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path: root/drivers/rtc/rtc-pcf8523.c
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Diffstat (limited to 'drivers/rtc/rtc-pcf8523.c')
-rw-r--r--drivers/rtc/rtc-pcf8523.c494
1 files changed, 494 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
new file mode 100644
index 000000000..6174b3fd4
--- /dev/null
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012 Avionic Design GmbH
+ */
+
+#include <linux/bcd.h>
+#include <linux/bitfield.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/of.h>
+#include <linux/pm_wakeirq.h>
+
+#define PCF8523_REG_CONTROL1 0x00
+#define PCF8523_CONTROL1_CAP_SEL BIT(7)
+#define PCF8523_CONTROL1_STOP BIT(5)
+#define PCF8523_CONTROL1_AIE BIT(1)
+
+#define PCF8523_REG_CONTROL2 0x01
+#define PCF8523_CONTROL2_AF BIT(3)
+
+#define PCF8523_REG_CONTROL3 0x02
+#define PCF8523_CONTROL3_PM GENMASK(7,5)
+#define PCF8523_PM_STANDBY 0x7
+#define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
+#define PCF8523_CONTROL3_BSF BIT(3)
+
+#define PCF8523_REG_SECONDS 0x03
+#define PCF8523_SECONDS_OS BIT(7)
+
+#define PCF8523_REG_MINUTES 0x04
+#define PCF8523_REG_HOURS 0x05
+#define PCF8523_REG_DAYS 0x06
+#define PCF8523_REG_WEEKDAYS 0x07
+#define PCF8523_REG_MONTHS 0x08
+#define PCF8523_REG_YEARS 0x09
+
+#define PCF8523_REG_MINUTE_ALARM 0x0a
+#define PCF8523_REG_HOUR_ALARM 0x0b
+#define PCF8523_REG_DAY_ALARM 0x0c
+#define PCF8523_REG_WEEKDAY_ALARM 0x0d
+#define ALARM_DIS BIT(7)
+
+#define PCF8523_REG_OFFSET 0x0e
+#define PCF8523_OFFSET_MODE BIT(7)
+
+#define PCF8523_TMR_CLKOUT_CTRL 0x0f
+
+struct pcf8523 {
+ struct rtc_device *rtc;
+ struct regmap *regmap;
+};
+
+static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
+{
+ u32 load, value = 0;
+
+ load = 12500;
+ of_property_read_u32(node, "quartz-load-femtofarads", &load);
+
+ switch (load) {
+ default:
+ dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
+ load);
+ fallthrough;
+ case 12500:
+ value |= PCF8523_CONTROL1_CAP_SEL;
+ break;
+ case 7000:
+ break;
+ }
+
+ return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+ PCF8523_CONTROL1_CAP_SEL, value);
+}
+
+static irqreturn_t pcf8523_irq(int irq, void *dev_id)
+{
+ struct pcf8523 *pcf8523 = dev_id;
+ u32 value;
+ int err;
+
+ err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
+ if (err < 0)
+ return IRQ_HANDLED;
+
+ if (value & PCF8523_CONTROL2_AF) {
+ value &= ~PCF8523_CONTROL2_AF;
+ regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value);
+ rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);
+
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ u8 regs[7];
+ int err;
+
+ err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
+ sizeof(regs));
+ if (err < 0)
+ return err;
+
+ if (regs[0] & PCF8523_SECONDS_OS)
+ return -EINVAL;
+
+ tm->tm_sec = bcd2bin(regs[0] & 0x7f);
+ tm->tm_min = bcd2bin(regs[1] & 0x7f);
+ tm->tm_hour = bcd2bin(regs[2] & 0x3f);
+ tm->tm_mday = bcd2bin(regs[3] & 0x3f);
+ tm->tm_wday = regs[4] & 0x7;
+ tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1;
+ tm->tm_year = bcd2bin(regs[6]) + 100;
+
+ return 0;
+}
+
+static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ u8 regs[7];
+ int err;
+
+ err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+ PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
+ if (err < 0)
+ return err;
+
+ /* This will purposely overwrite PCF8523_SECONDS_OS */
+ regs[0] = bin2bcd(tm->tm_sec);
+ regs[1] = bin2bcd(tm->tm_min);
+ regs[2] = bin2bcd(tm->tm_hour);
+ regs[3] = bin2bcd(tm->tm_mday);
+ regs[4] = tm->tm_wday;
+ regs[5] = bin2bcd(tm->tm_mon + 1);
+ regs[6] = bin2bcd(tm->tm_year - 100);
+
+ err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
+ sizeof(regs));
+ if (err < 0) {
+ /*
+ * If the time cannot be set, restart the RTC anyway. Note
+ * that errors are ignored if the RTC cannot be started so
+ * that we have a chance to propagate the original error.
