Date:	Tue, 26 Aug 2014 14:42:53 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Chris Zhong <zyw@...k-chips.com>
Cc:	robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	sameo@...ux.intel.com, lee.jones@...aro.org, lgirdwood@...il.com,
	broonie@...nel.org, a.zummo@...ertech.it, mturquette@...aro.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	rtc-linux@...glegroups.com, grant.likely@...aro.org,
	hl@...k-chips.com, huangtao@...k-chips.com, cf@...k-chips.com,
	zhangqing@...k-chips.com, xxx@...k-chips.com,
	dianders@...omium.org, heiko@...ech.de, olof@...om.net,
	sonnyrao@...omium.org, dtor@...omium.org,
	javier.martinez@...labora.co.uk, kever.yang@...k-chips.com
Subject: Re: [PATCH v6 3/5] RTC: RK808: add RTC driver for RK808

Hi Chris,

On Tue, Aug 26, 2014 at 10:14:56PM +0800, Chris Zhong wrote:
> Adding RTC driver for supporting RTC device present inside RK808 PMIC.
> 
> Signed-off-by: Chris Zhong <zyw@...k-chips.com>
> Signed-off-by: Zhang Qing <zhangqing@...k-chips.com>
> 
> ---
> 
> Changes in v6:
> Adviced by doug
> - move RTC_READSEL setting into probe
> 
> Changes in v5:
> - fixed a bug about set_time failed
> 
> Changes in v4:
> - use &client->dev replace rk808->dev
> 
> Changes in v3: None
> Changes in v2:
> Adviced by javier.martinez
> - Add a separate clock driver, rather than in RTC driver
> 
>  drivers/rtc/Kconfig     |   10 ++
>  drivers/rtc/Makefile    |    1 +
>  drivers/rtc/rtc-rk808.c |  412 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 423 insertions(+)
>  create mode 100644 drivers/rtc/rtc-rk808.c
> 
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index a168e96..aeab9d9 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -288,6 +288,16 @@ config RTC_DRV_MAX77686
>  	  This driver can also be built as a module. If so, the module
>  	  will be called rtc-max77686.
>  
> +config RTC_DRV_RK808
> +	tristate "Rockchip RK808 RTC"
> +	depends on MFD_RK808
> +	help
> +	  If you say yes here you will get support for the
> +	  RTC of RK808 PMIC.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called rk808-rtc.
> +
>  config RTC_DRV_RS5C372
>  	tristate "Ricoh R2025S/D, RS5C372A/B, RV5C386, RV5C387A"
>  	help
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 56f061c..91fe4647 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -109,6 +109,7 @@ obj-$(CONFIG_RTC_DRV_PUV3)	+= rtc-puv3.o
>  obj-$(CONFIG_RTC_DRV_PXA)	+= rtc-pxa.o
>  obj-$(CONFIG_RTC_DRV_R9701)	+= rtc-r9701.o
>  obj-$(CONFIG_RTC_DRV_RC5T583)	+= rtc-rc5t583.o
> +obj-$(CONFIG_RTC_DRV_RK808)	+= rtc-rk808.o
>  obj-$(CONFIG_RTC_DRV_RP5C01)	+= rtc-rp5c01.o
>  obj-$(CONFIG_RTC_DRV_RS5C313)	+= rtc-rs5c313.o
>  obj-$(CONFIG_RTC_DRV_RS5C348)	+= rtc-rs5c348.o
> diff --git a/drivers/rtc/rtc-rk808.c b/drivers/rtc/rtc-rk808.c
> new file mode 100644
> index 0000000..00cd997
> --- /dev/null
> +++ b/drivers/rtc/rtc-rk808.c
> @@ -0,0 +1,412 @@
> +/*
> + * RTC driver for Rockchip RK808
> + *
> + * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/rtc.h>
> +#include <linux/bcd.h>
> +#include <linux/mfd/rk808.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +
> +/* RTC_CTRL_REG bitfields */
> +#define BIT_RTC_CTRL_REG_STOP_RTC_M		BIT(0)
> +#define BIT_RTC_CTRL_REG_RTC_READSEL_M		BIT(7)
> +#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M	BIT(3)
> +#define RTC_STATUS_MASK		0xFE
> +
> +#define SECONDS_REG_MSK		0x7F
> +#define MINUTES_REG_MAK		0x7F
> +#define HOURS_REG_MSK		0x3F
> +#define DAYS_REG_MSK		0x3F
> +#define MONTHS_REG_MSK		0x1F
> +#define YEARS_REG_MSK		0xFF
> +#define WEEKS_REG_MSK		0x7
> +
> +/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
> +
> +#define NUM_TIME_REGS	(RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
