1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Real Time Clock (RTC) Driver for sd3078
  4 * Copyright (C) 2018 Zoro Li
  5 */
  6
  7#include <linux/bcd.h>
  8#include <linux/i2c.h>
  9#include <linux/module.h>
 10#include <linux/regmap.h>
 11#include <linux/rtc.h>
 12#include <linux/slab.h>
 13
 14#define SD3078_REG_SC			0x00
 15#define SD3078_REG_MN			0x01
 16#define SD3078_REG_HR			0x02
 17#define SD3078_REG_DW			0x03
 18#define SD3078_REG_DM			0x04
 19#define SD3078_REG_MO			0x05
 20#define SD3078_REG_YR			0x06
 21
 22#define SD3078_REG_CTRL1		0x0f
 23#define SD3078_REG_CTRL2		0x10
 24#define SD3078_REG_CTRL3		0x11
 25
 26#define KEY_WRITE1		0x80
 27#define KEY_WRITE2		0x04
 28#define KEY_WRITE3		0x80
 29
 30#define NUM_TIME_REGS   (SD3078_REG_YR - SD3078_REG_SC + 1)
 31
 32/*
 33 * The sd3078 has write protection
 34 * and we can choose whether or not to use it.
 35 * Write protection is turned off by default.
 36 */
 37#define WRITE_PROTECT_EN	0
 38
 39struct sd3078 {
 40	struct rtc_device	*rtc;
 41	struct regmap		*regmap;
 42};
 43
 44/*
 45 * In order to prevent arbitrary modification of the time register,
 46 * when modification of the register,
 47 * the "write" bit needs to be written in a certain order.
 48 * 1. set WRITE1 bit
 49 * 2. set WRITE2 bit
 50 * 3. set WRITE3 bit
 51 */
 52static void sd3078_enable_reg_write(struct sd3078 *sd3078)
 53{
 54	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL2,
 55			   KEY_WRITE1, KEY_WRITE1);
 56	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL1,
 57			   KEY_WRITE2, KEY_WRITE2);
 58	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL1,
 59			   KEY_WRITE3, KEY_WRITE3);
 60}
 61
 62#if WRITE_PROTECT_EN
 63/*
 64 * In order to prevent arbitrary modification of the time register,
 65 * we should disable the write function.
 66 * when disable write,
 67 * the "write" bit needs to be clear in a certain order.
 68 * 1. clear WRITE2 bit
 69 * 2. clear WRITE3 bit
 70 * 3. clear WRITE1 bit
 71 */
 72static void sd3078_disable_reg_write(struct sd3078 *sd3078)
 73{
 74	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL1,
 75			   KEY_WRITE2, 0);
 76	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL1,
 77			   KEY_WRITE3, 0);
 78	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL2,
 79			   KEY_WRITE1, 0);
 80}
 81#endif
 82
 83static int sd3078_rtc_read_time(struct device *dev, struct rtc_time *tm)
 84{
 85	unsigned char hour;
 86	unsigned char rtc_data[NUM_TIME_REGS] = {0};
 87	struct i2c_client *client = to_i2c_client(dev);
 88	struct sd3078 *sd3078 = i2c_get_clientdata(client);
 89	int ret;
 90
 91	ret = regmap_bulk_read(sd3078->regmap, SD3078_REG_SC, rtc_data,
 92			       NUM_TIME_REGS);
 93	if (ret < 0) {
 94		dev_err(dev, "reading from RTC failed with err:%d\n", ret);
 95		return ret;
 96	}
 97
 98	tm->tm_sec	= bcd2bin(rtc_data[SD3078_REG_SC] & 0x7F);
 99	tm->tm_min	= bcd2bin(rtc_data[SD3078_REG_MN] & 0x7F);
100
101	/*
102	 * The sd3078 supports 12/24 hour mode.
103	 * When getting time,
104	 * we need to convert the 12 hour mode to the 24 hour mode.
