From e04d1ce9bbb49862fd8266da764f5ebf67baaac0 Mon Sep 17 00:00:00 2001 From: Michael Jones Date: Mon, 17 Aug 2015 17:45:32 -0700 Subject: [PATCH] hwmon: (ltc2978) Add polling for chips requiring it 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 [Guenter Roeck: simplifications and formatting changes] Signed-off-by: Guenter Roeck --- 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 +#include #include #include #include @@ -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