[PATCH v7 23/24] rtc: Add driver for Maxim 77802 PMIC Real-Time-Clock

Krzysztof Kozlowski
2014-07-07T06:06:50Z

On pi?, 2014-07-04 at 22:24 +0200, Javier Martinez Canillas wrote:
> The MAX7802 PMIC has a Real-Time-Clock (RTC) with two alarms.
> This patch adds support for the RTC and is based on a driver
> added by Simon Glass to the Chrome OS kernel 3.8 tree.
>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> ---
>
> Changes since v6:
> - Remove unused code for SMPL and WTSR. Suggested by Krzysztof Kozlowski.
> - Don't spam the kernel log with unimportant info and just print for debug.
> Suggested by Krzysztof Kozlowski.
> - Use ARRAY_SIZE() instead of constant value. Suggested by Krzysztof Kozlowski.
> - Remove duplicated register setup. Suggested by Krzysztof Kozlowski.
> - Don't free/unregister managed allocated resources.
> Suggested by Krzysztof Kozlowski.
> ---
> drivers/rtc/Kconfig | 10 +
> drivers/rtc/Makefile | 1 +
> drivers/rtc/rtc-max77802.c | 508 +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 519 insertions(+)
> create mode 100644 drivers/rtc/rtc-max77802.c

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

Best regards,
Krzysztof

>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index a672dd1..243ac72 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_MAX77802
> + tristate "Maxim 77802 RTC"
> + depends on MFD_MAX77686
> + help
> + If you say yes here you will get support for the
> + RTC of Maxim MAX77802 PMIC.
> +
> + This driver can also be built as a module. If so, the module
> + will be called rtc-max77802.
> +
> config RTC_DRV_RS5C372
> tristate "Ricoh R2025S/D, RS5C372A/B, RV5C386, RV5C387A"
> help
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 70347d0..247de78 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -81,6 +81,7 @@ obj-$(CONFIG_RTC_DRV_MAX8998) += rtc-max8998.o
> obj-$(CONFIG_RTC_DRV_MAX8997) += rtc-max8997.o
> obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o
> obj-$(CONFIG_RTC_DRV_MAX77686) += rtc-max77686.o
> +obj-$(CONFIG_RTC_DRV_MAX77802) += rtc-max77802.o
> obj-$(CONFIG_RTC_DRV_MC13XXX) += rtc-mc13xxx.o
> obj-$(CONFIG_RTC_DRV_MCP795) += rtc-mcp795.o
> obj-$(CONFIG_RTC_DRV_MSM6242) += rtc-msm6242.o
> diff --git a/drivers/rtc/rtc-max77802.c b/drivers/rtc/rtc-max77802.c
> new file mode 100644
> index 0000000..f8898ff
> --- /dev/null
> +++ b/drivers/rtc/rtc-max77802.c
> @@ -0,0 +1,508 @@
> +/*
> + * RTC driver for Maxim MAX77802
> + *
> + * Copyright (C) 2013 Google, Inc
> + *
> + * Copyright (C) 2012 Samsung Electronics Co.Ltd
> + *
> + * based on rtc-max8997.c
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + *
> + */
> +
> +#include <linux/slab.h>
> +#include <linux/rtc.h>
> +#include <linux/delay.h>
> +#include <linux/mutex.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/mfd/max77686-private.h>
> +#include <linux/irqdomain.h>
> +#include <linux/regmap.h>
> +
> +/* RTC Control Register */
> +#define BCD_EN_SHIFT 0
> +#define BCD_EN_MASK (1 << BCD_EN_SHIFT)
> +#define MODEL24_SHIFT 1
> +#define MODEL24_MASK (1 << MODEL24_SHIFT)
> +/* RTC Update Register1 */
> +#define RTC_UDR_SHIFT 0
> +#define RTC_UDR_MASK (1 << RTC_UDR_SHIFT)
> +#define RTC_RBUDR_SHIFT 4
> +#define RTC_RBUDR_MASK (1 << RTC_RBUDR_SHIFT)
> +/* RTC Hour register */
> +#define HOUR_PM_SHIFT 6
> +#define HOUR_PM_MASK (1 << HOUR_PM_SHIFT)
> +/* RTC Alarm Enable */
> +#define ALARM_ENABLE_SHIFT 7
> +#define ALARM_ENABLE_MASK (1 << ALARM_ENABLE_SHIFT)
> +
> +/* For the RTCAE1 register, we write this value to enable the alarm */
> +#define ALARM_ENABLE_VALUE 0x77
> +
> +#define MAX77802_RTC_UPDATE_DELAY_US 200
> +
> +enum {
> + RTC_SEC = 0,
> + RTC_MIN,
