Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932521Ab1EZORn (ORCPT ); Thu, 26 May 2011 10:17:43 -0400 Received: from imr4.ericy.com ([198.24.6.8]:41318 "EHLO imr4.ericy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932372Ab1EZORm (ORCPT ); Thu, 26 May 2011 10:17:42 -0400 Date: Thu, 26 May 2011 07:16:52 -0700 From: Guenter Roeck To: Ashish Jangam CC: Randy Dunlap , Dajun Chen , "linux-kernel@vger.kernel.org" , "lm-sensors@lm-sensors.org" Subject: Re: [PATCHv3 6/11] HWMON: Support of fixed point conversion for bat temperature Message-ID: <20110526141652.GA29634@ericsson.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 19114 Lines: 551 On Thu, May 26, 2011 at 08:19:12AM -0400, Ashish Jangam wrote: > Hi Guenter, > > Existing fixed point conversion logic is modified to support battery temperature. This modified logic was compiled, linked & tested successfully. > > Signed-off-by: Ashish Jangam > Signed-off-by: David Dajun Chen > -- > diff --git a/Documentation/hwmon/da9052 b/Documentation/hwmon/da9052 > new file mode 100755 > index 0000000..aab7318 > --- /dev/null > +++ b/Documentation/hwmon/da9052 > @@ -0,0 +1,61 @@ > +Kernel driver da9052-hwmon > +========================== > + > +Supported chips: > + * Dialog Semiconductors DA9052 PMICs > + Prefix: 'da9052' > + Datasheet: Kindly visit www.dialog-semiconductor.com and request for the > + official datasheet. > + > +Authors: David Dajun Chen > + > +Description > +----------- > + > +The DA9052 provides an Analogue to Digital Converter (ADC) with 10 bits > +resolution and track and hold circuitry combined with an analogue input > +multiplexer. The analogue input multiplexer will allow conversion of up to 10 > +different inputs. The track and hold circuit ensures stable input voltages at > +the input of the ADC during the conversion. > + > +The ADC is used to measure the following inputs: > +Channel 0: VDDOUT - measurement of the system voltage > +Channel 1: ICH - internal battery charger current measurement > +Channel 2: TBAT - output from the battery NTC > +Channel 3: VBAT - measurement of the battery voltage > +Channel 4: ADC_IN4 - high impedance input (0 - 2.5V) > +Channel 5: ADC_IN5 - high impedance input (0 - 2.5V) > +Channel 6: ADC_IN6 - high impedance input (0 - 2.5V) > +Channel 7: XY - TSI interface to measure the X and Y voltage of the touch > +screen resistive potentiometers > +Channel 8: Internal Tjunc. - sense (internal temp. sensor) > +Channel 9: VBBAT - measurement of the backup battery voltage > + > +By using sysfs attributes we can measure the system voltage VDDOUT, the battery > +charging current ICH, battery temperature TBAT, battery junction temperature > +TJUNC, battery voltage VBAT and the back up battery voltage VBBAT. > + > +Voltage Monitoring > +------------------ > + > +Voltages are sampled by a 10 bit ADC. Voltages in millivolts are 1.465 > +times the ADC value. > + > +Temperature Monitoring > +---------------------- > + > +Temperatures are sampled by a 10 bit ADC. Junction and battery temperatures > +are monitored by the ADC channels. > + > +The junction temperature is calculated: > + Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8 > +The junction temperature attribute is supported by the driver. > + > +The battery temperature is calculated: > + Degree Celcius = 1 / (t1 + 1/298)- 273 > +where t1 = (1/B)* ln(( ADCval * 2.5)/(R25*ITBAT*255)) > +Default values of R25, B, ITBAT are 10e3, 3380 and 50e-6 respectively. > +As the battery temperature computation depends on floating point > +computation and taking natural log the battery temperature attribute is > +not supported by the driver. > + The last three lines no longer apply. > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 3236a45..da5ff6d 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -303,6 +303,16 @@ config SENSORS_DS1621 > This driver can also be built as a module. If so, the module > will be called ds1621. > > +config SENSORS_DA9052_ADC > + tristate "Dialog DA9052 HWMON" > + depends on PMIC_DA9052 > + help > + Say y here to support the ADC found on > + Dialog Semiconductor DA9052 PMIC. > + > + This driver can also be built as module. If so, the