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rtc: ds1390: Add trickle charger device tree binding

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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>
This commit is contained in:
Ivan Grimaldi
2015-09-18 17:27:57 +02:00
committed by Alexandre Belloni
parent 2ec68825fc
commit fa395fb8fc
3 changed files with 83 additions and 2 deletions
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63
drivers/rtc/rtc-ds1390.c
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@@ -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)) {