105	 */
106	hour = rtc_data[SD3078_REG_HR];
107	if (hour & 0x80) /* 24H MODE */
108		tm->tm_hour = bcd2bin(rtc_data[SD3078_REG_HR] & 0x3F);
109	else if (hour & 0x20) /* 12H MODE PM */
110		tm->tm_hour = bcd2bin(rtc_data[SD3078_REG_HR] & 0x1F) + 12;
111	else /* 12H MODE AM */
112		tm->tm_hour = bcd2bin(rtc_data[SD3078_REG_HR] & 0x1F);
113
114	tm->tm_mday = bcd2bin(rtc_data[SD3078_REG_DM] & 0x3F);
115	tm->tm_wday = rtc_data[SD3078_REG_DW] & 0x07;
116	tm->tm_mon	= bcd2bin(rtc_data[SD3078_REG_MO] & 0x1F) - 1;
117	tm->tm_year = bcd2bin(rtc_data[SD3078_REG_YR]) + 100;
118
119	return 0;
120}
121
122static int sd3078_rtc_set_time(struct device *dev, struct rtc_time *tm)
123{
124	unsigned char rtc_data[NUM_TIME_REGS];
125	struct i2c_client *client = to_i2c_client(dev);
126	struct sd3078 *sd3078 = i2c_get_clientdata(client);
127	int ret;
128
129	rtc_data[SD3078_REG_SC] = bin2bcd(tm->tm_sec);
130	rtc_data[SD3078_REG_MN] = bin2bcd(tm->tm_min);
131	rtc_data[SD3078_REG_HR] = bin2bcd(tm->tm_hour) | 0x80;
132	rtc_data[SD3078_REG_DM] = bin2bcd(tm->tm_mday);
133	rtc_data[SD3078_REG_DW] = tm->tm_wday & 0x07;
134	rtc_data[SD3078_REG_MO] = bin2bcd(tm->tm_mon) + 1;
135	rtc_data[SD3078_REG_YR] = bin2bcd(tm->tm_year - 100);
136
137#if WRITE_PROTECT_EN
138	sd3078_enable_reg_write(sd3078);
139#endif
140
141	ret = regmap_bulk_write(sd3078->regmap, SD3078_REG_SC, rtc_data,
142				NUM_TIME_REGS);
143	if (ret < 0) {
144		dev_err(dev, "writing to RTC failed with err:%d\n", ret);
145		return ret;
146	}
147
148#if WRITE_PROTECT_EN
149	sd3078_disable_reg_write(sd3078);
150#endif
151
152	return 0;
153}
154
155static const struct rtc_class_ops sd3078_rtc_ops = {
156	.read_time	= sd3078_rtc_read_time,
157	.set_time	= sd3078_rtc_set_time,
158};
159
160static const struct regmap_config regmap_config = {
161	.reg_bits = 8,
162	.val_bits = 8,
163	.max_register = 0x11,
164};
165
166static int sd3078_probe(struct i2c_client *client)
167{
168	int ret;
169	struct sd3078 *sd3078;
170
171	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
172		return -ENODEV;
173
174	sd3078 = devm_kzalloc(&client->dev, sizeof(*sd3078), GFP_KERNEL);
175	if (!sd3078)
176		return -ENOMEM;
177
178	sd3078->regmap = devm_regmap_init_i2c(client, &regmap_config);
179	if (IS_ERR(sd3078->regmap)) {
180		dev_err(&client->dev, "regmap allocation failed\n");
181		return PTR_ERR(sd3078->regmap);
182	}
183
184	i2c_set_clientdata(client, sd3078);
185
186	sd3078->rtc = devm_rtc_allocate_device(&client->dev);
187	if (IS_ERR(sd3078->rtc))
188		return PTR_ERR(sd3078->rtc);
189
190	sd3078->rtc->ops = &sd3078_rtc_ops;
191	sd3078->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
192	sd3078->rtc->range_max = RTC_TIMESTAMP_END_2099;
193
194	ret = devm_rtc_register_device(sd3078->rtc);
195	if (ret)
196		return ret;
197
198	sd3078_enable_reg_write(sd3078);
199
200	return 0;
201}
202
203static const struct i2c_device_id sd3078_id[] = {
204	{"sd3078", 0},
205	{ }
206};
207MODULE_DEVICE_TABLE(i2c, sd3078_id);
208
209static const __maybe_unused struct of_device_id rtc_dt_match[] = {
210	{ .compatible = "whwave,sd3078" },
211	{},
212};
213MODULE_DEVICE_TABLE(of, rtc_dt_match);
214
215static struct i2c_driver sd3078_driver = {
216	.driver     = {
217		.name   = "sd3078",
218		.of_match_table = of_match_ptr(rtc_dt_match),
219	},
220	.probe      = sd3078_probe,
221	.id_table   = sd3078_id,
222};
223
224module_i2c_driver(sd3078_driver);
225
226MODULE_AUTHOR("Dianlong Li <long17.cool@163.com>");
227MODULE_DESCRIPTION("SD3078 RTC driver");
228MODULE_LICENSE("GPL v2");

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Real Time Clock (RTC) Driver for sd3078
  4 * Copyright (C) 2018 Zoro Li
  5 */
  6
  7#include <linux/bcd.h>
  8#include <linux/i2c.h>
  9#include <linux/module.h>
 10#include <linux/regmap.h>
 11#include <linux/rtc.h>
 12#include <linux/slab.h>
 13
 14#define SD3078_REG_SC			0x00
 15#define SD3078_REG_MN			0x01
 16#define SD3078_REG_HR			0x02
 17#define SD3078_REG_DW			0x03
 18#define SD3078_REG_DM			0x04
 19#define SD3078_REG_MO			0x05
 20#define SD3078_REG_YR			0x06
 21
 22#define SD3078_REG_CTRL1		0x0f
 23#define SD3078_REG_CTRL2		0x10
 24#define SD3078_REG_CTRL3		0x11
 25
 26#define KEY_WRITE1		0x80
 27#define KEY_WRITE2		0x04
 28#define KEY_WRITE3		0x80
 29
 30#define NUM_TIME_REGS   (SD3078_REG_YR - SD3078_REG_SC + 1)
 31
 32/*
 33 * The sd3078 has write protection
 34 * and we can choose whether or not to use it.
