Re: [PATCH 5/5] rtc: rtc-rc5t583: add ricoh rc5t619 RTC driver

From: Andreas Kemnade
Date: Mon Oct 21 2019 - 17:14:27 EST

Hi,

On Mon, 21 Oct 2019 12:15:28 +0200
Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> wrote:

> Hi,
>
> The subject line is weird, how is it related to rc5t583?
>
well, yes, rc5t583 driver source was opened next to the window where I wrote
the commit message...

> On 21/10/2019 07:41:04+0200, Andreas Kemnade wrote:
> > config RTC_DRV_S35390A
> > tristate "Seiko Instruments S-35390A"
> > select BITREVERSE
> > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> > index 6b09c21dc1b6..1d0673fd0954 100644
> > --- a/drivers/rtc/Makefile
> > +++ b/drivers/rtc/Makefile
> > @@ -136,6 +136,7 @@ obj-$(CONFIG_RTC_DRV_PXA) += rtc-pxa.o
> > obj-$(CONFIG_RTC_DRV_R7301) += rtc-r7301.o
> > obj-$(CONFIG_RTC_DRV_R9701) += rtc-r9701.o
> > obj-$(CONFIG_RTC_DRV_RC5T583) += rtc-rc5t583.o
> > +obj-$(CONFIG_RTC_DRV_RC5T619) += rtc-rc5t619.o
> > obj-$(CONFIG_RTC_DRV_RK808) += rtc-rk808.o
> > obj-$(CONFIG_RTC_DRV_RP5C01) += rtc-rp5c01.o
> > obj-$(CONFIG_RTC_DRV_RS5C313) += rtc-rs5c313.o
> > diff --git a/drivers/rtc/rtc-rc5t619.c b/drivers/rtc/rtc-rc5t619.c
> > new file mode 100644
> > index 000000000000..311788ff0723
> > --- /dev/null
> > +++ b/drivers/rtc/rtc-rc5t619.c
> > @@ -0,0 +1,476 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * drivers/rtc/rtc-ricoh619.c
> > + *
> > + * Real time clock driver for RICOH R5T619 power management chip.
> > + *
> > + * Copyright (C) 2019 Andreas Kemnade
> > + *
> > + * Based on code
> > + * Copyright (C) 2012-2014 RICOH COMPANY,LTD
> > + *
> > + * Based on code
> > + * Copyright (C) 2011 NVIDIA Corporation
>
> Based on is not useful.
>
Well, ok, I guess 90 % of the lines are rewritten by me.
So I could remove all that Based on copyright notices?

> > + */
> > +
> > +/* #define debug 1 */
> > +/* #define verbose_debug 1 */
> > +
>
> No dead code please.
>
ok.

> > +#include <linux/kernel.h>
> > +#include <linux/device.h>
> > +#include <linux/errno.h>
> > +#include <linux/init.h>
> > +#include <linux/module.h>
> > +#include <linux/mfd/rn5t618.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/bcd.h>
> > +#include <linux/rtc.h>
> > +#include <linux/slab.h>
> > +#include <linux/irqdomain.h>
> > +
> > +struct rc5t619_rtc {
> > + int irq;
> > + struct rtc_device *rtc;
> > + struct rn5t618 *rn5t618;
> > +};
> > +
> > +#define CTRL1_ALARM_ENABLED 0x40
> > +#define CTRL1_24HR 0x20
> > +#define CTRL1_PERIODIC_MASK 0xf
> > +
> > +#define CTRL2_PON 0x10
> > +#define CTRL2_ALARM_STATUS 0x80
> > +#define CTRL2_CTFG 0x4
> > +#define CTRL2_CTC 0x1
> > +
> > +static int rc5t619_rtc_periodic_disable(struct device *dev)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > + int err;
> > +
> > + /* disable function */
> > + err = regmap_update_bits(rtc->rn5t618->regmap,
> > + RN5T618_RTC_CTRL1, CTRL1_PERIODIC_MASK, 0);
> > + if (err < 0)
> > + return err;
> > +
> > + /* clear alarm flag and CTFG */
> > + err = regmap_update_bits(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2,
> > + CTRL2_ALARM_STATUS | CTRL2_CTFG | CTRL2_CTC, 0);
> > + if (err < 0)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int rc5t619_rtc_clk_adjust(struct device *dev, uint8_t clk)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > +
> > + return regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_ADJUST, clk);
>
> Is it useful to have a function for a single regmap_write?

well, I could live without.
>
> Also what is that adjusting? If this is adding/removing clock cycles,
> you need to use .set_offset and .read_offset.
>
It the moment I am just clearing it at init. Since I do not know the
exact meaning of the value, I am not offering it through set_offset/read_offset.

