The RTCs of the family are able to produce square wave output for RTC
calibration purposes or for an external usage.
Signed-off-by: Kirill Kapranov <kirill.kapranov@xxxxxxxxxxxxxx>
---
drivers/rtc/rtc-abx80x.c | 126 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 126 insertions(+)
diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index 9b0138d07232..153d89b56da9 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -51,6 +51,9 @@
#define ABX8XX_IRQ_AIE BIT(2)
#define ABX8XX_IRQ_IM_1_4 (0x3 << 5)
+#define ABX8XX_REG_SQW 0x13
+#define ABX8XX_SQW_MODE_BITS 5
+
#define ABX8XX_REG_CD_TIMER_CTL 0x18
#define ABX8XX_REG_OSC 0x1c
@@ -117,6 +120,15 @@ struct abx80x_priv {
struct watchdog_device wdog;
};
+union abx8xx_reg_sqw {
+ struct {
+ unsigned int sqws:5;
+ int:2;
+ unsigned int sqwe:2;
+ };
+ int val;
+} __packed;
+
static int abx80x_write_config_key(struct i2c_client *client, u8 key)
{
if (i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY, key) < 0) {
@@ -486,9 +498,119 @@ static ssize_t oscillator_show(struct device *dev,
static DEVICE_ATTR_RW(oscillator);
+#define SQFS_COUNT (1 << ABX8XX_SQW_MODE_BITS)
+/* The index of the array is the value to be written to the 'Square Wave Function
+ * Select' register to make the RTC generate the required square wave.
+ */
+static const char *const sqfs[SQFS_COUNT] = {
+ "1_century", "32768_Hz", "8192_Hz", "4096_Hz",
+ "2048_Hz", "1024_Hz", "512_Hz", "256_Hz",
+ "128_Hz", "64_Hz", "32_Hz", "16_Hz",
+ "8_Hz", "4_Hz", "2_Hz", "1_Hz",
+ "1/2_Hz", "1/4_Hz", "1/8_Hz", "1/16_Hz",
+ "1/32_Hz", "1_min", "16384_Hz", "100_Hz",
+ "1_hour", "1_day", "TIRQ", "nTIRQ",
+ "1_year", "1_Hz_to_Counters", "1/32_Hz_from_Acal", "1/8_Hz_from_Acal",
+};
+
+static const bool valid_for_rc_mode[SQFS_COUNT] = {
+ true, false, false, false,
+ false, false, false, false,
+ true, true, true, true,
+ true, true, true, true,
+ true, true, true, true,
+ true, true, false, false,
+ true, true, true, true,
+ true, true, true, true,
+};
+
+static int sqw_set(struct i2c_client *client, const char *buf)
+{
+ union abx8xx_reg_sqw reg_sqw;
+ int retval;
+
+ reg_sqw.val = i2c_smbus_read_byte_data(client, ABX8XX_REG_SQW);
+ if (reg_sqw.val < 0)
+ goto err;
+
+ if (sysfs_streq(buf, "none")) {
+ reg_sqw.sqwe = 0;
+ dev_info(&client->dev, "sqw output disabled\n");
+ } else {
+ int idx = __sysfs_match_string(sqfs, SQFS_COUNT, buf);
+
+ if (idx < 0)
+ return idx;
+
+ if (abx80x_is_rc_mode(client) && !valid_for_rc_mode[idx])
+ dev_warn(&client->dev, "sqw frequency %s valid only in xt mode\n",
+ sqfs[idx]);
+
+ dev_info(&client->dev, "sqw output enabled @ %s\n", sqfs[idx]);
+ reg_sqw.sqwe = 1;
+ reg_sqw.sqws = idx;
+ }
+
+ retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_SQW, reg_sqw.val);
+ if (retval < 0)
+ goto err;
+
+ return 0;
+err:
+ dev_err(&client->dev, "Failed to set SQW\n");
+ return retval;
+
+}
+
+static ssize_t sqw_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int retval;
+
+ retval = sqw_set(to_i2c_client(dev->parent), buf);
+ if (retval)
+ return retval;
+ else
+ return count;
+}
+
+static ssize_t sqw_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev->parent);
+ union abx8xx_reg_sqw reg_sqw;
+ int len = 0;
+ int i;
+
+ reg_sqw.val = i2c_smbus_read_byte_data(client, ABX8XX_REG_SQW);
+ if (reg_sqw.val < 0) {
+ dev_err(dev, "Failed to read SQW\n");
+ sprintf(buf, "\n");
+ return reg_sqw.val;
+ }
+
+ if (reg_sqw.sqwe)
+ len += scnprintf(buf+len, PAGE_SIZE - len, "none ");
+ else
+ len += scnprintf(buf+len, PAGE_SIZE - len, "[none] ");
+
+ for (i = 0; i < SQFS_COUNT; ++i) {
+ if (reg_sqw.sqwe && i == reg_sqw.sqws)
+ len += scnprintf(buf+len, PAGE_SIZE - len, "[%s] ", sqfs[i]);
+ else
+ len += scnprintf(buf+len, PAGE_SIZE - len, "%s ", sqfs[i]);
+ }
+
+ return len;
+}
+
+static DEVICE_ATTR_RW(sqw);
+
static struct attribute *rtc_calib_attrs[] = {
&dev_attr_autocalibration.attr,
&dev_attr_oscillator.attr,
+ &dev_attr_sqw.attr,
NULL,
};
@@ -686,6 +808,7 @@ static int abx80x_probe(struct i2c_client *client,
unsigned int lot;
unsigned int wafer;
unsigned int uid;
+ const char *sqw_mode_name;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
@@ -800,6 +923,9 @@ static int abx80x_probe(struct i2c_client *client,
abx80x_enable_trickle_charger(client, trickle_cfg);
}
+ if (!of_property_read_string(np, "sqw", &sqw_mode_name))
+ sqw_set(client, sqw_mode_name);
+
err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CD_TIMER_CTL,
BIT(2));
if (err)
--
2.11.0
