rtc: add RTC class driver for the Maxim MAX6900
Signed-off-by: Dale Farnsworth.org <dale@farnsworth.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dale Farnsworth
Linus Torvalds
Родитель
e9f2bd8191
Коммит
aa5bd7e929
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@ -334,6 +334,16 @@ config RTC_DRV_TEST
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This driver can also be built as a module. If so, the module
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will be called rtc-test.
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config RTC_DRV_MAX6900
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tristate "Maxim 6900"
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depends on RTC_CLASS && I2C
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help
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If you say yes here you will get support for the
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Maxim MAX6900 I2C RTC chip.
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This driver can also be built as a module. If so, the module
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will be called rtc-max6900.
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config RTC_DRV_MAX6902
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tristate "Maxim 6902"
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depends on RTC_CLASS && SPI
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@ -35,6 +35,7 @@ obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
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obj-$(CONFIG_RTC_DRV_SA1100) += rtc-sa1100.o
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obj-$(CONFIG_RTC_DRV_VR41XX) += rtc-vr41xx.o
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obj-$(CONFIG_RTC_DRV_PL031) += rtc-pl031.o
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obj-$(CONFIG_RTC_DRV_MAX6900) += rtc-max6900.o
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obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o
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obj-$(CONFIG_RTC_DRV_V3020) += rtc-v3020.o
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obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
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@ -0,0 +1,311 @@
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/*
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* rtc class driver for the Maxim MAX6900 chip
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*
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* Author: Dale Farnsworth <dale@farnsworth.org>
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*
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* based on previously existing rtc class drivers
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*
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* 2007 (c) MontaVista, Software, Inc. This file is licensed under
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* the terms of the GNU General Public License version 2. This program
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* is licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/bcd.h>
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#include <linux/rtc.h>
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#include <linux/delay.h>
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#define DRV_NAME "max6900"
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#define DRV_VERSION "0.1"
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/*
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* register indices
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*/
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#define MAX6900_REG_SC 0 /* seconds 00-59 */
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#define MAX6900_REG_MN 1 /* minutes 00-59 */
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#define MAX6900_REG_HR 2 /* hours 00-23 */
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#define MAX6900_REG_DT 3 /* day of month 00-31 */
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#define MAX6900_REG_MO 4 /* month 01-12 */
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#define MAX6900_REG_DW 5 /* day of week 1-7 */
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#define MAX6900_REG_YR 6 /* year 00-99 */
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#define MAX6900_REG_CT 7 /* control */
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#define MAX6900_REG_LEN 8
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#define MAX6900_REG_CT_WP (1 << 7) /* Write Protect */
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/*
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* register read/write commands
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*/
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#define MAX6900_REG_CONTROL_WRITE 0x8e
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#define MAX6900_REG_BURST_READ 0xbf
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#define MAX6900_REG_BURST_WRITE 0xbe
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#define MAX6900_REG_RESERVED_READ 0x96
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#define MAX6900_IDLE_TIME_AFTER_WRITE 3 /* specification says 2.5 mS */
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#define MAX6900_I2C_ADDR 0xa0
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static unsigned short normal_i2c[] = {
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MAX6900_I2C_ADDR >> 1,
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I2C_CLIENT_END
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};
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I2C_CLIENT_INSMOD; /* defines addr_data */
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static int max6900_probe(struct i2c_adapter *adapter, int addr, int kind);
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static int max6900_i2c_read_regs(struct i2c_client *client, u8 *buf)
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{
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u8 reg_addr[1] = { MAX6900_REG_BURST_READ };
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struct i2c_msg msgs[2] = {
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{
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.addr = client->addr,
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.flags = 0, /* write */
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.len = sizeof(reg_addr),
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.buf = reg_addr
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},
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{
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.addr = client->addr,
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.flags = I2C_M_RD,
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.len = MAX6900_REG_LEN,
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.buf = buf
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}
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};
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int rc;
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rc = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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if (rc != ARRAY_SIZE(msgs)) {
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dev_err(&client->dev, "%s: register read failed\n",
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__FUNCTION__);
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return -EIO;
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}
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return 0;
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}
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static int max6900_i2c_write_regs(struct i2c_client *client, u8 const *buf)
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{
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u8 i2c_buf[MAX6900_REG_LEN + 1] = { MAX6900_REG_BURST_WRITE };
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struct i2c_msg msgs[1] = {
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{
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.addr = client->addr,
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.flags = 0, /* write */
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.len = MAX6900_REG_LEN + 1,
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.buf = i2c_buf
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}
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};
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int rc;
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memcpy(&i2c_buf[1], buf, MAX6900_REG_LEN);
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rc = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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if (rc != ARRAY_SIZE(msgs)) {
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dev_err(&client->dev, "%s: register write failed\n",
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__FUNCTION__);
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return -EIO;
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}
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msleep(MAX6900_IDLE_TIME_AFTER_WRITE);
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return 0;
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}
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static int max6900_i2c_validate_client(struct i2c_client *client)
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{
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u8 regs[MAX6900_REG_LEN];
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u8 zero_mask[MAX6900_REG_LEN] = {
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0x80, /* seconds */
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0x80, /* minutes */
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0x40, /* hours */
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0xc0, /* day of month */
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0xe0, /* month */
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0xf8, /* day of week */
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0x00, /* year */
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0x7f, /* control */
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};
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int i;
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int rc;
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int reserved;
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reserved = i2c_smbus_read_byte_data(client, MAX6900_REG_RESERVED_READ);
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if (reserved != 0x07)
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return -ENODEV;
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rc = max6900_i2c_read_regs(client, regs);
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if (rc < 0)