> + RTC_HOUR,
> + RTC_WEEKDAY,
> + RTC_MONTH,
> + RTC_YEAR,
> + RTC_DATE,
> + RTC_NR_TIME
> +};
> +
> +struct max77802_rtc_info {
> + struct device *dev;
> + struct max77686_dev *max77802;
> + struct i2c_client *rtc;
> + struct rtc_device *rtc_dev;
> + struct mutex lock;
> +
> + struct regmap *regmap;
> +
> + int virq;
> + int rtc_24hr_mode;
> +};
> +
> +enum MAX77802_RTC_OP {
> + MAX77802_RTC_WRITE,
> + MAX77802_RTC_READ,
> +};
> +
> +static inline int max77802_rtc_calculate_wday(u8 shifted)
> +{
> + int counter = -1;
> +
> + while (shifted) {
> + shifted >>= 1;
> + counter++;
> + }
> +
> + return counter;
> +}
> +
> +static void max77802_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
> + int rtc_24hr_mode)
> +{
> + tm->tm_sec = data[RTC_SEC] & 0xff;
> + tm->tm_min = data[RTC_MIN] & 0xff;
> + if (rtc_24hr_mode)
> + tm->tm_hour = data[RTC_HOUR] & 0x1f;
> + else {
> + tm->tm_hour = data[RTC_HOUR] & 0x0f;
> + if (data[RTC_HOUR] & HOUR_PM_MASK)
> + tm->tm_hour += 12;
> + }
> +
> + tm->tm_wday = max77802_rtc_calculate_wday(data[RTC_WEEKDAY] & 0xff);
> + tm->tm_mday = data[RTC_DATE] & 0x1f;
> + tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
> +
> + tm->tm_year = data[RTC_YEAR] & 0xff;
> + tm->tm_yday = 0;
> + tm->tm_isdst = 0;
> +}
> +
> +static int max77802_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
> +{
> + data[RTC_SEC] = tm->tm_sec;
> + data[RTC_MIN] = tm->tm_min;
> + data[RTC_HOUR] = tm->tm_hour;
> + data[RTC_WEEKDAY] = 1 << tm->tm_wday;
> + data[RTC_DATE] = tm->tm_mday;
> + data[RTC_MONTH] = tm->tm_mon + 1;
> + data[RTC_YEAR] = tm->tm_year;
> +
> + return 0;
> +}
> +
> +static int max77802_rtc_update(struct max77802_rtc_info *info,
> + enum MAX77802_RTC_OP op)
> +{
> + int ret;
> + unsigned int data;
> +
> + if (op == MAX77802_RTC_WRITE)
> + data = 1 << RTC_UDR_SHIFT;
> + else
> + data = 1 << RTC_RBUDR_SHIFT;
> +
> + ret = regmap_update_bits(info->max77802->regmap,
> + MAX77802_RTC_UPDATE0, data, data);
> + if (ret < 0)
> + dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
> + __func__, ret, data);
> + else {
> + /* Minimum delay required before RTC update. */
> + usleep_range(MAX77802_RTC_UPDATE_DELAY_US,
> + MAX77802_RTC_UPDATE_DELAY_US * 2);
> + }
> +
> + return ret;
> +}
> +
> +static int max77802_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> + struct max77802_rtc_info *info = dev_get_drvdata(dev);
> + u8 data[RTC_NR_TIME];
> + int ret;
> +
> + mutex_lock(&info->lock);
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_READ);
> + if (ret < 0)
> + goto out;
> +
> + ret = regmap_bulk_read(info->max77802->regmap,
> + MAX77802_RTC_SEC, data, RTC_NR_TIME);
> + if (ret < 0) {
> + dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,
> + ret);
> + goto out;
> + }
> +
> + max77802_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
> +
> + ret = rtc_valid_tm(tm);
> +
> +out:
> + mutex_unlock(&info->lock);
> + return ret;
> +}
> +
> +static int max77802_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> + struct max77802_rtc_info *info = dev_get_drvdata(dev);
> + u8 data[RTC_NR_TIME];
> + int ret;
> +
> + ret = max77802_rtc_tm_to_data(tm, data);
> + if (ret < 0)
> + return ret;
> +
> + mutex_lock(&info->lock);
> +
> + ret = regmap_bulk_write(info->max77802->regmap,
> + MAX77802_RTC_SEC, data, RTC_NR_TIME);
> + if (ret < 0) {
> + dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
> + ret);
> + goto out;
> + }
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
> +
> +out:
> + mutex_unlock(&info->lock);
> + return ret;
> +}
> +
> +static int max77802_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> + struct max77802_rtc_info *info = dev_get_drvdata(dev);
