1 // SPDX-License-Identifier: GPL-2.0-only
2 /* drivers/rtc/rtc-v3020.c
3  *
4  * Copyright (C) 2006 8D Technologies inc.
5  * Copyright (C) 2004 Compulab Ltd.
6  *
7  * Driver for the V3020 RTC
8  *
9  * Changelog:
10  *
11  *  10-May-2006: Raphael Assenat <raph@8d.com>
12  *				- Converted to platform driver
13  *				- Use the generic rtc class
14  *
15  *  ??-???-2004: Someone at Compulab
16  *			- Initial driver creation.
17  */
18 #include <linux/platform_device.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/rtc.h>
22 #include <linux/types.h>
23 #include <linux/bcd.h>
24 #include <linux/platform_data/rtc-v3020.h>
25 #include <linux/delay.h>
26 #include <linux/gpio.h>
27 #include <linux/slab.h>
28 
29 #include <linux/io.h>
30 
31 #undef DEBUG
32 
33 struct v3020;
34 
35 struct v3020_chip_ops {
36 	int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
37 		      struct v3020_platform_data *pdata);
38 	void (*unmap_io)(struct v3020 *chip);
39 	unsigned char (*read_bit)(struct v3020 *chip);
40 	void (*write_bit)(struct v3020 *chip, unsigned char bit);
41 };
42 
43 #define V3020_CS	0
44 #define V3020_WR	1
45 #define V3020_RD	2
46 #define V3020_IO	3
47 
48 struct v3020 {
49 	/* MMIO access */
50 	void __iomem *ioaddress;
51 	int leftshift;
52 
53 	/* GPIO access */
54 	struct gpio *gpio;
55 
56 	const struct v3020_chip_ops *ops;
57 
58 	struct rtc_device *rtc;
59 };
60 
61 
v3020_mmio_map(struct v3020 * chip,struct platform_device * pdev,struct v3020_platform_data * pdata)62 static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
63 			  struct v3020_platform_data *pdata)
64 {
65 	if (pdev->num_resources != 1)
66 		return -EBUSY;
67 
68 	if (pdev->resource[0].flags != IORESOURCE_MEM)
69 		return -EBUSY;
70 
71 	chip->leftshift = pdata->leftshift;
72 	chip->ioaddress = ioremap(pdev->resource[0].start, 1);
73 	if (chip->ioaddress == NULL)
74 		return -EBUSY;
75 
76 	return 0;
77 }
78 
v3020_mmio_unmap(struct v3020 * chip)79 static void v3020_mmio_unmap(struct v3020 *chip)
80 {
81 	iounmap(chip->ioaddress);
82 }
83 
v3020_mmio_write_bit(struct v3020 * chip,unsigned char bit)84 static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
85 {
86 	writel(bit << chip->leftshift, chip->ioaddress);
87 }
88 
v3020_mmio_read_bit(struct v3020 * chip)89 static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
90 {
91 	return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
92 }
93 
94 static const struct v3020_chip_ops v3020_mmio_ops = {
95 	.map_io		= v3020_mmio_map,
96 	.unmap_io	= v3020_mmio_unmap,
97 	.read_bit	= v3020_mmio_read_bit,
98 	.write_bit	= v3020_mmio_write_bit,
99 };
100 
101 static struct gpio v3020_gpio[] = {
102 	{ 0, GPIOF_OUT_INIT_HIGH, "RTC CS"},
103 	{ 0, GPIOF_OUT_INIT_HIGH, "RTC WR"},
104 	{ 0, GPIOF_OUT_INIT_HIGH, "RTC RD"},
105 	{ 0, GPIOF_OUT_INIT_HIGH, "RTC IO"},
106 };
107 
v3020_gpio_map(struct v3020 * chip,struct platform_device * pdev,struct v3020_platform_data * pdata)108 static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
109 			  struct v3020_platform_data *pdata)
110 {
111 	int err;
112 
113 	v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
114 	v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
115 	v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
116 	v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
117 
118 	err = gpio_request_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
119 
120 	if (!err)
121 		chip->gpio = v3020_gpio;
122 
123 	return err;
124 }
125 
v3020_gpio_unmap(struct v3020 * chip)126 static void v3020_gpio_unmap(struct v3020 *chip)
127 {
128 	gpio_free_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
129 }
130 
v3020_gpio_write_bit(struct v3020 * chip,unsigned char bit)131 static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
