rtc: rv8803: Always apply the I²C workaround
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 <benoit@wsystem.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Benoît Thébaudeau
Alexandre Belloni
parent
a1e98e0970
commit
d522649e26
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@ -20,6 +20,8 @@
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#include <linux/module.h>
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#include <linux/rtc.h>
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#define RV8803_I2C_TRY_COUNT 4
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#define RV8803_SEC 0x00
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#define RV8803_MIN 0x01
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#define RV8803_HOUR 0x02
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@ -57,19 +59,85 @@ struct rv8803_data {
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u8 ctrl;
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};
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static int rv8803_read_reg(const struct i2c_client *client, u8 reg)
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{
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int try = RV8803_I2C_TRY_COUNT;
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s32 ret;
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/*
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* There is a 61µs window during which the RTC does not acknowledge I2C
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* transfers. In that case, ensure that there are multiple attempts.
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*/
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do
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ret = i2c_smbus_read_byte_data(client, reg);
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while ((ret == -ENXIO || ret == -EIO) && --try);
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if (ret < 0)
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dev_err(&client->dev, "Unable to read register 0x%02x\n", reg);
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return ret;
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}
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static int rv8803_read_regs(const struct i2c_client *client,
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u8 reg, u8 count, u8 *values)
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{
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int try = RV8803_I2C_TRY_COUNT;
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s32 ret;
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do
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ret = i2c_smbus_read_i2c_block_data(client, reg, count, values);
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while ((ret == -ENXIO || ret == -EIO) && --try);
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if (ret != count) {
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dev_err(&client->dev,
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"Unable to read registers 0x%02x..0x%02x\n",
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reg, reg + count - 1);
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return ret < 0 ? ret : -EIO;
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}
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return 0;
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}
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static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value)
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{
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int try = RV8803_I2C_TRY_COUNT;
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s32 ret;
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do
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ret = i2c_smbus_write_byte_data(client, reg, value);
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while ((ret == -ENXIO || ret == -EIO) && --try);
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if (ret)
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dev_err(&client->dev, "Unable to write register 0x%02x\n", reg);
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return ret;
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}
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static int rv8803_write_regs(const struct i2c_client *client,
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u8 reg, u8 count, const u8 *values)
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{
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int try = RV8803_I2C_TRY_COUNT;
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s32 ret;
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do
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ret = i2c_smbus_write_i2c_block_data(client, reg, count,
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values);
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while ((ret == -ENXIO || ret == -EIO) && --try);
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if (ret)
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dev_err(&client->dev,
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"Unable to write registers 0x%02x..0x%02x\n",
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reg, reg + count - 1);
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return ret;
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}
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static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
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{
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struct i2c_client *client = dev_id;
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struct rv8803_data *rv8803 = i2c_get_clientdata(client);
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unsigned long events = 0;
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int flags, try = 0;
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int flags;
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mutex_lock(&rv8803->flags_lock);
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do {
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flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
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try++;
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} while (((flags == -ENXIO) || (flags == -EIO)) && (try < 4));
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flags = rv8803_read_reg(client, RV8803_FLAG);
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if (flags <= 0) {
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mutex_unlock(&rv8803->flags_lock);
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return IRQ_NONE;
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@ -101,9 +169,8 @@ static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
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if (events) {
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rtc_update_irq(rv8803->rtc, 1, events);
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i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
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i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
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rv8803->ctrl);
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rv8803_write_reg(client, RV8803_FLAG, flags);
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rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl);
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}
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mutex_unlock(&rv8803->flags_lock);
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@ -119,7 +186,7 @@ static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
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u8 *date = date1;
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int ret, flags;
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flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
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flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
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if (flags < 0)
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return flags;
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@ -128,16 +195,14 @@ static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
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return -EINVAL;
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}
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ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
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7, date);
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if (ret != 7)
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return ret < 0 ? ret : -EIO;
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ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date);
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if (ret)
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return ret;
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if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
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ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
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7, date2);
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if (ret != 7)
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return ret < 0 ? ret : -EIO;
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ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2);
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if (ret)
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return ret;
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if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
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date = date2;
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@ -171,21 +236,20 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
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date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
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date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);
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ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC,
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7, date);
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if (ret < 0)
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ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date);
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if (ret)
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return ret;
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mutex_lock(&rv8803->flags_lock);
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flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
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flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
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if (flags < 0) {
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mutex_unlock(&rv8803->flags_lock);
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return flags;
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}
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ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
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flags & ~RV8803_FLAG_V2F);
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ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
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flags & ~RV8803_FLAG_V2F);
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mutex_unlock(&rv8803->flags_lock);
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@ -199,12 +263,11 @@ static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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u8 alarmvals[3];
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int flags, ret;
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ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN,
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3, alarmvals);
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if (ret != 3)
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return ret < 0 ? ret : -EIO;