+ */
+ regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+ PCF8523_CONTROL1_STOP, 0);
+ return err;
+ }
+
+ return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+ PCF8523_CONTROL1_STOP, 0);
+}
+
+static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ u8 regs[4];
+ u32 value;
+ int err;
+
+ err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
+ sizeof(regs));
+ if (err < 0)
+ return err;
+
+ tm->time.tm_sec = 0;
+ tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
+ tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
+ tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
+ tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
+
+ err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
+ if (err < 0)
+ return err;
+ tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
+
+ err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
+ if (err < 0)
+ return err;
+ tm->pending = !!(value & PCF8523_CONTROL2_AF);
+
+ return 0;
+}
+
+static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+
+ return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
+ PCF8523_CONTROL1_AIE, enabled ?
+ PCF8523_CONTROL1_AIE : 0);
+}
+
+static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ u8 regs[5];
+ int err;
+
+ err = pcf8523_irq_enable(dev, 0);
+ if (err)
+ return err;
+
+ err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
+ if (err < 0)
+ return err;
+
+ regs[0] = bin2bcd(tm->time.tm_min);
+ regs[1] = bin2bcd(tm->time.tm_hour);
+ regs[2] = bin2bcd(tm->time.tm_mday);
+ regs[3] = ALARM_DIS;
+
+ err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
+ sizeof(regs));
+ if (err < 0)
+ return err;
+
+ if (tm->enabled)
+ return pcf8523_irq_enable(dev, tm->enabled);
+
+ return 0;
+}
+
+static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ int ret;
+ u32 value;
+
+ switch(param->param) {
+
+ case RTC_PARAM_BACKUP_SWITCH_MODE:
+ ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
+ if (ret < 0)
+ return ret;
+
+ value = FIELD_GET(PCF8523_CONTROL3_PM, value);
+
+ switch(value) {
+ case 0x0:
+ case 0x4:
+ param->uvalue = RTC_BSM_LEVEL;
+ break;
+ case 0x1:
+ case 0x5:
+ param->uvalue = RTC_BSM_DIRECT;
+ break;
+ case PCF8523_PM_STANDBY:
+ param->uvalue = RTC_BSM_STANDBY;
+ break;
+ default:
+ param->uvalue = RTC_BSM_DISABLED;
+ }
+
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ u8 mode;
+
+ switch(param->param) {
+ case RTC_PARAM_BACKUP_SWITCH_MODE:
+ switch (param->uvalue) {
+ case RTC_BSM_DISABLED:
+ mode = 0x2;
+ break;
+ case RTC_BSM_DIRECT:
+ mode = 0x1;
+ break;
+ case RTC_BSM_LEVEL:
+ mode = 0x0;
+ break;
+ case RTC_BSM_STANDBY:
+ mode = PCF8523_PM_STANDBY;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
+ PCF8523_CONTROL3_PM,
+ FIELD_PREP(PCF8523_CONTROL3_PM, mode));
+
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
+ unsigned long arg)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ unsigned int flags = 0;
+ u32 value;
+ int ret;
+
+ switch (cmd) {
+ case RTC_VL_READ:
+ ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
+ if (ret < 0)
+ return ret;
+
+ if (value & PCF8523_CONTROL3_BLF)
+ flags |= RTC_VL_BACKUP_LOW;
+
+ ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
+ if (ret < 0)
+ return ret;
+
+ if (value & PCF8523_SECONDS_OS)
+ flags |= RTC_VL_DATA_INVALID;
+
+ return put_user(flags, (unsigned int __user *)arg);
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
+static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ int err;
+ u32 value;
+ s8 val;
+
+ err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
+ if (err < 0)
+ return err;
+
+ /* sign extend the 7-bit offset value */
+ val = value << 1;
+ *offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
+
+ return 0;
+}