> +#define NUM_ALARM_REGS	(RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)
> +
> +struct rk808_rtc {
> +	struct rk808 *rk808;
> +	struct rtc_device *rtc;
> +	int irq;
> +};
> +
> +/* Read current time and date in RTC */
> +static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
> +{
> +	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +	struct rk808 *rk808 = rk808_rtc->rk808;
> +	u8 rtc_data[NUM_TIME_REGS];
> +	int ret;
> +
> +	ret = regmap_bulk_read(rk808->regmap, RK808_SECONDS_REG,
> +			       rtc_data, NUM_TIME_REGS);
> +	if (ret) {
> +		dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
> +		return ret;
> +	}
> +
> +	tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
> +	tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
> +	tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
> +	tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
> +	tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
> +	tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
> +	tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
> +	dev_dbg(dev, "RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
> +		1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
> +		tm->tm_wday, tm->tm_hour , tm->tm_min, tm->tm_sec);
> +
> +	return 0;
> +}
> +
> +/* Set current time and date in RTC */
> +static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +	struct rk808 *rk808 = rk808_rtc->rk808;
> +	u8 rtc_data[NUM_TIME_REGS];
> +	int ret;
> +
> +	rtc_data[0] = bin2bcd(tm->tm_sec);
> +	rtc_data[1] = bin2bcd(tm->tm_min);
> +	rtc_data[2] = bin2bcd(tm->tm_hour);
> +	rtc_data[3] = bin2bcd(tm->tm_mday);
> +	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
> +	rtc_data[5] = bin2bcd(tm->tm_year - 100);
> +	rtc_data[6] = bin2bcd(tm->tm_wday);
> +	dev_dbg(dev, "set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
> +		1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
> +		tm->tm_wday, tm->tm_hour , tm->tm_min, tm->tm_sec);
> +
> +	/* Stop RTC while updating the RTC registers */
> +	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
> +				 BIT_RTC_CTRL_REG_STOP_RTC_M,
> +				 BIT_RTC_CTRL_REG_STOP_RTC_M);
> +	if (ret) {
> +		dev_err(dev, "Failed to update RTC control: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG,
> +				rtc_data, NUM_TIME_REGS);
> +	if (ret) {
> +		dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
> +		return ret;
> +	}
> +	/* Start RTC again */
> +	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
> +				 BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
> +	if (ret) {
> +		dev_err(dev, "Failed to update RTC control: %d\n", ret);
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +/* Read alarm time and date in RTC */
> +static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> +	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +	struct rk808 *rk808 = rk808_rtc->rk808;
> +	u8 alrm_data[NUM_ALARM_REGS];
> +	uint32_t int_reg;
> +	int ret;
> +
> +	ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG,
> +			       alrm_data, NUM_ALARM_REGS);
> +
> +	alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
> +	alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
> +	alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
> +	alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
> +	alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
> +	alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
> +
> +	ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg);
> +	if (ret) {
> +		dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
> +		return ret;
> +	}
> +
> +	dev_dbg(dev, "alrm read RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
