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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-08-05 09:48:22 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-08-05 09:48:22 -0400 |
commit | 6c84239d595dc6ffe39f0f03dae2f64ed200db95 (patch) | |
tree | 3aea4368a644be16e44612c964aa26152854e1ae /drivers/rtc/rtc-max6916.c | |
parent | d4c06c708123c652025d04fe77b7e39448077395 (diff) | |
parent | 6f367788d6333a41fefd013975b0b160d5c0a1c8 (diff) | |
download | lwn-6c84239d595dc6ffe39f0f03dae2f64ed200db95.tar.gz lwn-6c84239d595dc6ffe39f0f03dae2f64ed200db95.zip |
Merge tag 'rtc-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux
Pull RTC updates from Alexandre Belloni:
"RTC for 4.8
Cleanups:
- huge cleanup of rtc-generic and char/genrtc this allowed to cleanup
rtc-cmos, rtc-sh, rtc-m68k, rtc-powerpc and rtc-parisc
- move mn10300 to rtc-cmos
Subsystem:
- fix wakealarms after hibernate
- multiples fixes for rctest
- simplify implementations of .read_alarm
New drivers:
- Maxim MAX6916
Drivers:
- ds1307: fix weekday
- m41t80: add wakeup support
- pcf85063: add support for PCF85063A variant
- rv8803: extend i2c fix and other fixes
- s35390a: fix alarm reading, this fixes instant reboot after
shutdown for QNAP TS-41x
- s3c: clock fixes"
* tag 'rtc-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (65 commits)
rtc: rv8803: Clear V1F when setting the time
rtc: rv8803: Stop the clock while setting the time
rtc: rv8803: Always apply the I²C workaround
rtc: rv8803: Fix read day of week
rtc: rv8803: Remove the check for valid time
rtc: rv8803: Kconfig: Indicate rx8900 support
rtc: asm9260: remove .owner field for driver
rtc: at91sam9: Fix missing spin_lock_init()
rtc: m41t80: add suspend handlers for alarm IRQ
rtc: m41t80: make it a real error message
rtc: pcf85063: Add support for the PCF85063A device
rtc: pcf85063: fix year range
rtc: hym8563: in .read_alarm set .tm_sec to 0 to signal minute accuracy
rtc: explicitly set tm_sec = 0 for drivers with minute accurancy
rtc: s3c: Add s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq()
rtc: s3c: Remove unnecessary call to disable already disabled clock
rtc: abx80x: use devm_add_action_or_reset()
rtc: m41t80: use devm_add_action_or_reset()
rtc: fix a typo and reduce three empty lines to one
rtc: s35390a: improve two comments in .set_alarm
...
Diffstat (limited to 'drivers/rtc/rtc-max6916.c')
-rw-r--r-- | drivers/rtc/rtc-max6916.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-max6916.c b/drivers/rtc/rtc-max6916.c new file mode 100644 index 000000000000..623ab27b2757 --- /dev/null +++ b/drivers/rtc/rtc-max6916.c @@ -0,0 +1,164 @@ +/* rtc-max6916.c + * + * Driver for MAXIM max6916 Low Current, SPI Compatible + * Real Time Clock + * + * Author : Venkat Prashanth B U <venkat.prashanth2498@gmail.com> + * + * 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. + * + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> +#include <linux/bcd.h> + +/* Registers in max6916 rtc */ + +#define MAX6916_SECONDS_REG 0x01 +#define MAX6916_MINUTES_REG 0x02 +#define MAX6916_HOURS_REG 0x03 +#define MAX6916_DATE_REG 0x04 +#define MAX6916_MONTH_REG 0x05 +#define MAX6916_DAY_REG 0x06 +#define MAX6916_YEAR_REG 0x07 +#define MAX6916_CONTROL_REG 0x08 +#define MAX6916_STATUS_REG 0x0C +#define MAX6916_CLOCK_BURST 0x3F + +static int max6916_read_reg(struct device *dev, unsigned char address, + unsigned char *data) +{ + struct spi_device *spi = to_spi_device(dev); + + *data = address | 0x80; + + return spi_write_then_read(spi, data, 1, data, 1); +} + +static int max6916_write_reg(struct device *dev, unsigned char address, + unsigned char data) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[2]; + + buf[0] = address & 0x7F; + buf[1] = data; + + return spi_write_then_read(spi, buf, 2, NULL, 0); +} + +static int max6916_read_time(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + int err; + unsigned char buf[8]; + + buf[0] = MAX6916_CLOCK_BURST | 0x80; + + err = spi_write_then_read(spi, buf, 1, buf, 8); + + if (err) + return err; + + dt->tm_sec = bcd2bin(buf[0]); + dt->tm_min = bcd2bin(buf[1]); + dt->tm_hour = bcd2bin(buf[2] & 0x3F); + dt->tm_mday = bcd2bin(buf[3]); + dt->tm_mon = bcd2bin(buf[4]) - 1; + dt->tm_wday = bcd2bin(buf[5]) - 1; + dt->tm_year = bcd2bin(buf[6]) + 100; + + return rtc_valid_tm(dt); +} + +static int max6916_set_time(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[9]; + + if (dt->tm_year < 100 || dt->tm_year > 199) { + dev_err(&spi->dev, "Year must be between 2000 and 2099. It's %d.\n", + dt->tm_year + 1900); + return -EINVAL; + } + + buf[0] = MAX6916_CLOCK_BURST & 0x7F; + buf[1] = bin2bcd(dt->tm_sec); + buf[2] = bin2bcd(dt->tm_min); + buf[3] = (bin2bcd(dt->tm_hour) & 0X3F); + buf[4] = bin2bcd(dt->tm_mday); + buf[5] = bin2bcd(dt->tm_mon + 1); + buf[6] = bin2bcd(dt->tm_wday + 1); + buf[7] = bin2bcd(dt->tm_year % 100); + buf[8] = bin2bcd(0x00); + + /* write the rtc settings */ + return spi_write_then_read(spi, buf, 9, NULL, 0); +} + +static const struct rtc_class_ops max6916_rtc_ops = { + .read_time = max6916_read_time, + .set_time = max6916_set_time, +}; + +static int max6916_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + unsigned char data; + int res; + + /* spi setup with max6916 in mode 3 and bits per word as 8 */ + spi->mode = SPI_MODE_3; + spi->bits_per_word = 8; + spi_setup(spi); + + /* RTC Settings */ + res = max6916_read_reg(&spi->dev, MAX6916_SECONDS_REG, &data); + if (res) + return res; + + /* Disable the write protect of rtc */ + max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data); + data = data & ~(1 << 7); + max6916_write_reg(&spi->dev, MAX6916_CONTROL_REG, data); + + /*Enable oscillator,disable oscillator stop flag, glitch filter*/ + max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data); + data = data & 0x1B; + max6916_write_reg(&spi->dev, MAX6916_STATUS_REG, data); + + /* display the settings */ + max6916_read_reg(&spi->dev, MAX6916_CONTROL_REG, &data); + dev_info(&spi->dev, "MAX6916 RTC CTRL Reg = 0x%02x\n", data); + + max6916_read_reg(&spi->dev, MAX6916_STATUS_REG, &data); + dev_info(&spi->dev, "MAX6916 RTC Status Reg = 0x%02x\n", data); + + rtc = devm_rtc_device_register(&spi->dev, "max6916", + &max6916_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + spi_set_drvdata(spi, rtc); + + return 0; +} + +static struct spi_driver max6916_driver = { + .driver = { + .name = "max6916", + }, + .probe = max6916_probe, +}; +module_spi_driver(max6916_driver); + +MODULE_DESCRIPTION("MAX6916 SPI RTC DRIVER"); +MODULE_AUTHOR("Venkat Prashanth B U <venkat.prashanth2498@gmail.com>"); +MODULE_LICENSE("GPL v2"); |