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Linux/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                 .owner = THIS_MODULE,
284         },
285 };
286 
287 module_platform_driver(i2c_pca_pf_driver);
288 
289 MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
290 MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
291 MODULE_LICENSE("GPL");
292 

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