+
+static int pcf8523_rtc_set_offset(struct device *dev, long offset)
+{
+ struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
+ long reg_m0, reg_m1;
+ u32 value;
+
+ reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
+ reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
+
+ if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
+ value = reg_m0 & 0x7f;
+ else
+ value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
+
+ return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
+}
+
+static const struct rtc_class_ops pcf8523_rtc_ops = {
+ .read_time = pcf8523_rtc_read_time,
+ .set_time = pcf8523_rtc_set_time,
+ .read_alarm = pcf8523_rtc_read_alarm,
+ .set_alarm = pcf8523_rtc_set_alarm,
+ .alarm_irq_enable = pcf8523_irq_enable,
+ .ioctl = pcf8523_rtc_ioctl,
+ .read_offset = pcf8523_rtc_read_offset,
+ .set_offset = pcf8523_rtc_set_offset,
+ .param_get = pcf8523_param_get,
+ .param_set = pcf8523_param_set,
+};
+
+static const struct regmap_config regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = 0x13,
+};
+
+static int pcf8523_probe(struct i2c_client *client)
+{
+ struct pcf8523 *pcf8523;
+ struct rtc_device *rtc;
+ bool wakeup_source = false;
+ u32 value;
+ int err;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
+ if (!pcf8523)
+ return -ENOMEM;
+
+ pcf8523->regmap = devm_regmap_init_i2c(client, &regmap_config);
+ if (IS_ERR(pcf8523->regmap))
+ return PTR_ERR(pcf8523->regmap);
+
+ i2c_set_clientdata(client, pcf8523);
+
+ rtc = devm_rtc_allocate_device(&client->dev);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+ pcf8523->rtc = rtc;
+
+ err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
+ if (err < 0)
+ dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
+ err);
+
+ err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
+ if (err < 0)
+ return err;
+
+ if (value & PCF8523_SECONDS_OS) {
+ err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
+ if (err < 0)
+ return err;
+
+ if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
+ err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
+ value & ~PCF8523_CONTROL3_PM);
+ if (err < 0)
+ return err;
+ }
+ }
+
+ rtc->ops = &pcf8523_rtc_ops;
+ rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ rtc->range_max = RTC_TIMESTAMP_END_2099;
+ set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
+ clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
+
+ if (client->irq > 0) {
+ err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
+ if (err < 0)
+ return err;
+
+ err = devm_request_threaded_irq(&client->dev, client->irq,
+ NULL, pcf8523_irq,
+ IRQF_SHARED | IRQF_ONESHOT | IRQF_TRIGGER_LOW,
+ dev_name(&rtc->dev), pcf8523);
+ if (err)
+ return err;
+
+ dev_pm_set_wake_irq(&client->dev, client->irq);
+ }
+
+ wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
+ if (client->irq > 0 || wakeup_source)
+ device_init_wakeup(&client->dev, true);
+
+ return devm_rtc_register_device(rtc);
+}
+
+static const struct i2c_device_id pcf8523_id[] = {
+ { "pcf8523", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, pcf8523_id);
+
+static const struct of_device_id pcf8523_of_match[] = {
+ { .compatible = "nxp,pcf8523" },
+ { .compatible = "microcrystal,rv8523" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, pcf8523_of_match);
+
+static struct i2c_driver pcf8523_driver = {
+ .driver = {
+ .name = "rtc-pcf8523",
+ .of_match_table = pcf8523_of_match,
+ },
+ .probe_new = pcf8523_probe,
+ .id_table = pcf8523_id,
+};
+module_i2c_driver(pcf8523_driver);
+
+MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
+MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
+MODULE_LICENSE("GPL v2");
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-08 11:52:06 +0000