Re: [PATCH v5 2/3] rtc: support for the Amlogic on-chip RTC

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

On 08/11/2024 13:54:42+0800, Xianwei Zhao via B4 Relay wrote:
> +static int aml_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +	u32 time_sec;
> +
> +	/* if RTC disabled, read time failed */
> +	if (!rtc->rtc_enabled) {
> +		dev_err(dev, "RTC disabled, read time failed\n");

These messages should be dropped, they probably won't be seen by any
user.

> +		return -EINVAL;
> +	}
> +
> +	regmap_read(rtc->map, RTC_REAL_TIME, &time_sec);
> +	if (rtc->config->gray_stored)
> +		time_sec = gray_to_binary(time_sec);
> +	rtc_time64_to_tm(time_sec, tm);
> +	dev_dbg(dev, "%s: read time = %us\n", __func__, time_sec);
> +
> +	return 0;
> +}
> +
> +static int aml_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +	u32 time_sec;
> +
> +	/* if RTC disabled, first enable it */
> +	if (!rtc->rtc_enabled) {
> +		regmap_write_bits(rtc->map, RTC_CTRL, RTC_ENABLE, RTC_ENABLE);
> +		usleep_range(100, 200);
> +		rtc->rtc_enabled = regmap_test_bits(rtc->map, RTC_CTRL, RTC_ENABLE);
> +		if (!rtc->rtc_enabled) {
> +			dev_err(dev, "RTC enable failed\n");
> +			return -EINVAL;
> +		}
> +	}
> +
> +	time_sec = rtc_tm_to_time64(tm);
> +	if (rtc->config->gray_stored)
> +		time_sec = binary_to_gray(time_sec);
> +	regmap_write(rtc->map, RTC_COUNTER_REG, time_sec);
> +	dev_dbg(dev, "%s: set time = %us\n", __func__, time_sec);
> +
> +	return 0;
> +}
> +
> +static int aml_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +	time64_t alarm_sec;
> +
> +	/* if RTC disabled, set alarm failed */
> +	if (!rtc->rtc_enabled) {
> +		dev_err(dev, "RTC disabled, set alarm failed\n");
> +		return -EINVAL;
> +	}
> +
> +	regmap_update_bits(rtc->map, RTC_CTRL,
> +			   RTC_ALRM0_EN, RTC_ALRM0_EN);
> +	regmap_update_bits(rtc->map, RTC_INT_MASK,
> +			   RTC_ALRM0_IRQ_MSK, 0);
> +
> +	alarm_sec = rtc_tm_to_time64(&alarm->time);
> +	if (rtc->config->gray_stored)
> +		alarm_sec = binary_to_gray(alarm_sec);
> +	regmap_write(rtc->map, RTC_ALARM0_REG, alarm_sec);
> +
> +	dev_dbg(dev, "%s: alarm->enabled=%d alarm_set=%llds\n", __func__,
> +		alarm->enabled, alarm_sec);
> +
> +	return 0;
> +}
> +
> +static int aml_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +	u32 alarm_sec;
> +	int alarm_enable;
> +	int alarm_mask;
> +
> +	/* if RTC disabled, read alarm failed */
> +	if (!rtc->rtc_enabled) {
> +		dev_err(dev, "RTC disabled, read alarm failed\n");
> +		return -EINVAL;
> +	}
> +
> +	regmap_read(rtc->map, RTC_ALARM0_REG, &alarm_sec);
> +	if (rtc->config->gray_stored)
> +		alarm_sec = gray_to_binary(alarm_sec);
> +	rtc_time64_to_tm(alarm_sec, &alarm->time);
> +
> +	alarm_enable = regmap_test_bits(rtc->map, RTC_CTRL, RTC_ALRM0_EN);
> +	alarm_mask = regmap_test_bits(rtc->map, RTC_INT_MASK, RTC_ALRM0_IRQ_MSK);
> +	alarm->enabled = (alarm_enable && !alarm_mask) ? 1 : 0;
> +	dev_dbg(dev, "%s: alarm->enabled=%d alarm=%us\n", __func__,
> +		alarm->enabled, alarm_sec);
> +
> +	return 0;
> +}
> +
> +static int aml_rtc_read_offset(struct device *dev, long *offset)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +	u32 reg_val;
> +	long val;
> +	int sign, match_counter, enable;
> +
> +	/* if RTC disabled, read offset failed */
> +	if (!rtc->rtc_enabled) {
