On Wed, 7 Dec 2022 at 04:08, Simon Glass sjg@chromium.org wrote:
Hi Sergei,
On Tue, 6 Dec 2022 at 23:07, Sergei Antonov saproj@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@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_GPIOhelpSay "yes" here to get support for Holtek HT1380/HT1381Serial 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?
Not in the U-Boot repo yet. I am going to submit a .dts file binding to this driver. But I need to submit 2 more device drivers first. I guess, submitting .dts should be the final step.
I believe the standard name should be rst-gpios (i.e. plural)?
I grepped files in arch/arm/dts and it was not clear. There were more plural names however. So I can change it to plural in v3.
- */
+#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?
Like I2C it uses a pin for clock and a pin for data in/out. Unlike I2C it does not use addressing. I am not sure whether this driver can utilize some of the existing I2C code in U-Boot. Wrote my own bit banging routines.
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 ?
OK. Will be done in v3. I put extra brackets expecting reviewers to criticize code readability :).
/* 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.
Thanks! Did not know it.
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