> + u8 data[RTC_NR_TIME];
> + unsigned int val;
> + int ret;
> +
> + mutex_lock(&info->lock);
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_READ);
> + if (ret < 0)
> + goto out;
> +
> + ret = regmap_bulk_read(info->max77802->regmap,
> + MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
> + if (ret < 0) {
> + dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
> + __func__, __LINE__, ret);
> + goto out;
> + }
> +
> + max77802_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
> +
> + alrm->enabled = 0;
> + ret = regmap_read(info->max77802->regmap,
> + MAX77802_RTC_AE1, &val);
> + if (ret < 0) {
> + dev_err(info->dev, "%s:%d fail to read alarm enable(%d)\n",
> + __func__, __LINE__, ret);
> + goto out;
> + }
> + if (val)
> + alrm->enabled = 1;
> +
> + alrm->pending = 0;
> + ret = regmap_read(info->max77802->regmap, MAX77802_REG_STATUS2, &val);
> + if (ret < 0) {
> + dev_err(info->dev, "%s:%d fail to read status2 reg(%d)\n",
> + __func__, __LINE__, ret);
> + goto out;
> + }
> +
> + if (val & (1 << 2)) /* RTCA1 */
> + alrm->pending = 1;
> +
> +out:
> + mutex_unlock(&info->lock);
> + return 0;
> +}
> +
> +static int max77802_rtc_stop_alarm(struct max77802_rtc_info *info)
> +{
> + int ret;
> +
> + if (!mutex_is_locked(&info->lock))
> + dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_READ);
> + if (ret < 0)
> + goto out;
> +
> + ret = regmap_write(info->max77802->regmap,
> + MAX77802_RTC_AE1, 0);
> + if (ret < 0) {
> + dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
> + __func__, ret);
> + goto out;
> + }
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
> +out:
> + return ret;
> +}
> +
> +static int max77802_rtc_start_alarm(struct max77802_rtc_info *info)
> +{
> + int ret;
> +
> + if (!mutex_is_locked(&info->lock))
> + dev_warn(info->dev, "%s: should have mutex locked\n",
> + __func__);
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_READ);
> + if (ret < 0)
> + goto out;
> +
> + ret = regmap_write(info->max77802->regmap,
> + MAX77802_RTC_AE1,
> + ALARM_ENABLE_VALUE);
> +
> + if (ret < 0) {
> + dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
> + __func__, ret);
> + goto out;
> + }
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
> +out:
> + return ret;
> +}
> +
> +static int max77802_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> + struct max77802_rtc_info *info = dev_get_drvdata(dev);
> + u8 data[RTC_NR_TIME];
> + int ret;
> +
> + ret = max77802_rtc_tm_to_data(&alrm->time, data);
> + if (ret < 0)
> + return ret;
> +
> + mutex_lock(&info->lock);
> +
> + ret = max77802_rtc_stop_alarm(info);
> + if (ret < 0)
> + goto out;
> +
> + ret = regmap_bulk_write(info->max77802->regmap,
> + MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
> +
> + if (ret < 0) {
> + dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
> + __func__, ret);
> + goto out;
> + }
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
> + if (ret < 0)
> + goto out;
> +
> + if (alrm->enabled)
> + ret = max77802_rtc_start_alarm(info);
> +out:
> + mutex_unlock(&info->lock);
> + return ret;
> +}
> +
> +static int max77802_rtc_alarm_irq_enable(struct device *dev,
> + unsigned int enabled)
> +{
> + struct max77802_rtc_info *info = dev_get_drvdata(dev);
> + int ret;
> +
> + mutex_lock(&info->lock);
> + if (enabled)
> + ret = max77802_rtc_start_alarm(info);
> + else
> + ret = max77802_rtc_stop_alarm(info);
> + mutex_unlock(&info->lock);
> +
> + return ret;
> +}
> +
> +static irqreturn_t max77802_rtc_alarm_irq(int irq, void *data)
> +{
> + struct max77802_rtc_info *info = data;
> +
> + dev_dbg(info->dev, "%s:irq(%d)\n", __func__, irq);
> +
> + rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static const struct rtc_class_ops max77802_rtc_ops = {
> + .read_time = max77802_rtc_read_time,
> + .set_time = max77802_rtc_set_time,
> + .read_alarm = max77802_rtc_read_alarm,
> + .set_alarm = max77802_rtc_set_alarm,
> + .alarm_irq_enable = max77802_rtc_alarm_irq_enable,
> +};
> +
> +static int max77802_rtc_init_reg(struct max77802_rtc_info *info)
> +{
> + u8 data[2];
> + int ret;
> +
> + max77802_rtc_update(info, MAX77802_RTC_READ);
> +
> + /* Set RTC control register : Binary mode, 24hour mdoe */
> + data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
> + data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
> +
> + info->rtc_24hr_mode = 1;
> +
> + ret = regmap_bulk_write(info->max77802->regmap,
> + MAX77802_RTC_CONTROLM, data, ARRAY_SIZE(data));
> + if (ret < 0) {
> + dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
> + __func__, ret);
> + return ret;
> + }
> +
> + ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
> + return ret;
> +}
> +
> +static int max77802_rtc_probe(struct platform_device *pdev)
> +{
> + struct max77686_dev *max77802 = dev_get_drvdata(pdev->dev.parent);
> + struct max77802_rtc_info *info;
> + int ret;
> +
> + dev_dbg(&pdev->dev, "%s\n", __func__);
> +
> + info = devm_kzalloc(&pdev->dev, sizeof(struct max77802_rtc_info),
> + GFP_KERNEL);
> + if (!info)
> + return -ENOMEM;
> +
> + mutex_init(&info->lock);
> + info->dev = &pdev->dev;
> + info->max77802 = max77802;
> + info->rtc = max77802->i2c;
> +
> + platform_set_drvdata(pdev, info);
> +
> + ret = max77802_rtc_init_reg(info);
> +
> + if (ret < 0) {
> + dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
> + return ret;
> + }
> +
> + device_init_wakeup(&pdev->dev, 1);
> +
> + info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max77802-rtc",
> + &max77802_rtc_ops, THIS_MODULE);
> +
> + if (IS_ERR(info->rtc_dev)) {
> + ret = PTR_ERR(info->rtc_dev);
> + dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
> + if (ret == 0)
> + ret = -EINVAL;
> + return ret;
> + }
> + info->virq = regmap_irq_get_virq(max77802->rtc_irq_data,
> + MAX77686_RTCIRQ_RTCA1);
> +
> + if (info->virq <= 0) {
> + dev_err(&pdev->dev, "Failed to get virtual IRQ %d\n",
> + MAX77686_RTCIRQ_RTCA1);
> + ret = -EINVAL;
> + return ret;
> + }
> +
> + ret = devm_request_threaded_irq(&pdev->dev, info->virq, NULL,
> + max77802_rtc_alarm_irq, 0, "rtc-alarm1",
> + info);
> + if (ret < 0)
> + dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
> + info->virq, ret);
> +
> + return ret;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int max77802_rtc_suspend(struct device *dev)
> +{
> + if (device_may_wakeup(dev)) {
> + struct max77802_rtc_info *info = dev_get_drvdata(dev);
> +
> + return enable_irq_wake(info->virq);
> + }
> +
> + return 0;
> +}
> +
> +static int max77802_rtc_resume(struct device *dev)
> +{
> + if (device_may_wakeup(dev)) {
> + struct max77802_rtc_info *info = dev_get_drvdata(dev);
> +
> + return disable_irq_wake(info->virq);
> + }
> +
> + return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(max77802_rtc_pm_ops,
> + max77802_rtc_suspend, max77802_rtc_resume);
> +
> +static const struct platform_device_id rtc_id[] = {
> + { "max77802-rtc", 0 },
> + {},
> +};
> +
> +static struct platform_driver max77802_rtc_driver = {
> + .driver = {
> + .name = "max77802-rtc",
> + .owner = THIS_MODULE,
> + .pm = &max77802_rtc_pm_ops,
> + },
> + .probe = max77802_rtc_probe,
> + .id_table = rtc_id,
> +};
> +
> +module_platform_driver(max77802_rtc_driver);
> +
> +MODULE_DESCRIPTION("Maxim MAX77802 RTC driver");
> +MODULE_AUTHOR("Simon Glass <sjg@chromium.org>");
> +MODULE_LICENSE("GPL");