module > + will be called da9052-hwmon. > + > config SENSORS_I5K_AMB > tristate "FB-DIMM AMB temperature sensor on Intel 5000 series chipsets" > depends on PCI && EXPERIMENTAL > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index f7c0c28..88b81ca 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -42,6 +42,7 @@ obj-$(CONFIG_SENSORS_ASC7621) += asc7621.o > obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o > obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o > obj-$(CONFIG_SENSORS_PKGTEMP) += pkgtemp.o > +obj-$(CONFIG_SENSORS_DA9052_ADC) += da9052-hwmon.o > obj-$(CONFIG_SENSORS_DME1737) += dme1737.o > obj-$(CONFIG_SENSORS_DS620) += ds620.o > obj-$(CONFIG_SENSORS_DS1621) += ds1621.o > diff --git a/drivers/hwmon/da9052-hwmon.c b/drivers/hwmon/da9052-hwmon.c > new file mode 100755 > index 0000000..f961d0b > --- /dev/null > +++ b/drivers/hwmon/da9052-hwmon.c > @@ -0,0 +1,379 @@ > +/* > + * HWMON Driver for Dialog DA9052 > + * > + * Copyright(c) 2011 Dialog Semiconductor Ltd. > + * > + * Author: David Dajun Chen > + * > + * 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; either version 2 of the License, or (at your > + * option) any later version. > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct da9052_hwmon { > + struct da9052 *da9052; > + struct device *class_device; > + struct mutex hwmon_lock; > +}; > +static const char * const input_names[] = { > + [DA9052_ADC_VDDOUT] = "VDDOUT", > + [DA9052_ADC_ICH] = "CHARGING CURRENT", > + [DA9052_ADC_TBAT] = "BATTERY TEMP", > + [DA9052_ADC_VBAT] = "BATTERY VOLTAGE", > + [DA9052_ADC_IN4] = "ADC IN4", > + [DA9052_ADC_IN5] = "ADC IN5", > + [DA9052_ADC_IN6] = "ADC IN6", > + [DA9052_ADC_TJUNC] = "BATTERY JUNCTION TEMP", > + [DA9052_ADC_VBBAT] = "BACK-UP BATTERY VOLTAGE", > +}; > + > +static int da9052_enable_vddout_channel(struct da9052 *da9052) > +{ > + int ret; > + > + ret = da9052_reg_read(da9052, DA9052_ADC_CONT_REG); > + if (ret < 0) > + return ret; > + > + ret |= DA9052_ADCCONT_AUTOVDDEN; > + return da9052_reg_write(da9052, DA9052_ADC_CONT_REG, ret); > +} > + > +static int da9052_disable_vddout_channel(struct da9052 *da9052) > +{ > + int ret; > + > + ret = da9052_reg_read(da9052, DA9052_ADC_CONT_REG); > + if (ret < 0) > + return ret; > + > + ret &= ~DA9052_ADCCONT_AUTOVDDEN; > + return da9052_reg_write(da9052, DA9052_ADC_CONT_REG, ret); > + > +} > + > +static ssize_t da9052_read_vddout(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + struct da9052_hwmon *hwmon = dev_get_drvdata(dev); > + int ret; > + int vdd = -1; > + > + mutex_lock(&hwmon->hwmon_lock); > + > + ret = da9052_enable_vddout_channel(hwmon->da9052); > + if (ret < 0) > + goto hwmon_err; > + > + ret = da9052_reg_read(hwmon->da9052, DA9052_VDD_RES_REG); > + if (ret < 0) > + pr_err("failed to read VDD_RES_REG\n"); > + else > + vdd = ret; > + This is a bit misleading, and wrong. There are other cases where you don't actually read VDD (if you fail to enable the channel), but then you actually return an error. I think you should just go with if (ret < 0) goto hwmon_err; vdd = ret; and, if you really want to be noisy, add the pr_err() into the error path. > + ret = da9052_disable_vddout_channel(hwmon->da9052); > + if (ret < 0) > + goto hwmon_err; > + > + if (vdd) { > + mutex_unlock(&hwmon->hwmon_lock); > + return sprintf(buf, "%d\n", vdd); > + } No good. You end up returning 0 (because ret == 0), ie no error, but don't display a value. You would have to set ret = -ESOMETHING here. But is VDD==0 really an error, or does it just mean that the voltage is zero ? > +hwmon_err: > + mutex_unlock(&hwmon->hwmon_lock); > + return ret; > +} > + > +static ssize_t da9052_read_ich(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + struct da9052_hwmon *hwmon = dev_get_drvdata(dev); > + int ret; > + > + ret = da9052_reg_read(hwmon->da9052, DA9052_ICHG_AV_REG); > + if (ret < 0) > + return ret; > + > + /* Equivalent to 3.9mA/bit in register ICHG_AV */ > + ret = DIV_ROUND_CLOSEST(ret * 39, 10); > + return sprintf(buf, "%d\n", ret); > +} > + > +#define BCONST 3 > +#define TBAT 3355705 > +#define CAL_LOG2(nr) ((int)((ilog2(nr) - ilog2(100)) * 693147181LL)) > +/* > + The battery temperature