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path: root/drivers/rtc/rtc-ds1307.c
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Diffstat (limited to 'drivers/rtc/rtc-ds1307.c')
-rw-r--r--drivers/rtc/rtc-ds1307.c411
1 files changed, 409 insertions, 2 deletions
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index cf685f67b391..b2156ee5bae1 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -19,6 +19,9 @@
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/string.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/clk-provider.h>
/*
* We can't determine type by probing, but if we expect pre-Linux code
@@ -89,6 +92,7 @@ enum ds_type {
# define DS1340_BIT_OSF 0x80
#define DS1337_REG_STATUS 0x0f
# define DS1337_BIT_OSF 0x80
+# define DS3231_BIT_EN32KHZ 0x08
# define DS1337_BIT_A2I 0x02
# define DS1337_BIT_A1I 0x01
#define DS1339_REG_ALARM1_SECS 0x07
@@ -118,6 +122,9 @@ struct ds1307 {
u8 length, u8 *values);
s32 (*write_block_data)(const struct i2c_client *client, u8 command,
u8 length, const u8 *values);
+#ifdef CONFIG_COMMON_CLK
+ struct clk_hw clks[2];
+#endif
};
struct chip_desc {
@@ -842,6 +849,378 @@ out:
return;
}
+/*----------------------------------------------------------------------*/
+
+#ifdef CONFIG_RTC_DRV_DS1307_HWMON
+
+/*
+ * Temperature sensor support for ds3231 devices.
+ */
+
+#define DS3231_REG_TEMPERATURE 0x11
+
+/*
+ * A user-initiated temperature conversion is not started by this function,
+ * so the temperature is updated once every 64 seconds.
+ */
+static int ds3231_hwmon_read_temp(struct device *dev, s16 *mC)
+{
+ struct ds1307 *ds1307 = dev_get_drvdata(dev);
+ u8 temp_buf[2];
+ s16 temp;
+ int ret;
+
+ ret = ds1307->read_block_data(ds1307->client, DS3231_REG_TEMPERATURE,
+ sizeof(temp_buf), temp_buf);
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(temp_buf))
+ return -EIO;
+
+ /*
+ * Temperature is represented as a 10-bit code with a resolution of
+ * 0.25 degree celsius and encoded in two's complement format.
+ */
+ temp = (temp_buf[0] << 8) | temp_buf[1];
+ temp >>= 6;
+ *mC = temp * 250;
+
+ return 0;
+}
+
+static ssize_t ds3231_hwmon_show_temp(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int ret;
+ s16 temp;
+
+ ret = ds3231_hwmon_read_temp(dev, &temp);
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%d\n", temp);
+}
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ds3231_hwmon_show_temp,
+ NULL, 0);
+
+static struct attribute *ds3231_hwmon_attrs[] = {
+ &sensor_dev_attr_temp1_input.dev_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(ds3231_hwmon);
+
+static void ds1307_hwmon_register(struct ds1307 *ds1307)
+{
+ struct device *dev;
+
+ if (ds1307->type != ds_3231)
+ return;
+
+ dev = devm_hwmon_device_register_with_groups(&ds1307->client->dev,
+ ds1307->client->name,
+ ds1307, ds3231_hwmon_groups);
+ if (IS_ERR(dev)) {
+ dev_warn(&ds1307->client->dev,
+ "unable to register hwmon device %ld\n", PTR_ERR(dev));
+ }
+}
+
+#else
+
+static void ds1307_hwmon_register(struct ds1307 *ds1307)
+{
+}
+
+#endif /* CONFIG_RTC_DRV_DS1307_HWMON */
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * Square-wave output support for DS3231
+ * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
+ */
+#ifdef CONFIG_COMMON_CLK
+
+enum {
+ DS3231_CLK_SQW = 0,
+ DS3231_CLK_32KHZ,
+};
+
+#define clk_sqw_to_ds1307(clk) \
+ container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
+#define clk_32khz_to_ds1307(clk) \
+ container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
+
+static int ds3231_clk_sqw_rates[] = {
+ 1,
+ 1024,
+ 4096,
+ 8192,
+};
+
+static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
+{
+ struct i2c_client *client = ds1307->client;
+ struct mutex *lock = &ds1307->rtc->ops_lock;
+ int control;
+ int ret;
+
+ mutex_lock(lock);
+
+ control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
+ if (control < 0) {
+ ret = control;
+ goto out;
+ }
+
+ control &= ~mask;
+ control |= value;
+
+ ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
+out:
+ mutex_unlock(lock);
+
+ return ret;
+}
+
+static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+ int control;
