Initial import

1 files changed, 207 insertions, 0 deletions

diff --git a/drivers/hwmon/ab8500.c b/drivers/hwmon/ab8500.c
new file mode 100644
index 000000000..8b6a4f4c8
--- /dev/null
+++ b/drivers/hwmon/ab8500.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) ST-Ericsson 2010 - 2013
+ * Author: Martin Persson <martin.persson@stericsson.com>
+ *         Hongbo Zhang <hongbo.zhang@linaro.org>
+ * License Terms: GNU General Public License v2
+ *
+ * When the AB8500 thermal warning temperature is reached (threshold cannot
+ * be changed by SW), an interrupt is set, and if no further action is taken
+ * within a certain time frame, kernel_power_off will be called.
+ *
+ * When AB8500 thermal shutdown temperature is reached a hardware shutdown of
+ * the AB8500 will occur.
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/mfd/abx500.h>
+#include <linux/mfd/abx500/ab8500-bm.h>
+#include <linux/mfd/abx500/ab8500-gpadc.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/power/ab8500.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include "abx500.h"
+
+#define DEFAULT_POWER_OFF_DELAY	(HZ * 10)
+#define THERMAL_VCC		1800
+#define PULL_UP_RESISTOR	47000
+/* Number of monitored sensors should not greater than NUM_SENSORS */
+#define NUM_MONITORED_SENSORS	4
+
+struct ab8500_gpadc_cfg {
+	const struct abx500_res_to_temp *temp_tbl;
+	int tbl_sz;
+	int vcc;
+	int r_up;
+};
+
+struct ab8500_temp {
+	struct ab8500_gpadc *gpadc;
+	struct ab8500_btemp *btemp;
+	struct delayed_work power_off_work;
+	struct ab8500_gpadc_cfg cfg;
+	struct abx500_temp *abx500_data;
+};
+
+/*
+ * The hardware connection is like this:
+ * VCC----[ R_up ]-----[ NTC ]----GND
+ * where R_up is pull-up resistance, and GPADC measures voltage on NTC.
+ * and res_to_temp table is strictly sorted by falling resistance values.
+ */
+static int ab8500_voltage_to_temp(struct ab8500_gpadc_cfg *cfg,
+		int v_ntc, int *temp)
+{
+	int r_ntc, i = 0, tbl_sz = cfg->tbl_sz;
+	const struct abx500_res_to_temp *tbl = cfg->temp_tbl;
+
+	if (cfg->vcc < 0 || v_ntc >= cfg->vcc)
+		return -EINVAL;
+
+	r_ntc = v_ntc * cfg->r_up / (cfg->vcc - v_ntc);
+	if (r_ntc > tbl[0].resist || r_ntc < tbl[tbl_sz - 1].resist)
+		return -EINVAL;
+
+	while (!(r_ntc <= tbl[i].resist && r_ntc > tbl[i + 1].resist) &&
+			i < tbl_sz - 2)
+		i++;
+
+	/* return milli-Celsius */
+	*temp = tbl[i].temp * 1000 + ((tbl[i + 1].temp - tbl[i].temp) * 1000 *
+		(r_ntc - tbl[i].resist)) / (tbl[i + 1].resist - tbl[i].resist);
+
+	return 0;
+}
+
+static int ab8500_read_sensor(struct abx500_temp *data, u8 sensor, int *temp)
+{
+	int voltage, ret;
+	struct ab8500_temp *ab8500_data = data->plat_data;
+
+	if (sensor == BAT_CTRL) {
+		*temp = ab8500_btemp_get_batctrl_temp(ab8500_data->btemp);
+	} else if (sensor == BTEMP_BALL) {
+		*temp = ab8500_btemp_get_temp(ab8500_data->btemp);
+	} else {
+		voltage = ab8500_gpadc_convert(ab8500_data->gpadc, sensor);
