Support Holtek HT1380/HT1381 Serial Timekeeper Chip. It provides seconds , minutes, hours, day of the week, date, month and year information.
Datasheet: https://www.holtek.com.tw/documents/10179/11842/ht1380_1v130.pdf
Signed-off-by: Sergei Antonov saproj@gmail.com ---
v2: * The RESET pin is now to be described as ACTIVE_LOW in dts.
Changes suggested by Simon Glass: * a more detailed driver description in Kconfig * multi-line comments' style * enum for 0x80 and the 0x20 at top of file * lower-case hex constants * function comments for ht1380_reset_on/off * blank line before returns
PROTECT remains in a function scope for the sake of locality of definitions.
drivers/rtc/Kconfig | 8 + drivers/rtc/Makefile | 1 + drivers/rtc/ht1380.c | 337 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 346 insertions(+) create mode 100644 drivers/rtc/ht1380.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 23963271928a..eed48e35a578 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -220,4 +220,12 @@ config RTC_ZYNQMP Say "yes" here to support the on chip real time clock present on Xilinx ZynqMP SoC.
+config RTC_HT1380 + bool "Enable Holtek HT1380/HT1381 RTC driver" + depends on DM_RTC && DM_GPIO + help + Say "yes" here to get support for Holtek HT1380/HT1381 + Serial Timekeeper IC which provides seconds, minutes, hours, + day of the week, date, month and year information. + endmenu diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 009dd9d28c95..f3164782b605 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_RTC_DS3231) += ds3231.o obj-$(CONFIG_RTC_DS3232) += ds3232.o obj-$(CONFIG_RTC_EMULATION) += emul_rtc.o obj-$(CONFIG_RTC_FTRTC010) += ftrtc010.o +obj-$(CONFIG_RTC_HT1380) += ht1380.o obj-$(CONFIG_SANDBOX) += i2c_rtc_emul.o obj-$(CONFIG_RTC_IMXDI) += imxdi.o obj-$(CONFIG_RTC_ISL1208) += isl1208.o diff --git a/drivers/rtc/ht1380.c b/drivers/rtc/ht1380.c new file mode 100644 index 000000000000..25335227d893 --- /dev/null +++ b/drivers/rtc/ht1380.c @@ -0,0 +1,337 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Holtek HT1380/HT1381 Serial Timekeeper Chip + * + * Communication with the chip is vendor-specific. + * It is done via 3 GPIO pins: reset, clock, and data. + * Describe in .dts this way: + * + * rtc { + * compatible = "holtek,ht1380"; + * rst-gpio = <&gpio 19 GPIO_ACTIVE_LOW>; + * clk-gpio = <&gpio 20 GPIO_ACTIVE_HIGH>; + * dat-gpio = <&gpio 21 GPIO_ACTIVE_HIGH>; + * }; + * + */ + +#include <common.h> +#include <dm.h> +#include <rtc.h> +#include <bcd.h> +#include <asm/gpio.h> +#include <linux/delay.h> + +struct ht1380_priv { + struct gpio_desc rst_desc; + struct gpio_desc clk_desc; + struct gpio_desc dat_desc; +}; + +enum registers { + SEC, + MIN, + HOUR, + MDAY, + MONTH, + WDAY, + YEAR, + WP, + N_REGS +}; + +enum hour_mode { + AMPM_MODE = 0x80, /* RTC is in AM/PM mode */ + PM_NOW = 0x20, /* set if PM, clear if AM */ +}; + +static const int BURST = 0xbe; +static const int READ = 1; + +static void ht1380_half_period_delay(void) +{ + /* + * Delay for half a period. 