--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * RTC driver for the SD2405AL Real-Time Clock
+ *
+ * Datasheet:
+ * https://image.dfrobot.com/image/data/TOY0021/SD2405AL%20datasheet%20(Angelo%20v0.1).pdf
+ *
+ * Copyright (C) 2024 Tóth János <gomba007@gmail.com>
+ */
+
+#include <linux/bcd.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+
+/* Real time clock registers */
+#define SD2405AL_REG_T_SEC 0x00
+#define SD2405AL_REG_T_MIN 0x01
+#define SD2405AL_REG_T_HOUR 0x02
+# define SD2405AL_BIT_12H_PM BIT(5)
+# define SD2405AL_BIT_24H BIT(7)
+#define SD2405AL_REG_T_WEEK 0x03
+#define SD2405AL_REG_T_DAY 0x04
+#define SD2405AL_REG_T_MON 0x05
+#define SD2405AL_REG_T_YEAR 0x06
+
+#define SD2405AL_NUM_T_REGS (SD2405AL_REG_T_YEAR - SD2405AL_REG_T_SEC + 1)
+
+/* Control registers */
+#define SD2405AL_REG_CTR1 0x0F
+# define SD2405AL_BIT_WRTC2 BIT(2)
+# define SD2405AL_BIT_WRTC3 BIT(7)
+#define SD2405AL_REG_CTR2 0x10
+# define SD2405AL_BIT_WRTC1 BIT(7)
+#define SD2405AL_REG_CTR3 0x11
+#define SD2405AL_REG_TTF 0x12
+#define SD2405AL_REG_CNTDWN 0x13
+
+/* General RAM */
+#define SD2405AL_REG_M_START 0x14
+#define SD2405AL_REG_M_END 0x1F
+
+struct sd2405al {
+ struct device *dev;
+ struct rtc_device *rtc;
+ struct regmap *regmap;
+};
+
+static int sd2405al_enable_reg_write(struct sd2405al *sd2405al)
+{
+ int ret;
+
+ /* order of writes is important */
+ ret = regmap_update_bits(sd2405al->regmap, SD2405AL_REG_CTR2,
+ SD2405AL_BIT_WRTC1, SD2405AL_BIT_WRTC1);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_update_bits(sd2405al->regmap, SD2405AL_REG_CTR1,
+ SD2405AL_BIT_WRTC2 | SD2405AL_BIT_WRTC3,
+ SD2405AL_BIT_WRTC2 | SD2405AL_BIT_WRTC3);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int sd2405al_disable_reg_write(struct sd2405al *sd2405al)
+{
+ int ret;
+
+ /* order of writes is important */
+ ret = regmap_update_bits(sd2405al->regmap, SD2405AL_REG_CTR1,
+ SD2405AL_BIT_WRTC2 | SD2405AL_BIT_WRTC3, 0x00);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_update_bits(sd2405al->regmap, SD2405AL_REG_CTR2,
+ SD2405AL_BIT_WRTC1, 0x00);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int sd2405al_read_time(struct device *dev, struct rtc_time *time)
+{
+ u8 data[SD2405AL_NUM_T_REGS] = { 0 };
+ struct sd2405al *sd2405al = dev_get_drvdata(dev);
+ int ret;
+
+ ret = regmap_bulk_read(sd2405al->regmap, SD2405AL_REG_T_SEC, data,
+ SD2405AL_NUM_T_REGS);
+ if (ret < 0)
+ return ret;
+
+ time->tm_sec = bcd2bin(data[SD2405AL_REG_T_SEC] & 0x7F);
+ time->tm_min = bcd2bin(data[SD2405AL_REG_T_MIN] & 0x7F);
+
+ if (data[SD2405AL_REG_T_HOUR] & SD2405AL_BIT_24H)
+ time->tm_hour = bcd2bin(data[SD2405AL_REG_T_HOUR] & 0x3F);
+ else
+ if (data[SD2405AL_REG_T_HOUR] & SD2405AL_BIT_12H_PM)
+ time->tm_hour = bcd2bin(data[SD2405AL_REG_T_HOUR]
+ & 0x1F) + 12;
+ else /* 12 hour mode, AM */
+ time->tm_hour = bcd2bin(data[SD2405AL_REG_T_HOUR]
+ & 0x1F);
+
+ time->tm_wday = bcd2bin(data[SD2405AL_REG_T_WEEK] & 0x07);
+ time->tm_mday = bcd2bin(data[SD2405AL_REG_T_DAY] & 0x3F);
+ time->tm_mon = bcd2bin(data[SD2405AL_REG_T_MON] & 0x1F) - 1;
