[PATCH] I2C: Add support for Maxim/Dallas DS1374 Real-Time Clock Chip (1/2) (c124a78d) · Commits · e / devices / android_kernel_sony_msm8994

drivers/i2c/chips/Kconfig

+11 −0

Original line number	Original line	Diff line number	Diff line
	@@ -417,6 +417,17 @@ config SENSORS_DS1337
	This driver can also be built as a module. If so, the module		This driver can also be built as a module. If so, the module
	will be called ds1337.		will be called ds1337.

			config SENSORS_DS1374
			tristate "Maxim/Dallas Semiconductor DS1374 Real Time Clock"
			depends on I2C && EXPERIMENTAL
			select I2C_SENSOR
			help
			If you say yes here you get support for Dallas Semiconductor
			DS1374 real-time clock chips.

			This driver can also be built as a module. If so, the module
			will be called ds1374.

	config SENSORS_EEPROM		config SENSORS_EEPROM
	tristate "EEPROM reader"		tristate "EEPROM reader"
	depends on I2C && EXPERIMENTAL		depends on I2C && EXPERIMENTAL

drivers/i2c/chips/Makefile

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -14,6 +14,7 @@ obj-$(CONFIG_SENSORS_ADM1031) += adm1031.o
	obj-$(CONFIG_SENSORS_ADM9240) += adm9240.o		obj-$(CONFIG_SENSORS_ADM9240) += adm9240.o
	obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o		obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o
	obj-$(CONFIG_SENSORS_DS1337) += ds1337.o		obj-$(CONFIG_SENSORS_DS1337) += ds1337.o
			obj-$(CONFIG_SENSORS_DS1374) += ds1374.o
	obj-$(CONFIG_SENSORS_DS1621) += ds1621.o		obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
	obj-$(CONFIG_SENSORS_EEPROM) += eeprom.o		obj-$(CONFIG_SENSORS_EEPROM) += eeprom.o
	obj-$(CONFIG_SENSORS_FSCHER) += fscher.o		obj-$(CONFIG_SENSORS_FSCHER) += fscher.o

drivers/i2c/chips/ds1374.c

0 → 100644

+266 −0

Original line number	Original line	Diff line number	Diff line
			/*
			* drivers/i2c/chips/ds1374.c
			*
			* I2C client/driver for the Maxim/Dallas DS1374 Real-Time Clock
			*
			* Author: Randy Vinson <rvinson@mvista.com>
			*
			* Based on the m41t00.c by Mark Greer <mgreer@mvista.com>
			*
			* 2005 (c) MontaVista Software, Inc. This file is licensed under
			* the terms of the GNU General Public License version 2. This program
			* is licensed "as is" without any warranty of any kind, whether express
			* or implied.
			*/
			/*
			* This i2c client/driver wedges between the drivers/char/genrtc.c RTC
			* interface and the SMBus interface of the i2c subsystem.
			* It would be more efficient to use i2c msgs/i2c_transfer directly but, as
			* recommened in .../Documentation/i2c/writing-clients section
			* "Sending and receiving", using SMBus level communication is preferred.
			*/

			#include <linux/kernel.h>
			#include <linux/module.h>
			#include <linux/interrupt.h>
			#include <linux/i2c.h>
			#include <linux/rtc.h>
			#include <linux/bcd.h>

			#include <asm/time.h>
			#include <asm/rtc.h>

			#define DS1374_REG_TOD0 0x00
			#define DS1374_REG_TOD1 0x01
			#define DS1374_REG_TOD2 0x02
			#define DS1374_REG_TOD3 0x03
			#define DS1374_REG_WDALM0 0x04
			#define DS1374_REG_WDALM1 0x05
			#define DS1374_REG_WDALM2 0x06
			#define DS1374_REG_CR 0x07
			#define DS1374_REG_SR 0x08
			#define DS1374_REG_SR_OSF 0x80
			#define DS1374_REG_TCR 0x09

			#define DS1374_DRV_NAME "ds1374"

			static DECLARE_MUTEX(ds1374_mutex);

			static struct i2c_driver ds1374_driver;
			static struct i2c_client *save_client;

			static unsigned short ignore[] = { I2C_CLIENT_END };
			static unsigned short normal_addr[] = { 0x68, I2C_CLIENT_END };

			static struct i2c_client_address_data addr_data = {
			.normal_i2c = normal_addr,
			.normal_i2c_range = ignore,
			.probe = ignore,
			.probe_range = ignore,
			.ignore = ignore,
			.ignore_range = ignore,
			.force = ignore,
			};

			static ulong ds1374_read_rtc(void)
			{
			ulong time = 0;
			int reg = DS1374_REG_WDALM0;

			while (reg--) {
			s32 tmp;
			if ((tmp = i2c_smbus_read_byte_data(save_client, reg)) < 0) {
			dev_warn(&save_client->dev,
			"can't read from rtc chip\n");
			return 0;
			}
			time = (time << 8) \| (tmp & 0xff);
			}
			return time;
			}

			static void ds1374_write_rtc(ulong time)
			{
			int reg;

			for (reg = DS1374_REG_TOD0; reg < DS1374_REG_WDALM0; reg++) {
			if (i2c_smbus_write_byte_data(save_client, reg, time & 0xff)
			< 0) {
			dev_warn(&save_client->dev,
			"can't write to rtc chip\n");
			break;
			}
			time = time >> 8;
			}
			}

