NCT1008 temperature sensor driver

Replace the PM-only driver for NCT1008 with a new version written by
Varun Wadekar and Dmitriy Gruzman.  Add a callback to an alarm
function specified in the board platform data.

Change-Id: Ib429533930ee75af3402d24b0bc286da9f6ee67b
Signed-off-by: Todd Poynor <toddpoynor@google.com>

1 files changed, 226 insertions, 74 deletions

diff --git a/drivers/misc/nct1008.c b/drivers/misc/nct1008.c
index a29e984bc4c6..4ae48e4003aa 100755
--- a/drivers/misc/nct1008.c
+++ b/drivers/misc/nct1008.c
@@ -1,139 +1,291 @@
 /*
- * Copyright (C) 2010 Motorola, Inc.
+ * drivers/misc/nct1008.c
+ *
+ * Driver for NCT1008, temperature monitoring device from ON Semiconductors
+ *
+ * Copyright (c) 2010, NVIDIA Corporation.
  *
  * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
+ * 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.
  *
- * 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.
+ * 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
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-#include <linux/i2c.h>
-#include <linux/irq.h>
-#include <linux/input.h>
+
 #include <linux/interrupt.h>
-#include <linux/nct1008.h>
-#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
 #include <linux/slab.h>
-#include <linux/types.h>
-#include <linux/uaccess.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+
+#include <linux/nct1008.h>
 
-#define NCT_BIT_CONFIG_RUN_STOP 6
+#define DRIVER_NAME "nct1008"
+
+/* Register Addresses */
+#define LOCAL_TEMP_RD			0x00
+#define STATUS_RD			0x02
+#define CONFIG_RD			0x03
+
+#define CONFIG_WR			0x09
+#define CONV_RATE_WR			0x0A
+#define LOCAL_TEMP_HI_LIMIT_WR		0x0B
+#define EXT_TEMP_HI_LIMIT_HI_BYTE	0x0D
+#define OFFSET_WR			0x11
+#define EXT_THERM_LIMIT_WR		0x19
+#define LOCAL_THERM_LIMIT_WR		0x20
+#define THERM_HYSTERESIS_WR		0x21
+
+/* Configuration Register Bits */
+#define EXTENDED_RANGE_BIT		(0x1 << 2)
+#define THERM2_BIT			(0x1 << 5)
+#define STANDBY_BIT			(0x1 << 6)
+
+/* Max Temperature Measurements */
+#define EXTENDED_RANGE_OFFSET		64U
+#define STANDARD_RANGE_MAX		127U
+#define EXTENDED_RANGE_MAX		(150U + EXTENDED_RANGE_OFFSET)
 
 struct nct1008_data {
+	struct work_struct work;
 	struct i2c_client *client;
+	struct mutex mutex;
+	u8 config;
+	void (*alarm_fn)(bool raised);
 };
 
-static uint32_t nct1008_debug;
-module_param_named(temp_debug, nct1008_debug, uint, 0664);
+static void nct1008_enable(struct i2c_client *client)
+{
+	struct nct1008_data *data = i2c_get_clientdata(client);
+
+	i2c_smbus_write_byte_data(client, CONFIG_WR,
+				  data->config & ~STANDBY_BIT);
+}
 
-static int nct1008_run(struct nct1008_data *nct, u8 run)
+static void nct1008_disable(struct i2c_client *client)
 {
-	int err;
-	u8 rd_val;
-	u8 wr_val;
+	struct nct1008_data *data = i2c_get_clientdata(client);
 
-	rd_val = i2c_smbus_read_byte_data(nct->client, NCT_CONFIG_RD);
-	if (rd_val < 0) {
-		pr_err("%s: config register read fail: %d\n", __func__, rd_val);
-		return rd_val;
+	i2c_smbus_write_byte_data(client, CONFIG_WR,
+				  data->config | STANDBY_BIT);
+}
+
+
+static void nct1008_work_func(struct work_struct *work)
+{
+	struct nct1008_data *data = container_of(work, struct nct1008_data, work);
+	int irq = data->client->irq;
+
+	mutex_lock(&data->mutex);
+
+	if (data->alarm_fn) {
+		/* Therm2 line is active low */
+		data->alarm_fn(!gpio_get_value(irq_to_gpio(irq)));
 	}
 
