medfield: Add Thermal Driver

This is the basic thermal sensor driver for Intel MID platform using the
Medfield chipset. It plugs in via the thermal drivers and provides sensor
readings for the device sensors.

Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 575 insertions, 0 deletions

diff --git a/drivers/platform/x86/intel_mid_thermal.c b/drivers/platform/x86/intel_mid_thermal.c
new file mode 100644
index 000000000000..1215c3096868
--- /dev/null
+++ b/drivers/platform/x86/intel_mid_thermal.c
@@ -0,0 +1,575 @@
+/*
+ * 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 <asm/intel_scu_ipc.h>
+
+/* Number of thermal sensors */
+#define MSIC_THERMAL_SENSORS   4
+
+/* ADC1 - thermal registers */
+#define MSIC_THERM_ADC1CNTL1   0x1C0
+#define MSIC_ADC_ENBL          0x10
+#define MSIC_ADC_START         0x08
+
+#define MSIC_THERM_ADC1CNTL3   0x1C2
+#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
+#define ADC_CHANLS_MAX         15 /* Number of ADC channels */
+#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    0x1C5   /* increments by 1 */
+#define ADC_DATA_START_ADDR     0x1D4   /* 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_scu_ipc_iowrite8(MSIC_THERM_ADC1CNTL3, MSIC_ADCRRDATA_ENBL);
+       if (ret)
+               return ret;
+
+       /* Re-toggle the RRDATARD bit (temporary workaround) */
+       ret = intel_scu_ipc_iowrite8(MSIC_THERM_ADC1CNTL3, MSIC_ADCTHERM_ENBL);
+       if (ret)
+               return ret;
+
+       /* Read the higher bits of data */
+       ret = intel_scu_ipc_ioread8(addr, &data);
+       if (ret)
+               return ret;
+
+       /* Shift bits to accomodate the lower two data bits */
+       adc_val = (data << 2);
+       addr++;
+
+       ret = intel_scu_ipc_ioread8(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_scu_ipc_ioread8(MSIC_THERM_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_scu_ipc_iowrite8(MSIC_THERM_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_scu_ipc_iowrite8(base_addr, SKIN_SENSOR0_CODE);
+       if (ret)
+               return ret;
+
+       ret = intel_scu_ipc_iowrite8(base_addr + 1, SKIN_SENSOR1_CODE);
+       if (ret)
+               return ret;
+
+       ret = intel_scu_ipc_iowrite8(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_scu_ipc_iowrite8(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_scu_ipc_ioread8(addr, &data);
+       if (ret)
+               return ret;
+       /* Set the stop bit to zero */
+       return intel_scu_ipc_iowrite8(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_scu_ipc_ioread8(MSIC_THERM_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_scu_ipc_ioread8(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_scu_ipc_ioread8(MSIC_THERM_ADC1CNTL3, &data);
+       if (ret)
+               return ret;
+
+       if (data & MSIC_ADCTHERM_MASK)
+               dev_warn(dev, "ADCTHERM already set");
+
+       /* 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
+ * @pdev: platform device structure
+ *
+ * mid thermal resume: re-initializes the adc. Can sleep.
+ */
+static int mid_thermal_resume(struct platform_device *pdev)
+{
+       return mid_initialize_adc(&pdev->dev);
+}
+
+/**
+ * mid_thermal_suspend - suspend routine
+ * @pdev: platform device structure
+ *
+ * mid thermal suspend implements the suspend functionality
+ * by stopping the ADC. Can sleep.
+ */
+static int mid_thermal_suspend(struct platform_device *pdev, pm_message_t mesg)
+{
+       /*
+        * 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);
+}
+
+/**
+ * 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++) {
+               pinfo->tzd[i] = thermal_zone_device_register(name[i],
+                                       0, initialize_sensor(i),
+                                       &tzd_ops, 0, 0, 0, 0);
+               if (IS_ERR(pinfo->tzd[i]))
+                       goto reg_fail;
+       }
+
+       pinfo->pdev = pdev;
+       platform_set_drvdata(pdev, pinfo);
+       return 0;
+
+reg_fail:
+       ret = PTR_ERR(pinfo->tzd[i]);
+       while (--i >= 0)
+               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++)
+               thermal_zone_device_unregister(pinfo->tzd[i]);
+
+       platform_set_drvdata(pdev, NULL);
+
+       /* Stop the ADC */
+       return configure_adc(0);
+}
+
+/*********************************************************************
+ *             Driver initialisation and finalization
+ *********************************************************************/
+
+#define DRIVER_NAME "msic_sensor"
+
+static const struct platform_device_id therm_id_table[] = {
+       { DRIVER_NAME, 1 },
+};
+
+static struct platform_driver mid_thermal_driver = {
+       .driver = {
+               .name = DRIVER_NAME,
+               .owner = THIS_MODULE,
+       },
+       .probe = mid_thermal_probe,
+       .suspend = mid_thermal_suspend,
+       .resume = mid_thermal_resume,
+       .remove = __devexit_p(mid_thermal_remove),
+       .id_table = therm_id_table,
+};
+
+static int __init mid_thermal_module_init(void)
+{
+       return platform_driver_register(&mid_thermal_driver);
+}
+
+static void __exit mid_thermal_module_exit(void)
+{
+       platform_driver_unregister(&mid_thermal_driver);
+}
+
+module_init(mid_thermal_module_init);
+module_exit(mid_thermal_module_exit);
+
+MODULE_AUTHOR("Durgadoss R <durgadoss.r@intel.com>");
+MODULE_DESCRIPTION("Intel Medfield Platform Thermal Driver");
+MODULE_LICENSE("GPL");