 35 * Write protection is turned off by default.
 36 */
 37#define WRITE_PROTECT_EN	0
 38
 39struct sd3078 {
 40	struct rtc_device	*rtc;
 41	struct regmap		*regmap;
 42};
 43
 44/*
 45 * In order to prevent arbitrary modification of the time register,
 46 * when modification of the register,
 47 * the "write" bit needs to be written in a certain order.
 48 * 1. set WRITE1 bit
 49 * 2. set WRITE2 bit
 50 * 3. set WRITE3 bit
 51 */
 52static void sd3078_enable_reg_write(struct sd3078 *sd3078)
 53{
 54	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL2,
 55			   KEY_WRITE1, KEY_WRITE1);
 56	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL1,
 57			   KEY_WRITE2, KEY_WRITE2);
 58	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL1,
 59			   KEY_WRITE3, KEY_WRITE3);
 60}
 61
 62#if WRITE_PROTECT_EN
 63/*
 64 * In order to prevent arbitrary modification of the time register,
 65 * we should disable the write function.
 66 * when disable write,
 67 * the "write" bit needs to be clear in a certain order.
 68 * 1. clear WRITE2 bit
 69 * 2. clear WRITE3 bit
 70 * 3. clear WRITE1 bit
 71 */
 72static void sd3078_disable_reg_write(struct sd3078 *sd3078)
 73{
 74	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL1,
 75			   KEY_WRITE2, 0);
 76	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL1,
 77			   KEY_WRITE3, 0);
 78	regmap_update_bits(sd3078->regmap, SD3078_REG_CTRL2,
 79			   KEY_WRITE1, 0);
 80}
 81#endif
 82
 83static int sd3078_rtc_read_time(struct device *dev, struct rtc_time *tm)
 84{
 85	unsigned char hour;
 86	unsigned char rtc_data[NUM_TIME_REGS] = {0};
 87	struct i2c_client *client = to_i2c_client(dev);
 88	struct sd3078 *sd3078 = i2c_get_clientdata(client);
 89	int ret;
 90
 91	ret = regmap_bulk_read(sd3078->regmap, SD3078_REG_SC, rtc_data,
 92			       NUM_TIME_REGS);
 93	if (ret < 0) {
 94		dev_err(dev, "reading from RTC failed with err:%d\n", ret);
 95		return ret;
 96	}
 97
 98	tm->tm_sec	= bcd2bin(rtc_data[SD3078_REG_SC] & 0x7F);
 99	tm->tm_min	= bcd2bin(rtc_data[SD3078_REG_MN] & 0x7F);
100
101	/*
102	 * The sd3078 supports 12/24 hour mode.
103	 * When getting time,
104	 * we need to convert the 12 hour mode to the 24 hour mode.