			static void ds1374_check_rtc_status(void)
			{
			s32 tmp;

			tmp = i2c_smbus_read_byte_data(save_client, DS1374_REG_SR);
			if (tmp < 0) {
			dev_warn(&save_client->dev,
			"can't read status from rtc chip\n");
			return;
			}
			if (tmp & DS1374_REG_SR_OSF) {
			dev_warn(&save_client->dev,
			"oscillator discontinuity flagged, time unreliable\n");
			tmp &= ~DS1374_REG_SR_OSF;
			tmp = i2c_smbus_write_byte_data(save_client, DS1374_REG_SR,
			tmp & 0xff);
			if (tmp < 0)
			dev_warn(&save_client->dev,
			"can't clear discontinuity notification\n");
			}
			}

			ulong ds1374_get_rtc_time(void)
			{
			ulong t1, t2;
			int limit = 10; /* arbitrary retry limit */

			down(&ds1374_mutex);

			/*
			* Since the reads are being performed one byte at a time using
			* the SMBus vs a 4-byte i2c transfer, there is a chance that a
			* carry will occur during the read. To detect this, 2 reads are
			* performed and compared.
			*/
			do {
			t1 = ds1374_read_rtc();
			t2 = ds1374_read_rtc();
			} while (t1 != t2 && limit--);

			up(&ds1374_mutex);

			if (t1 != t2) {
			dev_warn(&save_client->dev,
			"can't get consistent time from rtc chip\n");
			t1 = 0;
			}

			return t1;
			}

			static void ds1374_set_tlet(ulong arg)
			{
			ulong t1, t2;
			int limit = 10; /* arbitrary retry limit */

			t1 = (ulong ) arg;

			down(&ds1374_mutex);

			/*
			* Since the writes are being performed one byte at a time using
			* the SMBus vs a 4-byte i2c transfer, there is a chance that a
			* carry will occur during the write. To detect this, the write
			* value is read back and compared.
			*/
			do {
			ds1374_write_rtc(t1);
			t2 = ds1374_read_rtc();
			} while (t1 != t2 && limit--);

			up(&ds1374_mutex);

			if (t1 != t2)
			dev_warn(&save_client->dev,
			"can't confirm time set from rtc chip\n");
			}

			ulong new_time;

			DECLARE_TASKLET_DISABLED(ds1374_tasklet, ds1374_set_tlet, (ulong) & new_time);

			int ds1374_set_rtc_time(ulong nowtime)
			{
			new_time = nowtime;

			if (in_interrupt())
			tasklet_schedule(&ds1374_tasklet);
			else
			ds1374_set_tlet((ulong) & new_time);

			return 0;
			}

			/*
			*****************************************************************************
			*
			* Driver Interface
			*
			*****************************************************************************
			*/
			static int ds1374_probe(struct i2c_adapter *adap, int addr, int kind)
			{
			struct i2c_client *client;
			int rc;

			client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
			if (!client)
			return -ENOMEM;

			memset(client, 0, sizeof(struct i2c_client));
			strncpy(client->name, DS1374_DRV_NAME, I2C_NAME_SIZE);
			client->flags = I2C_DF_NOTIFY;
			client->addr = addr;
			client->adapter = adap;
			client->driver = &ds1374_driver;

			if ((rc = i2c_attach_client(client)) != 0) {
			kfree(client);
			return rc;
			}

			save_client = client;

			ds1374_check_rtc_status();

			return 0;
			}

			static int ds1374_attach(struct i2c_adapter *adap)
			{
			return i2c_probe(adap, &addr_data, ds1374_probe);
			}

			static int ds1374_detach(struct i2c_client *client)
			{
			int rc;

			if ((rc = i2c_detach_client(client)) == 0) {
			kfree(i2c_get_clientdata(client));
			tasklet_kill(&ds1374_tasklet);
			}
			return rc;
			}

			static struct i2c_driver ds1374_driver = {
			.owner = THIS_MODULE,
			.name = DS1374_DRV_NAME,
			.id = I2C_DRIVERID_DS1374,
			.flags = I2C_DF_NOTIFY,
			.attach_adapter = ds1374_attach,
			.detach_client = ds1374_detach,
			};

			static int __init ds1374_init(void)
			{
			return i2c_add_driver(&ds1374_driver);
			}

			static void __exit ds1374_exit(void)
			{
			i2c_del_driver(&ds1374_driver);
			}

			module_init(ds1374_init);
			module_exit(ds1374_exit);

			MODULE_AUTHOR("Randy Vinson <rvinson@mvista.com>");
			MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC I2C Client Driver");
			MODULE_LICENSE("GPL");

include/linux/i2c-id.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -108,6 +108,7 @@
	#define I2C_DRIVERID_TDA7313 62 /* TDA7313 audio processor */		#define I2C_DRIVERID_TDA7313 62 /* TDA7313 audio processor */
	#define I2C_DRIVERID_MAX6900 63 /* MAX6900 real-time clock */		#define I2C_DRIVERID_MAX6900 63 /* MAX6900 real-time clock */
	#define I2C_DRIVERID_SAA7114H 64 /* video decoder */		#define I2C_DRIVERID_SAA7114H 64 /* video decoder */
			#define I2C_DRIVERID_DS1374 65 /* DS1374 real time clock */


	#define I2C_DRIVERID_EXP0 0xF0 /* experimental use id's */		#define I2C_DRIVERID_EXP0 0xF0 /* experimental use id's */