> +		1900 + alrm->time.tm_year, alrm->time.tm_mon + 1,
> +		alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour,
> +		alrm->time.tm_min, alrm->time.tm_sec);
> +
> +	alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
> +
> +	return 0;
> +}
> +
> +static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
> +{
> +	struct rk808 *rk808 = rk808_rtc->rk808;
> +	int ret;
> +
> +	ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
> +				 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
> +
> +	return ret;
> +}
> +
> +static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
> +{
> +	struct rk808 *rk808 = rk808_rtc->rk808;
> +	int ret;
> +
> +	ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
> +				 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
> +				 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
> +
> +	return ret;
> +}
> +
> +static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> +	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +	struct rk808 *rk808 = rk808_rtc->rk808;
> +	u8 alrm_data[NUM_ALARM_REGS];
> +	int ret;
> +
> +	ret = rk808_rtc_stop_alarm(rk808_rtc);
> +	if (ret) {
> +		dev_err(dev, "Failed to stop alarm: %d\n", ret);
> +		return ret;
> +	}
> +	dev_dbg(dev, "alrm set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
> +		1900 + alrm->time.tm_year, alrm->time.tm_mon + 1,
> +		alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour,
> +		alrm->time.tm_min, alrm->time.tm_sec);
> +
> +	alrm_data[0] = bin2bcd(alrm->time.tm_sec);
> +	alrm_data[1] = bin2bcd(alrm->time.tm_min);
> +	alrm_data[2] = bin2bcd(alrm->time.tm_hour);
> +	alrm_data[3] = bin2bcd(alrm->time.tm_mday);
> +	alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
> +	alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
> +
> +	ret = regmap_bulk_write(rk808->regmap, RK808_ALARM_SECONDS_REG,
> +				alrm_data, NUM_ALARM_REGS);
> +	if (ret) {
> +		dev_err(dev, "Failed to bulk write: %d\n", ret);
> +		return ret;
> +	}
> +	if (alrm->enabled) {
> +		ret = rk808_rtc_start_alarm(rk808_rtc);
> +		if (ret) {
> +			dev_err(dev, "Failed to start alarm: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +	return 0;
> +}
> +
> +static int rk808_rtc_alarm_irq_enable(struct device *dev,
> +				      unsigned int enabled)
> +{
> +	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
> +
> +	if (enabled)
> +		return rk808_rtc_start_alarm(rk808_rtc);
> +
> +	return rk808_rtc_stop_alarm(rk808_rtc);
> +}
> +
> +/*
> + * We will just handle setting the frequency and make use the framework for
> + * reading the periodic interupts.
> + *
> + * @freq: Current periodic IRQ freq:
> + * bit 0: every second
> + * bit 1: every minute
> + * bit 2: every hour
> + * bit 3: every day
> + */
> +static irqreturn_t rk808_alarm_irq(int irq, void *data)
> +{
> +	struct rk808_rtc *rk808_rtc = data;
> +	struct rk808 *rk808 = rk808_rtc->rk808;
> +	struct i2c_client *client = rk808->i2c;
> +	uint32_t rtc_ctl;
> +	int ret;
> +
> +	ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
> +			   RTC_STATUS_MASK);
> +	if (ret) {
> +		dev_err(&client->dev,
> +			"%s:Failed to update RTC status: %d\n", __func__, ret);
> +		return ret;
> +	}
> +
> +	rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
> +	dev_dbg(&client->dev,
> +		 "%s:irq=%d,rtc_ctl=0x%x\n", __func__, irq, rtc_ctl);
> +	return IRQ_HANDLED;
> +}
> +
> +static const struct rtc_class_ops rk808_rtc_ops = {
> +	.read_time = rk808_rtc_readtime,
> +	.set_time = rk808_rtc_set_time,
> +	.read_alarm = rk808_rtc_readalarm,
> +	.set_alarm = rk808_rtc_setalarm,
> +	.alarm_irq_enable = rk808_rtc_alarm_irq_enable,
> +};
> +
> +#ifdef CONFIG_PM