105	 */
106	hour = rtc_data[SD3078_REG_HR];
107	if (hour & 0x80) /* 24H MODE */
108		tm->tm_hour = bcd2bin(rtc_data[SD3078_REG_HR] & 0x3F);
109	else if (hour & 0x20) /* 12H MODE PM */
110		tm->tm_hour = bcd2bin(rtc_data[SD3078_REG_HR] & 0x1F) + 12;
111	else /* 12H MODE AM */
112		tm->tm_hour = bcd2bin(rtc_data[SD3078_REG_HR] & 0x1F);
113
114	tm->tm_mday = bcd2bin(rtc_data[SD3078_REG_DM] & 0x3F);
115	tm->tm_wday = rtc_data[SD3078_REG_DW] & 0x07;
116	tm->tm_mon	= bcd2bin(rtc_data[SD3078_REG_MO] & 0x1F) - 1;
117	tm->tm_year = bcd2bin(rtc_data[SD3078_REG_YR]) + 100;
118
119	return 0;
120}
121
122static int sd3078_rtc_set_time(struct device *dev, struct rtc_time *tm)
123{
124	unsigned char rtc_data[NUM_TIME_REGS];
125	struct i2c_client *client = to_i2c_client(dev);
126	struct sd3078 *sd3078 = i2c_get_clientdata(client);
127	int ret;
128
129	rtc_data[SD3078_REG_SC] = bin2bcd(tm->tm_sec);
130	rtc_data[SD3078_REG_MN] = bin2bcd(tm->tm_min);
131	rtc_data[SD3078_REG_HR] = bin2bcd(tm->tm_hour) | 0x80;
132	rtc_data[SD3078_REG_DM] = bin2bcd(tm->tm_mday);
133	rtc_data[SD3078_REG_DW] = tm->tm_wday & 0x07;
134	rtc_data[SD3078_REG_MO] = bin2bcd(tm->tm_mon) + 1;
135	rtc_data[SD3078_REG_YR] = bin2bcd(tm->tm_year - 100);
136
137#if WRITE_PROTECT_EN
138	sd3078_enable_reg_write(sd3078);
139#endif
140
141	ret = regmap_bulk_write(sd3078->regmap, SD3078_REG_SC, rtc_data,
142				NUM_TIME_REGS);
143	if (ret < 0) {
144		dev_err(dev, "writing to RTC failed with err:%d\n", ret);
145		return ret;
146	}
147
148#if WRITE_PROTECT_EN
149	sd3078_disable_reg_write(sd3078);
150#endif
151
152	return 0;
153}
154
155static const struct rtc_class_ops sd3078_rtc_ops = {
156	.read_time	= sd3078_rtc_read_time,
157	.set_time	= sd3078_rtc_set_time,
158};
159
160static const struct regmap_config regmap_config = {
161	.reg_bits = 8,
162	.val_bits = 8,
163	.max_register = 0x11,
164};
165
166static int sd3078_probe(struct i2c_client *client)
167{
168	int ret;
169	struct sd3078 *sd3078;
170
171	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
172		return -ENODEV;
173
174	sd3078 = devm_kzalloc(&client->dev, sizeof(*sd3078), GFP_KERNEL);
175	if (!sd3078)
176		return -ENOMEM;
177
178	sd3078->regmap = devm_regmap_init_i2c(client, &regmap_config);
179	if (IS_ERR(sd3078->regmap)) {
180		dev_err(&client->dev, "regmap allocation failed\n");
181		return PTR_ERR(sd3078->regmap);
182	}
183
184	i2c_set_clientdata(client, sd3078);
185
186	sd3078->rtc = devm_rtc_allocate_device(&client->dev);
187	if (IS_ERR(sd3078->rtc))
188		return PTR_ERR(sd3078->rtc);
189
190	sd3078->rtc->ops = &sd3078_rtc_ops;
191	sd3078->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
192	sd3078->rtc->range_max = RTC_TIMESTAMP_END_2099;
193
194	ret = devm_rtc_register_device(sd3078->rtc);
195	if (ret)
196		return ret;
197
198	sd3078_enable_reg_write(sd3078);
199
200	return 0;
201}
202
203static const struct i2c_device_id sd3078_id[] = {
204	{ "sd3078" },
205	{ }
206};
207MODULE_DEVICE_TABLE(i2c, sd3078_id);
208
209static const __maybe_unused struct of_device_id rtc_dt_match[] = {
210	{ .compatible = "whwave,sd3078" },
211	{},
212};
213MODULE_DEVICE_TABLE(of, rtc_dt_match);
214
215static struct i2c_driver sd3078_driver = {
216	.driver     = {
217		.name   = "sd3078",
218		.of_match_table = of_match_ptr(rtc_dt_match),
219	},
220	.probe      = sd3078_probe,
221	.id_table   = sd3078_id,
222};
223
224module_i2c_driver(sd3078_driver);
225
226MODULE_AUTHOR("Dianlong Li <long17.cool@163.com>");
227MODULE_DESCRIPTION("SD3078 RTC driver");
228MODULE_LICENSE("GPL v2");