1 // SPDX-License-Identifier: GPL-2.0-only
12 #define DRIVER_NAME "rtc-pcf8523"
20 #define REG_CONTROL3_PM_VDD (1 << 6) /* switch-over disabled */
23 #define REG_CONTROL3_BLF (1 << 2) /* battery low bit, read-only */
44 	msgs[0].addr = client->addr;  in pcf8523_read()
49 	msgs[1].addr = client->addr;  in pcf8523_read()
54 	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));  in pcf8523_read()
69 	msg.addr = client->addr;  in pcf8523_write()
74 	err = i2c_transfer(client->adapter, &msg, 1);  in pcf8523_write()
104 	of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads",  in pcf8523_load_capacitance()
109 		dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",  in pcf8523_load_capacitance()
182 	u8 start = REG_SECONDS, regs[7];  in pcf8523_rtc_read_time()  local
191 		return -EINVAL;  in pcf8523_rtc_read_time()
194 	msgs[0].addr = client->addr;  in pcf8523_rtc_read_time()
197 	msgs[0].buf = &start;  in pcf8523_rtc_read_time()
199 	msgs[1].addr = client->addr;  in pcf8523_rtc_read_time()
204 	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));  in pcf8523_rtc_read_time()
209 		return -EINVAL;  in pcf8523_rtc_read_time()
211 	tm->tm_sec = bcd2bin(regs[0] & 0x7f);  in pcf8523_rtc_read_time()
212 	tm->tm_min = bcd2bin(regs[1] & 0x7f);  in pcf8523_rtc_read_time()
213 	tm->tm_hour = bcd2bin(regs[2] & 0x3f);  in pcf8523_rtc_read_time()
214 	tm->tm_mday = bcd2bin(regs[3] & 0x3f);  in pcf8523_rtc_read_time()
215 	tm->tm_wday = regs[4] & 0x7;  in pcf8523_rtc_read_time()
216 	tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1;  in pcf8523_rtc_read_time()
217 	tm->tm_year = bcd2bin(regs[6]) + 100;  in pcf8523_rtc_read_time()
230 	 * The hardware can only store values between 0 and 99 in it's YEAR  in pcf8523_rtc_set_time()
232 	 * After 2100-02-28 we could start interpreting the year to be in the  in pcf8523_rtc_set_time()
234 	 * because the chip handles YEAR=0x00 (and the out-of-spec  in pcf8523_rtc_set_time()
235 	 * YEAR=0xa0) as a leap year, but 2100 isn't.  in pcf8523_rtc_set_time()
237 	if (tm->tm_year < 100 || tm->tm_year >= 200)  in pcf8523_rtc_set_time()
238 		return -EINVAL;  in pcf8523_rtc_set_time()
246 	regs[1] = bin2bcd(tm->tm_sec);  in pcf8523_rtc_set_time()
247 	regs[2] = bin2bcd(tm->tm_min);  in pcf8523_rtc_set_time()
248 	regs[3] = bin2bcd(tm->tm_hour);  in pcf8523_rtc_set_time()
249 	regs[4] = bin2bcd(tm->tm_mday);  in pcf8523_rtc_set_time()
250 	regs[5] = tm->tm_wday;  in pcf8523_rtc_set_time()
251 	regs[6] = bin2bcd(tm->tm_mon + 1);  in pcf8523_rtc_set_time()
252 	regs[7] = bin2bcd(tm->tm_year - 100);  in pcf8523_rtc_set_time()
254 	msg.addr = client->addr;  in pcf8523_rtc_set_time()
259 	err = i2c_transfer(client->adapter, &msg, 1);  in pcf8523_rtc_set_time()
291 		return -ENOIOCTLCMD;  in pcf8523_rtc_ioctl()
309 	/* sign extend the 7-bit offset value */  in pcf8523_rtc_read_offset()
322 	reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);  in pcf8523_rtc_set_offset()
323 	reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);  in pcf8523_rtc_set_offset()
325 	if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))  in pcf8523_rtc_set_offset()
347 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))  in pcf8523_probe()
348 		return -ENODEV;  in pcf8523_probe()
352 		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",  in pcf8523_probe()
359 	rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME,  in pcf8523_probe()
392 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");