rtc: Add driver for SD2405AL (5af858ac) · Commits · git / linux-nf

MAINTAINERS

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		@@ -6474,6 +6474,12 @@ F: include/net/devlink.h
		F: include/uapi/linux/devlink.h
		F: net/devlink/

		DFROBOT SD2405AL RTC DRIVER
		M: Tóth János <gomba007@gmail.com>
		L: linux-rtc@vger.kernel.org
		S: Maintained
		F: drivers/rtc/rtc-sd2405al.c

		DH ELECTRONICS IMX6 DHCOM/DHCOR BOARD SUPPORT
		M: Christoph Niedermaier <cniedermaier@dh-electronics.com>
		L: kernel@dh-electronics.com

drivers/rtc/Kconfig

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		@@ -743,6 +743,16 @@ config RTC_DRV_S5M
		This driver can also be built as a module. If so, the module
		will be called rtc-s5m.

		config RTC_DRV_SD2405AL
		tristate "DFRobot SD2405AL"
		select REGMAP_I2C
		help
		If you say yes here you will get support for the
		DFRobot SD2405AL I2C RTC Module.

		This driver can also be built as a module. If so, the module
		will be called rtc-sd2405al.

		config RTC_DRV_SD3078
		tristate "ZXW Shenzhen whwave SD3078"
		select REGMAP_I2C

drivers/rtc/Makefile

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		@@ -162,6 +162,7 @@ obj-$(CONFIG_RTC_DRV_S3C) += rtc-s3c.o
		obj-$(CONFIG_RTC_DRV_S5M) += rtc-s5m.o
		obj-$(CONFIG_RTC_DRV_SA1100) += rtc-sa1100.o
		obj-$(CONFIG_RTC_DRV_SC27XX) += rtc-sc27xx.o
		obj-$(CONFIG_RTC_DRV_SD2405AL) += rtc-sd2405al.o
		obj-$(CONFIG_RTC_DRV_SD3078) += rtc-sd3078.o
		obj-$(CONFIG_RTC_DRV_SH) += rtc-sh.o
		obj-$(CONFIG_RTC_DRV_SNVS) += rtc-snvs.o

drivers/rtc/rtc-sd2405al.c

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		// 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");