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 = -ENOMEM; 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); 298 299