From: Michael Jones <mike@xxxxxxxxxxxxx>
Some of the LTC chips supported by this driver have to be polled
to ensure that they are ready to accept commands.
Signed-off-by: Michael Jones <mike@xxxxxxxxxxxxx>
[Guenter Roeck: simplifications and formatting changes]
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
drivers/hwmon/pmbus/ltc2978.c | 111 ++++++++++++++++++++++++++++++++++++++----
1 file changed, 101 insertions(+), 10 deletions(-)
diff --git a/drivers/hwmon/pmbus/ltc2978.c b/drivers/hwmon/pmbus/ltc2978.c
index 60fe8f9839d3..f1c69c9de849 100644
--- a/drivers/hwmon/pmbus/ltc2978.c
+++ b/drivers/hwmon/pmbus/ltc2978.c
@@ -3,6 +3,7 @@
*
* Copyright (c) 2011 Ericsson AB.
* Copyright (c) 2013, 2014, 2015 Guenter Roeck
+ * Copyright (c) 2015 Linear Technology
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -15,6 +16,8 @@
* GNU General Public License for more details.
*/
+#include <linux/delay.h>
+#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
@@ -32,6 +35,7 @@ enum chips { ltc2974, ltc2975, ltc2977, ltc2978, ltc2980, ltc3880, ltc3882,
#define LTC2978_MFR_VIN_PEAK 0xde
#define LTC2978_MFR_TEMPERATURE_PEAK 0xdf
#define LTC2978_MFR_SPECIAL_ID 0xe7 /* Undocumented on LTC3882 */
+#define LTC2978_MFR_COMMON 0xef
/* LTC2974, LTC2975, LCT2977, LTC2980, LTC2978, and LTM2987 */
#define LTC2978_MFR_VOUT_MIN 0xfb
@@ -82,6 +86,11 @@ enum chips { ltc2974, ltc2975, ltc2977, ltc2978, ltc2980, ltc3880, ltc3882,
#define LTC3880_NUM_PAGES 2
#define LTC3883_NUM_PAGES 1
+#define LTC_POLL_TIMEOUT 100 /* in milli-seconds */
+
+#define LTC_NOT_BUSY BIT(5)
+#define LTC_NOT_PENDING BIT(4)
+
/*
* LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
* happens pretty much each time chip data is updated. Raw peak data therefore
@@ -105,8 +114,81 @@ struct ltc2978_data {
#define to_ltc2978_data(x) container_of(x, struct ltc2978_data, info)
#define FEAT_CLEAR_PEAKS BIT(0)
+#define FEAT_NEEDS_POLLING BIT(1)
#define has_clear_peaks(d) ((d)->features & FEAT_CLEAR_PEAKS)
+#define needs_polling(d) ((d)->features & FEAT_NEEDS_POLLING)
+
+static int ltc_wait_ready(struct i2c_client *client)
+{
+ unsigned long timeout = jiffies + msecs_to_jiffies(LTC_POLL_TIMEOUT);
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct ltc2978_data *data = to_ltc2978_data(info);
+ int status;
+ u8 mask;
+
+ if (!needs_polling(data))
+ return 0;
+
+ /*
+ * LTC3883 does not support LTC_NOT_PENDING, even though
+ * the datasheet claims that it does.