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return rc;
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for (i = 0; i < MAX6900_REG_LEN; ++i) {
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if (regs[i] & zero_mask[i])
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return -ENODEV;
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}
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return 0;
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}
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static int max6900_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
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{
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int rc;
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u8 regs[MAX6900_REG_LEN];
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rc = max6900_i2c_read_regs(client, regs);
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if (rc < 0)
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return rc;
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tm->tm_sec = BCD2BIN(regs[MAX6900_REG_SC]);
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tm->tm_min = BCD2BIN(regs[MAX6900_REG_MN]);
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tm->tm_hour = BCD2BIN(regs[MAX6900_REG_HR] & 0x3f);
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tm->tm_mday = BCD2BIN(regs[MAX6900_REG_DT]);
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tm->tm_mon = BCD2BIN(regs[MAX6900_REG_MO]) - 1;
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tm->tm_year = BCD2BIN(regs[MAX6900_REG_YR]) + 100;
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tm->tm_wday = BCD2BIN(regs[MAX6900_REG_DW]);
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return 0;
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}
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static int max6900_i2c_clear_write_protect(struct i2c_client *client)
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{
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int rc;
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rc = i2c_smbus_write_byte_data (client, MAX6900_REG_CONTROL_WRITE, 0);
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if (rc < 0) {
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dev_err(&client->dev, "%s: control register write failed\n",
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__FUNCTION__);
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return -EIO;
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}
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return 0;
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}
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static int max6900_i2c_set_time(struct i2c_client *client,
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struct rtc_time const *tm)
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{
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u8 regs[MAX6900_REG_LEN];
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int rc;
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rc = max6900_i2c_clear_write_protect(client);
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if (rc < 0)
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return rc;
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regs[MAX6900_REG_SC] = BIN2BCD(tm->tm_sec);
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regs[MAX6900_REG_MN] = BIN2BCD(tm->tm_min);
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regs[MAX6900_REG_HR] = BIN2BCD(tm->tm_hour);
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regs[MAX6900_REG_DT] = BIN2BCD(tm->tm_mday);
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regs[MAX6900_REG_MO] = BIN2BCD(tm->tm_mon + 1);
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regs[MAX6900_REG_YR] = BIN2BCD(tm->tm_year - 100);
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regs[MAX6900_REG_DW] = BIN2BCD(tm->tm_wday);
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regs[MAX6900_REG_CT] = MAX6900_REG_CT_WP; /* set write protect */
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rc = max6900_i2c_write_regs(client, regs);
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if (rc < 0)
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return rc;
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return 0;
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}
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static int max6900_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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return max6900_i2c_read_time(to_i2c_client(dev), tm);
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}
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static int max6900_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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return max6900_i2c_set_time(to_i2c_client(dev), tm);
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}
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static int max6900_attach_adapter(struct i2c_adapter *adapter)
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{
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return i2c_probe(adapter, &addr_data, max6900_probe);
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}
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static int max6900_detach_client(struct i2c_client *client)
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{
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struct rtc_device *const rtc = i2c_get_clientdata(client);
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if (rtc)
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rtc_device_unregister(rtc);
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return i2c_detach_client(client);
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}
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static struct i2c_driver max6900_driver = {
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.driver = {
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.name = DRV_NAME,
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},
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.id = I2C_DRIVERID_MAX6900,
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.attach_adapter = max6900_attach_adapter,
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.detach_client = max6900_detach_client,
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};
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static const struct rtc_class_ops max6900_rtc_ops = {
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.read_time = max6900_rtc_read_time,
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.set_time = max6900_rtc_set_time,
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};
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static int max6900_probe(struct i2c_adapter *adapter, int addr, int kind)
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{
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int rc = 0;
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struct i2c_client *client = NULL;
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struct rtc_device *rtc = NULL;
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if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
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rc = -ENODEV;
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goto failout;
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}
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client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
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if (client == NULL) {
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rc = -ENOMEM;
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goto failout;
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}
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client->addr = addr;
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client->adapter = adapter;
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client->driver = &max6900_driver;
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strlcpy(client->name, DRV_NAME, I2C_NAME_SIZE);
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if (kind < 0) {
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rc = max6900_i2c_validate_client(client);
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if (rc < 0)
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goto failout;
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}
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rc = i2c_attach_client(client);
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if (rc < 0)
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goto failout;
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dev_info(&client->dev,
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"chip found, driver version " DRV_VERSION "\n");
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rtc = rtc_device_register(max6900_driver.driver.name,
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&client->dev,
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&max6900_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc)) {
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rc = PTR_ERR(rtc);
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goto failout_detach;
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}
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i2c_set_clientdata(client, rtc);
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return 0;
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failout_detach:
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i2c_detach_client(client);
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failout:
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kfree(client);
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return rc;
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}
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static int __init max6900_init(void)
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{
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return i2c_add_driver(&max6900_driver);
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}
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static void __exit max6900_exit(void)
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{
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i2c_del_driver(&max6900_driver);
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}
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MODULE_DESCRIPTION("Maxim MAX6900 RTC driver");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(DRV_VERSION);
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module_init(max6900_init);
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module_exit(max6900_exit);
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