/*
* intel_mid_thermal.c - Intel MID platform thermal driver
*
* Copyright (C) 2011 Intel Corporation
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* 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
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Author: Durgadoss R <durgadoss.r@intel.com>
*/
#define pr_fmt(fmt) "intel_mid_thermal: " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/param.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/pm.h>
#include <linux/thermal.h>
#include <linux/mfd/intel_msic.h>
/* Number of thermal sensors */
#define MSIC_THERMAL_SENSORS 4
/* ADC1 - thermal registers */
#define MSIC_ADC_ENBL 0x10
#define MSIC_ADC_START 0x08
#define MSIC_ADCTHERM_ENBL 0x04
#define MSIC_ADCRRDATA_ENBL 0x05
#define MSIC_CHANL_MASK_VAL 0x0F
#define MSIC_STOPBIT_MASK 16
#define MSIC_ADCTHERM_MASK 4
/* Number of ADC channels */
#define ADC_CHANLS_MAX 15
#define ADC_LOOP_MAX (ADC_CHANLS_MAX - MSIC_THERMAL_SENSORS)
/* ADC channel code values */
#define SKIN_SENSOR0_CODE 0x08
#define SKIN_SENSOR1_CODE 0x09
#define SYS_SENSOR_CODE 0x0A
#define MSIC_DIE_SENSOR_CODE 0x03
#define SKIN_THERM_SENSOR0 0
#define SKIN_THERM_SENSOR1 1
#define SYS_THERM_SENSOR2 2
#define MSIC_DIE_THERM_SENSOR3 3
/* ADC code range */
#define ADC_MAX 977
#define ADC_MIN 162
#define ADC_VAL0C 887
#define ADC_VAL20C 720
#define ADC_VAL40C 508
#define ADC_VAL60C 315
/* ADC base addresses */
#define ADC_CHNL_START_ADDR INTEL_MSIC_ADC1ADDR0 /* increments by 1 */
#define ADC_DATA_START_ADDR INTEL_MSIC_ADC1SNS0H /* increments by 2 */
/* MSIC die attributes */
#define MSIC_DIE_ADC_MIN 488
#define MSIC_DIE_ADC_MAX 1004
/* This holds the address of the first free ADC channel,
* among the 15 channels
*/
static int channel_index;
struct platform_info {
struct platform_device *pdev;
struct thermal_zone_device *tzd[MSIC_THERMAL_SENSORS];
};
struct thermal_device_info {
unsigned int chnl_addr;
int direct;
/* This holds the current temperature in millidegree celsius */
long curr_temp;
};
/**
* to_msic_die_temp - converts adc_val to msic_die temperature
* @adc_val: ADC value to be converted
*
* Can sleep
*/
static int to_msic_die_temp(uint16_t adc_val)
{
return (368 * (adc_val) / 1000) - 220;
}
/**
* is_valid_adc - checks whether the adc code is within the defined range
* @min: minimum value for the sensor
* @max: maximum value for the sensor
*
* Can sleep
*/
static int is_valid_adc(uint16_t adc_val, uint16_t min, uint16_t max)
{
return (adc_val >= min) && (adc_val <= max);
}
/**
* adc_to_temp - converts the ADC code to temperature in C
* @direct: true if ths channel is direct index
* @adc_val: the adc_val that needs to be converted
* @tp: temperature return value
*
* Linear approximation is used to covert the skin adc value into temperature.
* This technique is used to avoid very long look-up table to get
* the appropriate temp value from ADC value.
* The adc code vs sensor temp curve is split into five parts
* to achieve very close approximate temp value with less than
* 0.5C error
*/
static int adc_to_temp(int direct, uint16_t adc_val, unsigned long *tp)
{
int temp;
/* Direct conversion for die temperature */
if (direct) {
if (is_valid_adc(adc_val, MSIC_DIE_ADC_MIN, MSIC_DIE_ADC_MAX)) {
*tp = to_msic_die_temp(adc_val) * 1000;
return 0;
}
return -ERANGE;
}
if (!is_valid_adc(adc_val, ADC_MIN, ADC_MAX))
return -ERANGE;
/* Linear approximation for skin temperature */
if (adc_val > ADC_VAL0C)
temp = 177 - (adc_val/5);
else if ((adc_val <= ADC_VAL0C) && (adc_val > ADC_VAL20C))
temp = 111 - (adc_val/8);
else if ((adc_val <= ADC_VAL20C) && (adc_val > ADC_VAL40C))
temp = 92 - (adc_val/10);
else if ((adc_val <= ADC_VAL40C) && (adc_val > ADC_VAL60C))
temp = 91 - (adc_val/10);
else
temp = 112 - (adc_val/6);
/* Convert temperature in celsius to milli degree celsius */
*tp = temp * 1000;
return 0;
}
/**
* mid_read_temp - read sensors for temperature
* @temp: holds the current temperature for the sensor after reading
*
* reads the adc_code from the channel and converts it to real
* temperature. The converted value is stored in temp.