I'd change this to CONFIG_PM_SLEEP ...

> +/* Turn off the alarm if it should not be a wake source. */
> +static int rk808_rtc_suspend(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev);
> +
> +	if (device_may_wakeup(dev))
> +		enable_irq_wake(rk808_rtc->irq);
> +
> +	return 0;
> +}
> +
> +/* Enable the alarm if it should be enabled (in case it was disabled to
> + * prevent use as a wake source).
> + */
> +static int rk808_rtc_resume(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev);
> +
> +	if (device_may_wakeup(dev))
> +		disable_irq_wake(rk808_rtc->irq);
> +
> +	return 0;
> +}
> +#else
> +#define rk808_rtc_suspend NULL
> +#define rk808_rtc_resume NULL

... dropped this #else branch ...

> +#endif
> +
> +static const struct dev_pm_ops rk808_rtc_pm_ops = {
> +	.suspend = rk808_rtc_suspend,
> +	.resume = rk808_rtc_resume,
> +	.poweroff = rk808_rtc_suspend,
> +};

... and replaced this with:

static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
			 rk808_rtc_suspend, rk808_rtc_resume);

> +
> +/* 2012.1.1 12:00:00 Saturday */
> +struct rtc_time tm_def = {
> +			.tm_wday = 6,
> +			.tm_year = 114,
> +			.tm_mon = 0,
> +			.tm_mday = 1,
> +			.tm_hour = 12,
> +			.tm_min = 0,
> +			.tm_sec = 0,
> +};
> +
> +static int rk808_rtc_probe(struct platform_device *pdev)
> +{
> +	struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
> +	struct rk808_rtc *rk808_rtc;
> +	struct rtc_time tm;
> +	int ret;
> +
> +	rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
> +	if (rk808_rtc == NULL)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, rk808_rtc);
> +	rk808_rtc->rk808 = rk808;
> +
> +	/* start rtc running by default.
> +	 * RK808 has a shadowed register for saving a "frozen" RTC time.
> +	 * When user setting "RTC_READSEL" to 1, the time will save in this
> +	 * shadowed register. In this case, user read rtc time register,
> +	 * actually get the time of that moment. We need the real time,
> +	 * so clr this bit.
> +	 */
> +	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
> +				 BIT_RTC_CTRL_REG_STOP_RTC_M |
> +				 BIT_RTC_CTRL_REG_RTC_READSEL_M, 0);
> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"Failed to update RTC control: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
> +			   RTC_STATUS_MASK);
> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"Failed to write RTC status: %d\n", ret);
> +			return ret;
> +	}
> +
> +	/* set init time */
> +	ret = rk808_rtc_readtime(&pdev->dev, &tm);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to read RTC time\n");
> +		return ret;
> +	}
> +	ret = rtc_valid_tm(&tm);
> +	if (ret) {
> +		dev_warn(&pdev->dev, "invalid date/time and init time\n");
> +		rk808_rtc_set_time(&pdev->dev, &tm_def);
> +	}
> +
> +	device_init_wakeup(&pdev->dev, 1);
> +
> +	rk808_rtc->rtc = devm_rtc_device_register(&pdev->dev, "rk808-rtc",
> +						  &rk808_rtc_ops, THIS_MODULE);
> +	if (IS_ERR(rk808_rtc->rtc)) {
> +		ret = PTR_ERR(rk808_rtc->rtc);
> +		return ret;
> +	}
> +
> +	rk808_rtc->irq  = platform_get_irq(pdev, 0);

There is an extra space in front of '='.

> +	if (rk808_rtc->irq <= 0) {
> +		dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
> +			rk808_rtc->irq);
> +		return rk808_rtc->irq;

This is wrong. Either this is a warning and you should not return
negative value and let the driver bind, or it is an error (and then you
need to change dev_warn into dev_err) and you need to make sure you do
not return success (0) even if rk808_rtc->irq is 0.

Thanks.
-- 
Dmitry
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