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Message-ID: <7c24377d-a02f-4488-be7b-0725d559994d@amlogic.com>
Date: Fri, 8 Nov 2024 13:47:33 +0800
From: Xianwei Zhao <xianwei.zhao@...ogic.com>
To: Christophe JAILLET <christophe.jaillet@...adoo.fr>,
Xianwei Zhao via B4 Relay <devnull+xianwei.zhao.amlogic.com@...nel.org>
Cc: linux-amlogic@...ts.infradead.org, linux-rtc@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Yiting Deng <yiting.deng@...ogic.com>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>
Subject: Re: [PATCH RESEND v4 2/3] rtc: support for the Amlogic on-chip RTC
Hi Christophe,
Thanks for your review. Most will take your advice.
On 2024/11/1 17:15, Christophe JAILLET wrote:
> [ EXTERNAL EMAIL ]
>
> Le 01/11/2024 à 03:06, Xianwei Zhao via B4 Relay a écrit :
>> From: Yiting Deng <yiting.deng-LpR1jeaWuhtBDgjK7y7TUQ@...lic.gmane.org>
>>
>> This is the third amlogic driver. The RTC hardware of A4 SoC is different
>> from the previous one. This RTC hardware includes a timing function and
>> an alarm function. But the existing has only timing function, alarm
>> function is using the system clock to implement a virtual alarm. Add
>> the RTC driver to support it.
>>
>> Signed-off-by: Yiting Deng
>> <yiting.deng-LpR1jeaWuhtBDgjK7y7TUQ@...lic.gmane.org>
>> Signed-off-by: Xianwei Zhao
>> <xianwei.zhao-LpR1jeaWuhtBDgjK7y7TUQ@...lic.gmane.org>
>
> ...
>
>> diff --git a/drivers/rtc/rtc-amlogic-a4.c b/drivers/rtc/rtc-amlogic-a4.c
>> new file mode 100644
>> index 000000000000..decd74df225c
>> --- /dev/null
>> +++ b/drivers/rtc/rtc-amlogic-a4.c
>> @@ -0,0 +1,473 @@
>> +// SPDX-License-Identifier: (GPL-2.0-only OR MIT)
>> +/*
>> + * Copyright (C) 2024 Amlogic, Inc. All rights reserved
>> + * Author: Yiting Deng
>> <yiting.deng-LpR1jeaWuhtBDgjK7y7TUQ@...lic.gmane.org>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +#include <linux/bitfield.h>
>> +#include <linux/rtc.h>
>> +#include <linux/clk.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/time64.h>
>> +#include <linux/delay.h>
>
> Nitpick: sometimes, alphabetical order is preferred.
>
>> +
>> +/* rtc oscillator rate */
>> +#define OSC_32K (32768)
>> +#define OSC_24M (24000000)
>
> Nitpick: maybe these () could be removed to ease reading?
>
>> +
>> +#define RTC_CTRL (0x0 << 2) /* Control RTC */
>> +#define RTC_ALRM0_EN BIT(0)
>> +#define RTC_OSC_SEL BIT(8)
>> +#define RTC_ENABLE BIT(12)
>
> ...
>
>> +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);
>
> Should we have something like:
>
> if (!rtc->rtc_enabled) {
> dev_err(dev, "<something>");
> return -EINVAL;
> }
>
> if enabling fails?
>
>> + }
>> +
>> + 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 = 0;
>
> Nitpick: No need to init.
>
>> +
>> + /* 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_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, ®_val);
>> + enable = FIELD_GET(RTC_ADJ_VALID, reg_val);
>> + if (!enable) {
>> + val = 0;
>
> Nitpick: If val was initialised above, you could save 2 lines of code here.
>
I'll leave it as it is, and seting value here is a better representation
of the meaning of the variable.
>> + } 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_probe(struct platform_device *pdev)
>> +{
>> + struct aml_rtc_data *rtc;
>
> Nitpick: defining:
> struct device *dev = &pdev->dev;
>
> would simplify code bellow.
>
>> + void __iomem *base;
>> + int ret = 0;
>> +
>> + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
>> + if (!rtc)
>> + return -ENOMEM;
>> +
>> + rtc->config = of_device_get_match_data(&pdev->dev);
>> + if (!rtc->config)
>> + return -ENODEV;
>> +
>> + base = devm_platform_ioremap_resource(pdev, 0);
>> + if (IS_ERR(base))
>> + return dev_err_probe(&pdev->dev, PTR_ERR(base),
>> "resource ioremap failed\n");
>> +
>> + rtc->map = devm_regmap_init_mmio(&pdev->dev, base,
>> &aml_rtc_regmap_config);
>> + if (IS_ERR(rtc->map))
>> + return dev_err_probe(&pdev->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(&pdev->dev, "osc");
>> + if (IS_ERR(rtc->rtc_clk))
>> + return dev_err_probe(&pdev->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(&pdev->dev, -EINVAL, "Invalid clock
>> configuration\n");
>> +
>> + rtc->sys_clk = devm_clk_get(&pdev->dev, "sys");
>
> Maybe devm_clk_get_enabled() to simplify code below and the .remove()
> function?
>
>> + if (IS_ERR(rtc->sys_clk))
>> + return dev_err_probe(&pdev->dev, PTR_ERR(rtc->sys_clk),
>> + "failed to get rtc sys clk\n");
>> + ret = clk_prepare_enable(rtc->sys_clk);
>> + if (ret)
>> + return dev_err_probe(&pdev->dev, ret, "Failed to enable
>> clk!\n");
>> +
>> + aml_rtc_init(rtc);
>> +
>> + device_init_wakeup(&pdev->dev, 1);
>> + platform_set_drvdata(pdev, rtc);
>> +
>> + rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
>> + if (IS_ERR(rtc->rtc_dev)) {
>> + ret = PTR_ERR(rtc->rtc_dev);
>> + goto err_clk;
>> + }
>> +
>> + ret = devm_request_irq(&pdev->dev, rtc->irq, aml_rtc_handler,
>> + IRQF_ONESHOT, "aml-rtc alarm", rtc);
>> + if (ret) {
>> + dev_err_probe(&pdev->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);
>
> Should device_init_wakeup(..., 0) be called here?
> (as in the remove function)
>
>> +
>> + return ret;
>> +}
>
> ...
>
>> +static SIMPLE_DEV_PM_OPS(aml_rtc_pm_ops,
>> + aml_rtc_suspend, aml_rtc_resume);
>> +
>> +static int aml_rtc_remove(struct platform_device *pdev)
>
> Should'nt it return void?
> Compilation fails with latest -next.
>
>> +{
>> + struct aml_rtc_data *rtc = dev_get_drvdata(&pdev->dev);
>> +
>> + /* disable RTC */
>> + regmap_write_bits(rtc->map, RTC_CTRL, RTC_ENABLE, 0);
>> + clk_disable_unprepare(rtc->sys_clk);
>> + device_init_wakeup(&pdev->dev, 0);
>> +
>> + return 0;
>> +}
>
> ...
>
> CJ
>
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