*
* Can sleep
*/
static int mid_read_temp(struct thermal_zone_device *tzd, unsigned long *temp)
{
struct thermal_device_info *td_info = tzd->devdata;
uint16_t adc_val, addr;
uint8_t data = 0;
int ret;
unsigned long curr_temp;
addr = td_info->chnl_addr;
/* Enable the msic for conversion before reading */
ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, MSIC_ADCRRDATA_ENBL);
if (ret)
return ret;
/* Re-toggle the RRDATARD bit (temporary workaround) */
ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, MSIC_ADCTHERM_ENBL);
if (ret)
return ret;
/* Read the higher bits of data */
ret = intel_msic_reg_read(addr, &data);
if (ret)
return ret;
/* Shift bits to accommodate the lower two data bits */
adc_val = (data << 2);
addr++;
ret = intel_msic_reg_read(addr, &data);/* Read lower bits */
if (ret)
return ret;
/* Adding lower two bits to the higher bits */
data &= 03;
adc_val += data;
/* Convert ADC value to temperature */
ret = adc_to_temp(td_info->direct, adc_val, &curr_temp);
if (ret == 0)
*temp = td_info->curr_temp = curr_temp;
return ret;
}
/**
* configure_adc - enables/disables the ADC for conversion
* @val: zero: disables the ADC non-zero:enables the ADC
*
* Enable/Disable the ADC depending on the argument
*
* Can sleep
*/
static int configure_adc(int val)
{
int ret;
uint8_t data;
ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL1, &data);
if (ret)
return ret;
if (val) {
/* Enable and start the ADC */
data |= (MSIC_ADC_ENBL | MSIC_ADC_START);
} else {
/* Just stop the ADC */
data &= (~MSIC_ADC_START);
}
return intel_msic_reg_write(INTEL_MSIC_ADC1CNTL1, data);
}
/**
* set_up_therm_channel - enable thermal channel for conversion
* @base_addr: index of free msic ADC channel
*
* Enable all the three channels for conversion
*
* Can sleep
*/
static int set_up_therm_channel(u16 base_addr)
{
int ret;
/* Enable all the sensor channels */
ret = intel_msic_reg_write(base_addr, SKIN_SENSOR0_CODE);
if (ret)
return ret;
ret = intel_msic_reg_write(base_addr + 1, SKIN_SENSOR1_CODE);
if (ret)
return ret;
ret = intel_msic_reg_write(base_addr + 2, SYS_SENSOR_CODE);
if (ret)
return ret;
/* Since this is the last channel, set the stop bit
* to 1 by ORing the DIE_SENSOR_CODE with 0x10 */
ret = intel_msic_reg_write(base_addr + 3,
(MSIC_DIE_SENSOR_CODE | 0x10));
if (ret)
return ret;
/* Enable ADC and start it */
return configure_adc(1);
}
/**
* reset_stopbit - sets the stop bit to 0 on the given channel
* @addr: address of the channel
*
* Can sleep
*/
static int reset_stopbit(uint16_t addr)
{
int ret;
uint8_t data;
ret = intel_msic_reg_read(addr, &data);
if (ret)
return ret;
/* Set the stop bit to zero */
return intel_msic_reg_write(addr, (data & 0xEF));
}
/**
* find_free_channel - finds an empty channel for conversion
*
* If the ADC is not enabled then start using 0th channel
* itself. Otherwise find an empty channel by looking for a
* channel in which the stopbit is set to 1. returns the index
* of the first free channel if succeeds or an error code.
*
* Context: can sleep
*
* FIXME: Ultimately the channel allocator will move into the intel_scu_ipc
* code.
*/
static int find_free_channel(void)
{
int ret;
int i;
uint8_t data;
/* check whether ADC is enabled */
ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL1, &data);
if (ret)
return ret;
if ((data & MSIC_ADC_ENBL) == 0)
return 0;
/* ADC is already enabled; Looking for an empty channel */
for (i = 0; i < ADC_CHANLS_MAX; i++) {
ret = intel_msic_reg_read(ADC_CHNL_START_ADDR + i, &data);
if (ret)
return ret;
if (data & MSIC_STOPBIT_MASK) {
ret = i;
break;
}
}
return (ret > ADC_LOOP_MAX) ? (-EINVAL) : ret;
}
/**
* mid_initialize_adc - initializing the ADC
* @dev: our device structure
*
* Initialize the ADC for reading thermistor values. Can sleep.
