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