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Date: Mon, 29 Nov 2021 12:20:06 +0100
From: Alexandre Belloni <alexandre.belloni@...tlin.com>
To: Vincent Shih <vincent.sunplus@...il.com>
Cc: a.zummo@...ertech.it, p.zabel@...gutronix.de,
linux-kernel@...r.kernel.org, linux-rtc@...r.kernel.org,
robh+dt@...nel.org, devicetree@...r.kernel.org,
wells.lu@...plus.com,
in-reply-to=1635834123-24668-1-git-send-email-vincent.shih@...plus.com,
Vincent Shih <vincent.shih@...plus.com>
Subject: Re: [PATCH v2 1/2] rtc: Add driver for Sunplus SP7021
Hello,
On 09/11/2021 14:38:17+0800, Vincent Shih wrote:
> +#define RTC_REG_NAME "rtc_reg"
> +
> +#define RTC_CTRL 0x40
> +#define TIMER_FREEZE (0x1 << 5)
> +#define TIMER_FREEZE_MASK (1 << (5 + 16))
> +#define DIS_SYS_RST_RTC (0x1 << 4)
> +#define DIS_SYS_RST_RTC_MASK (1 << (4 + 16))
> +#define RTC32K_MODE_RESET (0x1 << 3)
> +#define RTC32K_MODE_RESET_MASK (1 << (3 + 16))
> +#define ALARM_EN_OVERDUE (0x1 << 2)
> +#define ALARM_EN_OVERDUE_MASK (1 << (2 + 16))
> +#define ALARM_EN_PMC (0x1 << 1)
> +#define ALARM_EN_PMC_MASK (1 << (1 + 16))
> +#define ALARM_EN (0x1 << 0)
> +#define ALARM_EN_MASK (1 << (0 + 16))
You should definitively use BIT() and probably GENMASK
> +#define RTC_TIMER_OUT 0x44
> +#define RTC_DIVIDER 0x48
> +#define RTC_TIMER_SET 0x4c
> +#define RTC_ALARM_SET 0x50
> +#define RTC_USER_DATA 0x54
> +#define RTC_RESET_RECORD 0x58
> +#define RTC_BATTERY_CTRL 0x5c
> +#define BAT_CHARGE_RSEL_2K_OHM (0x0 << 2)
> +#define BAT_CHARGE_RSEL_250_OHM (0x1 << 2)
> +#define BAT_CHARGE_RSEL_50_OHM (0x2 << 2)
> +#define BAT_CHARGE_RSEL_0_OHM (0x3 << 2)
Using FIELD_GET and FIELD_PREP later on will simplify those defines.
> +#define BAT_CHARGE_RSEL_MASK (0x3 << (2 + 16))
> +#define BAT_CHARGE_DSEL_ON (0x0 << 1)
> +#define BAT_CHARGE_DSEL_OFF (0x1 << 1)
> +#define BAT_CHARGE_DSEL_MASK (0x1 << (1 + 16))
> +#define BAT_CHARGE_EN (0x1 << 0)
> +#define BAT_CHARGE_EN_MASK (0x1 << (0 + 16))
> +#define RTC_TRIM_CTRL 0x60
> +
> +struct sunplus_rtc {
> + struct clk *rtcclk;
> + struct reset_control *rstc;
> + void __iomem *base;
> + u32 ohms;
> +};
> +
> +struct sunplus_rtc sp_rtc;
> +
> +static void sp_get_seconds(unsigned long *secs)
> +{
> + *secs = (unsigned long)readl(sp_rtc.base + RTC_TIMER_OUT);
> +}
> +
> +static void sp_set_seconds(unsigned long secs)
> +{
> + writel((u32)secs, sp_rtc.base + RTC_TIMER_SET);
> +}
> +
> +static int sp_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> + unsigned long secs;
> +
> + sp_get_seconds(&secs);
> + rtc_time64_to_tm(secs, tm);
> + dev_dbg(dev, "%s: RTC date/time to %d-%d-%d, %02d:%02d:%02d.\r\n",
> + __func__, tm->tm_mday, tm->tm_mon + 1, tm->tm_year,
> + tm->tm_hour, tm->tm_min, tm->tm_sec);
You should use %ptR or simplify remove this debug message as the core
has a tracepoint
> +
> + return rtc_valid_tm(tm);
This is uneccessary as the first thing the core does is check the
validity.