132 {
133 	gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
134 	gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
135 	gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
136 	udelay(1);
137 	gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
138 	gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
139 }
140 
v3020_gpio_read_bit(struct v3020 * chip)141 static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
142 {
143 	int bit;
144 
145 	gpio_direction_input(chip->gpio[V3020_IO].gpio);
146 	gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
147 	gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
148 	udelay(1);
149 	bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
150 	udelay(1);
151 	gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
152 	gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
153 
154 	return bit;
155 }
156 
157 static const struct v3020_chip_ops v3020_gpio_ops = {
158 	.map_io		= v3020_gpio_map,
159 	.unmap_io	= v3020_gpio_unmap,
160 	.read_bit	= v3020_gpio_read_bit,
161 	.write_bit	= v3020_gpio_write_bit,
162 };
163 
v3020_set_reg(struct v3020 * chip,unsigned char address,unsigned char data)164 static void v3020_set_reg(struct v3020 *chip, unsigned char address,
165 			unsigned char data)
166 {
167 	int i;
168 	unsigned char tmp;
169 
170 	tmp = address;
171 	for (i = 0; i < 4; i++) {
172 		chip->ops->write_bit(chip, (tmp & 1));
173 		tmp >>= 1;
174 		udelay(1);
175 	}
176 
177 	/* Commands dont have data */
178 	if (!V3020_IS_COMMAND(address)) {
179 		for (i = 0; i < 8; i++) {
180 			chip->ops->write_bit(chip, (data & 1));
181 			data >>= 1;
182 			udelay(1);
183 		}
184 	}
185 }
186 
v3020_get_reg(struct v3020 * chip,unsigned char address)187 static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
188 {
189 	unsigned int data = 0;
190 	int i;
191 
192 	for (i = 0; i < 4; i++) {
193 		chip->ops->write_bit(chip, (address & 1));
194 		address >>= 1;
195 		udelay(1);
196 	}
197 
198 	for (i = 0; i < 8; i++) {
199 		data >>= 1;
200 		if (chip->ops->read_bit(chip))
201 			data |= 0x80;
202 		udelay(1);
203 	}
204 
205 	return data;
206 }
207 
v3020_read_time(struct device * dev,struct rtc_time * dt)208 static int v3020_read_time(struct device *dev, struct rtc_time *dt)
209 {
210 	struct v3020 *chip = dev_get_drvdata(dev);
211 	int tmp;
212 
213 	/* Copy the current time to ram... */
214 	v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
215 
216 	/* ...and then read constant values. */
217 	tmp = v3020_get_reg(chip, V3020_SECONDS);
218 	dt->tm_sec	= bcd2bin(tmp);
219 	tmp = v3020_get_reg(chip, V3020_MINUTES);
220 	dt->tm_min	= bcd2bin(tmp);
221 	tmp = v3020_get_reg(chip, V3020_HOURS);
222 	dt->tm_hour	= bcd2bin(tmp);
223 	tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
224 	dt->tm_mday	= bcd2bin(tmp);
225 	tmp = v3020_get_reg(chip, V3020_MONTH);
226 	dt->tm_mon    = bcd2bin(tmp) - 1;
227 	tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
228 	dt->tm_wday	= bcd2bin(tmp);
229 	tmp = v3020_get_reg(chip, V3020_YEAR);
230 	dt->tm_year = bcd2bin(tmp)+100;
231 
232 	dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
233 	dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
234 	dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
235 	dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
236 	dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
237 	dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
238 	dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
239 	dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
240 
241 	return 0;
242 }
243 
244 
v3020_set_time(struct device * dev,struct rtc_time * dt)245 static int v3020_set_time(struct device *dev, struct rtc_time *dt)
246 {
247 	struct v3020 *chip = dev_get_drvdata(dev);
