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Linux/drivers/rtc/rtc-v3020.c

  1 /* drivers/rtc/rtc-v3020.c
  2  *
  3  * Copyright (C) 2006 8D Technologies inc.
  4  * Copyright (C) 2004 Compulab Ltd.
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License version 2 as
  8  * published by the Free Software Foundation.
  9  *
 10  * Driver for the V3020 RTC
 11  *
 12  * Changelog:
 13  *
 14  *  10-May-2006: Raphael Assenat <raph@8d.com>
 15  *                              - Converted to platform driver
 16  *                              - Use the generic rtc class
 17  *
 18  *  ??-???-2004: Someone at Compulab
 19  *                      - Initial driver creation.
 20  *
 21  */
 22 #include <linux/platform_device.h>
 23 #include <linux/module.h>
 24 #include <linux/init.h>
 25 #include <linux/rtc.h>
 26 #include <linux/types.h>
 27 #include <linux/bcd.h>
 28 #include <linux/rtc-v3020.h>
 29 #include <linux/delay.h>
 30 #include <linux/gpio.h>
 31 #include <linux/slab.h>
 32 
 33 #include <linux/io.h>
 34 
 35 #undef DEBUG
 36 
 37 struct v3020;
 38 
 39 struct v3020_chip_ops {
 40         int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
 41                       struct v3020_platform_data *pdata);
 42         void (*unmap_io)(struct v3020 *chip);
 43         unsigned char (*read_bit)(struct v3020 *chip);
 44         void (*write_bit)(struct v3020 *chip, unsigned char bit);
 45 };
 46 
 47 #define V3020_CS        0
 48 #define V3020_WR        1
 49 #define V3020_RD        2
 50 #define V3020_IO        3
 51 
 52 struct v3020 {
 53         /* MMIO access */
 54         void __iomem *ioaddress;
 55         int leftshift;
 56 
 57         /* GPIO access */
 58         struct gpio *gpio;
 59 
 60         struct v3020_chip_ops *ops;
 61 
 62         struct rtc_device *rtc;
 63 };
 64 
 65 
 66 static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
 67                           struct v3020_platform_data *pdata)
 68 {
 69         if (pdev->num_resources != 1)
 70                 return -EBUSY;
 71 
 72         if (pdev->resource[0].flags != IORESOURCE_MEM)
 73                 return -EBUSY;
 74 
 75         chip->leftshift = pdata->leftshift;
 76         chip->ioaddress = ioremap(pdev->resource[0].start, 1);
 77         if (chip->ioaddress == NULL)
 78                 return -EBUSY;
 79 
 80         return 0;
 81 }
 82 
 83 static void v3020_mmio_unmap(struct v3020 *chip)
 84 {
 85         iounmap(chip->ioaddress);
 86 }
 87 
 88 static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
 89 {
 90         writel(bit << chip->leftshift, chip->ioaddress);
 91 }
 92 
 93 static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
 94 {
 95         return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
 96 }
 97 
 98 static struct v3020_chip_ops v3020_mmio_ops = {
 99         .map_io         = v3020_mmio_map,
100         .unmap_io       = v3020_mmio_unmap,
101         .read_bit       = v3020_mmio_read_bit,
102         .write_bit      = v3020_mmio_write_bit,
103 };
104 
105 static struct gpio v3020_gpio[] = {
106         { 0, GPIOF_OUT_INIT_HIGH, "RTC CS"},
107         { 0, GPIOF_OUT_INIT_HIGH, "RTC WR"},
108         { 0, GPIOF_OUT_INIT_HIGH, "RTC RD"},
109         { 0, GPIOF_OUT_INIT_HIGH, "RTC IO"},
110 };
111 
112 static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
113                           struct v3020_platform_data *pdata)
114 {
115         int err;
116 
117         v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
118         v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
119         v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
120         v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
121 
122         err = gpio_request_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
123 
124         if (!err)
125                 chip->gpio = v3020_gpio;
126 
127         return err;
128 }
129 
130 static void v3020_gpio_unmap(struct v3020 *chip)
131 {
132         gpio_free_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
133 }
134 
135 static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
136 {
137         gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
138         gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
139         gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
140         udelay(1);
141         gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
142         gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
143 }
144 
145 static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
146 {
147         int bit;
148 
149         gpio_direction_input(chip->gpio[V3020_IO].gpio);
150         gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
151         gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
152         udelay(1);
153         bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
154         udelay(1);
155         gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
156         gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
157 
158         return bit;
159 }
160 
161 static struct v3020_chip_ops v3020_gpio_ops = {
162         .map_io         = v3020_gpio_map,
163         .unmap_io       = v3020_gpio_unmap,
164         .read_bit       = v3020_gpio_read_bit,
165         .write_bit      = v3020_gpio_write_bit,
166 };
167 
168 static void v3020_set_reg(struct v3020 *chip, unsigned char address,
169                         unsigned char data)
170 {
171         int i;
172         unsigned char tmp;
173 
174         tmp = address;
175         for (i = 0; i < 4; i++) {
176                 chip->ops->write_bit(chip, (tmp & 1));
177                 tmp >>= 1;
178                 udelay(1);
179         }
180 
181         /* Commands dont have data */
182         if (!V3020_IS_COMMAND(address)) {
183                 for (i = 0; i < 8; i++) {
184                         chip->ops->write_bit(chip, (data & 1));
185                         data >>= 1;
186                         udelay(1);
187                 }
188         }
189 }
190 
191 static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
192 {
193         unsigned int data = 0;
194         int i;
195 
196         for (i = 0; i < 4; i++) {
197                 chip->ops->write_bit(chip, (address & 1));
198                 address >>= 1;
199                 udelay(1);
200         }
201 
202         for (i = 0; i < 8; i++) {
203                 data >>= 1;
204                 if (chip->ops->read_bit(chip))