> +		dev_err(dev, "RTC disabled, read offset failed\n");
> +		return -EINVAL;
> +	}
> +
> +	regmap_read(rtc->map, RTC_SEC_ADJUST_REG, &reg_val);
> +	enable = FIELD_GET(RTC_ADJ_VALID, reg_val);
> +	if (!enable) {
> +		val = 0;
> +	} else {
> +		sign = FIELD_GET(RTC_SEC_ADJUST_CTRL, reg_val);
> +		match_counter = FIELD_GET(RTC_MATCH_COUNTER, reg_val);
> +		val = 1000000000 / (match_counter + 1);
> +		if (sign == RTC_SWALLOW_SECOND)
> +			val = -val;
> +	}
> +	*offset = val;
> +
> +	return 0;
> +}
> +
> +static int aml_rtc_set_offset(struct device *dev, long offset)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +	int sign = 0;
> +	int match_counter = 0;
> +	int enable = 0;
> +	u32 reg_val;
> +
> +	/* if RTC disabled, set offset failed */
> +	if (!rtc->rtc_enabled) {
> +		dev_err(dev, "RTC disabled, set offset failed\n");
> +		return -EINVAL;
> +	}
> +
> +	if (offset) {
> +		enable = 1;
> +		sign = offset < 0 ? RTC_SWALLOW_SECOND : RTC_INSERT_SECOND;
> +		match_counter = 1000000000 / abs(offset) - 1;
> +		if (match_counter < 0 || match_counter > RTC_MATCH_COUNTER)
> +			return -EINVAL;
> +	}
> +
> +	reg_val = FIELD_PREP(RTC_ADJ_VALID, enable) |
> +		  FIELD_PREP(RTC_SEC_ADJUST_CTRL, sign) |
> +		  FIELD_PREP(RTC_MATCH_COUNTER, match_counter);
> +	regmap_write(rtc->map, RTC_SEC_ADJUST_REG, reg_val);
> +
> +	return 0;
> +}
> +
> +static int aml_rtc_alarm_enable(struct device *dev, unsigned int enabled)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +
> +	if (enabled) {
> +		regmap_update_bits(rtc->map, RTC_CTRL,
> +				   RTC_ALRM0_EN, RTC_ALRM0_EN);
> +		regmap_update_bits(rtc->map, RTC_INT_MASK,
> +				   RTC_ALRM0_IRQ_MSK, 0);
> +	} else {
> +		regmap_update_bits(rtc->map, RTC_INT_MASK,
> +				   RTC_ALRM0_IRQ_MSK, RTC_ALRM0_IRQ_MSK);
> +		regmap_update_bits(rtc->map, RTC_CTRL,
> +				   RTC_ALRM0_EN, 0);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct rtc_class_ops aml_rtc_ops = {
> +	.read_time = aml_rtc_read_time,
> +	.set_time = aml_rtc_set_time,
> +	.read_alarm = aml_rtc_read_alarm,
> +	.set_alarm = aml_rtc_set_alarm,
> +	.alarm_irq_enable = aml_rtc_alarm_enable,
> +	.read_offset = aml_rtc_read_offset,
> +	.set_offset = aml_rtc_set_offset,
> +};
> +
> +static irqreturn_t aml_rtc_handler(int irq, void *data)
> +{
> +	struct aml_rtc_data *rtc = (struct aml_rtc_data *)data;
> +
> +	regmap_write(rtc->map, RTC_ALARM0_REG, 0);
> +	regmap_write(rtc->map, RTC_INT_CLR, RTC_ALRM0_IRQ_STATUS);
> +
> +	rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static void aml_rtc_init(struct aml_rtc_data *rtc)
> +{
> +	u32 reg_val = 0;
> +
> +	rtc->rtc_enabled = regmap_test_bits(rtc->map, RTC_CTRL, RTC_ENABLE);
> +	if (!rtc->rtc_enabled) {
> +		if (clk_get_rate(rtc->rtc_clk) == OSC_24M) {
> +			/* select 24M oscillator */
> +			regmap_write_bits(rtc->map, RTC_CTRL, RTC_OSC_SEL, RTC_OSC_SEL);
> +
> +			/*
> +			 * Set RTC oscillator to freq_out to freq_in/((N0*M0+N1*M1)/(M0+M1))
> +			 * Enable clock_in gate of oscillator 24MHz
> +			 * Set N0 to 733, N1 to 732
> +			 */
> +			reg_val = FIELD_PREP(RTC_OSCIN_IN_EN, 1)
> +				  | FIELD_PREP(RTC_OSCIN_OUT_CFG, 1)
> +				  | FIELD_PREP(RTC_OSCIN_OUT_N0M0, RTC_OSCIN_OUT_32K_N0)
> +				  | FIELD_PREP(RTC_OSCIN_OUT_N1M1, RTC_OSCIN_OUT_32K_N1);
> +			regmap_write_bits(rtc->map, RTC_OSCIN_CTRL0, RTC_OSCIN_IN_EN