+ time->tm_year = bcd2bin(data[SD2405AL_REG_T_YEAR]) + 100;
+
+ dev_dbg(sd2405al->dev, "read time: %ptR (%d)\n", time, time->tm_wday);
+
+ return 0;
+}
+
+static int sd2405al_set_time(struct device *dev, struct rtc_time *time)
+{
+ u8 data[SD2405AL_NUM_T_REGS];
+ struct sd2405al *sd2405al = dev_get_drvdata(dev);
+ int ret;
+
+ data[SD2405AL_REG_T_SEC] = bin2bcd(time->tm_sec);
+ data[SD2405AL_REG_T_MIN] = bin2bcd(time->tm_min);
+ data[SD2405AL_REG_T_HOUR] = bin2bcd(time->tm_hour) | SD2405AL_BIT_24H;
+ data[SD2405AL_REG_T_DAY] = bin2bcd(time->tm_mday);
+ data[SD2405AL_REG_T_WEEK] = bin2bcd(time->tm_wday);
+ data[SD2405AL_REG_T_MON] = bin2bcd(time->tm_mon) + 1;
+ data[SD2405AL_REG_T_YEAR] = bin2bcd(time->tm_year - 100);
+
+ ret = sd2405al_enable_reg_write(sd2405al);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_bulk_write(sd2405al->regmap, SD2405AL_REG_T_SEC, data,
+ SD2405AL_NUM_T_REGS);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(sd2405al->regmap, SD2405AL_REG_TTF, 0x00);
+ if (ret < 0)
+ return ret;
+
+ ret = sd2405al_disable_reg_write(sd2405al);
+ if (ret < 0)
+ return ret;
+
+ dev_dbg(sd2405al->dev, "set time: %ptR (%d)\n", time, time->tm_wday);
+
+ return 0;
+}
+
+static const struct rtc_class_ops sd2405al_rtc_ops = {
+ .read_time = sd2405al_read_time,
+ .set_time = sd2405al_set_time,
+};
+
+static const struct regmap_config sd2405al_regmap_conf = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = SD2405AL_REG_M_END,
+};
+
+static int sd2405al_probe(struct i2c_client *client)
+{
+ struct sd2405al *sd2405al;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ sd2405al = devm_kzalloc(&client->dev, sizeof(*sd2405al), GFP_KERNEL);
+ if (!sd2405al)
+ return -ENOMEM;
+
+ sd2405al->dev = &client->dev;
+
+ sd2405al->regmap = devm_regmap_init_i2c(client, &sd2405al_regmap_conf);
+ if (IS_ERR(sd2405al->regmap))
+ return PTR_ERR(sd2405al->regmap);
+
+ sd2405al->rtc = devm_rtc_allocate_device(&client->dev);
+ if (IS_ERR(sd2405al->rtc))
+ return PTR_ERR(sd2405al->rtc);
+
+ sd2405al->rtc->ops = &sd2405al_rtc_ops;
+ sd2405al->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ sd2405al->rtc->range_max = RTC_TIMESTAMP_END_2099;
+
+ dev_set_drvdata(&client->dev, sd2405al);
+
+ ret = devm_rtc_register_device(sd2405al->rtc);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static const struct i2c_device_id sd2405al_id[] = {
+ { "sd2405al" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, sd2405al_id);
+
+static const __maybe_unused struct of_device_id sd2405al_of_match[] = {
+ { .compatible = "dfrobot,sd2405al" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sd2405al_of_match);
+
+static struct i2c_driver sd2405al_driver = {
+ .driver = {
+ .name = "sd2405al",
+ .of_match_table = of_match_ptr(sd2405al_of_match),
+ },
+ .probe = sd2405al_probe,
+ .id_table = sd2405al_id,
+};
+
+module_i2c_driver(sd2405al_driver);
+
+MODULE_AUTHOR("Tóth János <gomba007@gmail.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SD2405AL RTC driver");
projects / thirdparty / kernel / linux.git / commitdiff