+ int rate_sel = 0;
+
+ control = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_CONTROL);
+ if (control < 0)
+ return control;
+ if (control & DS1337_BIT_RS1)
+ rate_sel += 1;
+ if (control & DS1337_BIT_RS2)
+ rate_sel += 2;
+
+ return ds3231_clk_sqw_rates[rate_sel];
+}
+
+static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ int i;
+
+ for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
+ if (ds3231_clk_sqw_rates[i] <= rate)
+ return ds3231_clk_sqw_rates[i];
+ }
+
+ return 0;
+}
+
+static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+ int control = 0;
+ int rate_sel;
+
+ for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
+ rate_sel++) {
+ if (ds3231_clk_sqw_rates[rate_sel] == rate)
+ break;
+ }
+
+ if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
+ return -EINVAL;
+
+ if (rate_sel & 1)
+ control |= DS1337_BIT_RS1;
+ if (rate_sel & 2)
+ control |= DS1337_BIT_RS2;
+
+ return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
+ control);
+}
+
+static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+
+ return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
+}
+
+static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+
+ ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
+}
+
+static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+ int control;
+
+ control = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_CONTROL);
+ if (control < 0)
+ return control;
+
+ return !(control & DS1337_BIT_INTCN);
+}
+
+static const struct clk_ops ds3231_clk_sqw_ops = {
+ .prepare = ds3231_clk_sqw_prepare,
+ .unprepare = ds3231_clk_sqw_unprepare,
+ .is_prepared = ds3231_clk_sqw_is_prepared,
+ .recalc_rate = ds3231_clk_sqw_recalc_rate,
+ .round_rate = ds3231_clk_sqw_round_rate,
+ .set_rate = ds3231_clk_sqw_set_rate,
+};
+
+static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ return 32768;
+}
+
+static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
+{
+ struct i2c_client *client = ds1307->client;
+ struct mutex *lock = &ds1307->rtc->ops_lock;
+ int status;
+ int ret;
+
+ mutex_lock(lock);
+
+ status = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
+ if (status < 0) {
+ ret = status;
+ goto out;
+ }
+
+ if (enable)
+ status |= DS3231_BIT_EN32KHZ;
+ else
+ status &= ~DS3231_BIT_EN32KHZ;
+
+ ret = i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, status);
+out:
+ mutex_unlock(lock);
+
+ return ret;
+}
+
+static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
+
+ return ds3231_clk_32khz_control(ds1307, true);
+}
+
+static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
+
+ ds3231_clk_32khz_control(ds1307, false);
+}
+
+static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
+ int status;
+
+ status = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_STATUS);
+ if (status < 0)
+ return status;
+
+ return !!(status & DS3231_BIT_EN32KHZ);
+}
+
+static const struct clk_ops ds3231_clk_32khz_ops = {
+ .prepare = ds3231_clk_32khz_prepare,
+ .unprepare = ds3231_clk_32khz_unprepare,
+ .is_prepared = ds3231_clk_32khz_is_prepared,
+ .recalc_rate = ds3231_clk_32khz_recalc_rate,
+};
+
+static struct clk_init_data ds3231_clks_init[] = {
+ [DS3231_CLK_SQW] = {
+ .name = "ds3231_clk_sqw",
+ .ops = &ds3231_clk_sqw_ops,
+ .flags = CLK_IS_ROOT,
+ },
+ [DS3231_CLK_32KHZ] = {
+ .name = "ds3231_clk_32khz",
+ .ops = &ds3231_clk_32khz_ops,
+ .flags = CLK_IS_ROOT,
+ },
+};
+
+static int ds3231_clks_register(struct ds1307 *ds1307)
+{
+ struct i2c_client *client = ds1307->client;
+ struct device_node *node = client->dev.of_node;
+ struct clk_onecell_data *onecell;
+ int i;
+
+ onecell = devm_kzalloc(&client->dev, sizeof(*onecell), GFP_KERNEL);
+ if (!onecell)
+ return -ENOMEM;
+
+ onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
+ onecell->clks = devm_kcalloc(&client->dev, onecell->clk_num,
+ sizeof(onecell->clks[0]), GFP_KERNEL);
+ if (!onecell->clks)
+ return -ENOMEM;
+
+ for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
+ struct clk_init_data init = ds3231_clks_init[i];
+
+ /*
+ * Interrupt signal due to alarm conditions and square-wave
+ * output share same pin, so don't initialize both.