> +}
> +
> +int sp_rtc_get_time(struct rtc_time *tm)
This function seems unused.
> +{
> + unsigned long secs;
> +
> + sp_get_seconds(&secs);
> + rtc_time64_to_tm(secs, tm);
> +
> + return 0;
> +}
> +
> +static int sp_rtc_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> + dev_dbg(&pdev->dev, "[RTC] Debug: %s(%d)\n", __func__, __LINE__);
> +
> + // Keep RTC from system reset
> + writel(DIS_SYS_RST_RTC_MASK | DIS_SYS_RST_RTC, sp_rtc.base + RTC_CTRL);
> +
> + return 0;
> +}
> +
> +static int sp_rtc_resume(struct platform_device *pdev)
> +{
> + /* */
> + /* Because RTC is still powered during suspend, */
> + /* there is nothing to do here. */
> + /* */
I'd prefer this comment to use a more common formatting.
> + dev_dbg(&pdev->dev, "[RTC] Debug: %s(%d)\n", __func__, __LINE__);
> +
> + // Keep RTC from system reset
> + writel(DIS_SYS_RST_RTC_MASK | DIS_SYS_RST_RTC, sp_rtc.base + RTC_CTRL);
> +
Isn't that already done on suspend?
> + return 0;
> +}
> +
> +static int sp_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> + unsigned long secs;
> +
> + secs = rtc_tm_to_time64(tm);
> + dev_dbg(dev, "%s, secs = %lu\n", __func__, secs);
> + sp_set_seconds(secs);
> +
> + return 0;
> +}
> +
> +static int sp_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> + unsigned long alarm_time;
> +
> + alarm_time = rtc_tm_to_time64(&alrm->time);
> + dev_dbg(dev, "%s, alarm_time: %u\n", __func__, (u32)(alarm_time));
> + writel((u32)alarm_time, sp_rtc.base + RTC_ALARM_SET);
> +
> + return 0;
> +}
> +
> +static int sp_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> + unsigned int alarm_time;
> +
> + alarm_time = readl(sp_rtc.base + RTC_ALARM_SET);
> + dev_dbg(dev, "%s, alarm_time: %u\n", __func__, alarm_time);
> +
> + if (alarm_time == 0) {
> + // alarm is disabled
This comment is not really useful
> + alrm->enabled = 0;
> + } else {
> + // alarm is enabled
Ditto
> + alrm->enabled = 1;
> + rtc_time64_to_tm((unsigned long)(alarm_time), &alrm->time);
This should be done in either case.
> + }
> +
> + return 0;
> +}
> +
> +static int sp_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
> +{
> + if (enabled)
> + writel((TIMER_FREEZE_MASK | DIS_SYS_RST_RTC_MASK | RTC32K_MODE_RESET_MASK |
> + ALARM_EN_OVERDUE_MASK | ALARM_EN_PMC_MASK | ALARM_EN_MASK) |
> + (DIS_SYS_RST_RTC | ALARM_EN_OVERDUE | ALARM_EN_PMC |
> + ALARM_EN), sp_rtc.base + RTC_CTRL);
> + else
> + writel((ALARM_EN_OVERDUE_MASK | ALARM_EN_PMC_MASK | ALARM_EN_MASK) | 0x0,
> + sp_rtc.base + RTC_CTRL);
> +
> + return 0;
> +}
> +
> +static const struct rtc_class_ops sp_rtc_ops = {
> + .read_time = sp_rtc_read_time,
> + .set_time = sp_rtc_set_time,
> + .set_alarm = sp_rtc_set_alarm,
> + .read_alarm = sp_rtc_read_alarm,
> + .alarm_irq_enable = sp_rtc_alarm_irq_enable,
> +};
> +
> +static irqreturn_t rtc_irq_handler(int irq, void *dev_id)
> +{
> + struct platform_device *plat_dev = dev_id;
> + struct rtc_device *rtc = platform_get_drvdata(plat_dev);
> +
> + rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