> +					  | RTC_OSCIN_OUT_CFG | RTC_OSCIN_OUT_N0M0
> +					  | RTC_OSCIN_OUT_N1M1, reg_val);
> +
> +			/* Set M0 to 2, M1 to 3, so freq_out = 32768 Hz*/
> +			reg_val = FIELD_PREP(RTC_OSCIN_OUT_N0M0, RTC_OSCIN_OUT_32K_M0)
> +				  | FIELD_PREP(RTC_OSCIN_OUT_N1M1, RTC_OSCIN_OUT_32K_M1);
> +			regmap_write_bits(rtc->map, RTC_OSCIN_CTRL1, RTC_OSCIN_OUT_N0M0
> +					  | RTC_OSCIN_OUT_N1M1, reg_val);
> +		} else {
> +			/* select 32K oscillator */
> +			regmap_write_bits(rtc->map, RTC_CTRL, RTC_OSC_SEL, 0);
> +		}
> +	}
> +	regmap_write_bits(rtc->map, RTC_INT_MASK,
> +			  RTC_ALRM0_IRQ_MSK, RTC_ALRM0_IRQ_MSK);
> +	regmap_write_bits(rtc->map, RTC_CTRL, RTC_ALRM0_EN, 0);
> +}
> +
> +static int aml_rtc_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct aml_rtc_data *rtc;
> +	void __iomem *base;
> +	int ret = 0;
> +
> +	rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
> +	if (!rtc)
> +		return -ENOMEM;
> +
> +	rtc->config = of_device_get_match_data(dev);
> +	if (!rtc->config)
> +		return -ENODEV;
> +
> +	base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(base))
> +		return dev_err_probe(dev, PTR_ERR(base), "resource ioremap failed\n");
> +
> +	rtc->map = devm_regmap_init_mmio(dev, base, &aml_rtc_regmap_config);
> +	if (IS_ERR(rtc->map))
> +		return dev_err_probe(dev, PTR_ERR(rtc->map), "regmap init failed\n");
> +
> +	rtc->irq = platform_get_irq(pdev, 0);
> +	if (rtc->irq < 0)
> +		return rtc->irq;
> +
> +	rtc->rtc_clk = devm_clk_get(dev, "osc");
> +	if (IS_ERR(rtc->rtc_clk))
> +		return dev_err_probe(dev, PTR_ERR(rtc->rtc_clk),
> +				     "failed to find rtc clock\n");
> +	if (clk_get_rate(rtc->rtc_clk) != OSC_32K && clk_get_rate(rtc->rtc_clk) != OSC_24M)
> +		return dev_err_probe(dev, -EINVAL, "Invalid clock configuration\n");
> +
> +	rtc->sys_clk = devm_clk_get_enabled(dev, "sys");
> +	if (IS_ERR(rtc->sys_clk))
> +		return dev_err_probe(dev, PTR_ERR(rtc->sys_clk),
> +				     "failed to get_enable rtc sys clk\n");
> +	aml_rtc_init(rtc);
> +
> +	device_init_wakeup(dev, 1);
> +	platform_set_drvdata(pdev, rtc);
> +
> +	rtc->rtc_dev = devm_rtc_allocate_device(dev);
> +	if (IS_ERR(rtc->rtc_dev)) {
> +		ret = PTR_ERR(rtc->rtc_dev);
> +		goto err_clk;
> +	}
> +
> +	ret = devm_request_irq(dev, rtc->irq, aml_rtc_handler,
> +			       IRQF_ONESHOT, "aml-rtc alarm", rtc);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "IRQ%d request failed, ret = %d\n",
> +			      rtc->irq, ret);
> +		goto err_clk;
> +	}
> +
> +	rtc->rtc_dev->ops = &aml_rtc_ops;
> +	rtc->rtc_dev->range_min = 0;
> +	rtc->rtc_dev->range_max = U32_MAX;
> +
> +	ret = devm_rtc_register_device(rtc->rtc_dev);
> +	if (ret) {
> +		dev_err_probe(&pdev->dev, ret, "Failed to register RTC device: %d\n", ret);
> +		goto err_clk;
> +	}
> +
> +	return 0;
> +err_clk:
> +	clk_disable_unprepare(rtc->sys_clk);
> +	device_init_wakeup(dev, 0);
> +
> +	return ret;
> +}
> +
> +static int aml_rtc_suspend(struct device *dev)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +
> +	if (device_may_wakeup(dev))
> +		enable_irq_wake(rtc->irq);
> +
> +	return 0;
> +}
> +
> +static int aml_rtc_resume(struct device *dev)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(dev);
> +
> +	if (device_may_wakeup(dev))
> +		disable_irq_wake(rtc->irq);
> +
> +	return 0;
> +}

