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/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
  26 #include <asm/irq.h>
  27 #include <asm/io.h>
  28
  29 #define res_len(r)              ((r)->end - (r)->start + 1)
  30
  31 struct i2c_pca_pf_data {
  32         void __iomem                    *reg_base;
  33         int                             irq;    /* if 0, use polling */
  34         int                             gpio;
  35         wait_queue_head_t               wait;
  36         struct i2c_adapter              adap;
  37         struct i2c_algo_pca_data        algo_data;
  38         unsigned long                   io_base;
  39         unsigned long                   io_size;
  40 };
  41
  42 /* Read/Write functions for different register alignments */
  43
  44 static int i2c_pca_pf_readbyte8(void *pd, int reg)
  45 {
  46         struct i2c_pca_pf_data *i2c = pd;
  47         return ioread8(i2c->reg_base + reg);
  48 }
  49
  50 static int i2c_pca_pf_readbyte16(void *pd, int reg)
  51 {
  52         struct i2c_pca_pf_data *i2c = pd;
  53         return ioread8(i2c->reg_base + reg * 2);
  54 }
  55
  56 static int i2c_pca_pf_readbyte32(void *pd, int reg)
  57 {
  58         struct i2c_pca_pf_data *i2c = pd;
  59         return ioread8(i2c->reg_base + reg * 4);
  60 }
  61
  62 static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
  63 {
  64         struct i2c_pca_pf_data *i2c = pd;
  65         iowrite8(val, i2c->reg_base + reg);
  66 }
  67
  68 static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
  69 {
  70         struct i2c_pca_pf_data *i2c = pd;
  71         iowrite8(val, i2c->reg_base + reg * 2);
  72 }
  73
  74 static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
  75 {
  76         struct i2c_pca_pf_data *i2c = pd;
  77         iowrite8(val, i2c->reg_base + reg * 4);
  78 }
  79
  80
  81 static int i2c_pca_pf_waitforcompletion(void *pd)
  82 {
  83         struct i2c_pca_pf_data *i2c = pd;
  84         int ret = 0;
  85
  86         if (i2c->irq) {
  87                 ret = wait_event_interruptible(i2c->wait,
  88                         i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  89                         & I2C_PCA_CON_SI);
  90         } else {
  91                 /*
  92                  * Do polling...
  93                  * XXX: Could get stuck in extreme cases!
  94                  *      Maybe add timeout, but using irqs is preferred anyhow.
  95                  */
  96                 while ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  97                                 & I2C_PCA_CON_SI) == 0)
  98                         udelay(100);
  99         }
 100
 101         return ret;
 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 = -EIO;
 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), "PCA9564 at 0x%08lx",
 176                 (unsigned long) res->start);
 177         i2c->adap.algo_data = &i2c->algo_data;
 178         i2c->adap.dev.parent = &pdev->dev;
 179         i2c->adap.timeout = platform_data->timeout;
 180
 181         i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
 182         i2c->algo_data.data = i2c;
 183
 184         switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
 185         case IORESOURCE_MEM_32BIT:
 186                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
 187                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
 188                 break;
 189         case IORESOURCE_MEM_16BIT:
 190                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
 191                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
 192                 break;
 193         case IORESOURCE_MEM_8BIT:
 194         default:
 195                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
 196                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
 197                 break;
 198         }
 199
 200         i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
 201
 202         i2c->gpio = platform_data->gpio;
 203         i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
 204
 205         /* Use gpio_is_valid() when in mainline */
 206         if (i2c->gpio > -1) {
 207                 ret = gpio_request(i2c->gpio, i2c->adap.name);
 208                 if (ret == 0) {
 209                         gpio_direction_output(i2c->gpio, 1);
 210                         i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
 211                 } else {
 212                         printk(KERN_WARNING "%s: Registering gpio failed!\n",
 213                                 i2c->adap.name);
 214                         i2c->gpio = ret;
 215                 }
 216         }
 217
 218         if (irq) {
 219                 ret = request_irq(irq, i2c_pca_pf_handler,
 220                         IRQF_TRIGGER_FALLING, i2c->adap.name, i2c);
 221                 if (ret)
 222                         goto e_reqirq;
 223         }
 224
 225         if (i2c_pca_add_numbered_bus(&i2c->adap) < 0) {
 226                 ret = -ENODEV;
 227                 goto e_adapt;
 228         }
 229
 230         platform_set_drvdata(pdev, i2c);
 231
 232         printk(KERN_INFO "%s registered.\n", i2c->adap.name);
 233
 234         return 0;
 235
 236 e_adapt:
 237         if (irq)
 238                 free_irq(irq, i2c);
 239 e_reqirq:
 240         if (i2c->gpio > -1)
 241                 gpio_free(i2c->gpio);
 242
 243         iounmap(i2c->reg_base);
 244 e_remap:
 245         kfree(i2c);
 246 e_alloc:
 247         release_mem_region(res->start, res_len(res));
 248 e_print:
 249         printk(KERN_ERR "Registering PCA9564 FAILED! (%d)\n", ret);
 250         return ret;
 251 }
 252
 253 static int __devexit i2c_pca_pf_remove(struct platform_device *pdev)
 254 {
 255         struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
 256         platform_set_drvdata(pdev, NULL);
 257
 258         i2c_del_adapter(&i2c->adap);
 259
 260         if (i2c->irq)
 261                 free_irq(i2c->irq, i2c);
 262
 263         if (i2c->gpio > -1)
 264                 gpio_free(i2c->gpio);
 265
 266         iounmap(i2c->reg_base);
 267         release_mem_region(i2c->io_base, i2c->io_size);
 268         kfree(i2c);
 269
 270         return 0;
 271 }
 272
 273 static struct platform_driver i2c_pca_pf_driver = {
 274         .probe = i2c_pca_pf_probe,
 275         .remove = __devexit_p(i2c_pca_pf_remove),
 276         .driver = {
 277                 .name = "i2c-pca-platform",
 278                 .owner = THIS_MODULE,
 279         },
 280 };
 281
 282 static int __init i2c_pca_pf_init(void)
 283 {
 284         return platform_driver_register(&i2c_pca_pf_driver);
 285 }
 286
 287 static void __exit i2c_pca_pf_exit(void)
 288 {
 289         platform_driver_unregister(&i2c_pca_pf_driver);
 290 }
 291
 292 MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
 293 MODULE_DESCRIPTION("I2C-PCA9564 platform driver");
 294 MODULE_LICENSE("GPL");
 295
 296 module_init(i2c_pca_pf_init);
 297 module_exit(i2c_pca_pf_exit);
 298