diff options
| -rw-r--r-- | Documentation/devicetree/bindings/rtc/maxim-ds1302.txt | 46 | ||||
| -rw-r--r-- | drivers/rtc/Kconfig | 15 | ||||
| -rw-r--r-- | drivers/rtc/rtc-ds1302.c | 348 |
3 files changed, 212 insertions, 197 deletions
diff --git a/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt b/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt new file mode 100644 index 000000000000..ba470c56cdec --- /dev/null +++ b/Documentation/devicetree/bindings/rtc/maxim-ds1302.txt @@ -0,0 +1,46 @@ +* Maxim/Dallas Semiconductor DS-1302 RTC + +Simple device which could be used to store date/time between reboots. + +The device uses the standard MicroWire half-duplex transfer timing. +Master output is set on low clock and sensed by the RTC on the rising +edge. Master input is set by the RTC on the trailing edge and is sensed +by the master on low clock. + +Required properties: + +- compatible : Should be "maxim,ds1302" + +Required SPI properties: + +- reg : Should be address of the device chip select within + the controller. + +- spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V, + and 2MHz if powered at 5V. + +- spi-3wire : The device has a shared signal IN/OUT line. + +- spi-lsb-first : DS-1302 requires least significant bit first + transfers. + +- spi-cs-high: DS-1302 has active high chip select line. This is + required unless inverted in hardware. + +Example: + +spi@901c { + #address-cells = <1>; + #size-cells = <0>; + compatible = "icpdas,lp8841-spi-rtc"; + reg = <0x901c 0x1>; + + rtc@0 { + compatible = "maxim,ds1302"; + reg = <0>; + spi-max-frequency = <500000>; + spi-3wire; + spi-lsb-first; + spi-cs-high; + }; +}; diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 3e84315c6f12..f1e1f502be5d 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -634,6 +634,15 @@ config RTC_DRV_M41T94 This driver can also be built as a module. If so, the module will be called rtc-m41t94. +config RTC_DRV_DS1302 + tristate "Dallas/Maxim DS1302" + depends on SPI + help + If you say yes here you get support for the Dallas DS1302 RTC chips. + + This driver can also be built as a module. If so, the module + will be called rtc-ds1302. + config RTC_DRV_DS1305 tristate "Dallas/Maxim DS1305/DS1306" help @@ -834,12 +843,6 @@ config RTC_DRV_DS1286 help If you say yes here you get support for the Dallas DS1286 RTC chips. -config RTC_DRV_DS1302 - tristate "Dallas DS1302" - depends on SH_SECUREEDGE5410 - help - If you say yes here you get support for the Dallas DS1302 RTC chips. - config RTC_DRV_DS1511 tristate "Dallas DS1511" depends on HAS_IOMEM diff --git a/drivers/rtc/rtc-ds1302.c b/drivers/rtc/rtc-ds1302.c index 6bef7a5233c4..5cdc0f201b34 100644 --- a/drivers/rtc/rtc-ds1302.c +++ b/drivers/rtc/rtc-ds1302.c @@ -9,16 +9,17 @@ * this archive for more details. */ +#include <linux/bcd.h> #include <linux/init.h> -#include <linux/module.h> +#include <linux/io.h> #include <linux/kernel.h> -#include <linux/platform_device.h> +#include <linux/module.h> +#include <linux/of.h> #include <linux/rtc.h> -#include <linux/io.h> -#include <linux/bcd.h> +#include <linux/spi/spi.h> #define DRV_NAME "rtc-ds1302" -#define DRV_VERSION "0.1.1" +#define DRV_VERSION "1.0.0" #define RTC_CMD_READ 0x81 /* Read command */ #define RTC_CMD_WRITE 0x80 /* Write command */ @@ -28,6 +29,8 @@ #define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */ #define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */ +#define RTC_CLCK_BURST 0x1F /* Address of clock burst */ +#define RTC_CLCK_LEN 0x08 /* Size of clock burst */ #define RTC_ADDR_CTRL 0x07 /* Address of control register */ #define RTC_ADDR_YEAR 0x06 /* Address of year register */ #define RTC_ADDR_DAY 0x05 /* Address of day of week register */ @@ -37,217 +40,180 @@ #define RTC_ADDR_MIN 0x01 /* Address of minute register */ #define RTC_ADDR_SEC 0x00 /* Address of second register */ -#ifdef CONFIG_SH_SECUREEDGE5410 -#include <asm/rtc.h> -#include <mach/secureedge5410.h> - -#define RTC_RESET 0x1000 -#define RTC_IODATA 0x0800 -#define RTC_SCLK 0x0400 - -#define set_dp(x) SECUREEDGE_WRITE_IOPORT(x, 0x1c00) -#define get_dp() SECUREEDGE_READ_IOPORT() -#define ds1302_set_tx() -#define ds1302_set_rx() - -static inline int ds1302_hw_init(void) +static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *time) { - return 0; + struct spi_device *spi = dev_get_drvdata(dev); + u8 buf[1 + RTC_CLCK_LEN]; + u8 *bp = buf; + int status; + + /* Enable writing */ + bp = buf; + *bp++ = RTC_ADDR_CTRL << 1 | RTC_CMD_WRITE; + *bp++ = RTC_CMD_WRITE_ENABLE; + + status = spi_write_then_read(spi, buf, 2, + NULL, 0); + if (!status) + return status; + + /* Write registers starting at the first time/date address. */ + bp = buf; + *bp++ = RTC_CLCK_BURST << 1 | RTC_CMD_WRITE; + + *bp++ = bin2bcd(time->tm_sec); + *bp++ = bin2bcd(time->tm_min); + *bp++ = bin2bcd(time->tm_hour); + *bp++ = bin2bcd(time->tm_mday); + *bp++ = bin2bcd(time->tm_mon + 1); + *bp++ = time->tm_wday; + *bp++ = bin2bcd(time->tm_year % 100); + *bp++ = RTC_CMD_WRITE_DISABLE; + + /* use write-then-read since dma from stack is nonportable */ + return spi_write_then_read(spi, buf, sizeof(buf), + NULL, 0); } -static inline void ds1302_reset(void) +static int ds1302_rtc_get_time(struct device *dev, struct rtc_time *time) { - set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); + struct spi_device *spi = dev_get_drvdata(dev); + u8 addr = RTC_CLCK_BURST << 1 | RTC_CMD_READ; + u8 buf[RTC_CLCK_LEN - 1]; + int status; + + /* Use write-then-read to get all the date/time registers + * since dma from stack is nonportable + */ + status = spi_write_then_read(spi, &addr, sizeof(addr), + buf, sizeof(buf)); + if (status < 0) + return status; + + /* Decode the registers */ + time->tm_sec = bcd2bin(buf[RTC_ADDR_SEC]); + time->tm_min = bcd2bin(buf[RTC_ADDR_MIN]); + time->tm_hour = bcd2bin(buf[RTC_ADDR_HOUR]); + time->tm_wday = buf[RTC_ADDR_DAY] - 1; + time->tm_mday = bcd2bin(buf[RTC_ADDR_DATE]); + time->tm_mon = bcd2bin(buf[RTC_ADDR_MON]) - 1; + time->tm_year = bcd2bin(buf[RTC_ADDR_YEAR]) + 100; + + /* Time may not be set */ + return rtc_valid_tm(time); } -static inline void ds1302_clock(void) -{ - set_dp(get_dp() | RTC_SCLK); /* clock high */ - set_dp(get_dp() & ~RTC_SCLK); /* clock low */ -} - -static inline void ds1302_start(void) -{ - set_dp(get_dp() | RTC_RESET); -} - -static inline void ds1302_stop(void) -{ - set_dp(get_dp() & ~RTC_RESET); -} - -static inline void ds1302_txbit(int bit) -{ - set_dp((get_dp() & ~RTC_IODATA) | (bit ? RTC_IODATA : 0)); -} - -static inline int ds1302_rxbit(void) -{ - return !!