is calculated: > + Degree Celcius = 1 / (t1 + 1/298)- 273 > + where t1 = (1/B)* ln((ADCval * 2.5)/(R25*ITBAT*255)) > + And R25 = 10e3, B = 3380 and ITBAT = 50e-6 > +*/ Please use /* * */ for multi-line comments. > +static int cal_temperature(int adc_val) > +{ > + > + int log_val; > + unsigned int temp, deg_celcius; > + > + /* Formula 2.5/(R25*ITBAT*255) gets reduced to 0.02 > + Convert float value to fixed point using a multiplier */ > + log_val = adc_val * 2; > + > + temp = BCONST * (CAL_LOG2(log_val) * 10000) + TBAT; This doesn't look good. As written, CAL_LOG2 together with the additional multiplication by 10,000 and by 3 must result in an integer overflow. 693,147,181 * 10,000 * 3 = 20,794,415,430,000 which is way too large for an int. > + > + /* ln(x) = log2(x) * ln(2) = log2(x) * 0.693147181 > + log2(float) is converted to fixed point as log2(nr) - log2(dr) */ Please use /* * */ for multi-line comments. > + deg_celcius = ((1000000000/temp) - 273); > + > + /* Battery temperature in degree celcius */ > + return deg_celcius; > +} > + > +static ssize_t da9052_read_tbat(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + struct da9052_hwmon *hwmon = dev_get_drvdata(dev); > + int ret; > + int tbat; > + > + ret = da9052_reg_read(hwmon->da9052, DA9052_TBAT_RES_REG); > + if (ret < 0) > + return ret; > + > + tbat = cal_temperature(ret); > + > + return sprintf(buf, "%d\n", (tbat*1000)); > +} > + > +static ssize_t da9052_read_vbat(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + struct da9052_hwmon *hwmon = dev_get_drvdata(dev); > + int ret; > + > + ret = da9052_adc_manual_read(hwmon->da9052, DA9052_ADC_VBAT); > + if (ret < 0) > + return ret; > + > + return sprintf(buf, "%d\n", ret); > +} > + > +static ssize_t da9052_read_misc_channel(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + struct da9052_hwmon *hwmon = dev_get_drvdata(dev); > + int channel = to_sensor_dev_attr(devattr)->index; > + int ret; > + > + ret = da9052_adc_manual_read(hwmon->da9052, channel); > + if (ret < 0) > + return ret; > + > + return sprintf(buf, "%d\n", ret); > +} > + > +static ssize_t da9052_read_tjunc(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + struct da9052_hwmon *hwmon = dev_get_drvdata(dev); > + int temp; > + int ret; > + > + ret = da9052_reg_read(hwmon->da9052, DA9052_TJUNC_RES_REG); > + if (ret < 0) > + return ret; > + > + temp = ret; > + > + ret = da9052_reg_read(hwmon->da9052, DA9052_T_OFFSET_REG); > + if (ret < 0) > + return ret; > + > + /* Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8 */ > + ret = 1708 * (temp - ret) - 108800; > + return sprintf(buf, "%d\n", ret); > +} > + > +static ssize_t da9052_read_vbbat(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + struct da9052_hwmon *hwmon = dev_get_drvdata(dev); > + int ret; > + > + ret = da9052_adc_manual_read(hwmon->da9052, DA9052_ADC_VBBAT); > + if (ret < 0) > + return ret; > + > + return sprintf(buf, "%d\n", ret); > + > +} > + > +static ssize_t da9052_hwmon_show_name(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + return sprintf(buf, "da9052-hwmon\n"); > +} > + > +static ssize_t show_label(struct device *dev, > + struct device_attribute *devattr, char *buf) > +{ > + return sprintf(buf, "%s\n", > + input_names[to_sensor_dev_attr(devattr)->index]); > +} > + > +static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, da9052_read_vddout, NULL, > + DA9052_ADC_ICH); > +static SENSOR_DEVICE_ATTR(in0_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_ICH); > +static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, da9052_read_vbat, NULL, > + DA9052_ADC_VBAT); > +static SENSOR_DEVICE_ATTR(in3_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_VBAT); > +static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, da9052_read_misc_channel, NULL, > + DA9052_ADC_IN4); > +static SENSOR_DEVICE_ATTR(in4_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_IN4); > +static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, da9052_read_misc_channel, NULL, > + DA9052_ADC_IN5); > +static SENSOR_DEVICE_ATTR(in5_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_IN5); > +static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, da9052_read_misc_channel, NULL, > + DA9052_ADC_IN6); > +static