[PATCH] rtc: add ht1380 driver
Simon Glass
sjg at chromium.org
Wed Dec 7 02:08:32 CET 2022
Hi Sergei,
On Tue, 6 Dec 2022 at 23:07, Sergei Antonov <saproj at gmail.com> wrote:
>
> 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 at 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.
Perhaps mention how it is connected, i.e. three GPIOs.
> +
> 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>;
> + * };
Is there a binding file for this?
I believe the standard name should be rst-gpios (i.e. plural)?
> + *
> + */
> +
> +#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;
> +
Is this some sort of I2C protocol?
> + 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;
Drop extra brackets ?
> +
> + /* 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);
You can pass GPIOD_IS_OUT as the last param and drop the extra code below.
> + 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),
> +};
> --
> 2.34.1
>
Regards,
Simon
More information about the U-Boot
mailing list