> > +}
> > +
> > +static int rc5t619_rtc_pon_get_clr(struct device *dev, uint8_t *pon_f)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > + int err;
> > + unsigned int reg_data;
> > +
> > + err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &reg_data);
> > + if (err < 0)
> > + return err;
> > +
> > + if (reg_data & CTRL2_PON) {
> > + *pon_f = 1;
> > + /* clear VDET PON */
> > + reg_data &= ~(CTRL2_PON | CTRL2_CTC | 0x4a); /* 0101-1011 */
> > + reg_data |= 0x20; /* 0010-0000 */
>
> Is it possible to have more defines for those magic values?
>
Well, I only have some GPLed source code as documentation, no good documentation.
So I only know that one bit must be VDET.
rtc-rc5t583 seems not to be helpful to find these magic numbers.
0x40 might be VDET. At least that is conform with rtc-rs5c348.c.
rc5t583 seems not to know a VDET.
But there seems to be no clear duplicate anywhere of those two
ctrl registers. It seems that the rc5t619 is a cross of everything, having
6 byte bcd time in common with everything.
So we have to keep a bit of magic here.

> > + err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2,
> > + reg_data);
> > + } else {
> > + *pon_f = 0;
> > + }
> > +
> > + return err;
> > +}
> > +
> > +/* 0-12hour, 1-24hour */
> > +static int rc5t619_rtc_24hour_mode_set(struct device *dev, int mode)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > +
> > + return regmap_update_bits(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1,
> > + CTRL1_24HR, mode ? CTRL1_24HR : 0);
>
> Is it useful to have a function for a single regmap_update_bits?
>
Again I could live without that.

> > +}
> > +
> > +
> > +static int rc5t619_rtc_read_time(struct device *dev, struct rtc_time *tm)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > + u8 buff[7];
> > + int err;
> > + int cent_flag;
> > +
> > + err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
> > + buff, sizeof(buff));
> > + if (err < 0) {
> > + dev_err(dev, "failed to read time: %d\n", err);
>
> Please reconsider adding so many strings in the driver, they add almost
> no value but will increase the kernel memory footprint.
>
Well, removing all those things which are just i2c io errors makes sense.

> > + return err;
> > + }
> > +
> > + if (buff[5] & 0x80)
> A define for the century bit would be good.
>
yes, that is a clearly understood bit.

> > + cent_flag = 1;
> > + else
> > + cent_flag = 0;
> > +
> > + buff[5] = buff[5] & 0x1f; /* bit5 19_20 */
>
> This assignment is unnecessary, you can mask the value when using it.
>
ok.

> Is the RTC 1900-2099 or 2000-2199? Please include the ouput of rtc-range
> in the commit log:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/rtc-tools.git/tree/rtc-range.c
>
# ./rtc-range

Testing 2000-02-28 23:59:59.
OK

Testing 2038-01-19 03:14:07.
OK

Testing 2069-12-31 23:59:59.
OK

Testing 2099-12-31 23:59:59.
KO RTC_RD_TIME returned 22 (line 138)

Testing 2100-02-28 23:59:59.
KO RTC_RD_TIME returned 22 (line 138)

Testing 2106-02-07 06:28:15.
OK

Testing 2262-04-11 23:47:16.
KO Read back 2102-04-11 23:47:16.

I think it is 1900 to 2099.

