From d522649e2686ec98eb03078583736fdcb4ef8880 Mon Sep 17 00:00:00 2001 From: Benoît Thébaudeau Date: Thu, 21 Jul 2016 12:41:30 +0200 Subject: rtc: rv8803: Always apply the I²C workaround MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The I²C NACK issue of the RV-8803 may occur after any I²C START condition, depending on the timings. Consequently, the workaround must be applied for all the I²C transfers. This commit abstracts the I²C transfer code into register access functions. This avoids duplicating the I²C workaround everywhere. This also avoids the duplication of the code handling the return value of i2c_smbus_read_i2c_block_data(). Error messages are issued in case of definitive register access failures (if the workaround fails). This change also makes the I²C transfer return value checks consistent. Signed-off-by: Benoît Thébaudeau Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-rv8803.c | 179 ++++++++++++++++++++++++++++++----------------- 1 file changed, 113 insertions(+), 66 deletions(-) (limited to 'drivers/rtc') diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c index aa1d6b67a9ee..09ab5cb1fa8a 100644 --- a/drivers/rtc/rtc-rv8803.c +++ b/drivers/rtc/rtc-rv8803.c @@ -20,6 +20,8 @@ #include #include +#define RV8803_I2C_TRY_COUNT 4 + #define RV8803_SEC 0x00 #define RV8803_MIN 0x01 #define RV8803_HOUR 0x02 @@ -57,19 +59,85 @@ struct rv8803_data { u8 ctrl; }; +static int rv8803_read_reg(const struct i2c_client *client, u8 reg) +{ + int try = RV8803_I2C_TRY_COUNT; + s32 ret; + + /* + * There is a 61µs window during which the RTC does not acknowledge I2C + * transfers. In that case, ensure that there are multiple attempts. + */ + do + ret = i2c_smbus_read_byte_data(client, reg); + while ((ret == -ENXIO || ret == -EIO) && --try); + if (ret < 0) + dev_err(&client->dev, "Unable to read register 0x%02x\n", reg); + + return ret; +} + +static int rv8803_read_regs(const struct i2c_client *client, + u8 reg, u8 count, u8 *values) +{ + int try = RV8803_I2C_TRY_COUNT; + s32 ret; + + do + ret = i2c_smbus_read_i2c_block_data(client, reg, count, values); + while ((ret == -ENXIO || ret == -EIO) && --try); + if (ret != count) { + dev_err(&client->dev, + "Unable to read registers 0x%02x..0x%02x\n", + reg, reg + count - 1); + return ret < 0 ? ret : -EIO; + } + + return 0; +} + +static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value) +{ + int try = RV8803_I2C_TRY_COUNT; + s32 ret; + + do + ret = i2c_smbus_write_byte_data(client, reg, value); + while ((ret == -ENXIO || ret == -EIO) && --try); + if (ret) + dev_err(&client->dev, "Unable to write register 0x%02x\n", reg); + + return ret; +} + +static int rv8803_write_regs(const struct i2c_client *client, + u8 reg, u8 count, const u8 *values) +{ + int try = RV8803_I2C_TRY_COUNT; + s32 ret; + + do + ret = i2c_smbus_write_i2c_block_data(client, reg, count, + values); + while ((ret == -ENXIO || ret == -EIO) && --try); + if (ret) + dev_err(&client->dev, + "Unable to write registers 0x%02x..0x%02x\n", + reg, reg + count - 1); + + return ret; +} + static irqreturn_t rv8803_handle_irq(int irq, void *dev_id) { struct i2c_client *client = dev_id; struct rv8803_data *rv8803 = i2c_get_clientdata(client); unsigned long events = 0; - int flags, try = 0; + int flags; mutex_lock(&rv8803->flags_lock); - do { - flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); - try++; - } while (((flags == -ENXIO) || (flags == -EIO)) && (try < 4)); + flags = rv8803_read_reg(client, RV8803_FLAG); if (flags <= 0) { mutex_unlock(&rv8803->flags_lock); return IRQ_NONE; @@ -101,9 +169,8 @@ static irqreturn_t rv8803_handle_irq(int irq, void *dev_id) if (events) { rtc_update_irq(rv8803->rtc, 1, events); - i2c_smbus_write_byte_data(client, RV8803_FLAG, flags); - i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL, - rv8803->ctrl); + rv8803_write_reg(client, RV8803_FLAG, flags); + rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl); } mutex_unlock(&rv8803->flags_lock); @@ -119,7 +186,7 @@ static int rv8803_get_time(struct device *dev, struct rtc_time *tm) u8 *date = date1; int ret, flags; - flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG); + flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); if (flags < 0) return flags; @@ -128,16 +195,14 @@ static int rv8803_get_time(struct device *dev, struct rtc_time *tm) return -EINVAL; } - ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC, - 7, date); - if (ret != 7) - return ret < 0 ? ret : -EIO; + ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date); + if (ret) + return ret; if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) { - ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC, - 7, date2); - if (ret != 7) - return ret < 0 ? ret : -EIO; + ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2); + if (ret) + return ret; if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59)) date = date2; @@ -171,21 +236,20 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm) date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1); date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100); - ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC, - 7, date); - if (ret < 0) + ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date); + if (ret) return ret; mutex_lock(&rv8803->flags_lock); - flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG); + flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); if (flags < 