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         long ret = ~0;
  84         unsigned long timeout;
  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                 while (((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  94                                 & I2C_PCA_CON_SI) == 0)
  95                                 && (ret = time_before(jiffies, timeout)))
  96                         udelay(100);
  97         }
  98
  99         return ret > 0;
 100 }
 101
 102 static void i2c_pca_pf_dummyreset(void *pd)
 103 {
 104         struct i2c_pca_pf_data *i2c = pd;
 105         printk(KERN_WARNING "%s: No reset-pin found. Chip may get stuck!\n",
 106                 i2c->adap.name);
 107 }
 108
 109 static void i2c_pca_pf_resetchip(void *pd)
 110 {
 111         struct i2c_pca_pf_data *i2c = pd;
 112
 113         gpio_set_value(i2c->gpio, 0);
 114         ndelay(100);
 115         gpio_set_value(i2c->gpio, 1);
 116 }
 117
 118 static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
 119 {
 120         struct i2c_pca_pf_data *i2c = dev_id;
 121
 122         if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
 123                 return IRQ_NONE;
 124
 125         wake_up(&i2c->wait);
 126
 127         return IRQ_HANDLED;
 128 }
 129
 130
 131 static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
 132 {
 133         struct i2c_pca_pf_data *i2c;
 134         struct resource *res;
 135         struct i2c_pca9564_pf_platform_data *platform_data =
 136                                 pdev->dev.platform_data;
 137         int ret = 0;
 138         int irq;
 139
 140         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 141         irq = platform_get_irq(pdev, 0);
 142         /* If irq is 0, we do polling. */
 143
 144         if (res == NULL) {
 145                 ret = -ENODEV;
 146                 goto e_print;
 147         }
 148
 149         if (!request_mem_region(res->start, resource_size(res), res->name)) {
 150                 ret = -ENOMEM;
 151                 goto e_print;
 152         }
 153
 154         i2c = kzalloc(sizeof(struct i2c_pca_pf_data), GFP_KERNEL);
 155         if (!i2c) {
 156                 ret = -ENOMEM;
 157                 goto e_alloc;
 158         }
 159
 160         init_waitqueue_head(&i2c->wait);
 161
 162         i2c->reg_base = ioremap(res->start, resource_size(res));
 163         if (!i2c->reg_base) {
 164                 ret = -ENOMEM;
 165                 goto e_remap;
 166         }
 167         i2c->io_base = res->start;
 168         i2c->io_size = resource_size(res);
 169         i2c->irq = irq;
 170
 171         i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0;
 172         i2c->adap.owner = THIS_MODULE;
 173         snprintf(i2c->adap.name, sizeof(i2c->adap.name),
 174                  "PCA9564/PCA9665 at 0x%08lx",
 175                  (unsigned long) res->start);
 176         i2c->adap.algo_data = &i2c->algo_data;
 177         i2c->adap.dev.parent = &pdev->dev;
 178
 179         if (platform_data) {
 180                 i2c->adap.timeout = platform_data->timeout;
 181                 i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
 182                 i2c->gpio = platform_data->gpio;
 183         } else {
 184                 i2c->adap.timeout = HZ;
 185                 i2c->algo_data.i2c_clock = 59000;
 186                 i2c->gpio = -1;
 187         }
 188
 189         i2c->algo_data.data = i2c;
 190         i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
 191         i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
 192
 193         switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
 194         case IORESOURCE_MEM_32BIT:
 195                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
 196                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
 197                 break;
 198         case IORESOURCE_MEM_16BIT:
 199                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
 200                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
 201                 break;
 202         case IORESOURCE_MEM_8BIT:
 203         default:
 204                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
 205                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
 206                 break;
 207         }
 208
 209         /* Use gpio_is_valid() when in mainline */
 210         if (i2c->gpio > -1) {
 211                 ret = gpio_request(i2c->gpio, i2c->adap.name);
 212                 if (ret == 0) {
 213                         gpio_direction_output(i2c->gpio, 1);
 214                         i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
 215                 } else {
 216                         printk(KERN_WARNING "%s: Registering gpio failed!\n",
 217                                 i2c->adap.name);
 218                         i2c->gpio = ret;
 219                 }
 220         }
 221
 222         if (irq) {
 223                 ret = request_irq(irq, i2c_pca_pf_handler,
 224                         IRQF_TRIGGER_FALLING, i2c->adap.name, i2c);
 225                 if (ret)
 226                         goto e_reqirq;
 227         }
 228
 229         if (i2c_pca_add_numbered_bus(&i2c->adap) < 0) {
 230                 ret = -ENODEV;
 231                 goto e_adapt;
 232         }
 233
 234         platform_set_drvdata(pdev, i2c);
 235
 236         printk(KERN_INFO "%s registered.\n", i2c->adap.name);
 237
 238         return 0;
 239
 240 e_adapt:
 241         if (irq)
 242                 free_irq(irq, i2c);
 243 e_reqirq:
 244         if (i2c->gpio > -1)
 245                 gpio_free(i2c->gpio);
 246
 247         iounmap(i2c->reg_base);
 248 e_remap:
 249         kfree(i2c);
 250 e_alloc:
 251         release_mem_region(res->start, resource_size(res));
 252 e_print:
 253         printk(KERN_ERR "Registering PCA9564/PCA9665 FAILED! (%d)\n", ret);
 254         return ret;
 255 }
 256
 257 static int __devexit i2c_pca_pf_remove(struct platform_device *pdev)
 258 {
 259         struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
 260         platform_set_drvdata(pdev, NULL);
 261
 262         i2c_del_adapter(&i2c->adap);
 263
 264         if (i2c->irq)
 265                 free_irq(i2c->irq, i2c);
 266
 267         if (i2c->gpio > -1)
 268                 gpio_free(i2c->gpio);
 269
 270         iounmap(i2c->reg_base);
 271         release_mem_region(i2c->io_base, i2c->io_size);
 272         kfree(i2c);
 273
 274         return 0;
 275 }
 276
 277 static struct platform_driver i2c_pca_pf_driver = {
 278         .probe = i2c_pca_pf_probe,
 279         .remove = __devexit_p(i2c_pca_pf_remove),
 280         .driver = {
 281                 .name = "i2c-pca-platform",
 282                 .owner = THIS_MODULE,
 283         },
 284 };
 285
 286 static int __init i2c_pca_pf_init(void)
 287 {
 288         return platform_driver_register(&i2c_pca_pf_driver);
 289 }
 290
 291 static void __exit i2c_pca_pf_exit(void)
 292 {
 293         platform_driver_unregister(&i2c_pca_pf_driver);
 294 }
 295
 296 MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
 297 MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
 298 MODULE_LICENSE("GPL");
 299
 300 module_init(i2c_pca_pf_init);
 301 module_exit(i2c_pca_pf_exit);
 302