> > +
> > + tm->tm_sec = bcd2bin(buff[0]);
> > + tm->tm_min = bcd2bin(buff[1]);
> > + tm->tm_hour = bcd2bin(buff[2]); /* bit5 PA_H20 */
> > + tm->tm_wday = bcd2bin(buff[3]);
> > + tm->tm_mday = bcd2bin(buff[4]);
> > + tm->tm_mon = bcd2bin(buff[5]) - 1; /* back to system 0-11 */
> > + tm->tm_year = bcd2bin(buff[6]) + 100 * cent_flag;
> > +
> > + return 0;
> > +}
> > +
> > +static int rc5t619_rtc_set_time(struct device *dev, struct rtc_time *tm)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > + u8 buff[7];
> > + int err;
> > + int cent_flag;
> > +
> > + if (tm->tm_year >= 100)
> > + cent_flag = 1;
> > + else
> > + cent_flag = 0;
> > +
> > + tm->tm_mon = tm->tm_mon + 1;
>
> This assignment is not necessary.
>
ok.

> > + buff[0] = bin2bcd(tm->tm_sec);
> > + buff[1] = bin2bcd(tm->tm_min);
> > + buff[2] = bin2bcd(tm->tm_hour);
> > + buff[3] = bin2bcd(tm->tm_wday);
> > + buff[4] = bin2bcd(tm->tm_mday);
> > + buff[5] = bin2bcd(tm->tm_mon); /* system set 0-11 */
> > + buff[6] = bin2bcd(tm->tm_year - cent_flag * 100);
> > +
> > + if (cent_flag)
> > + buff[5] |= 0x80;
> > +
> > + err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
> > + buff, sizeof(buff));
> > + if (err < 0) {
> > + dev_err(dev, "failed to program new time: %d\n", err);
> > + return err;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int rc5t619_rtc_alarm_is_enabled(struct device *dev, uint8_t *enabled)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > + int err;
> > + unsigned int reg_data;
> > +
> > + err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &reg_data);
> > + if (err) {
> > + dev_err(dev, "read RTC_CTRL1 error %d\n", err);
> > + *enabled = 0;
>
> Is it necessary to set enabled here?
>
probably not.

> > + } else {
> > + if (reg_data & CTRL1_ALARM_ENABLED)
> > + *enabled = 1;
> > + else
> > + *enabled = 0;
> > + }
> > +
> > + return err;
> > +}
> > +
> > +/* 0-disable, 1-enable */
> > +static int rc5t619_rtc_alarm_enable(struct device *dev, unsigned int enabled)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > + int err;
>
> err is not necessary.
>
ok.

> > +
> > + err = regmap_update_bits(rtc->rn5t618->regmap,
> > + RN5T618_RTC_CTRL1,
> > + CTRL1_ALARM_ENABLED,
> > + enabled ? CTRL1_ALARM_ENABLED : 0);
> > + if (err < 0)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int rc5t619_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > + u8 buff[6];
> > + unsigned int buff_cent;
> > + int err;
> > + int cent_flag;
> > + unsigned int enabled_flag;
> > +
> > + err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_MONTH, &buff_cent);
> > + if (err < 0) {
> > + dev_err(dev, "failed to read time: %d\n", err);
> > + return err;
> > + }
> > +
> > + if (buff_cent & 0x80)
> > + cent_flag = 1;
> > + else
> > + cent_flag = 0;
> > +
> > + err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
> > + buff, sizeof(buff));
> > + if (err)
> > + return err;
> > +
> > + err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1,
> > + &enabled_flag);
> > + if (err)
> > + return err;
> > +
> > + if (enabled_flag & CTRL1_ALARM_ENABLED)
> > + enabled_flag = 1;
>
> Why don't you set alrm->enabled directly here?
>
> alrm->enabled = !!(enabled_flag & CTRL1_ALARM_ENABLED);
>
yes, makes sense.

> > + else
> > + enabled_flag = 0;
> > +
> > +
> > + buff[3] = buff[3] & 0x3f;
> > +
> > + alrm->time.tm_sec = bcd2bin(buff[0]);
> > + alrm->time.tm_min = bcd2bin(buff[1]);
> > + alrm->time.tm_hour = bcd2bin(buff[2]);
> > + alrm->time.tm_mday = bcd2bin(buff[3]);
> > + alrm->time.tm_mon = bcd2bin(buff[4]) - 1;
> > + alrm->time.tm_year = bcd2bin(buff[5]) + 100 * cent_flag;
> > + alrm->enabled = enabled_flag;
> > + dev_dbg(dev, "read alarm: %d/%d/%d %d:%d:%d\n",
>
> Use %ptR
>
oh, that is nice.

