Message-ID: <E2CAE7F7B064EA49B5CE7EE9A4BB167D151BDC3D33@KCINPUNHJCMS01.kpit.com>
Date:	Fri, 20 May 2011 16:27:18 +0530
From:	Ashish Jangam <Ashish.Jangam@...tcummins.com>
To:	Guenter Roeck <guenter.roeck@...csson.com>
CC:	Randy Dunlap <randy.dunlap@...cle.com>,
	Dajun Chen <Dajun.Chen@...semi.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"lm-sensors@...sensors.org" <lm-sensors@...sensors.org>
Subject: [PATCHv3 6/11] HWMON: Fixed point conversion gives linktime error

Hi,

As requested approximation of battery temperature calculation with fixed point conversion is tried but it causes couple of link time errors, like undefined reference to __aeabi_i2d at sprintf(). Have a look at the function da9052_read_tbat(); we feel that this function should not be supported else there will be a prerequisite to the support the required floating point library. Enabling FPE_NWFPE support in the kernel gives the same link time errors.

Also have a look at the rest of the code and let us know your comments.

Signed-off-by: Ashish Jangam <ashish.jangam@...tcummins.com>
                   David Dajun Chen <dchen@...semi.com>
--
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 <dchen@...semi.com>
+
+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.
+
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..6ec5b0b
--- /dev/null
+++ b/drivers/hwmon/da9052-hwmon.c
@@ -0,0 +1,377 @@
+/*
+ * HWMON Driver for Dialog DA9052
+ *
+ * Copyright(c) 2011 Dialog Semiconductor Ltd.
+ *
+ * Author: David Dajun Chen <dchen@...semi.com>
+ *
+ *  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/log2.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 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;
+
+       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);
+       }
+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         3380
+#define LOGN2          0.693147181
+#define TBAT_DIV               0.003355705
+/* ln(x) = log2(x) * ln(2) = log2(x) * 0.693147181
+   log2(float) gets convert to fixed point as = log2(nr) - log2(dr) */
+#define CAL_LOG2(nr)   ((ilog2(nr) - ilog2(100)) * LOGN2)
+/*
+       The battery temperature is calculated as:
+       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
+*/
+static int cal_temperature(int adc_val)
+{
+       int nr;
+       int temperature_k;
+
+       /* Formula 2.5/(R25*ITBAT*255) gets reduced to 2, for fixed point
+          conversion */
+       nr = adc_val * 2;
+
+       /* Temperature in Kelvin =
+          1 / ((1 / bconst) * CAL_LOG(nr) + 0.003355705) */
+       temperature_k = 10000 / (3 * CAL_LOG2(nr) + 34);
+
+       /* Battery temperature in degree celcius */
+       return temperature_k - 273;
+}
+
+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;
+       }
+
+       return 0;
+
+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 <dchen@...semi.com>");
+MODULE_DESCRIPTION("DA9052 HWMON driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:da9052-hwmon");


Regards,
Ashish

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