Building this, i got:

drivers/rtc/rtc-amlogic-a4.c:409:12: error: ‘aml_rtc_resume’ defined but not used [-Werror=unused-function]
  409 | static int aml_rtc_resume(struct device *dev)
      |            ^~~~~~~~~~~~~~
drivers/rtc/rtc-amlogic-a4.c:399:12: error: ‘aml_rtc_suspend’ defined but not used [-Werror=unused-function]
  399 | static int aml_rtc_suspend(struct device *dev)
      |            ^~~~~~~~~~~~~~~


> +
> +static SIMPLE_DEV_PM_OPS(aml_rtc_pm_ops,
> +			 aml_rtc_suspend, aml_rtc_resume);
> +
> +static void aml_rtc_remove(struct platform_device *pdev)
> +{
> +	struct aml_rtc_data *rtc = dev_get_drvdata(&pdev->dev);
> +
> +	/* disable RTC */
> +	regmap_write_bits(rtc->map, RTC_CTRL, RTC_ENABLE, 0);

You can't do this, this defeats the purpose of the RTC. Once started an
set, it must not be stopped.

> +	clk_disable_unprepare(rtc->sys_clk);
> +	device_init_wakeup(&pdev->dev, 0);
> +}
> +
> +static const struct aml_rtc_config a5_rtc_config = {
> +};
> +
> +static const struct aml_rtc_config a4_rtc_config = {
> +	.gray_stored = true,
> +};
> +
> +static const struct of_device_id aml_rtc_device_id[] = {
> +	{
> +		.compatible = "amlogic,a4-rtc",
> +		.data = &a4_rtc_config,
> +	},
> +	{
> +		.compatible = "amlogic,a5-rtc",
> +		.data = &a5_rtc_config,
> +	},
> +};
> +MODULE_DEVICE_TABLE(of, aml_rtc_device_id);
> +
> +static struct platform_driver aml_rtc_driver = {
> +	.probe = aml_rtc_probe,
> +	.remove = aml_rtc_remove,
> +	.driver = {
> +		.name = "aml-rtc",
> +		.pm = &aml_rtc_pm_ops,
> +		.of_match_table = aml_rtc_device_id,
> +	},
> +};
> +
> +module_platform_driver(aml_rtc_driver);
> +MODULE_DESCRIPTION("Amlogic RTC driver");
> +MODULE_AUTHOR("Yiting Deng <yiting.deng@amlogic.com>");
> +MODULE_LICENSE("GPL");
> 
> -- 
> 2.37.1
> 
> 

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

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