> > + (alrm->time.tm_mon), alrm->time.tm_mday, alrm->time.tm_year,
> > + alrm->time.tm_hour, alrm->time.tm_min, alrm->time.tm_sec);
> > +
> > + return 0;
> > +}
> > +
> > +static int rc5t619_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > + u8 buff[6];
> > + int err;
> > + int cent_flag;
> > +
> > + err = 0;
> > + rc5t619_rtc_alarm_enable(dev, 0);
>
> This may fail
>
will add checks

> > + if (rtc->irq == -1)
> > + return -EIO;
>
> This has to be -EINVAL to get UIE emulation working.
>
so then ordinary hwclock still works without irq?

> > +
> > + if (alrm->enabled == 0)
> > + return 0;
> > +
> > + if (alrm->time.tm_year >= 100)
> > + cent_flag = 1;
> > + else
> > + cent_flag = 0;
> > +
> > + alrm->time.tm_mon += 1;
> > + buff[0] = bin2bcd(alrm->time.tm_sec);
> > + buff[1] = bin2bcd(alrm->time.tm_min);
> > + buff[2] = bin2bcd(alrm->time.tm_hour);
> > + buff[3] = bin2bcd(alrm->time.tm_mday);
> > + buff[4] = bin2bcd(alrm->time.tm_mon);
> > + buff[5] = bin2bcd(alrm->time.tm_year - 100 * cent_flag);
> > + buff[3] |= 0x80; /* set DAL_EXT */
>
> This bit needs a define.
>
ok.

> > +
> > + err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
> > + buff, sizeof(buff));
> > + if (err) {
> > + dev_err(dev, "unable to set alarm: %d\n", err);
> > + return -EBUSY;
>
> Why EBUSY?
>
will just return err without message.
> > + }
> > +
> > + rc5t619_rtc_alarm_enable(dev, alrm->enabled);
>
> This may fail.
>
will add a check.

> > +
> > + return 0;
> > +}
> > +
> > +static const struct rtc_class_ops rc5t619_rtc_ops = {
> > + .read_time = rc5t619_rtc_read_time,
> > + .set_time = rc5t619_rtc_set_time,
> > + .set_alarm = rc5t619_rtc_set_alarm,
> > + .read_alarm = rc5t619_rtc_read_alarm,
> > + .alarm_irq_enable = rc5t619_rtc_alarm_enable,
> > +};
> > +
> > +static int rc5t619_rtc_alarm_flag_clr(struct device *dev)
> > +{
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > +
> > + /* clear alarm-D status bits.*/
> > + return regmap_update_bits(rtc->rn5t618->regmap,
> > + RN5T618_RTC_CTRL2,
> > + CTRL2_ALARM_STATUS | CTRL2_CTC, 0);
> > +}
> > +
> > +static irqreturn_t rc5t619_rtc_irq(int irq, void *data)
> > +{
> > + struct device *dev = data;
> > + struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
> > +
> > + rc5t619_rtc_alarm_flag_clr(dev);
> > +
> > + rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
> > + return IRQ_HANDLED;
> > +}
> > +
> > +
> > +static int rc5t619_rtc_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
> > + struct rc5t619_rtc *rtc;
> > + uint8_t pon_flag, alarm_flag;
> > + int err;
> > +
> > + rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
> > + if (IS_ERR(rtc)) {
> > + err = PTR_ERR(rtc);
> > + dev_err(&pdev->dev, "no enough memory for rc5t619_rtc using\n");
> > + return -ENOMEM;
> > + }
> > +
> > + rtc->rn5t618 = rn5t618;
> > +
> > + dev_set_drvdata(dev, rtc);
> > + rtc->irq = -1;
> > +
> > + if (rn5t618->irq_data)
> > + rtc->irq = regmap_irq_get_virq(rn5t618->irq_data,
> > + RN5T618_IRQ_RTC);
> > +
> > + if (rtc->irq < 0) {
> > + dev_err(dev, "no irq specified, wakeup is disabled\n");
> > + rtc->irq = -1;
> > + }
> > +
> > + /* get interrupt flag */
> > + err = rc5t619_rtc_alarm_is_enabled(dev, &alarm_flag);
> > + if (err)
> > + return err;
> > +
> > + /* get PON flag */
> > + err = rc5t619_rtc_pon_get_clr(&pdev->dev, &pon_flag);
> > + if (err) {
> > + dev_err(&pdev->dev, "get PON flag error: %d\n", err);
> > + return err;
> > + }
> > +
> > + /* using 24h-mode */
> > + err = rc5t619_rtc_24hour_mode_set(&pdev->dev, 1);
> > +
>
> Doesn't that corrupt the time if the RTC was previously set in 12h-mode?
>
>
Probably it can. but probably that is only important in a multi-boot scenario but
who knows... If that is important enough I can try to implement 12h mode.

