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authorIvan Grimaldi <grimaldi.ivan@gmail.com>2015-09-18 17:27:57 +0200
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2015-11-08 14:12:23 +0100
commitfa395fb8fc3206cdd70b046e0b98168576cc71ef (patch)
treed82868266fb4b87719ad11ea98d4db97dbc35378 /drivers/rtc
parent2ec68825fc55d1ddeb04ab861f3bfdbaa8e9f3c4 (diff)
downloadlinux-fa395fb8fc3206cdd70b046e0b98168576cc71ef.tar.bz2
rtc: ds1390: Add trickle charger device tree binding
Introduce a device tree binding for specifying the trickle charger configuration for ds1390. Signed-off-by: Ivan Grimaldi <grimaldi.ivan@gmail.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/Kconfig4
-rw-r--r--drivers/rtc/rtc-ds1390.c63
2 files changed, 65 insertions, 2 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 9d4290617cee..57c2dbc4f438 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -666,8 +666,8 @@ config RTC_DRV_DS1390
If you say yes here you get support for the
Dallas/Maxim DS1390/93/94 chips.
- This driver only supports the RTC feature, and not other chip
- features such as alarms and trickle charging.
+ This driver supports the RTC feature and trickle charging but not
+ other chip features such as alarms.
This driver can also be built as a module. If so, the module
will be called rtc-ds1390.
diff --git a/drivers/rtc/rtc-ds1390.c b/drivers/rtc/rtc-ds1390.c
index a4303b43a36a..b2b9454aa7a2 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)
{
@@ -67,6 +88,45 @@ static int ds1390_get_reg(struct device *dev, unsigned char address,
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)) {