diff options
| author | Ivan Grimaldi <grimaldi.ivan@gmail.com> | 2015-09-18 17:27:57 +0200 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2015-11-08 14:12:23 +0100 |
| commit | fa395fb8fc3206cdd70b046e0b98168576cc71ef (patch) | |
| tree | d82868266fb4b87719ad11ea98d4db97dbc35378 /drivers/rtc | |
| parent | 2ec68825fc55d1ddeb04ab861f3bfdbaa8e9f3c4 (diff) | |
| download | linux-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/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/rtc/rtc-ds1390.c | 63 |
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)) { |