248 
249 	dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
250 	dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
251 	dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
252 	dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
253 	dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
254 	dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
255 	dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
256 
257 	/* Write all the values to ram... */
258 	v3020_set_reg(chip, V3020_SECONDS,	bin2bcd(dt->tm_sec));
259 	v3020_set_reg(chip, V3020_MINUTES,	bin2bcd(dt->tm_min));
260 	v3020_set_reg(chip, V3020_HOURS,	bin2bcd(dt->tm_hour));
261 	v3020_set_reg(chip, V3020_MONTH_DAY,	bin2bcd(dt->tm_mday));
262 	v3020_set_reg(chip, V3020_MONTH,	bin2bcd(dt->tm_mon + 1));
263 	v3020_set_reg(chip, V3020_WEEK_DAY,	bin2bcd(dt->tm_wday));
264 	v3020_set_reg(chip, V3020_YEAR,		bin2bcd(dt->tm_year % 100));
265 
266 	/* ...and set the clock. */
267 	v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
268 
269 	/* Compulab used this delay here. I dont know why,
270 	 * the datasheet does not specify a delay. */
271 	/*mdelay(5);*/
272 
273 	return 0;
274 }
275 
276 static const struct rtc_class_ops v3020_rtc_ops = {
277 	.read_time	= v3020_read_time,
278 	.set_time	= v3020_set_time,
279 };
280 
rtc_probe(struct platform_device * pdev)281 static int rtc_probe(struct platform_device *pdev)
282 {
283 	struct v3020_platform_data *pdata = dev_get_platdata(&pdev->dev);
284 	struct v3020 *chip;
285 	int retval;
286 	int i;
287 
288 	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
289 	if (!chip)
290 		return -ENOMEM;
291 
292 	if (pdata->use_gpio)
293 		chip->ops = &v3020_gpio_ops;
294 	else
295 		chip->ops = &v3020_mmio_ops;
296 
297 	retval = chip->ops->map_io(chip, pdev, pdata);
298 	if (retval)
299 		return retval;
300 
301 	/* Make sure the v3020 expects a communication cycle
302 	 * by reading 8 times */
303 	for (i = 0; i < 8; i++)
304 		chip->ops->read_bit(chip);
305 
306 	/* Test chip by doing a write/read sequence
307 	 * to the chip ram */
308 	v3020_set_reg(chip, V3020_SECONDS, 0x33);
309 	if (v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
310 		retval = -ENODEV;
311 		goto err_io;
312 	}
313 
314 	/* Make sure frequency measurement mode, test modes, and lock
315 	 * are all disabled */
316 	v3020_set_reg(chip, V3020_STATUS_0, 0x0);
317 
318 	if (pdata->use_gpio)
319 		dev_info(&pdev->dev, "Chip available at GPIOs "
320 			 "%d, %d, %d, %d\n",
321 			 chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
322 			 chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
323 	else
324 		dev_info(&pdev->dev, "Chip available at "
325 			 "physical address 0x%llx,"
326 			 "data connected to D%d\n",
327 			 (unsigned long long)pdev->resource[0].start,
328 			 chip->leftshift);
329 
330 	platform_set_drvdata(pdev, chip);
331 
332 	chip->rtc = devm_rtc_device_register(&pdev->dev, "v3020",
333 					&v3020_rtc_ops, THIS_MODULE);
334 	if (IS_ERR(chip->rtc)) {
335 		retval = PTR_ERR(chip->rtc);
336 		goto err_io;
337 	}
338 
339 	return 0;
340 
341 err_io:
342 	chip->ops->unmap_io(chip);
343 
344 	return retval;
345 }
346 
rtc_remove(struct platform_device * dev)347 static int rtc_remove(struct platform_device *dev)
348 {
349 	struct v3020 *chip = platform_get_drvdata(dev);
350 
351 	chip->ops->unmap_io(chip);
352 
353 	return 0;
354 }
355 
356 static struct platform_driver rtc_device_driver = {
357 	.probe	= rtc_probe,
358 	.remove = rtc_remove,
359 	.driver = {
360 		.name	= "v3020",
361 	},
362 };
363 
364 module_platform_driver(rtc_device_driver);
365 
366 MODULE_DESCRIPTION("V3020 RTC");
367 MODULE_AUTHOR("Raphael Assenat");
368 MODULE_LICENSE("GPL");
369 MODULE_ALIAS("platform:v3020");
370