On Wed, 7 Dec 2022 at 04:08, Simon Glass <s...@chromium.org> wrote:
>
> Hi Sergei,
>
> On Tue, 6 Dec 2022 at 23:07, Sergei Antonov <sap...@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 <sap...@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?
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
