Message-ID: <20191021101528.GU3125@piout.net>
Date:   Mon, 21 Oct 2019 12:15:28 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Andreas Kemnade <andreas@...nade.info>
Cc:     lee.jones@...aro.org, a.zummo@...ertech.it,
        linux-kernel@...r.kernel.org, linux-rtc@...r.kernel.org,
        phh@....me, b.galvani@...il.com, stefan@...er.ch,
        letux-kernel@...nphoenux.org
Subject: Re: [PATCH 5/5] rtc: rtc-rc5t583: add ricoh rc5t619 RTC driver

Hi,

The subject line is weird, how is it related to rc5t583?

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.

> + */
> +
> +/* #define debug		1 */
> +/* #define verbose_debug	1 */
> +

No dead code please.

> +#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?

Also what is that adjusting? If this is adding/removing clock cycles,
you need to use .set_offset and .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?

> +		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?

> +}
> +
> +
> +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.

> +		return err;
> +	}
> +
> +	if (buff[5] & 0x80)
A define for the century bit would be good.

> +		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.

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

> +
> +	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.

> +	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?

> +	} 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.

> +
> +	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);

> +	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

> +		(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

> +	if (rtc->irq == -1)
> +		return -EIO;

This has to be -EINVAL to get UIE emulation working.

> +
> +	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.

> +
> +	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?

> +	}
> +
> +	rc5t619_rtc_alarm_enable(dev, alrm->enabled);

This may fail.

> +
> +	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?


> +	/* 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?

> +
> +	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

> +	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?

> +
> +	return 0;
> +}
> +
> +static struct platform_driver rc5t619_rtc_driver = {
> +	.driver	= {
> +		.name	= "rc5t619-rtc",
> +	},
> +	.probe	= rc5t619_rtc_probe,
> +	.remove	= rc5t619_rtc_remove,
> +};
> +
> +module_platform_driver(rc5t619_rtc_driver);
> +MODULE_ALIAS("platform:rc5t619-rtc");
> +MODULE_DESCRIPTION("RICOH RC5T619 RTC driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.11.0
> 

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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