+		if (voltage < 0)
+			return voltage;
+
+		ret = ab8500_voltage_to_temp(&ab8500_data->cfg, voltage, temp);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void ab8500_thermal_power_off(struct work_struct *work)
+{
+	struct ab8500_temp *ab8500_data = container_of(work,
+				struct ab8500_temp, power_off_work.work);
+	struct abx500_temp *abx500_data = ab8500_data->abx500_data;
+
+	dev_warn(&abx500_data->pdev->dev, "Power off due to critical temp\n");
+
+	kernel_power_off();
+}
+
+static ssize_t ab8500_show_name(struct device *dev,
+		struct device_attribute *devattr, char *buf)
+{
+	return sprintf(buf, "ab8500\n");
+}
+
+static ssize_t ab8500_show_label(struct device *dev,
+		struct device_attribute *devattr, char *buf)
+{
+	char *label;
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	int index = attr->index;
+
+	switch (index) {
+	case 1:
+		label = "ext_adc1";
+		break;
+	case 2:
+		label = "ext_adc2";
+		break;
+	case 3:
+		label = "bat_temp";
+		break;
+	case 4:
+		label = "bat_ctrl";
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return sprintf(buf, "%s\n", label);
+}
+
+static int ab8500_temp_irq_handler(int irq, struct abx500_temp *data)
+{
+	struct ab8500_temp *ab8500_data = data->plat_data;
+
+	dev_warn(&data->pdev->dev, "Power off in %d s\n",
+		 DEFAULT_POWER_OFF_DELAY / HZ);
+
+	schedule_delayed_work(&ab8500_data->power_off_work,
+		DEFAULT_POWER_OFF_DELAY);
+	return 0;
+}
+
+int abx500_hwmon_init(struct abx500_temp *data)
+{
+	struct ab8500_temp *ab8500_data;
+
+	ab8500_data = devm_kzalloc(&data->pdev->dev, sizeof(*ab8500_data),
+		GFP_KERNEL);
+	if (!ab8500_data)
+		return -ENOMEM;
+
+	ab8500_data->gpadc = ab8500_gpadc_get("ab8500-gpadc.0");
+	if (IS_ERR(ab8500_data->gpadc))
+		return PTR_ERR(ab8500_data->gpadc);
+
+	ab8500_data->btemp = ab8500_btemp_get();
+	if (IS_ERR(ab8500_data->btemp))
+		return PTR_ERR(ab8500_data->btemp);
+
+	INIT_DELAYED_WORK(&ab8500_data->power_off_work,
+			  ab8500_thermal_power_off);
+
+	ab8500_data->cfg.vcc = THERMAL_VCC;
+	ab8500_data->cfg.r_up = PULL_UP_RESISTOR;
+	ab8500_data->cfg.temp_tbl = ab8500_temp_tbl_a_thermistor;
+	ab8500_data->cfg.tbl_sz = ab8500_temp_tbl_a_size;
+
+	data->plat_data = ab8500_data;
+
+	/*
+	 * ADC_AUX1 and ADC_AUX2, connected to external NTC
+	 * BTEMP_BALL and BAT_CTRL, fixed usage
+	 */
+	data->gpadc_addr[0] = ADC_AUX1;
+	data->gpadc_addr[1] = ADC_AUX2;
+	data->gpadc_addr[2] = BTEMP_BALL;
+	data->gpadc_addr[3] = BAT_CTRL;
+	data->monitored_sensors = NUM_MONITORED_SENSORS;
+
+	data->ops.read_sensor = ab8500_read_sensor;
+	data->ops.irq_handler = ab8500_temp_irq_handler;
+	data->ops.show_name = ab8500_show_name;
+	data->ops.show_label = ab8500_show_label;
+	data->ops.is_visible = NULL;
+
+	return 0;
+}
+EXPORT_SYMBOL(abx500_hwmon_init);
+
+MODULE_AUTHOR("Hongbo Zhang <hongbo.zhang@linaro.org>");
+MODULE_DESCRIPTION("AB8500 temperature driver");
+MODULE_LICENSE("GPL");