*/
static int mid_initialize_adc(struct device *dev)
{
u8 data;
u16 base_addr;
int ret;
/*
* Ensure that adctherm is disabled before we
* initialize the ADC
*/
ret = intel_msic_reg_read(INTEL_MSIC_ADC1CNTL3, &data);
if (ret)
return ret;
data &= ~MSIC_ADCTHERM_MASK;
ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, data);
if (ret)
return ret;
/* Index of the first channel in which the stop bit is set */
channel_index = find_free_channel();
if (channel_index < 0) {
dev_err(dev, "No free ADC channels");
return channel_index;
}
base_addr = ADC_CHNL_START_ADDR + channel_index;
if (!(channel_index == 0 || channel_index == ADC_LOOP_MAX)) {
/* Reset stop bit for channels other than 0 and 12 */
ret = reset_stopbit(base_addr);
if (ret)
return ret;
/* Index of the first free channel */
base_addr++;
channel_index++;
}
ret = set_up_therm_channel(base_addr);
if (ret) {
dev_err(dev, "unable to enable ADC");
return ret;
}
dev_dbg(dev, "ADC initialization successful");
return ret;
}
/**
* initialize_sensor - sets default temp and timer ranges
* @index: index of the sensor
*
* Context: can sleep
*/
static struct thermal_device_info *initialize_sensor(int index)
{
struct thermal_device_info *td_info =
kzalloc(sizeof(struct thermal_device_info), GFP_KERNEL);
if (!td_info)
return NULL;
/* Set the base addr of the channel for this sensor */
td_info->chnl_addr = ADC_DATA_START_ADDR + 2 * (channel_index + index);
/* Sensor 3 is direct conversion */
if (index == 3)
td_info->direct = 1;
return td_info;
}
/**
* mid_thermal_resume - resume routine
* @dev: device structure
*
* mid thermal resume: re-initializes the adc. Can sleep.
*/
static int mid_thermal_resume(struct device *dev)
{
return mid_initialize_adc(dev);
}
/**
* mid_thermal_suspend - suspend routine
* @dev: device structure
*
* mid thermal suspend implements the suspend functionality
* by stopping the ADC. Can sleep.
*/
static int mid_thermal_suspend(struct device *dev)
{
/*
* This just stops the ADC and does not disable it.
* temporary workaround until we have a generic ADC driver.
* If 0 is passed, it disables the ADC.
*/
return configure_adc(0);
}
static SIMPLE_DEV_PM_OPS(mid_thermal_pm,
mid_thermal_suspend, mid_thermal_resume);
/**
* read_curr_temp - reads the current temperature and stores in temp
* @temp: holds the current temperature value after reading
*
* Can sleep
*/
static int read_curr_temp(struct thermal_zone_device *tzd, unsigned long *temp)
{
WARN_ON(tzd == NULL);
return mid_read_temp(tzd, temp);
}
/* Can't be const */
static struct thermal_zone_device_ops tzd_ops = {
.get_temp = read_curr_temp,
};
/**
* mid_thermal_probe - mfld thermal initialize
* @pdev: platform device structure
*
* mid thermal probe initializes the hardware and registers
* all the sensors with the generic thermal framework. Can sleep.
*/
static int mid_thermal_probe(struct platform_device *pdev)
{
static char *name[MSIC_THERMAL_SENSORS] = {
"skin0", "skin1", "sys", "msicdie"
};
int ret;
int i;
struct platform_info *pinfo;
pinfo = kzalloc(sizeof(struct platform_info), GFP_KERNEL);
if (!pinfo)
return -ENOMEM;
/* Initializing the hardware */
ret = mid_initialize_adc(&pdev->dev);
if (ret) {
dev_err(&pdev->dev, "ADC init failed");
kfree(pinfo);
return ret;
}
/* Register each sensor with the generic thermal framework*/
for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
struct thermal_device_info *td_info = initialize_sensor(i);
if (!td_info) {
ret = -ENOMEM;
goto err;
}
pinfo->tzd[i] = thermal_zone_device_register(name[i],
0, 0, td_info, &tzd_ops, NULL, 0, 0);
if (IS_ERR(pinfo->tzd[i])) {
kfree(td_info);
ret = PTR_ERR(pinfo->tzd[i]);
goto err;
}
}
pinfo->pdev = pdev;
platform_set_drvdata(pdev, pinfo);
return 0;
err:
while (--i >= 0) {
kfree(pinfo->tzd[i]->devdata);
thermal_zone_device_unregister(pinfo->tzd[i]);
}
configure_adc(0);
kfree(pinfo);
return ret;
}
/**
* mid_thermal_remove - mfld thermal finalize
* @dev: platform device structure
*
* MLFD thermal remove unregisters all the sensors from the generic
* thermal framework. Can sleep.
*/
static int mid_thermal_remove(struct platform_device *pdev)
{
int i;
struct platform_info *pinfo = platform_get_drvdata(pdev);
for (i = 0; i < MSIC_THERMAL_SENSORS; i++) {
kfree(pinfo->tzd[i]->devdata);
thermal_zone_device_unregister(pinfo->tzd[i]);
}
kfree(pinfo);
/* Stop the ADC */
return configure_adc(0);
}
#define DRIVER_NAME "msic_thermal"
static const struct platform_device_id therm_id_table[] = {
{ DRIVER_NAME, 1 },
{ "msic_thermal", 1 },
{ }
};
static struct platform_driver mid_thermal_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.pm = &mid_thermal_pm,
},
.probe = mid_thermal_probe,
.remove = mid_thermal_remove,
.id_table = therm_id_table,
};
module_platform_driver(mid_thermal_driver);
MODULE_AUTHOR("Durgadoss R <durgadoss.r@intel.com>");
MODULE_DESCRIPTION("Intel Medfield Platform Thermal Driver");
MODULE_LICENSE("GPL");