Re: [PATCH 02/07] HWMON: DA9052/53 hwmon driver v1

From: Guenter Roeck
Date: Mon Feb 06 2012 - 12:55:33 EST

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In reply to: Ashish Jangam: "[PATCH 02/07] HWMON: DA9052/53 hwmon driver v1"
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On Mon, 2012-02-06 at 07:39 -0500, Ashish Jangam wrote:
> The DA9052 PMIC provides an Analogue to Digital Converter with 10 bits
> resolution and 10 channels.
>
> This patch montiors the DA9052 PMIC's ADC channels mostly for battery
> parameters like battery temperature, junction temperature, battery
> current etc.
>
> This patch is functionally tested on Samsung SMDKV6410.
>
Hi Ashish,

Looks pretty good. Couple of comments below.

> Signed-off-by: David Dajun Chen <dchen@xxxxxxxxxxx>
> Signed-off-by: Ashish Jangam <ashish.jangam@xxxxxxxxxxxxxxx>
> ---
> Documentation/hwmon/da9052 | 59 +++++++
> drivers/hwmon/Kconfig | 10 ++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/da9052-hwmon.c | 343 ++++++++++++++++++++++++++++++++++++++++++

Can you consider adding yourself or David as maintainer ? Not a must,
but no one else would really be able to support the driver.

> 4 files changed, 413 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/hwmon/da9052
> create mode 100644 drivers/hwmon/da9052-hwmon.c
> diff --git a/Documentation/hwmon/da9052 b/Documentation/hwmon/da9052
> new file mode 100644
> index 0000000..3035bae
> --- /dev/null
> +++ b/Documentation/hwmon/da9052
> @@ -0,0 +1,59 @@
> +Supported chips:
> + * Dialog Semiconductors DA9052-BC and DA9053-AA/Bx PMICs
> + Prefix: 'da9052'
> + Datasheet: Kindly visit www.dialog-semiconductor.com and request for the
> + official datasheet.
> +
Maybe, but that doesn't seem to be straightforward. The web site has no
search field, and I am not sure who to contact in the contact list. And
since there does not seem to be support in the US, I am not sure if one
is expected to contact someone in Europe or Taiwan or some other place.

Maybe you can let me know how exactly to get the datasheets - I like to
keep those around for chips we are supporting.

Just saying ... for now I gave up trying, meaning some my feedback is
guesswork and may be wrong.

> +Authors: David Dajun Chen <dchen@xxxxxxxxxxx>
> +
> +Description
> +-----------
> +
> +The DA9052/53 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.

ERROR: trailing whitespace
#121: FILE: Documentation/hwmon/da9052:38:
+Voltages are sampled by a 10 bit ADC. $

> +
> +The battery voltage is calculated as:
> + Milli volt = ((ADC value * 1000) / 512) + 2500
> +
> +The voltages on ADC channels 4, 5 and 6 are calculated as:
> + Milli volt = (ADC value * 2500) / 1023
> +
> +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.
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 24d584a..a35d914 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -313,6 +313,16 @@ 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/DA9053 HWMON"

"HWMON" is a bit redundant here. Should probably be "ADC".

> + depends on PMIC_DA9052
> + help
> + Say y here to support the ADC found on Dialog Semiconductor
> + DA9052-BC and DA9053-AA/Bx PMICs.
> +
> + This driver can also be built as module. If so, the module
> + will be called da9052-hwmon.
> +
> config SENSORS_EXYNOS4_TMU
> tristate "Temperature sensor on Samsung EXYNOS4"
> depends on ARCH_EXYNOS4
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 8251ce8..5fe96e5 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -42,6 +42,7 @@ obj-$(CONFIG_SENSORS_APPLESMC) += applesmc.o
> obj-$(CONFIG_SENSORS_ASC7621) += asc7621.o
> obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o
> obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.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 100644
> index 0000000..d83f988
> --- /dev/null
> +++ b/drivers/hwmon/da9052-hwmon.c
> @@ -0,0 +1,343 @@
> +/*
> + * HWMON Driver for Dialog DA9052
> + *
> + * Copyright(c) 2012 Dialog Semiconductor Ltd.
> + *
> + * Author: David Dajun Chen <dchen@xxxxxxxxxxx>
> + *
> + * 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 <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/mfd/da9052/da9052.h>
> +#include <linux/mfd/da9052/reg.h>
> +
> +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 inline int volt_reg_to_mV(int value)
> +{
> + return ((value * 1000) / 512) + 2500;
> +}
> +
> +static inline int input_volt_to_mV(int value)
> +{
> + return (value * 2500) / 1023;
> +}
> +
> +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, vdd;
> +
> + mutex_lock(&hwmon->hwmon_lock);
> +
> + ret = da9052_enable_vddout_channel(hwmon->da9052);
> + if (ret < 0)
> + goto hwmon_err;
> +
> + vdd = da9052_reg_read(hwmon->da9052, DA9052_VDD_RES_REG);
> + if (vdd < 0) {
> + ret = vdd;
> + goto hwmon_err_release;
> + }
> +
> + ret = da9052_disable_vddout_channel(hwmon->da9052);
> + if (ret < 0)
> + goto hwmon_err;
> +
> + mutex_unlock(&hwmon->hwmon_lock);
> + vdd = volt_reg_to_mV(vdd);
> + return sprintf(buf, "%d\n", vdd);
> +
return sprintf(buf, "%d\n", volt_reg_to_mV(vdd));