> + dev_dbg(&plat_dev->dev, "[RTC] ALARM INT\n");
> +
> + return IRQ_HANDLED;
> +}
> +
> +/* ---------------------------------------------------------------------------------------------- */
> +/* bat_charge_rsel bat_charge_dsel bat_charge_en Remarks */
> +/* x x 0 Disable */
> +/* 0 0 1 0.86mA (2K Ohm with diode) */
> +/* 1 0 1 1.81mA (250 Ohm with diode) */
> +/* 2 0 1 2.07mA (50 Ohm with diode) */
> +/* 3 0 1 16.0mA (0 Ohm with diode) */
> +/* 0 1 1 1.36mA (2K Ohm without diode) */
> +/* 1 1 1 3.99mA (250 Ohm without diode) */
> +/* 2 1 1 4.41mA (50 Ohm without diode) */
> +/* 3 1 1 16.0mA (0 Ohm without diode) */
> +/* ---------------------------------------------------------------------------------------------- */
> +static void sp_rtc_set_trickle_charger(struct device dev)
> +{
> + int ret;
> + u32 rsel;
> +
> + ret = of_property_read_u32(dev.of_node, "trickle-resistor-ohms", &sp_rtc.ohms);
> + if (ret)
> + return;
> +
> + switch (sp_rtc.ohms) {
> + case 2000:
> + rsel = BAT_CHARGE_RSEL_2K_OHM;
> + break;
> + case 250:
> + rsel = BAT_CHARGE_RSEL_250_OHM;
> + break;
> + case 50:
> + rsel = BAT_CHARGE_RSEL_50_OHM;
> + break;
> + case 0:
> + rsel = BAT_CHARGE_RSEL_0_OHM;
> + break;
> + default:
> + return;
> + }
> +
> + writel(BAT_CHARGE_RSEL_MASK | rsel, sp_rtc.base + RTC_BATTERY_CTRL);
> +
> + ret = of_property_read_bool(dev.of_node, "trickle-diode-disable");
This property is deprecated and used to be about disabling the charger,
it has been replaced by aux-voltage-chargeable.
I guess we need a new property, probably "trickle-diode" that would take
a string parameter as some RTCs will need to know which type of diode
has to be enabled (e.g. rv1805 would need "standard" or "schottky")
> + if (ret)
> + writel(BAT_CHARGE_DSEL_MASK | BAT_CHARGE_DSEL_OFF, sp_rtc.base + RTC_BATTERY_CTRL);
> + else
> + writel(BAT_CHARGE_DSEL_MASK | BAT_CHARGE_DSEL_ON, sp_rtc.base + RTC_BATTERY_CTRL);
> +
> + writel(BAT_CHARGE_EN_MASK | BAT_CHARGE_EN, sp_rtc.base + RTC_BATTERY_CTRL);
> +}
> +
> +static int sp_rtc_probe(struct platform_device *plat_dev)
> +{
> + struct rtc_device *rtc;
> + struct resource *res;
> + const struct rtc_class_ops *rtc_ops;
> + void __iomem *reg_base;
> + int ret, irq;
> +
> + memset(&sp_rtc, 0, sizeof(sp_rtc));
> +
> + // find and map our resources
> + res = platform_get_resource_byname(plat_dev, IORESOURCE_MEM, RTC_REG_NAME);
> +
> + if (res) {
> + dev_dbg(&plat_dev->dev, "res = 0x%x\n", res->start);
> +
> + reg_base = devm_ioremap_resource(&plat_dev->dev, res);
> + if (IS_ERR(reg_base)) {
> + dev_err(&plat_dev->dev, "%s devm_ioremap_resource fail\n", RTC_REG_NAME);
> + return PTR_ERR(reg_base);
> + }
> +
> + dev_dbg(&plat_dev->dev, "reg_base = 0x%lx\n", (unsigned long)reg_base);
> + }
> +
> + sp_rtc.base = reg_base;
> + rtc_ops = &sp_rtc_ops;
> +
> + // Keep RTC from system reset
> + writel(DIS_SYS_RST_RTC_MASK | DIS_SYS_RST_RTC, sp_rtc.base + RTC_CTRL);
> +
I guess this is already done in .suspend, are you sure you need that in
all those locations?
