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Commit e04d1ce9 authored by Michael Jones's avatar Michael Jones Committed by Guenter Roeck
Browse files

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: default avatarMichael Jones <mike@proclivis.com>
[Guenter Roeck: simplifications and formatting changes]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent d830e27d

drivers/hwmon/pmbus/ltc2978.c

+101 −10
Original line number Original line Diff line number Diff line
@@ -3,6 +3,7 @@ 
 *

 *

 * Copyright (c) 2011 Ericsson AB.

 * Copyright (c) 2011 Ericsson AB.

 * Copyright (c) 2013, 2014, 2015 Guenter Roeck

 * Copyright (c) 2013, 2014, 2015 Guenter Roeck

 * Copyright (c) 2015 Linear Technology

 *

 *

 * This program is free software; you can redistribute it and/or modify

 * 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

 * it under the terms of the GNU General Public License as published by
@@ -15,6 +16,8 @@ 
 * GNU General Public License for more details.

 * GNU General Public License for more details.

 */

 */





#include <linux/delay.h>

#include <linux/jiffies.h>

#include <linux/kernel.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/module.h>

#include <linux/init.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_VIN_PEAK		0xde

#define LTC2978_MFR_TEMPERATURE_PEAK	0xdf

#define LTC2978_MFR_TEMPERATURE_PEAK	0xdf

#define LTC2978_MFR_SPECIAL_ID		0xe7	/* Undocumented on LTC3882 */

#define LTC2978_MFR_SPECIAL_ID		0xe7	/* Undocumented on LTC3882 */

#define LTC2978_MFR_COMMON		0xef





/* LTC2974, LTC2975, LCT2977, LTC2980, LTC2978, and LTM2987 */

/* LTC2974, LTC2975, LCT2977, LTC2980, LTC2978, and LTM2987 */

#define LTC2978_MFR_VOUT_MIN		0xfb

#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 LTC3880_NUM_PAGES		2

#define LTC3883_NUM_PAGES		1

#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

 * 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

 * 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 to_ltc2978_data(x)  container_of(x, struct ltc2978_data, info)





#define FEAT_CLEAR_PEAKS	BIT(0)

#define FEAT_CLEAR_PEAKS	BIT(0)

#define FEAT_NEEDS_POLLING	BIT(1)





#define has_clear_peaks(d)	((d)->features & FEAT_CLEAR_PEAKS)

#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)

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;

	int ret;





	ret = pmbus_read_word_data(client, page, reg);

	ret = ltc_read_word_data(client, page, reg);

	if (ret >= 0) {

	if (ret >= 0) {

		if (lin11_to_val(ret) > lin11_to_val(*pmax))

		if (lin11_to_val(ret) > lin11_to_val(*pmax))

			*pmax = ret;

			*pmax = ret;
@@ -140,7 +222,7 @@ static int ltc_get_min(struct ltc2978_data *data, struct i2c_client *client, 
{

{

	int ret;

	int ret;





	ret = pmbus_read_word_data(client, page, reg);

	ret = ltc_read_word_data(client, page, reg);

	if (ret >= 0) {

	if (ret >= 0) {

		if (lin11_to_val(ret) < lin11_to_val(*pmin))

		if (lin11_to_val(ret) < lin11_to_val(*pmin))

			*pmin = ret;

			*pmin = ret;
@@ -162,7 +244,7 @@ static int ltc2978_read_word_data_common(struct i2c_client *client, int page, 
				  &data->vin_max);

				  &data->vin_max);

		break;

		break;

	case PMBUS_VIRT_READ_VOUT_MAX:

	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) {

		if (ret >= 0) {

			/*

			/*

			 * VOUT is 16 bit unsigned with fixed exponent,

			 * 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;

		ret = 0;

		break;

		break;

	default:

	default:

		ret = ltc_wait_ready(client);

		if (ret < 0)

			return ret;

		ret = -ENODATA;

		ret = -ENODATA;

		break;

		break;

	}

	}
@@ -202,7 +287,7 @@ static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg) 
				  &data->vin_min);

				  &data->vin_min);

		break;

		break;

	case PMBUS_VIRT_READ_VOUT_MIN:

	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) {

		if (ret >= 0) {

			/*

			/*

			 * VOUT_MIN is known to not be supported on some lots

			 * 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;

	int ret;





	if (has_clear_peaks(data))

	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

	else

		ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);

		ret = ltc_write_byte(client, page, PMBUS_CLEAR_FAULTS);





	return ret;

	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);

		ret = ltc2978_clear_peaks(data, client, page);

		break;

		break;

	default:

	default:

		ret = ltc_wait_ready(client);

		if (ret < 0)

			return ret;

		ret = -ENODATA;

		ret = -ENODATA;

		break;

		break;

	}

	}
@@ -530,6 +618,9 @@ static int ltc2978_probe(struct i2c_client *client, 




	info = &data->info;

	info = &data->info;

	info->write_word_data = ltc2978_write_word_data;

	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_min = 0x7bff;

	data->vin_max = 0x7c00;

	data->vin_max = 0x7c00;
@@ -588,7 +679,7 @@ static int ltc2978_probe(struct i2c_client *client, 
	case ltc3880:

	case ltc3880:

	case ltc3887:

	case ltc3887:

	case ltm4676:

	case ltm4676:

		data->features |= FEAT_CLEAR_PEAKS;

		data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;

		info->read_word_data = ltc3880_read_word_data;

		info->read_word_data = ltc3880_read_word_data;

		info->pages = LTC3880_NUM_PAGES;

		info->pages = LTC3880_NUM_PAGES;

		info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN

		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;

		  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;

		break;

		break;

	case ltc3882:

	case ltc3882:

		data->features |= FEAT_CLEAR_PEAKS;

		data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;

		info->read_word_data = ltc3880_read_word_data;

		info->read_word_data = ltc3880_read_word_data;

		info->pages = LTC3880_NUM_PAGES;

		info->pages = LTC3880_NUM_PAGES;

		info->func[0] = PMBUS_HAVE_VIN

		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;

		  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;

		break;

		break;

	case ltc3883:

	case ltc3883:

		data->features |= FEAT_CLEAR_PEAKS;

		data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;

		info->read_word_data = ltc3883_read_word_data;

		info->read_word_data = ltc3883_read_word_data;

		info->pages = LTC3883_NUM_PAGES;

		info->pages = LTC3883_NUM_PAGES;

		info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN

		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;

		  | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;

		break;

		break;

	case ltc3886:

	case ltc3886:

		data->features |= FEAT_CLEAR_PEAKS;

		data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;

		info->read_word_data = ltc3883_read_word_data;

		info->read_word_data = ltc3883_read_word_data;

		info->pages = LTC3880_NUM_PAGES;

		info->pages = LTC3880_NUM_PAGES;

		info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN

		info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN