From 59a8383adb75459c9d6766656bccc05950b783ea Mon Sep 17 00:00:00 2001 From: Mylène Josserand Date: Mon, 21 Mar 2016 18:06:09 +0100 Subject: rtc: abx80x: handle autocalibration MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The autocalibration is separated in two bits to set in Oscillator Control register (0x1c) : - OSEL bit to select the oscillator type (XT or RC). - ACAL bit to select the autocalibration type. These functionnalities are exported in sysfs entries : "oscillator" and "autocalibration". Respectively, the values are "xtal" for XT oscillator and "rc" for RC oscillator and 0 to disable the autocalibration cycle, 512 for a 512 seconds autocalibration cycle and 1024 for a cycle of 1024 seconds. Examples : Set to XT Oscillator echo xtal > /sys/class/rtc/rtc0/device/oscillator Activate an autocalibration every 512 seconds echo 512 > /sys/class/rtc/rtc0/device/autocalibration Signed-off-by: Mylène Josserand Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-abx80x.c | 219 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 219 insertions(+) diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c index d41bbcd653f6..0e4c9a0989d1 100644 --- a/drivers/rtc/rtc-abx80x.c +++ b/drivers/rtc/rtc-abx80x.c @@ -49,7 +49,19 @@ #define ABX8XX_REG_CD_TIMER_CTL 0x18 +#define ABX8XX_REG_OSC 0x1c +#define ABX8XX_OSC_FOS BIT(3) +#define ABX8XX_OSC_BOS BIT(4) +#define ABX8XX_OSC_ACAL_512 BIT(5) +#define ABX8XX_OSC_ACAL_1024 BIT(6) + +#define ABX8XX_OSC_OSEL BIT(7) + +#define ABX8XX_REG_OSS 0x1d +#define ABX8XX_OSS_OMODE BIT(4) + #define ABX8XX_REG_CFG_KEY 0x1f +#define ABX8XX_CFG_KEY_OSC 0xa1 #define ABX8XX_CFG_KEY_MISC 0x9d #define ABX8XX_REG_ID0 0x28 @@ -81,6 +93,20 @@ static struct abx80x_cap abx80x_caps[] = { [ABX80X] = {.pn = 0} }; +static int abx80x_is_rc_mode(struct i2c_client *client) +{ + int flags = 0; + + flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS); + if (flags < 0) { + dev_err(&client->dev, + "Failed to read autocalibration attribute\n"); + return flags; + } + + return (flags & ABX8XX_OSS_OMODE) ? 1 : 0; +} + static int abx80x_enable_trickle_charger(struct i2c_client *client, u8 trickle_cfg) { @@ -248,6 +274,174 @@ static int abx80x_set_alarm(struct device *dev, struct rtc_wkalrm *t) return 0; } +static int abx80x_rtc_set_autocalibration(struct device *dev, + int autocalibration) +{ + struct i2c_client *client = to_i2c_client(dev); + int retval, flags = 0; + + if ((autocalibration != 0) && (autocalibration != 1024) && + (autocalibration != 512)) { + dev_err(dev, "autocalibration value outside permitted range\n"); + return -EINVAL; + } + + flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC); + if (flags < 0) + return flags; + + if (autocalibration == 0) { + flags &= ~(ABX8XX_OSC_ACAL_512 | ABX8XX_OSC_ACAL_1024); + } else if (autocalibration == 1024) { + /* 1024 autocalibration is 0x10 */ + flags |= ABX8XX_OSC_ACAL_1024; + flags &= ~(ABX8XX_OSC_ACAL_512); + } else { + /* 512 autocalibration is 0x11 */ + flags |= (ABX8XX_OSC_ACAL_1024 | ABX8XX_OSC_ACAL_512); + } + + /* Unlock write access to Oscillator Control Register */ + retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY, + ABX8XX_CFG_KEY_OSC); + if (retval < 0) { + dev_err(dev, "Failed to write CONFIG_KEY register\n"); + return retval; + } + + retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags); + + return retval; +} + +static int abx80x_rtc_get_autocalibration(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + int flags = 0, autocalibration; + + flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC); + if (flags < 0) + return flags; + + if (flags & ABX8XX_OSC_ACAL_512) + autocalibration = 512; + else if (flags & ABX8XX_OSC_ACAL_1024) + autocalibration = 1024; + else + autocalibration = 0; + + return autocalibration; +} + +static ssize_t autocalibration_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int retval; + unsigned long autocalibration = 0; + + retval = kstrtoul(buf, 10, &autocalibration); + if (retval < 0) { + dev_err(dev, "Failed to store RTC autocalibration attribute\n"); + return -EINVAL; + } + + retval = abx80x_rtc_set_autocalibration(dev, autocalibration); + + return retval ? retval : count; +} + +static ssize_t autocalibration_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int autocalibration = 0; + + autocalibration = abx80x_rtc_get_autocalibration(dev); + if (autocalibration < 0) { + dev_err(dev, "Failed to read RTC autocalibration\n"); + sprintf(buf, "0\n"); + return autocalibration; + } + + return sprintf(buf, "%d\n", autocalibration); +} + +static DEVICE_ATTR_RW(autocalibration); + +static ssize_t oscillator_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + int retval, flags, rc_mode = 0; + + if (strncmp(buf, "rc", 2) == 0) { + rc_mode = 1; + } else if (strncmp(buf, "xtal", 4) == 0) { + rc_mode = 0; + } else { + dev_err(dev, "Oscillator selection value outside permitted ones\n"); + return -EINVAL; + } + + flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC); + if (flags < 0) + return flags; + + if (rc_mode == 0) + flags &= ~(ABX8XX_OSC_OSEL); + else + flags |= (ABX8XX_OSC_OSEL); + + /* Unlock write access on Oscillator Control register */ + retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY, + ABX8XX_CFG_KEY_OSC); + if (retval < 0) { + dev_err(dev, "Failed to write CONFIG_KEY register\n"); + return retval; + } + + retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags); + if (retval < 0) { + dev_err(dev, "Failed to write Oscillator Control register\n"); + return retval; + } + + return retval ? retval : count; +} + +static ssize_t oscillator_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int rc_mode = 0; + struct i2c_client *client = to_i2c_client(dev); + + rc_mode = abx80x_is_rc_mode(client); + + if (rc_mode < 0) { + dev_err(dev, "Failed to read RTC oscillator selection\n"); + sprintf(buf, "\n"); + return rc_mode; + } + + if (rc_mode) + return sprintf(buf, "rc\n"); + else + return sprintf(buf, "xtal\n"); +} + +static DEVICE_ATTR_RW(oscillator); + +static struct attribute *rtc_calib_attrs[] = { + &dev_attr_autocalibration.attr, + &dev_attr_oscillator.attr, + NULL, +}; + +static const struct attribute_group rtc_calib_attr_group = { + .attrs = rtc_calib_attrs, +}; + static int abx80x_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct i2c_client *client = to_i2c_client(dev); @@ -303,6 +497,13 @@ static int abx80x_dt_trickle_cfg(struct device_node *np) return (trickle_cfg | i); } +static void rtc_calib_remove_sysfs_group(void *_dev) +{ + struct device *dev = _dev; + + sysfs_remove_group(&dev->kobj, &rtc_calib_attr_group); +} + static int abx80x_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -405,6 +606,24 @@ static int abx80x_probe(struct i2c_client *client, } } + /* Export sysfs entries */ + err = sysfs_create_group(&(&client->dev)->kobj, &rtc_calib_attr_group); + if (err) { + dev_err(&client->dev, "Failed to create sysfs group: %d\n", + err); + return err; + } + + err = devm_add_action(&client->dev, rtc_calib_remove_sysfs_group, + &client->dev); + if (err) { + rtc_calib_remove_sysfs_group(&client->dev); + dev_err(&client->dev, + "Failed to add sysfs cleanup action: %d\n", + err); + return err; + } + return 0; } -- cgit v1.2.3-59-g8ed1b