio_free(i2c->gpio);
 271
 272         iounmap(i2c->reg_base);
 273         release_mem_region(i2c->io_base, i2c->io_size);
 274         kfree(i2c);
 275
 276         return 0;
 277 }
 278
 279 static struct platform_driver i2c_pca_pf_driver = {
 280         .probe = i2c_pca_pf_probe,
 281         .remove = __devexit_p(i2c_pca_pf_remove),
 282         .driver = {
 283                 .name = "i2c-pca-platform",
 284                 .owner = THIS_MODULE,
 285         },
 286 };
 287
 288 static int __init i2c_pca_pf_init(void)
 289 {
 290         return platform_driver_register(&i2c_pca_pf_driver);
 291 }
 292
 293 static void __exit i2c_pca_pf_exit(void)
 294 {
 295         platform_driver_unregister(&i2c_pca_pf_driver);
 296 }
 297
 298 MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
 299 MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
 300 MODULE_LICENSE("GPL");
 301
 302 module_init(i2c_pca_pf_init);
 303 module_exit(i2c_pca_pf_exit);
 304