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/gpio/consumer.h>
  26 #include <linux/io.h>
  27 #include <linux/of.h>
  28 #include <linux/of_device.h>
  29
  30 #include <asm/irq.h>
  31
  32 struct i2c_pca_pf_data {
  33         void __iomem                    *reg_base;
  34         int                             irq;    /* if 0, use polling */
  35         struct gpio_desc                *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         unsigned long timeout;
  86         long ret;
  87
  88         if (i2c->irq) {
  89                 ret = wait_event_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                 do {
  96                         ret = time_before(jiffies, timeout);
  97                         if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  98                                         & I2C_PCA_CON_SI)
  99                                 break;
 100                         udelay(100);
 101                 } while (ret);
 102         }
 103
 104         return ret > 0;
 105 }
 106
 107 static void i2c_pca_pf_dummyreset(void *pd)
 108 {
 109         struct i2c_pca_pf_data *i2c = pd;
 110
 111         dev_warn(&i2c->adap.dev, "No reset-pin found. Chip may get stuck!\n");
 112 }
 113
 114 static void i2c_pca_pf_resetchip(void *pd)
 115 {
 116         struct i2c_pca_pf_data *i2c = pd;
 117
 118         gpiod_set_value(i2c->gpio, 1);
 119         ndelay(100);
 120         gpiod_set_value(i2c->gpio, 0);
 121 }
 122
 123 static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
 124 {
 125         struct i2c_pca_pf_data *i2c = dev_id;
 126
 127         if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
 128                 return IRQ_NONE;
 129
 130         wake_up(&i2c->wait);
 131
 132         return IRQ_HANDLED;
 133 }
 134
 135
 136 static int i2c_pca_pf_probe(struct platform_device *pdev)
 137 {
 138         struct i2c_pca_pf_data *i2c;
 139         struct resource *res;
 140         struct i2c_pca9564_pf_platform_data *platform_data =
 141                                 dev_get_platdata(&pdev->dev);
 142         struct device_node *np = pdev->dev.of_node;
 143         int ret = 0;
 144         int irq;
 145
 146         irq = platform_get_irq(pdev, 0);
 147         /* If irq is 0, we do polling. */
 148         if (irq < 0)
 149                 irq = 0;
 150
 151         i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
 152         if (!i2c)
 153                 return -ENOMEM;
 154
 155         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 156         i2c->reg_base = devm_ioremap_resource(&pdev->dev, res);
 157         if (IS_ERR(i2c->reg_base))
 158                 return PTR_ERR(i2c->reg_base);
 159
 160
 161         init_waitqueue_head(&i2c->wait);
 162
 163         i2c->io_base = res->start;
 164         i2c->io_size = resource_size(res);
 165         i2c->irq = irq;
 166
 167         i2c->adap.nr = pdev->id;
 168         i2c->adap.owner = THIS_MODULE;
 169         snprintf(i2c->adap.name, sizeof(i2c->adap.name),
 170                  "PCA9564/PCA9665 at 0x%08lx",
 171                  (unsigned long) res->start);
 172         i2c->adap.algo_data = &i2c->algo_data;
 173         i2c->adap.dev.parent = &pdev->dev;
 174         i2c->adap.dev.of_node = np;
 175
 176         if (platform_data) {
 177                 i2c->adap.timeout = platform_data->timeout;
 178                 i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
 179                 if (gpio_is_valid(platform_data->gpio)) {
 180                         ret = devm_gpio_request_one(&pdev->dev,
 181                                                     platform_data->gpio,
 182                                                     GPIOF_ACTIVE_LOW,
 183                                                     i2c->adap.name);
 184                         if (ret == 0) {
 185                                 i2c->gpio = gpio_to_desc(platform_data->gpio);
 186                                 gpiod_direction_output(i2c->gpio, 0);
 187                         } else {
 188                                 dev_warn(&pdev->dev, "Registering gpio failed!\n");
 189                                 i2c->gpio = NULL;
 190                         }
 191                 }
 192         } else if (np) {
 193                 i2c->adap.timeout = HZ;
 194                 i2c->gpio = devm_gpiod_get_optional(&pdev->dev, "reset-gpios", GPIOD_OUT_LOW);
 195                 if (IS_ERR(i2c->gpio))
 196                         return PTR_ERR(i2c->gpio);
 197                 of_property_read_u32_index(np, "clock-frequency", 0,
 198                                            &i2c->algo_data.i2c_clock);
 199         } else {
 200                 i2c->adap.timeout = HZ;
 201                 i2c->algo_data.i2c_clock = 59000;
 202                 i2c->gpio = NULL;
 203         }
 204
 205         i2c->algo_data.data = i2c;
 206         i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
 207         if (i2c->gpio)
 208                 i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
 209         else
 210                 i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
 211
 212         switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
 213         case IORESOURCE_MEM_32BIT:
 214                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
 215                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
 216                 break;
 217         case IORESOURCE_MEM_16BIT:
 218                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
 219                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
 220                 break;
 221         case IORESOURCE_MEM_8BIT:
 222         default:
 223                 i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
 224                 i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
 225                 break;
 226         }
 227
 228         if (irq) {
 229                 ret = devm_request_irq(&pdev->dev, irq, i2c_pca_pf_handler,
 230                         IRQF_TRIGGER_FALLING, pdev->name, i2c);
 231                 if (ret)
 232                         return ret;
 233         }
 234
 235         ret = i2c_pca_add_numbered_bus(&i2c->adap);
 236         if (ret)
 237                 return ret;
 238
 239         platform_set_drvdata(pdev, i2c);
 240
 241         dev_info(&pdev->dev, "registered.\n");
 242
 243         return 0;
 244 }
 245
 246 static int i2c_pca_pf_remove(struct platform_device *pdev)
 247 {
 248         struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
 249
 250         i2c_del_adapter(&i2c->adap);
 251
 252         return 0;
 253 }
 254
 255 #ifdef CONFIG_OF
 256 static const struct of_device_id i2c_pca_of_match_table[] = {
 257         { .compatible = "nxp,pca9564" },
 258         { .compatible = "nxp,pca9665" },
 259         {},
 260 };
 261 MODULE_DEVICE_TABLE(of, i2c_pca_of_match_table);
 262 #endif
 263
 264 static struct platform_driver i2c_pca_pf_driver = {
 265         .probe = i2c_pca_pf_probe,
 266         .remove = i2c_pca_pf_remove,
 267         .driver = {
 268                 .name = "i2c-pca-platform",
 269                 .of_match_table = of_match_ptr(i2c_pca_of_match_table),
 270         },
 271 };
 272
 273 module_platform_driver(i2c_pca_pf_driver);
 274
 275 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
 276 MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
 277 MODULE_LICENSE("GPL");