Is there any testing tool for 12h vs. 24h? Or should I expand
rtc-range.c? BTW: apparently rtc-rc5t583.c seems not to properly care
about 24h mode too, so I took a bad example. Well, not tested that...

> > + /* disable rtc periodic function */
> > + err = rc5t619_rtc_periodic_disable(&pdev->dev);
> > + if (err) {
> > + dev_err(&pdev->dev, "disable rtc periodic int: %d\n", err);
> > + return err;
> > + }
> > +
> > + /* clearing RTC Adjust register */
> > + err = rc5t619_rtc_clk_adjust(&pdev->dev, 0);
> > + if (err) {
> > + dev_err(&pdev->dev, "unable to program RTC_ADJUST: %d\n", err);
> > + return err;
> > + }
> > +
> > + /* disable interrupt */
> > + err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
> > + if (err) {
> > + dev_err(&pdev->dev, "disable alarm interrupt: %d\n", err);
> > + return err;
> > + }
> > +
> > + if (pon_flag) {
> > + alarm_flag = 0;
> > + err = rc5t619_rtc_alarm_flag_clr(&pdev->dev);
> > + if (err) {
> > + dev_err(&pdev->dev,
> > + "pon=1 clear alarm flag error: %d\n", err);
> > + return err;
> > + }
> > + }
> > +
> > + device_init_wakeup(&pdev->dev, 1);
>
> Do you want to do that even without an irq?
>
probably not.

> > +
> > + rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
> > + &rc5t619_rtc_ops, THIS_MODULE);
> > +
>
> Please use devm_rtc_allocate_device and rtc_register_device
>
ok.

> > + if (IS_ERR(rtc->rtc)) {
> > + err = PTR_ERR(rtc->rtc);
> > + dev_err(dev, "RTC device register: err %d\n", err);
> > + return err;
> > + }
> > +
> > + /* set interrupt and enable it */
> > + if (rtc->irq != -1) {
> > + err = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
> > + rc5t619_rtc_irq,
> > + IRQF_ONESHOT,
> > + "rtc-rc5t619",
> > + &pdev->dev);
> > + if (err < 0) {
> > + dev_err(&pdev->dev, "request IRQ:%d fail\n", rtc->irq);
> > + rtc->irq = -1;
> > +
> > + err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
> > + if (err)
> > + return err;
> > +
> > + } else {
> > + /* enable wake */
> > + enable_irq_wake(rtc->irq);
> > + /* enable alarm_d */
> > + err = rc5t619_rtc_alarm_enable(&pdev->dev, alarm_flag);
> > + if (err) {
> > + dev_err(&pdev->dev, "failed rtc setup\n");
> > + return -EBUSY;
> > + }
> > + }
> > + } else {
> > + /* system don't want to using alarm interrupt, so close it */
> > + err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
> > + if (err) {
> > + dev_err(&pdev->dev, "disable rtc alarm error\n");
> > + return err;
> > + }
> > +
> > + dev_err(&pdev->dev, "ricoh61x interrupt is disabled\n");
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int rc5t619_rtc_remove(struct platform_device *pdev)
> > +{
> > + rc5t619_rtc_alarm_enable(&pdev->dev, 0);
>
> If the PMIC can be used to start the platform, you probably don't want
> to disable the alarm here. Even if it doesn't, is it actually useful to
> disable the alarm?
>

well, I think this is not executed if you do
rtcwake -m off -s something
At least my device powers on after that.

Somehow I expect the driver to clean up there. e.g. rc5t583 does that, too.
But no strong opinion here.

Regards,
Andreas

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