(get_dp() & RTC_IODATA); -} - -#else -#error "Add support for your platform" -#endif +static struct rtc_class_ops ds1302_rtc_ops = { + .read_time = ds1302_rtc_get_time, + .set_time = ds1302_rtc_set_time, +}; -static void ds1302_sendbits(unsigned int val) +static int ds1302_probe(struct spi_device *spi) { - int i; - - ds1302_set_tx(); - - for (i = 8; (i); i--, val >>= 1) { - ds1302_txbit(val & 0x1); - ds1302_clock(); + struct rtc_device *rtc; + u8 addr; + u8 buf[4]; + u8 *bp = buf; + int status; + + /* Sanity check board setup data. This may be hooked up + * in 3wire mode, but we don't care. Note that unless + * there's an inverter in place, this needs SPI_CS_HIGH! + */ + if (spi->bits_per_word && (spi->bits_per_word != 8)) { + dev_err(&spi->dev, "bad word length\n"); + return -EINVAL; + } else if (spi->max_speed_hz > 2000000) { + dev_err(&spi->dev, "speed is too high\n"); + return -EINVAL; + } else if (spi->mode & SPI_CPHA) { + dev_err(&spi->dev, "bad mode\n"); + return -EINVAL; } -} - -static unsigned int ds1302_recvbits(void) -{ - unsigned int val; - int i; - - ds1302_set_rx(); - for (i = 0, val = 0; (i < 8); i++) { - val |= (ds1302_rxbit() << i); - ds1302_clock(); + addr = RTC_ADDR_CTRL << 1 | RTC_CMD_READ; + status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1); + if (status < 0) { + dev_err(&spi->dev, "control register read error %d\n", + status); + return status; } - return val; -} - -static unsigned int ds1302_readbyte(unsigned int addr) -{ - unsigned int val; - - ds1302_reset(); - - ds1302_start(); - ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ); - val = ds1302_recvbits(); - ds1302_stop(); - - return val; -} - -static void ds1302_writebyte(unsigned int addr, unsigned int val) -{ - ds1302_reset(); - - ds1302_start(); - ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE); - ds1302_sendbits(val); - ds1302_stop(); -} - -static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm) -{ - tm->tm_sec = bcd2bin(ds1302_readbyte(RTC_ADDR_SEC)); - tm->tm_min = bcd2bin(ds1302_readbyte(RTC_ADDR_MIN)); - tm->tm_hour = bcd2bin(ds1302_readbyte(RTC_ADDR_HOUR)); - tm->tm_wday = bcd2bin(ds1302_readbyte(RTC_ADDR_DAY)); - tm->tm_mday = bcd2bin(ds1302_readbyte(RTC_ADDR_DATE)); - tm->tm_mon = bcd2bin(ds1302_readbyte(RTC_ADDR_MON)) - 1; - tm->tm_year = bcd2bin(ds1302_readbyte(RTC_ADDR_YEAR)); - - if (tm->tm_year < 70) - tm->tm_year += 100; - - dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " - "mday=%d, mon=%d, year=%d, wday=%d\n", - __func__, - tm->tm_sec, tm->tm_min, tm->tm_hour, - tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday); - - return rtc_valid_tm(tm); -} - -static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm) -{ - ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_ENABLE); - /* Stop RTC */ - ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80); - - ds1302_writebyte(RTC_ADDR_SEC, bin2bcd(tm->tm_sec)); - ds1302_writebyte(RTC_ADDR_MIN, bin2bcd(tm->tm_min)); - ds1302_writebyte(RTC_ADDR_HOUR, bin2bcd(tm->tm_hour)); - ds1302_writebyte(RTC_ADDR_DAY, bin2bcd(tm->tm_wday)); - ds1302_writebyte(RTC_ADDR_DATE, bin2bcd(tm->tm_mday)); - ds1302_writebyte(RTC_ADDR_MON, bin2bcd(tm->tm_mon + 1)); - ds1302_writebyte(RTC_ADDR_YEAR, bin2bcd(tm->tm_year % 100)); + if ((buf[0] & ~RTC_CMD_WRITE_DISABLE) != 