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/slab.h>
  16 #include <linux/delay.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/errno.h>
  19 #include <linux/i2c.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/i2c-algo-pca.h>
  23 #include <linux/i2c-pca-platform.h>
  24 #include <linux/gpio.h>
  25 #include <linux/io.h>
  26
  27 #include <asm/irq.h>
  28
  29 struct i2c_pca_pf_data {
  30         void __iomem                    *reg_base;
  31         int                             irq;    /* if 0, use polling */
  32         int                             gpio;
  33         wait_queue_head_t               wait;
  34         struct i2c_adapter              adap;
  35         struct i2c_algo_pca_data        algo_data;
  36         unsigned long                   io_base;
  37         unsigned long                   io_size;
  38 };
  39
  40 /* Read/Write functions for different register alignments */
  41
  42 static int i2c_pca_pf_readbyte8(void *pd, int reg)
  43 {
  44         struct i2c_pca_pf_data *i2c = pd;
  45         return ioread8(i2c->reg_base + reg);
  46 }
  47
  48 static int i2c_pca_pf_readbyte16(void *pd, int reg)
  49 {
  50         struct i2c_pca_pf_data *i2c = pd;
  51         return ioread8(i2c->reg_base + reg * 2);
  52 }
  53
  54 static int i2c_pca_pf_readbyte32(void *pd, int reg)
  55 {
  56         struct i2c_pca_pf_data *i2c = pd;
  57         return ioread8(i2c->reg_base + reg * 4);
  58 }
  59
  60 static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
  61 {
  62         struct i2c_pca_pf_data *i2c = pd;
  63         iowrite8(val, i2c->reg_base + reg);
  64 }
  65
  66 static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
  67 {
  68         struct i2c_pca_pf_data *i2c = pd;
  69         iowrite8(val, i2c->reg_base + reg * 2);
  70 }
  71
  72 static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
  73 {
  74         struct i2c_pca_pf_data *i2c = pd;
  75         iowrite8(val, i2c->reg_base + reg * 4);
  76 }
  77
  78
  79 static int i2c_pca_pf_waitforcompletion(void *pd)
  80 {
  81         struct i2c_pca_pf_data *i2c = pd;
  82         unsigned long timeout;
  83         long ret;
  84
  85         if (i2c->irq) {
  86                 ret = wait_event_timeout(i2c->wait,
  87                         i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  88                         & I2C_PCA_CON_SI, i2c->adap.timeout);
  89         } else {
  90                 /* Do polling */
  91                 timeout = jiffies + i2c->adap.timeout;
  92                 do {
  93                         ret = time_before(jiffies, timeout);
  94                         if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  95                                         & I2C_PCA_CON_SI)
  96                                 break;
  97                         udelay(100);
  98                 } while (ret);
  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(&i2c->wait);
 128
 129         return IRQ_HANDLED;
 130 }
 131
 132
 133 static int 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                                 dev_get_platdata(&pdev->dev);
 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, resource_size(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, resource_size(res));
 165         if (!i2c->reg_base) {
 166                 ret = -ENOMEM;
 167                 goto e_remap;
 168         }
 169         i2c->io_base = res->start;
 170         i2c->io_size = resource_size(res);
 171         i2c->irq = irq;
 172
 173         i2c->adap.nr = pdev->id;
 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, pdev->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, resource_size(res));
 254 e_print:
 255         printk(KERN_ERR "Registering PCA9564/PCA9665 FAILED! (%d)\n", ret);
 256         return ret;
 257 }
 258
 259 static int i2c_pca_pf_remove(struct platform_device *pdev)
 260 {
 261         struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
 262
 263         i2c_del_adapter(&i2c->adap);
 264
 265         if (i2c->irq)
 266                 free_irq(i2c->irq, i2c);
 267
 268         if (i2c->gpio > -1)
 269                 gpio_free(i2c->gpio);
 270
 271         iounmap(i2c->reg_base);
 272         release_mem_region(i2c->io_base, i2c->io_size);
 273         kfree(i2c);
 274
 275         return 0;
 276 }
 277
 278 static struct platform_driver i2c_pca_pf_driver = {
 279         .probe = i2c_pca_pf_probe,
 280         .remove = i2c_pca_pf_remove,
 281         .driver = {
 282                 .name = "i2c-pca-platform",
 283         },
 284 };
 285
 286 module_platform_driver(i2c_pca_pf_driver);
 287
 288 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
 289 MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
 290 MODULE_LICENSE("GPL");