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path: root/drivers/rtc/rtc-ds1390.c
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Diffstat (limited to 'drivers/rtc/rtc-ds1390.c')
-rw-r--r--drivers/rtc/rtc-ds1390.c66
1 files changed, 64 insertions, 2 deletions
diff --git a/drivers/rtc/rtc-ds1390.c b/drivers/rtc/rtc-ds1390.c
index e67bfcb3a..aa0d2c6f1 100644
--- a/drivers/rtc/rtc-ds1390.c
+++ b/drivers/rtc/rtc-ds1390.c
@@ -20,6 +20,7 @@
#include <linux/spi/spi.h>
#include <linux/bcd.h>
#include <linux/slab.h>
+#include <linux/of.h>
#define DS1390_REG_100THS 0x00
#define DS1390_REG_SECONDS 0x01
@@ -40,11 +41,31 @@
#define DS1390_REG_STATUS 0x0E
#define DS1390_REG_TRICKLE 0x0F
+#define DS1390_TRICKLE_CHARGER_ENABLE 0xA0
+#define DS1390_TRICKLE_CHARGER_250_OHM 0x01
+#define DS1390_TRICKLE_CHARGER_2K_OHM 0x02
+#define DS1390_TRICKLE_CHARGER_4K_OHM 0x03
+#define DS1390_TRICKLE_CHARGER_NO_DIODE 0x04
+#define DS1390_TRICKLE_CHARGER_DIODE 0x08
+
struct ds1390 {
struct rtc_device *rtc;
u8 txrx_buf[9]; /* cmd + 8 registers */
};
+static void ds1390_set_reg(struct device *dev, unsigned char address,
+ unsigned char data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[2];
+
+ /* MSB must be '1' to write */
+ buf[0] = address | 0x80;
+ buf[1] = data;
+
+ spi_write(spi, buf, 2);
+}
+
static int ds1390_get_reg(struct device *dev, unsigned char address,
unsigned char *data)
{
@@ -62,11 +83,50 @@ static int ds1390_get_reg(struct device *dev, unsigned char address,
if (status != 0)
return status;
- *data = chip->txrx_buf[1];
+ *data = chip->txrx_buf[0];
return 0;
}
+static void ds1390_trickle_of_init(struct spi_device *spi)
+{
+ u32 ohms = 0;
+ u8 value;
+
+ if (of_property_read_u32(spi->dev.of_node, "trickle-resistor-ohms",
+ &ohms))
+ goto out;
+
+ /* Enable charger */
+ value = DS1390_TRICKLE_CHARGER_ENABLE;
+ if (of_property_read_bool(spi->dev.of_node, "trickle-diode-disable"))
+ value |= DS1390_TRICKLE_CHARGER_NO_DIODE;
+ else
+ value |= DS1390_TRICKLE_CHARGER_DIODE;
+
+ /* Resistor select */
+ switch (ohms) {
+ case 250:
+ value |= DS1390_TRICKLE_CHARGER_250_OHM;
+ break;
+ case 2000:
+ value |= DS1390_TRICKLE_CHARGER_2K_OHM;
+ break;
+ case 4000:
+ value |= DS1390_TRICKLE_CHARGER_4K_OHM;
+ break;
+ default:
+ dev_warn(&spi->dev,
+ "Unsupported ohm value %02ux in dt\n", ohms);
+ return;
+ }
+
+ ds1390_set_reg(&spi->dev, DS1390_REG_TRICKLE, value);
+
+out:
+ return;
+}
+
static int ds1390_read_time(struct device *dev, struct rtc_time *dt)
{
struct spi_device *spi = to_spi_device(dev);
@@ -143,6 +203,9 @@ static int ds1390_probe(struct spi_device *spi)
return res;
}
+ if (spi->dev.of_node)
+ ds1390_trickle_of_init(spi);
+
chip->rtc = devm_rtc_device_register(&spi->dev, "ds1390",
&ds1390_rtc_ops, THIS_MODULE);
if (IS_ERR(chip->rtc)) {
@@ -156,7 +219,6 @@ static int ds1390_probe(struct spi_device *spi)
static struct spi_driver ds1390_driver = {
.driver = {
.name = "rtc-ds1390",
- .owner = THIS_MODULE,
},
.probe = ds1390_probe,
};