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ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals);
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if (ret)
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return ret;
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flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
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flags = rv8803_read_reg(client, RV8803_FLAG);
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if (flags < 0)
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return flags;
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@ -237,10 +300,10 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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mutex_lock(&rv8803->flags_lock);
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ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
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if (ret != 2) {
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ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl);
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if (ret) {
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mutex_unlock(&rv8803->flags_lock);
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return ret < 0 ? ret : -EIO;
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return ret;
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}
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alarmvals[0] = bin2bcd(alrm->time.tm_min);
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@ -249,8 +312,8 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
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rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
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err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
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rv8803->ctrl);
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err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
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rv8803->ctrl);
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if (err) {
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mutex_unlock(&rv8803->flags_lock);
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return err;
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@ -258,13 +321,12 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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}
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ctrl[1] &= ~RV8803_FLAG_AF;
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err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
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err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[1]);
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mutex_unlock(&rv8803->flags_lock);
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if (err)
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return err;
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err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN,
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3, alarmvals);
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err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals);
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if (err)
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return err;
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@ -274,8 +336,8 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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if (rv8803->rtc->aie_timer.enabled)
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rv8803->ctrl |= RV8803_CTRL_AIE;
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err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
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rv8803->ctrl);
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err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
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rv8803->ctrl);
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if (err)
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return err;
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}
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@ -304,21 +366,20 @@ static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
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}
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mutex_lock(&rv8803->flags_lock);
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flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
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flags = rv8803_read_reg(client, RV8803_FLAG);
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if (flags < 0) {
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mutex_unlock(&rv8803->flags_lock);
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return flags;
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}
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flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
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err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
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err = rv8803_write_reg(client, RV8803_FLAG, flags);
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mutex_unlock(&rv8803->flags_lock);
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if (err)
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return err;
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if (ctrl != rv8803->ctrl) {
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rv8803->ctrl = ctrl;
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err = i2c_smbus_write_byte_data(client, RV8803_CTRL,
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rv8803->ctrl);
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err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl);
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if (err)
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return err;
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}
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@ -334,7 +395,7 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
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switch (cmd) {
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case RTC_VL_READ:
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flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
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flags = rv8803_read_reg(client, RV8803_FLAG);
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if (flags < 0)
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return flags;
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@ -353,16 +414,16 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
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case RTC_VL_CLR:
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mutex_lock(&rv8803->flags_lock);
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flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
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flags = rv8803_read_reg(client, RV8803_FLAG);
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if (flags < 0) {
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mutex_unlock(&rv8803->flags_lock);
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return flags;
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}
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flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
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ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
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ret = rv8803_write_reg(client, RV8803_FLAG, flags);
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mutex_unlock(&rv8803->flags_lock);
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if (ret < 0)
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if (ret)
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return ret;
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return 0;
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@ -380,8 +441,8 @@ static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj,
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struct i2c_client *client = to_i2c_client(dev);
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int ret;
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ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]);
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if (ret < 0)
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ret = rv8803_write_reg(client, RV8803_RAM, buf[0]);
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if (ret)
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return ret;
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return 1;
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@ -395,7 +456,7 @@ static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj,
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struct i2c_client *client = to_i2c_client(dev);
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int ret;
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ret = i2c_smbus_read_byte_data(client, RV8803_RAM);
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ret = rv8803_read_reg(client, RV8803_RAM);
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if (ret < 0)
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return ret;
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@ -425,7 +486,7 @@ static int rv8803_probe(struct i2c_client *client,
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{
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struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
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struct rv8803_data *rv8803;
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int err, flags, try = 0;
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int err, flags;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
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I2C_FUNC_SMBUS_I2C_BLOCK)) {
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@ -442,16 +503,7 @@ static int rv8803_probe(struct i2c_client *client,
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rv8803->client = client;
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i2c_set_clientdata(client, rv8803);
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/*
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* There is a 60µs window where the RTC may not reply on the i2c bus in
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* that case, the transfer is not ACKed. In that case, ensure there are
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* multiple attempts.
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*/
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do {
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flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
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try++;
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} while (((flags == -ENXIO) || (flags == -EIO)) && (try < 4));
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flags = rv8803_read_reg(client, RV8803_FLAG);
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if (flags < 0)
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return flags;
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@ -486,12 +538,7 @@ static int rv8803_probe(struct i2c_client *client,
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return PTR_ERR(rv8803->rtc);
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}
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try = 0;
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do {
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err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
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RV8803_EXT_WADA);
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try++;
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} while (((err == -ENXIO) || (flags == -EIO)) && (try < 4));
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err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
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if (err)
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return err;
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