+ */
+ mask = LTC_NOT_BUSY;
+ if (data->id != ltc3883)
+ mask |= LTC_NOT_PENDING;
+
+ do {
+ status = pmbus_read_byte_data(client, 0, LTC2978_MFR_COMMON);
+ if (status == -EBADMSG || status == -ENXIO) {
+ /* PEC error or NACK: chip may be busy, try again */
+ usleep_range(50, 100);
+ continue;
+ }
+ if (status < 0)
+ return status;
+
+ if ((status & mask) == mask)
+ return 0;
+
+ usleep_range(50, 100);
+ } while (time_before(jiffies, timeout));
+
+ return -ETIMEDOUT;
+}
+
+static int ltc_read_word_data(struct i2c_client *client, int page, int reg)
+{
+ int ret;
+
+ ret = ltc_wait_ready(client);
+ if (ret < 0)
+ return ret;
+
+ return pmbus_read_word_data(client, page, reg);
+}
+
+static int ltc_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+ int ret;
+
+ ret = ltc_wait_ready(client);
+ if (ret < 0)
+ return ret;
+
+ return pmbus_read_byte_data(client, page, reg);
+}
+
+static int ltc_write_byte(struct i2c_client *client, int page, u8 byte)
+{
+ int ret;
+
+ ret = ltc_wait_ready(client);
+ if (ret < 0)
+ return ret;
+
+ return pmbus_write_byte(client, page, byte);
+}
static inline int lin11_to_val(int data)
{
@@ -126,7 +208,7 @@ static int ltc_get_max(struct ltc2978_data *data, struct i2c_client *client,
{
int ret;
- ret = pmbus_read_word_data(client, page, reg);
+ ret = ltc_read_word_data(client, page, reg);
if (ret >= 0) {
if (lin11_to_val(ret) > lin11_to_val(*pmax))
*pmax = ret;
@@ -140,7 +222,7 @@ static int ltc_get_min(struct ltc2978_data *data, struct i2c_client *client,
{
int ret;
- ret = pmbus_read_word_data(client, page, reg);
+ ret = ltc_read_word_data(client, page, reg);
if (ret >= 0) {
if (lin11_to_val(ret) < lin11_to_val(*pmin))
*pmin = ret;
@@ -162,7 +244,7 @@ static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
&data->vin_max);
break;
case PMBUS_VIRT_READ_VOUT_MAX:
- ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK);
+ ret = ltc_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK);
if (ret >= 0) {
/*
* VOUT is 16 bit unsigned with fixed exponent,
@@ -184,6 +266,9 @@ static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
ret = 0;
break;
default:
+ ret = ltc_wait_ready(client);
+ if (ret < 0)
+ return ret;
ret = -ENODATA;
break;
}
@@ -202,7 +287,7 @@ static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
&data->vin_min);
break;
case PMBUS_VIRT_READ_VOUT_MIN:
- ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_MIN);
+ ret = ltc_read_word_data(client, page, LTC2978_MFR_VOUT_MIN);
if (ret >= 0) {
/*
* VOUT_MIN is known to not be supported on some lots
@@ -353,9 +438,9 @@ static int ltc2978_clear_peaks(struct ltc2978_data *data,
int ret;
if (has_clear_peaks(data))
- ret = pmbus_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
+ ret = ltc_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
else
- ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
+ ret = ltc_write_byte(client, page, PMBUS_CLEAR_FAULTS);
return ret;
}
@@ -403,6 +488,9 @@ static int ltc2978_write_word_data(struct i2c_client *client, int page,
ret = ltc2978_clear_peaks(data, client, page);
break;
default:
+ ret = ltc_wait_ready(client);
+ if (ret < 0)
+ return ret;
ret = -ENODATA;
break;
}
@@ -530,6 +618,9 @@ static int ltc2978_probe(struct i2c_client *client,
info = &data->info;
info->write_word_data = ltc2978_write_word_data;
+ info->write_byte = ltc_write_byte;
+ info->read_word_data = ltc_read_word_data;
+ info->read_byte_data = ltc_read_byte_data;
data->vin_min = 0x7bff;
data->vin_max = 0x7c00;
@@ -588,7 +679,7 @@ static int ltc2978_probe(struct i2c_client *client,
case ltc3880:
case ltc3887:
case ltm4676:
- data->features |= FEAT_CLEAR_PEAKS;
+ data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;
info->read_word_data = ltc3880_read_word_data;
info->pages = LTC3880_NUM_PAGES;
info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
@@ -603,7 +694,7 @@ static int ltc2978_probe(struct i2c_client *client,
| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
break;
case ltc3882:
- data->features |= FEAT_CLEAR_PEAKS;
+ data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;
info->read_word_data = ltc3880_read_word_data;
info->pages = LTC3880_NUM_PAGES;
info->func[0] = PMBUS_HAVE_VIN
@@ -618,7 +709,7 @@ static int ltc2978_probe(struct i2c_client *client,
| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
break;
case ltc3883:
- data->features |= FEAT_CLEAR_PEAKS;
+ data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;
info->read_word_data = ltc3883_read_word_data;
info->pages = LTC3883_NUM_PAGES;
info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
@@ -629,7 +720,7 @@ static int ltc2978_probe(struct i2c_client *client,
| PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
break;
case ltc3886:
- data->features |= FEAT_CLEAR_PEAKS;
+ data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;
info->read_word_data = ltc3883_read_word_data;
info->pages = LTC3880_NUM_PAGES;
info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
--
2.1.4
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