would be a bit simpler. Same for similar code below.

> +hwmon_err_release:
> + da9052_disable_vddout_channel(hwmon->da9052);
> +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 */
> + return sprintf(buf, "%d\n", DIV_ROUND_CLOSEST(ret * 39, 10));
> +}
> +
> +static ssize_t da9052_read_tbat(struct device *dev,
> + struct device_attribute *devattr, char *buf)
> +{
> + struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
> +
> + return sprintf(buf, "%d\n", da9052_adc_read_temp(hwmon->da9052));
> +}
> +
> +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;
> +
> + ret = volt_reg_to_mV(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;
> + if (ret)
> + ret = input_volt_to_mV(ret);

That is just an unnecessary optimization. input_volt_to_mV() returns 0
if 0 is passed to it.

> +
> + 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 tjunc, toffset, result;
> +
> + tjunc = da9052_reg_read(hwmon->da9052, DA9052_TJUNC_RES_REG);
> + if (tjunc < 0)
> + return tjunc;
> +
> + toffset = da9052_reg_read(hwmon->da9052, DA9052_T_OFFSET_REG);
> + if (toffset < 0)
> + return toffset;
> +
> + if ((tjunc - toffset) == 0)

Unnecessary ( )

> + result = 0;
> + else
> + /* Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8 */
> + result = 1708 * (tjunc - toffset) - 108800;
> +

Hmm.
tjunc = 1, toffset = 2:
return 1708 * (-1) - 108800 = -108800 - 1708 = -110508
tjunc = 2, toffset = 2:
return 0
tjunc = 3, toffset = 2:
return 1780 * 1 - 108800 = -108800 + 1708 = -107092

I am not saying this is wrong, not having access to the data sheet, but
it is a bit odd. Why is the 0-difference case handled differently, and
why does it return 0 and not, say, -108800 ?

If tjunc - toffset < 0 is invalid (no idea if it is, of course), it
might make sense to detect that condition.

> + return sprintf(buf, "%d\n", result);
> +}
> +
> +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);

No conversion needed here ?

> +}
> +
> +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_VDDOUT);
> +static SENSOR_DEVICE_ATTR(in0_label, S_IRUGO, show_label, NULL,
> + DA9052_ADC_VDDOUT);
> +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);
> +

Since voltages and current follow the sensor index, it might make sense
to do the same with temperatures, ie use temp2 and temp8.

> +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_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_in9_input.dev_attr.attr,
> + &sensor_dev_attr_in9_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_temp2_input.dev_attr.attr,
> + &sensor_dev_attr_temp2_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 = devm_kzalloc(&pdev->dev, 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);
> + goto err_sysfs;
> + }
> +
> + return 0;
> +
> +err_sysfs:
> + sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group);
> +err_mem:
> + devm_kfree(&pdev->dev, 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);
> + devm_kfree(&pdev->dev, hwmon);
> +
> + return 0;
> +}
> +
> +static struct platform_driver da9052_hwmon_driver = {
> + .probe = da9052_hwmon_probe,
> + .remove = __devexit_p(da9052_hwmon_remove),
> + .driver = {
> + .name = "da9052-hwmon",
> + .owner = THIS_MODULE,
> + },
> +};
> +
> +module_platform_driver(da9052_hwmon_driver);
> +
> +MODULE_AUTHOR("David Dajun Chen <dchen@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("DA9052 HWMON driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:da9052-hwmon");
>
>

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