0) { + status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1); + if (status < 0) { + dev_err(&spi->dev, "control register read error %d\n", + status); + return status; + } + + if ((buf[0] & ~RTC_CMD_WRITE_DISABLE) != 0) { + dev_err(&spi->dev, "junk in control register\n"); + return -ENODEV; + } + } + if (buf[0] == 0) { + bp = buf; + *bp++ = RTC_ADDR_CTRL << 1 | RTC_CMD_WRITE; + *bp++ = RTC_CMD_WRITE_DISABLE; + + status = spi_write_then_read(spi, buf, 2, NULL, 0); + if (status < 0) { + dev_err(&spi->dev, "control register write error %d\n", + status); + return status; + } + + addr = RTC_ADDR_CTRL << 1 | RTC_CMD_READ; + status = spi_write_then_read(spi, &addr, sizeof(addr), buf, 1); + if (status < 0) { + dev_err(&spi->dev, + "error %d reading control register\n", + status); + return status; + } + + if (buf[0] != RTC_CMD_WRITE_DISABLE) { + dev_err(&spi->dev, "failed to detect chip\n"); + return -ENODEV; + } + } - /* Start RTC */ - ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80); + spi_set_drvdata(spi, spi); - ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_DISABLE); + rtc = devm_rtc_device_register(&spi->dev, "ds1302", + &ds1302_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) { + status = PTR_ERR(rtc); + dev_err(&spi->dev, "error %d registering rtc\n", status); + return status; + } return 0; } -static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd, - unsigned long arg) +static int ds1302_remove(struct spi_device *spi) { - switch (cmd) { -#ifdef RTC_SET_CHARGE - case RTC_SET_CHARGE: - { - int tcs_val; - - if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int))) - return -EFAULT; - - ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf)); - return 0; - } -#endif - } - - return -ENOIOCTLCMD; + spi_set_drvdata(spi, NULL); + return 0; } -static struct rtc_class_ops ds1302_rtc_ops = { - .read_time = ds1302_rtc_read_time, - .set_time = ds1302_rtc_set_time, - .ioctl = ds1302_rtc_ioctl, +#ifdef CONFIG_OF +static const struct of_device_id ds1302_dt_ids[] = { + { .compatible = "maxim,ds1302", }, + { /* sentinel */ } }; +MODULE_DEVICE_TABLE(of, ds1302_dt_ids); +#endif -static int __init ds1302_rtc_probe(struct platform_device *pdev) -{ - struct rtc_device *rtc; - - if (ds1302_hw_init()) { - dev_err(&pdev->dev, "Failed to init communication channel"); - return -EINVAL; - } - - /* Reset */ - ds1302_reset(); - - /* Write a magic value to the DS1302 RAM, and see if it sticks. */ - ds1302_writebyte(RTC_ADDR_RAM0, 0x42); - if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42) { - dev_err(&pdev->dev, "Failed to probe"); - return -ENODEV; - } - - rtc = devm_rtc_device_register(&pdev->dev, "ds1302", - &ds1302_rtc_ops, THIS_MODULE); - if (IS_ERR(rtc)) - return PTR_ERR(rtc); - - platform_set_drvdata(pdev, rtc); - - return 0; -} - -static struct platform_driver ds1302_platform_driver = { - .driver = { - .name = DRV_NAME, - }, +static struct spi_driver ds1302_driver = { + .driver.name = "rtc-ds1302", + .driver.of_match_table = of_match_ptr(ds1302_dt_ids), + .probe = ds1302_probe, + .remove = ds1302_remove, }; -module_platform_driver_probe(ds1302_platform_driver, ds1302_rtc_probe); +module_spi_driver(ds1302_driver); MODULE_DESCRIPTION("Dallas DS1302 RTC driver"); MODULE_VERSION(DRV_VERSION); |