diff options
Diffstat (limited to 'drivers/rtc/rtc-ds1390.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1390.c | 92 |
1 files changed, 82 insertions, 10 deletions
diff --git a/drivers/rtc/rtc-ds1390.c b/drivers/rtc/rtc-ds1390.c index be9d8c0a7e3a..f46428ca77cc 100644 --- a/drivers/rtc/rtc-ds1390.c +++ b/drivers/rtc/rtc-ds1390.c @@ -1,13 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC * * Copyright (C) 2008 Mercury IMC Ltd * Written by Mark Jackson <mpfj@mimc.co.uk> * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * * NOTE: Currently this driver only supports the bare minimum for read * and write the RTC. The extra features provided by the chip family * (alarms, trickle charger, different control registers) are unavailable. @@ -20,6 +17,7 @@ #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 +38,31 @@ #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 +80,50 @@ 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); @@ -93,7 +150,7 @@ static int ds1390_read_time(struct device *dev, struct rtc_time *dt) /* adjust for century bit */ dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0); - return rtc_valid_tm(dt); + return 0; } static int ds1390_set_time(struct device *dev, struct rtc_time *dt) @@ -132,10 +189,9 @@ static int ds1390_probe(struct spi_device *spi) spi_setup(spi); chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL); - if (!chip) { - dev_err(&spi->dev, "unable to allocate device memory\n"); + if (!chip) return -ENOMEM; - } + spi_set_drvdata(spi, chip); res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp); @@ -144,6 +200,9 @@ 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)) { @@ -154,12 +213,25 @@ static int ds1390_probe(struct spi_device *spi) return res; } +static const struct of_device_id ds1390_of_match[] __maybe_unused = { + { .compatible = "dallas,ds1390" }, + {} +}; +MODULE_DEVICE_TABLE(of, ds1390_of_match); + +static const struct spi_device_id ds1390_spi_ids[] = { + { .name = "ds1390" }, + {} +}; +MODULE_DEVICE_TABLE(spi, ds1390_spi_ids); + static struct spi_driver ds1390_driver = { .driver = { .name = "rtc-ds1390", - .owner = THIS_MODULE, + .of_match_table = of_match_ptr(ds1390_of_match), }, .probe = ds1390_probe, + .id_table = ds1390_spi_ids, }; module_spi_driver(ds1390_driver); |