0) { mutex_unlock(&rv8803->flags_lock); return flags; } - ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, - flags & ~RV8803_FLAG_V2F); + ret = rv8803_write_reg(rv8803->client, RV8803_FLAG, + flags & ~RV8803_FLAG_V2F); mutex_unlock(&rv8803->flags_lock); @@ -199,12 +263,11 @@ static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm) u8 alarmvals[3]; int flags, ret; - ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN, - 3, alarmvals); - if (ret != 3) - return ret < 0 ? ret : -EIO; + ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals); + if (ret) + return ret; - flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); + flags = rv8803_read_reg(client, RV8803_FLAG); if (flags < 0) return flags; @@ -237,10 +300,10 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) mutex_lock(&rv8803->flags_lock); - ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl); - if (ret != 2) { + ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl); + if (ret) { mutex_unlock(&rv8803->flags_lock); - return ret < 0 ? ret : -EIO; + return ret; } alarmvals[0] = bin2bcd(alrm->time.tm_min); @@ -249,8 +312,8 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) { rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE); - err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL, - rv8803->ctrl); + err = rv8803_write_reg(rv8803->client, RV8803_CTRL, + rv8803->ctrl); if (err) { mutex_unlock(&rv8803->flags_lock); return err; @@ -258,13 +321,12 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) } ctrl[1] &= ~RV8803_FLAG_AF; - err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]); + err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[1]); mutex_unlock(&rv8803->flags_lock); if (err) return err; - err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN, - 3, alarmvals); + err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals); if (err) return err; @@ -274,8 +336,8 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) if (rv8803->rtc->aie_timer.enabled) rv8803->ctrl |= RV8803_CTRL_AIE; - err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL, - rv8803->ctrl); + err = rv8803_write_reg(rv8803->client, RV8803_CTRL, + rv8803->ctrl); if (err) return err; } @@ -304,21 +366,20 @@ static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled) } mutex_lock(&rv8803->flags_lock); - flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); + flags = rv8803_read_reg(client, RV8803_FLAG); if (flags < 0) { mutex_unlock(&rv8803->flags_lock); return flags; } flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF); - err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags); + err = rv8803_write_reg(client, RV8803_FLAG, flags); mutex_unlock(&rv8803->flags_lock); if (err) return err; if (ctrl != rv8803->ctrl) { rv8803->ctrl = ctrl; - err = i2c_smbus_write_byte_data(client, RV8803_CTRL, - rv8803->ctrl); + err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl); if (err) return err; } @@ -334,7 +395,7 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) switch (cmd) { case RTC_VL_READ: - flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); + flags = rv8803_read_reg(client, RV8803_FLAG); if (flags < 0) return flags; @@ -353,16 +414,16 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) case RTC_VL_CLR: mutex_lock(&rv8803->flags_lock); - flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); + flags = rv8803_read_reg(client, RV8803_FLAG); if (flags < 0) { mutex_unlock(&rv8803->flags_lock); return flags; } flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F); - ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags); + ret = rv8803_write_reg(client, RV8803_FLAG, flags); mutex_unlock(&rv8803->flags_lock); - if (ret < 0) + if (ret) return ret; return 0; @@ -380,8 +441,8 @@ static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj, struct i2c_client *client = to_i2c_client(dev); int ret; - ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]); - if (ret < 0) + ret = rv8803_write_reg(client, RV8803_RAM, buf[0]); + if (ret) return ret; return 1; @@ -395,7 +456,7 @@ static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj, struct i2c_client *client = to_i2c_client(dev); int ret; - ret = i2c_smbus_read_byte_data(client, RV8803_RAM); + ret = rv8803_read_reg(client, RV8803_RAM); if (ret < 0) return ret; @@ -425,7 +486,7 @@ static int rv8803_probe(struct i2c_client *client, { struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); struct rv8803_data *rv8803; - int err, flags, try = 0; + int err, flags; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) { @@ -442,16 +503,7 @@ static int rv8803_probe(struct i2c_client *client, rv8803->client = client; i2c_set_clientdata(client, rv8803); - /* - * There is a 60µs window where the RTC may not reply on the i2c bus in - * that case, the transfer is not ACKed. In that case, ensure there are - * multiple attempts. - */ - do { - flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); - try++; - } while (((flags == -ENXIO) || (flags == -EIO)) && (try < 4)); - + flags = rv8803_read_reg(client, RV8803_FLAG); if (flags < 0) return flags; @@ -486,12 +538,7 @@ static int rv8803_probe(struct i2c_client *client, return PTR_ERR(rv8803->rtc); } - try = 0; - do { - err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT, - RV8803_EXT_WADA); - try++; - } while (((err == -ENXIO) || (flags == -EIO)) && (try < 4)); + err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA); if (err) return err; -- cgit v1.2.3