SENSOR_DEVICE_ATTR(in6_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_IN6); > +static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, da9052_read_vbbat, NULL, > + DA9052_ADC_VBBAT); > +static SENSOR_DEVICE_ATTR(in9_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_VBBAT); > +static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, da9052_read_ich, NULL, > + DA9052_ADC_ICH); > +static SENSOR_DEVICE_ATTR(curr1_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_ICH); > + > +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, da9052_read_tbat, NULL, > + DA9052_ADC_TBAT); > +static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_TBAT); > + > +static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, da9052_read_tjunc, NULL, > + DA9052_ADC_TJUNC); > +static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, show_label, NULL, > + DA9052_ADC_TJUNC); > + > +static DEVICE_ATTR(name, S_IRUGO, da9052_hwmon_show_name, NULL); > + > +static struct attribute *da9052_attr[] = { > + &dev_attr_name.attr, > + > + &sensor_dev_attr_in0_input.dev_attr.attr, > + &sensor_dev_attr_in0_label.dev_attr.attr, > + &sensor_dev_attr_curr1_input.dev_attr.attr, > + &sensor_dev_attr_curr1_label.dev_attr.attr, > + &sensor_dev_attr_temp1_input.dev_attr.attr, > + &sensor_dev_attr_temp1_label.dev_attr.attr, > + &sensor_dev_attr_in3_input.dev_attr.attr, > + &sensor_dev_attr_in3_label.dev_attr.attr, > + &sensor_dev_attr_in4_input.dev_attr.attr, > + &sensor_dev_attr_in4_label.dev_attr.attr, > + &sensor_dev_attr_in5_input.dev_attr.attr, > + &sensor_dev_attr_in5_label.dev_attr.attr, > + &sensor_dev_attr_in6_input.dev_attr.attr, > + &sensor_dev_attr_in6_label.dev_attr.attr, > + &sensor_dev_attr_temp1_input.dev_attr.attr, > + &sensor_dev_attr_temp1_label.dev_attr.attr, > + &sensor_dev_attr_temp2_input.dev_attr.attr, > + &sensor_dev_attr_temp2_label.dev_attr.attr, > + &sensor_dev_attr_in9_input.dev_attr.attr, > + &sensor_dev_attr_in9_label.dev_attr.attr, > + NULL > +}; > + > +static const struct attribute_group da9052_attr_group = {.attrs = da9052_attr}; > + > +static int __init da9052_hwmon_probe(struct platform_device *pdev) > +{ > + struct da9052_hwmon *hwmon; > + int ret; > + > + hwmon = kzalloc(sizeof(struct da9052_hwmon), GFP_KERNEL); > + if (!hwmon) > + return -ENOMEM; > + > + mutex_init(&hwmon->hwmon_lock); > + hwmon->da9052 = dev_get_drvdata(pdev->dev.parent); > + > + platform_set_drvdata(pdev, hwmon); > + > + ret = sysfs_create_group(&pdev->dev.kobj, &da9052_attr_group); > + if (ret) > + goto err_mem; > + > + hwmon->class_device = hwmon_device_register(&pdev->dev); > + if (IS_ERR(hwmon->class_device)) { > + ret = PTR_ERR(hwmon->class_device); > + sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group); > + goto err_mem; usually you would do ret = PTR_ERR(hwmon->class_device); goto err_sysfs; > + } > + > + return 0; > + and: err_sysfs: sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group); > +err_mem: > + kfree(hwmon); > + return ret; > +} > + > +static int __devexit da9052_hwmon_remove(struct platform_device *pdev) > +{ > + struct da9052_hwmon *hwmon = platform_get_drvdata(pdev); > + > + hwmon_device_unregister(hwmon->class_device); > + sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group); > + mutex_destroy(&hwmon->hwmon_lock); > + kfree(hwmon); > + > + return 0; > +} > + > +static struct platform_driver da9052_hwmon_driver = { > + .driver = { > + .name = "da9052-hwmon", > + .owner = THIS_MODULE, > + }, > + .probe = da9052_hwmon_probe, > + .remove = __devexit_p(da9052_hwmon_remove), > + > +}; > + > +static int __init da9052_hwmon_init(void) > +{ > + > + return platform_driver_register(&da9052_hwmon_driver); > +} > +module_init(da9052_hwmon_init); > + > +static void __exit da9052_hwmon_exit(void) > +{ > + platform_driver_unregister(&da9052_hwmon_driver); > +} > +module_exit(da9052_hwmon_exit); > + > +MODULE_AUTHOR("David Dajun Chen "); > +MODULE_DESCRIPTION("DA9052 HWMON driver"); > +MODULE_LICENSE("GPL v2"); > +MODULE_ALIAS("platform:da9052-hwmon"); > > > Regards, > Ashish > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/