-	if (nct1008_debug)
-		pr_info("%s: Previous config is 0x%02x\n", __func__, rd_val);
+	mutex_unlock(&data->mutex);
+}
+
+static irqreturn_t nct1008_irq(int irq, void *dev_id)
+{
+	struct nct1008_data *data = dev_id;
+	schedule_work(&data->work);
+
+	return IRQ_HANDLED;
+}
+
+static inline u8 value_to_temperature(bool extended, u8 value)
+{
+	return (extended ? (u8)(value - EXTENDED_RANGE_OFFSET) : value);
+}
+
+static inline u8 temperature_to_value(bool extended, u8 temp)
+{
+	return (extended ? (u8)(temp + EXTENDED_RANGE_OFFSET) : temp);
+}
+
+static int __devinit nct1008_configure_sensor(struct nct1008_data* data)
+{
+	struct i2c_client *client           = data->client;
+	struct nct1008_platform_data *pdata = client->dev.platform_data;
+	u8 value;
+	int err;
+
+	if (!pdata || !pdata->supported_hwrev)
+		return -ENODEV;
+
+	/*
+	 * Initial Configuration - device is placed in standby and
+	 * ALERT/THERM2 pin is configured as THERM2
+	 */
+	data->config = value = pdata->ext_range ?
+		(STANDBY_BIT | THERM2_BIT | EXTENDED_RANGE_BIT) :
+		(STANDBY_BIT | THERM2_BIT);
+
+	err = i2c_smbus_write_byte_data(client, CONFIG_WR, value);
+	if (err < 0)
+		goto error;
+
+	/* Temperature conversion rate */
+	err = i2c_smbus_write_byte_data(client, CONV_RATE_WR, pdata->conv_rate);
+	if (err < 0)
+		goto error;
 
-	if (run)
-		wr_val = rd_val & ~(1 << NCT_BIT_CONFIG_RUN_STOP);
-	else
-		wr_val = rd_val | (1 << NCT_BIT_CONFIG_RUN_STOP);
-	err = i2c_smbus_write_byte_data(nct->client, NCT_CONFIG_WR, wr_val);
-	if (err)
-		pr_err("%s: setting RUN/STOP failed: %d\n", __func__, err);
+	/* External temperature h/w shutdown limit */
+	value = temperature_to_value(pdata->ext_range, pdata->shutdown_ext_limit);
+	err = i2c_smbus_write_byte_data(client, EXT_THERM_LIMIT_WR, value);
+	if (err < 0)
+		goto error;
 
+	/* Local temperature h/w shutdown limit */
+	value = temperature_to_value(pdata->ext_range, pdata->shutdown_local_limit);
+	err = i2c_smbus_write_byte_data(client, LOCAL_THERM_LIMIT_WR, value);
+	if (err < 0)
+		goto error;
+
+	/* External Temperature Throttling limit */
+	value = temperature_to_value(pdata->ext_range, pdata->throttling_ext_limit);
+	err = i2c_smbus_write_byte_data(client, EXT_TEMP_HI_LIMIT_HI_BYTE, value);
+	if (err < 0)
+		goto error;
+
+	/* Local Temperature Throttling limit */
+	value = pdata->ext_range ? EXTENDED_RANGE_MAX : STANDARD_RANGE_MAX;
+	err = i2c_smbus_write_byte_data(client, LOCAL_TEMP_HI_LIMIT_WR, value);
+	if (err < 0)
+		goto error;
+
+	/* Remote channel offset */
+	err = i2c_smbus_write_byte_data(client, OFFSET_WR, pdata->offset);
+	if (err < 0)
+		goto error;
+
+	/* THERM hysteresis */
+	err = i2c_smbus_write_byte_data(client, THERM_HYSTERESIS_WR, pdata->hysteresis);
+	if (err < 0)
+		goto error;
+
+	data->alarm_fn = pdata->alarm_fn;
+	return 0;
+error:
 	return err;
 }
 
-static int nct1008_probe(struct i2c_client *client,
-			 const struct i2c_device_id *id)
+static int __devinit nct1008_configure_irq(struct nct1008_data *data)
+{
+	INIT_WORK(&data->work, nct1008_work_func);
+
+	return request_irq(data->client->irq, nct1008_irq, IRQF_TRIGGER_RISING |
+				IRQF_TRIGGER_FALLING, DRIVER_NAME, data);
+}
+
+static int __devinit nct1008_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
-	struct nct1008_data *nct;
+	struct nct1008_data *data;
+	int err;
+
+	data = kzalloc(sizeof(struct nct1008_data), GFP_KERNEL);
 
-	nct = kzalloc(sizeof(struct nct1008_data), GFP_KERNEL);
-	if (nct == NULL)
+	if (!data)
 		return -ENOMEM;
 
-	nct->client = client;
-	i2c_set_clientdata(client, nct);
+	data->client = client;
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->mutex);
+
+	err = nct1008_configure_sensor(data);	/* sensor is in standby */
+	if (err < 0)
+		goto error;
+
+	err = nct1008_configure_irq(data);
+	if (err < 0)
+		goto error;
+
+	nct1008_enable(client);		/* sensor is running */
+
+	schedule_work(&data->work);		/* check initial state */
 
 	return 0;
+
+error:
+	kfree(data);
+	return err;
 }
 
-static int nct1008_remove(struct i2c_client *client)
+static int __devexit nct1008_remove(struct i2c_client *client)
 {
-	struct nct1008_data *nct = i2c_get_clientdata(client);
+	struct nct1008_data *data = i2c_get_clientdata(client);
+
+	free_irq(data->client->irq, data);
+	cancel_work_sync(&data->work);
+	kfree(data);
 
-	kfree(nct);
 	return 0;
 }
 
-static int nct1008_suspend(struct i2c_client *client, pm_message_t mesg)
+#ifdef CONFIG_PM
+static int nct1008_suspend(struct i2c_client *client, pm_message_t state)
 {
-	struct nct1008_data *nct = i2c_get_clientdata(client);
-
-	if (nct1008_debug)
-		pr_info("%s: Suspending\n", __func__);
+	disable_irq(client->irq);
+	nct1008_disable(client);
 
-	return nct1008_run(nct, 0);
+	return 0;
 }
 
 static int nct1008_resume(struct i2c_client *client)
 {
-	struct nct1008_data *nct = i2c_get_clientdata(client);
+	struct nct1008_data *data = i2c_get_clientdata(client);
 
-	if (nct1008_debug)
-		pr_info("%s: Resuming\n", __func__);
+	nct1008_enable(client);
+	enable_irq(client->irq);
+	schedule_work(&data->work);
 
-	return nct1008_run(nct, 1);
+	return 0;
 }
+#endif
 
 static const struct i2c_device_id nct1008_id[] = {
-	{"nct1008", 0},
-	{}
+	{ DRIVER_NAME, 0 },
+	{ }
 };
+MODULE_DEVICE_TABLE(i2c, nct1008_id);
 
-static struct i2c_driver nct1008_i2c_driver = {
-	.probe = nct1008_probe,
-	.remove = nct1008_remove,
-	.suspend = nct1008_suspend,
-	.resume = nct1008_resume,
-	.id_table = nct1008_id,
+static struct i2c_driver nct1008_driver = {
 	.driver = {
-		.name = "nct1008",
-		.owner = THIS_MODULE,
+		.name	= DRIVER_NAME,
 	},
+	.probe		= nct1008_probe,
+	.remove		= __devexit_p(nct1008_remove),
+	.id_table	= nct1008_id,
+#ifdef CONFIG_PM
+	.suspend	= nct1008_suspend,
+	.resume		= nct1008_resume,
+#endif
 };
 
 static int __init nct1008_init(void)
 {
-	return i2c_add_driver(&nct1008_i2c_driver);
+	return i2c_add_driver(&nct1008_driver);
 }
 
 static void __exit nct1008_exit(void)
 {
-	i2c_del_driver(&nct1008_i2c_driver);
+	i2c_del_driver(&nct1008_driver);
 }
 
-module_init(nct1008_init);
-module_exit(nct1008_exit);
-
 MODULE_DESCRIPTION("Temperature sensor driver for OnSemi NCT1008");
-MODULE_AUTHOR("Motorola");
 MODULE_LICENSE("GPL");
+
+module_init (nct1008_init);
+module_exit (nct1008_exit);