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Date: Thu, 21 Jul 2016 12:41:30 +0200
From: Benoît Thébaudeau <benoit@...stem.com>
To: rtc-linux@...glegroups.com
Cc: linux-kernel@...r.kernel.org,
Alessandro Zummo <a.zummo@...ertech.it>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Benoît Thébaudeau <benoit@...stem.com>
Subject: [PATCH 4/6] 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@...stem.com>
---
drivers/rtc/rtc-rv8803.c | 179 ++++++++++++++++++++++++++++++-----------------
1 file changed, 113 insertions(+), 66 deletions(-)
diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
index aa1d6b6..09ab5cb 100644
--- a/drivers/rtc/rtc-rv8803.c
+++ b/drivers/rtc/rtc-rv8803.c
@@ -20,6 +20,8 @@
#include <linux/module.h>
#include <linux/rtc.h>
+#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;
--
2.5.0
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