> + // request irq
Useless comment
> + irq = platform_get_irq(plat_dev, 0);
> + if (irq < 0) {
> + dev_err(&plat_dev->dev, "platform_get_irq failed\n");
> + irq = IRQ_NOTCONNECTED;
> + }
> +
> + ret = devm_request_irq(&plat_dev->dev, irq, rtc_irq_handler,
> + IRQF_TRIGGER_RISING, "rtc irq", plat_dev);
> + if (ret) {
> + dev_err(&plat_dev->dev, "devm_request_irq failed: %d\n", ret);
> + return ret;
> + }
> +
> + // Setup trickle charger
> + if (plat_dev->dev.of_node)
> + sp_rtc_set_trickle_charger(plat_dev->dev);
> +
> + // reset
> + sp_rtc.rstc = devm_reset_control_get_exclusive(&plat_dev->dev, NULL);
> + if (IS_ERR(sp_rtc.rstc)) {
> + ret = dev_err_probe(&plat_dev->dev, PTR_ERR(sp_rtc.rstc),
> + "failed to retrieve reset controller\n");
> + return PTR_ERR(sp_rtc.rstc);
> + }
> +
> + // clk
> + sp_rtc.rtcclk = devm_clk_get(&plat_dev->dev, NULL);
> + if (IS_ERR(sp_rtc.rtcclk)) {
> + dev_err(&plat_dev->dev, "devm_clk_get fail\n");
> + return PTR_ERR(sp_rtc.rtcclk);
> + }
> +
> + ret = reset_control_deassert(sp_rtc.rstc);
> + if (ret)
> + return ret;
> +
> + ret = clk_prepare_enable(sp_rtc.rtcclk);
> + if (ret)
> + return ret;
> +
> + device_init_wakeup(&plat_dev->dev, 1);
> +
> + rtc = devm_rtc_allocate_device(&plat_dev->dev);
> + if (IS_ERR(rtc))
> + return PTR_ERR(rtc);
> +
> + rtc->range_max = U32_MAX;
> + rtc->range_min = 0;
> + rtc->ops = rtc_ops;
> +
> + ret = devm_rtc_register_device(rtc);
> + if (ret)
> + goto free_reset_assert_clk;
> +
> + platform_set_drvdata(plat_dev, rtc);
> + dev_info(&plat_dev->dev, "sp7021-rtc loaded\n");
This message needs to be removed, it is wrong and a proper message is
already printed by the core.
> +
> + return 0;
> +
> +free_reset_assert_clk:
> + reset_control_assert(sp_rtc.rstc);
> + clk_disable_unprepare(sp_rtc.rtcclk);
> +
> + return ret;
> +}
> +
> +static int sp_rtc_remove(struct platform_device *plat_dev)
> +{
> + reset_control_assert(sp_rtc.rstc);
> + clk_disable_unprepare(sp_rtc.rtcclk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id sp_rtc_of_match[] = {
> + { .compatible = "sunplus,sp7021-rtc" },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, sp_rtc_of_match);
> +
> +static struct platform_driver sp_rtc_driver = {
> + .probe = sp_rtc_probe,
> + .remove = sp_rtc_remove,
> + .suspend = sp_rtc_suspend,
> + .resume = sp_rtc_resume,
> + .driver = {
> + .name = "sp7021-rtc",
> + .owner = THIS_MODULE,
> + .of_match_table = sp_rtc_of_match,
> + },
> +};
> +module_platform_driver(sp_rtc_driver);
> +
> +MODULE_AUTHOR("Vincent Shih <vincent.shih@...plus.com>");
> +MODULE_DESCRIPTION("Sunplus RTC driver");
> +MODULE_LICENSE("GPL v2");
> +
> --
> 2.7.4
>
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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