1 us complies with the 500 KHz maximum + * input serial clock limit given by the datasheet. + */ + udelay(1); +} + +static int ht1380_send_byte(struct ht1380_priv *priv, int byte) +{ + int ret; + + for (int bit = 0; bit < 8; bit++) { + ret = dm_gpio_set_value(&priv->dat_desc, byte >> bit & 1); + if (ret) + break; + ht1380_half_period_delay(); + + ret = dm_gpio_set_value(&priv->clk_desc, 1); + if (ret) + break; + ht1380_half_period_delay(); + + ret = dm_gpio_set_value(&priv->clk_desc, 0); + if (ret) + break; + } + + return ret; +} + +/* + * Leave reset state. The transfer operation can then be started. + */ +static int ht1380_reset_off(struct ht1380_priv *priv) +{ + const unsigned int T_CC = 4; /* us, Reset to Clock Setup */ + int ret; + + /* + * Leave RESET state. + * Make sure we make the minimal delay required by the datasheet. + */ + ret = dm_gpio_set_value(&priv->rst_desc, 0); + udelay(T_CC); + + return ret; +} + +/* + * Enter reset state. Completes the transfer operation. + */ +static int ht1380_reset_on(struct ht1380_priv *priv) +{ + const unsigned int T_CWH = 4; /* us, Reset Inactive Time */ + int ret; + + /* + * Enter RESET state. + * Make sure we make the minimal delay required by the datasheet. + */ + ret = dm_gpio_set_value(&priv->rst_desc, 1); + udelay(T_CWH); + + return ret; +} + +static int ht1380_rtc_get(struct udevice *dev, struct rtc_time *tm) +{ + struct ht1380_priv *priv = dev_get_priv(dev); + int ret, i, bit, reg[N_REGS]; + + ret = dm_gpio_set_value(&priv->clk_desc, 0); + if (ret) + return ret; + + ret = dm_gpio_set_dir_flags(&priv->dat_desc, GPIOD_IS_OUT); + if (ret) + return ret; + + ret = ht1380_reset_off(priv); + if (ret) + goto exit; + + ret = ht1380_send_byte(priv, BURST + READ); + if (ret) + goto exit; + + ret = dm_gpio_set_dir_flags(&priv->dat_desc, GPIOD_IS_IN); + if (ret) + goto exit; + + for (i = 0; i < N_REGS; i++) { + reg[i] = 0; + + for (bit = 0; bit < 8; bit++) { + ht1380_half_period_delay(); + + ret = dm_gpio_set_value(&priv->clk_desc, 1); + if (ret) + goto exit; + ht1380_half_period_delay(); + + reg[i] |= dm_gpio_get_value(&priv->dat_desc) << bit; + ret = dm_gpio_set_value(&priv->clk_desc, 0); + if (ret) + goto exit; + } + } + + ret = -EINVAL; + + /* Correctness check: some bits are always zero */ + if ((reg[MIN] & 0x80) || (reg[HOUR] & 0x40) || (reg[MDAY] & 0xc0) || + (reg[MONTH] & 0xe0) || (reg[WDAY] & 0xf8) || (reg[WP] & 0x7f)) + goto exit; + + /* Correctness check: some registers are always non-zero */ + if (!reg[MDAY] || !reg[MONTH] || !reg[WDAY]) + goto exit; + + tm->tm_sec = bcd2bin(reg[SEC]); + tm->tm_min = bcd2bin(reg[MIN]); + if (reg[HOUR] & AMPM_MODE) { + /* AM-PM Mode, range is 01-12 */ + tm->tm_hour = bcd2bin(reg[HOUR] & 0x1f) % 12; + if (reg[HOUR] & PM_NOW) { + /* it is PM (otherwise AM) */ + tm->tm_hour += 12; + } + } else { + /* 24-hour Mode, range is 0-23 */ + tm->tm_hour = bcd2bin(reg[HOUR]); + } + tm->tm_mday = bcd2bin(reg[MDAY]); + tm->tm_mon = bcd2bin(reg[MONTH]); + tm->tm_year = 2000 + bcd2bin(reg[YEAR]); + tm->tm_wday = bcd2bin(reg[WDAY]) - 1; + tm->tm_yday = 0; + tm->tm_isdst = 0; + + ret = 0; + +exit: + ht1380_reset_on(priv); + + return ret; +} + +static int ht1380_write_protection_off(struct ht1380_priv *priv) +{ + int ret; + const int PROTECT = 0x8e; + + ret = ht1380_reset_off(priv); + if (ret) + return ret; + + ret = ht1380_send_byte(priv, PROTECT); + if (ret) + return ret; + ret = ht1380_send_byte(priv, 0); /* WP bit is 0 */ + if (ret) + return ret; + + return ht1380_reset_on(priv); +} + +static int ht1380_rtc_set(struct udevice *dev, const struct rtc_time *tm) +{ + struct ht1380_priv *priv = dev_get_priv(dev); + int ret, i, reg[N_REGS]; + + ret = dm_gpio_set_value(&priv->clk_desc, 0); + if (ret) + return ret; + + ret = dm_gpio_set_dir_flags(&priv->dat_desc, GPIOD_IS_OUT); + if (ret) + goto exit; + + ret = ht1380_write_protection_off(priv); + if (ret) + goto exit; + + reg[SEC] = bin2bcd(tm->tm_sec); + reg[MIN] = bin2bcd(tm->tm_min); + reg[HOUR] = bin2bcd(tm->tm_hour); + reg[MDAY] = bin2bcd(tm->tm_mday); + reg[MONTH] = bin2bcd(tm->tm_mon); + reg[WDAY] = bin2bcd(tm->tm_wday) + 1; + reg[YEAR] = bin2bcd(tm->tm_year - 2000); + reg[WP] = 0x80; /* WP bit is 1 */ + + ret = ht1380_reset_off(priv); + if (ret) + goto exit; + + ret = ht1380_send_byte(priv, BURST); + for (i = 0; i < N_REGS && ret; i++) + ret = ht1380_send_byte(priv, reg[i]); + +exit: + ht1380_reset_on(priv); + + return ret; +} + +static int ht1380_probe(struct udevice *dev) +{ + int ret; + struct ht1380_priv *priv; + + priv = dev_get_priv(dev); + if (!priv) + return -EINVAL; + + ret = gpio_request_by_name(dev, "rst-gpio", 0, + &priv->rst_desc, 0); + if (ret) + goto fail_rst; + + ret = gpio_request_by_name(dev, "clk-gpio", 0, + &priv->clk_desc, 0); + if (ret) + goto fail_clk; + + ret = gpio_request_by_name(dev, "dat-gpio", 0, + &priv->dat_desc, 0); + if (ret) + goto fail_dat; + + ret = dm_gpio_set_dir_flags(&priv->clk_desc, GPIOD_IS_OUT); + if (ret) + goto fail; + + ret = dm_gpio_set_dir_flags(&priv->rst_desc, GPIOD_IS_OUT); + if (ret) + goto fail; + + ret = ht1380_reset_on(priv); + if (ret) + goto fail; + + return 0; + +fail: + dm_gpio_free(dev, &priv->dat_desc); +fail_dat: + dm_gpio_free(dev, &priv->clk_desc); +fail_clk: + dm_gpio_free(dev, &priv->rst_desc); +fail_rst: + return ret; +} + +static int ht1380_remove(struct udevice *dev) +{ + struct ht1380_priv *priv = dev_get_priv(dev); + + dm_gpio_free(dev, &priv->rst_desc); + dm_gpio_free(dev, &priv->clk_desc); + dm_gpio_free(dev, &priv->dat_desc); + + return 0; +} + +static const struct rtc_ops ht1380_rtc_ops = { + .get = ht1380_rtc_get, + .set = ht1380_rtc_set, +}; + +static const struct udevice_id ht1380_rtc_ids[] = { + { .compatible = "holtek,ht1380" }, + { } +}; + +U_BOOT_DRIVER(rtc_ht1380) = { + .name = "rtc-ht1380", + .id = UCLASS_RTC, + .probe = ht1380_probe, + .remove = ht1380_remove, + .of_match = ht1380_rtc_ids, + .ops = &ht1380_rtc_ops, + .priv_auto = sizeof(struct ht1380_priv), +};