+ */
+ if (i == DS3231_CLK_SQW && test_bit(HAS_ALARM, &ds1307->flags))
+ continue;
+
+ /* optional override of the clockname */
+ of_property_read_string_index(node, "clock-output-names", i,
+ &init.name);
+ ds1307->clks[i].init = &init;
+
+ onecell->clks[i] = devm_clk_register(&client->dev,
+ &ds1307->clks[i]);
+ if (IS_ERR(onecell->clks[i]))
+ return PTR_ERR(onecell->clks[i]);
+ }
+
+ if (!node)
+ return 0;
+
+ of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
+
+ return 0;
+}
+
+static void ds1307_clks_register(struct ds1307 *ds1307)
+{
+ int ret;
+
+ if (ds1307->type != ds_3231)
+ return;
+
+ ret = ds3231_clks_register(ds1307);
+ if (ret) {
+ dev_warn(&ds1307->client->dev,
+ "unable to register clock device %d\n", ret);
+ }
+}
+
+#else
+
+static void ds1307_clks_register(struct ds1307 *ds1307)
+{
+}
+
+#endif /* CONFIG_COMMON_CLK */
+
static int ds1307_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -851,6 +1230,7 @@ static int ds1307_probe(struct i2c_client *client,
struct chip_desc *chip = &chips[id->driver_data];
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
bool want_irq = false;
+ bool ds1307_can_wakeup_device = false;
unsigned char *buf;
struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
irq_handler_t irq_handler = ds1307_irq;
@@ -898,6 +1278,20 @@ static int ds1307_probe(struct i2c_client *client,
ds1307->write_block_data = ds1307_write_block_data;
}
+#ifdef CONFIG_OF
+/*
+ * For devices with no IRQ directly connected to the SoC, the RTC chip
+ * can be forced as a wakeup source by stating that explicitly in
+ * the device's .dts file using the "wakeup-source" boolean property.
+ * If the "wakeup-source" property is set, don't request an IRQ.
+ * This will guarantee the 'wakealarm' sysfs entry is available on the device,
+ * if supported by the RTC.
+ */
+ if (of_property_read_bool(client->dev.of_node, "wakeup-source")) {
+ ds1307_can_wakeup_device = true;
+ }
+#endif
+
switch (ds1307->type) {
case ds_1337:
case ds_1339:
@@ -916,11 +1310,13 @@ static int ds1307_probe(struct i2c_client *client,
ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
/*
- * Using IRQ? Disable the square wave and both alarms.
+ * Using IRQ or defined as wakeup-source?
+ * Disable the square wave and both alarms.
* For some variants, be sure alarms can trigger when we're
* running on Vbackup (BBSQI/BBSQW)
*/
- if (ds1307->client->irq > 0 && chip->alarm) {
+ if (chip->alarm && (ds1307->client->irq > 0 ||
+ ds1307_can_wakeup_device)) {
ds1307->regs[0] |= DS1337_BIT_INTCN
| bbsqi_bitpos[ds1307->type];
ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
@@ -1135,6 +1531,14 @@ read_rtc:
return PTR_ERR(ds1307->rtc);
}
+ if (ds1307_can_wakeup_device) {
+ /* Disable request for an IRQ */
+ want_irq = false;
+ dev_info(&client->dev, "'wakeup-source' is set, request for an IRQ is disabled!\n");
+ /* We cannot support UIE mode if we do not have an IRQ line */
+ ds1307->rtc->uie_unsupported = 1;
+ }
+
if (want_irq) {
err = devm_request_threaded_irq(&client->dev,
client->irq, NULL, irq_handler,
@@ -1182,6 +1586,9 @@ read_rtc:
}
}
+ ds1307_hwmon_register(ds1307);
+ ds1307_clks_register(ds1307);
+
return 0;
exit: