Commit fa395fb8 authored by Ivan Grimaldi's avatar Ivan Grimaldi Committed by Alexandre Belloni
Browse files

rtc: ds1390: Add trickle charger device tree binding 



Introduce a device tree binding for specifying the trickle charger
configuration for ds1390.

Signed-off-by: default avatarIvan Grimaldi <grimaldi.ivan@gmail.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 2ec68825

Documentation/devicetree/bindings/rtc/dallas,ds1390.txt

0 → 100644
+18 −0
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* Dallas DS1390		SPI Serial Real-Time Clock



Required properties:

- compatible: Should contain "dallas,ds1390".

- reg: SPI address for chip



Optional properties:

- trickle-resistor-ohms : Selected resistor for trickle charger

	Values usable for ds1390 are 250, 2000, 4000

	Should be given if trickle charger should be enabled

- trickle-diode-disable : Do not use internal trickle charger diode

	Should be given if internal trickle charger diode should be disabled

Example:

	ds1390: rtc@68 {

		compatible = "dallas,ds1390";

		trickle-resistor-ohms = <250>;

		reg = <0>;

	};

drivers/rtc/Kconfig

+2 −2
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@@ -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.

drivers/rtc/rtc-ds1390.c

+63 −0
Original line number Diff line number Diff line
@@ -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)) {