205                         data |= 0x80;
206                 udelay(1);
207         }
208 
209         return data;
210 }
211 
212 static int v3020_read_time(struct device *dev, struct rtc_time *dt)
213 {
214         struct v3020 *chip = dev_get_drvdata(dev);
215         int tmp;
216 
217         /* Copy the current time to ram... */
218         v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
219 
220         /* ...and then read constant values. */
221         tmp = v3020_get_reg(chip, V3020_SECONDS);
222         dt->tm_sec      = bcd2bin(tmp);
223         tmp = v3020_get_reg(chip, V3020_MINUTES);
224         dt->tm_min      = bcd2bin(tmp);
225         tmp = v3020_get_reg(chip, V3020_HOURS);
226         dt->tm_hour     = bcd2bin(tmp);
227         tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
228         dt->tm_mday     = bcd2bin(tmp);
229         tmp = v3020_get_reg(chip, V3020_MONTH);
230         dt->tm_mon    = bcd2bin(tmp) - 1;
231         tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
232         dt->tm_wday     = bcd2bin(tmp);
233         tmp = v3020_get_reg(chip, V3020_YEAR);
234         dt->tm_year = bcd2bin(tmp)+100;
235 
236         dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
237         dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
238         dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
239         dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
240         dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
241         dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
242         dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
243         dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
244 
245         return 0;
246 }
247 
248 
249 static int v3020_set_time(struct device *dev, struct rtc_time *dt)
250 {
251         struct v3020 *chip = dev_get_drvdata(dev);
252 
253         dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
254         dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
255         dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
256         dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
257         dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
258         dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
259         dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
260 
261         /* Write all the values to ram... */
262         v3020_set_reg(chip, V3020_SECONDS,      bin2bcd(dt->tm_sec));
263         v3020_set_reg(chip, V3020_MINUTES,      bin2bcd(dt->tm_min));
264         v3020_set_reg(chip, V3020_HOURS,        bin2bcd(dt->tm_hour));
265         v3020_set_reg(chip, V3020_MONTH_DAY,    bin2bcd(dt->tm_mday));
266         v3020_set_reg(chip, V3020_MONTH,        bin2bcd(dt->tm_mon + 1));
267         v3020_set_reg(chip, V3020_WEEK_DAY,     bin2bcd(dt->tm_wday));
268         v3020_set_reg(chip, V3020_YEAR,         bin2bcd(dt->tm_year % 100));
269 
270         /* ...and set the clock. */
271         v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
272 
273         /* Compulab used this delay here. I dont know why,
274          * the datasheet does not specify a delay. */
275         /*mdelay(5);*/
276 
277         return 0;
278 }
279 
280 static const struct rtc_class_ops v3020_rtc_ops = {
281         .read_time      = v3020_read_time,
282         .set_time       = v3020_set_time,
283 };
284 
285 static int rtc_probe(struct platform_device *pdev)
286 {
287         struct v3020_platform_data *pdata = dev_get_platdata(&pdev->dev);
288         struct v3020 *chip;
289         int retval = -EBUSY;
290         int i;
291         int temp;
292 
293         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
294         if (!chip)
295                 return -ENOMEM;
296 
297         if (pdata->use_gpio)
298                 chip->ops = &v3020_gpio_ops;
299         else
300                 chip->ops = &v3020_mmio_ops;
301 
302         retval = chip->ops->map_io(chip, pdev, pdata);
303         if (retval)
304                 return retval;
305 
306         /* Make sure the v3020 expects a communication cycle
307          * by reading 8 times */
308         for (i = 0; i < 8; i++)
309                 temp = chip->ops->read_bit(chip);
310 
311         /* Test chip by doing a write/read sequence
312          * to the chip ram */
313         v3020_set_reg(chip, V3020_SECONDS, 0x33);
314         if (v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
315                 retval = -ENODEV;
316                 goto err_io;
317         }
318 
319         /* Make sure frequency measurement mode, test modes, and lock
320          * are all disabled */
321         v3020_set_reg(chip, V3020_STATUS_0, 0x0);
322 
323         if (pdata->use_gpio)
324                 dev_info(&pdev->dev, "Chip available at GPIOs "
325                          "%d, %d, %d, %d\n",
326                          chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
327                          chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
328         else
329                 dev_info(&pdev->dev, "Chip available at "
330                          "physical address 0x%llx,"
331                          "data connected to D%d\n",
332                          (unsigned long long)pdev->resource[0].start,
333                          chip->leftshift);
334 
335         platform_set_drvdata(pdev, chip);
336 
337         chip->rtc = devm_rtc_device_register(&pdev->dev, "v3020",
338                                         &v3020_rtc_ops, THIS_MODULE);
339         if (IS_ERR(chip->rtc)) {
340                 retval = PTR_ERR(chip->rtc);
341                 goto err_io;
342         }
343 
344         return 0;
345 
346 err_io:
347         chip->ops->unmap_io(chip);
348 
349         return retval;
350 }
351 
352 static int rtc_remove(struct platform_device *dev)
353 {
354         struct v3020 *chip = platform_get_drvdata(dev);
355 
356         chip->ops->unmap_io(chip);
357 
358         return 0;
359 }
360 
361 static struct platform_driver rtc_device_driver = {
362         .probe  = rtc_probe,
363         .remove = rtc_remove,
364         .driver = {
365                 .name   = "v3020",
366         },
367 };
368 
369 module_platform_driver(rtc_device_driver);
370 
371 MODULE_DESCRIPTION("V3020 RTC");
372 MODULE_AUTHOR("Raphael Assenat");
373 MODULE_LICENSE("GPL");
374 MODULE_ALIAS("platform:v3020");
375 

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