w1: ds2482: Manage SLPZ pin sleep state

Place SLPZ pin in sleep state at system suspend time if a GPIO is
provided by board platform data.

Change-Id: I93c61fa0ae474e968e0f909209c9bfcaafe3dd2c
Signed-off-by: Todd Poynor <toddpoynor@google.com>

2 files changed, 67 insertions, 1 deletions

diff --git a/drivers/w1/masters/ds2482.c b/drivers/w1/masters/ds2482.c
index e76a9b39abb..5e505d496f9 100644
--- a/drivers/w1/masters/ds2482.c
+++ b/drivers/w1/masters/ds2482.c
@@ -18,6 +18,8 @@
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/platform_data/ds2482.h>
 #include <asm/delay.h>
 
 #include "../w1.h"
@@ -84,7 +86,8 @@ static const u8 ds2482_chan_rd[8] =
 static int ds2482_probe(struct i2c_client *client,
 			const struct i2c_device_id *id);
 static int ds2482_remove(struct i2c_client *client);
-
+static int ds2482_suspend(struct device *dev);
+static int ds2482_resume(struct device *dev);
 
 /**
  * Driver data (common to all clients)
@@ -94,10 +97,16 @@ static const struct i2c_device_id ds2482_id[] = {
 	{ }
 };
 
+static const struct dev_pm_ops ds2482_pm_ops = {
+	.suspend = ds2482_suspend,
+	.resume = ds2482_resume,
+};
+
 static struct i2c_driver ds2482_driver = {
 	.driver = {
 		.owner	= THIS_MODULE,
 		.name	= "ds2482",
+		.pm = &ds2482_pm_ops,
 	},
 	.probe		= ds2482_probe,
 	.remove		= ds2482_remove,
@@ -119,6 +128,7 @@ struct ds2482_w1_chan {
 struct ds2482_data {
 	struct i2c_client	*client;
 	struct mutex		access_lock;
+	int			slpz_gpio;
 
 	/* 1-wire interface(s) */
 	int			w1_count;	/* 1 or 8 */
@@ -444,11 +454,31 @@ static u8 ds2482_w1_set_pullup(void *data, int delay)
 	return retval;
 }
 
+static int ds2482_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ds2482_data *data = i2c_get_clientdata(client);
+
+	if (data->slpz_gpio >= 0)
+		gpio_set_value(data->slpz_gpio, 0);
+	return 0;
+}
+
+static int ds2482_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ds2482_data *data = i2c_get_clientdata(client);
+
+	if (data->slpz_gpio >= 0)
+		gpio_set_value(data->slpz_gpio, 1);
+	return 0;
+}
 
 static int ds2482_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct ds2482_data *data;
+	struct ds2482_platform_data *pdata;
 	int err = -ENODEV;
 	int temp1;
 	int idx;
@@ -515,6 +545,16 @@ static int ds2482_probe(struct i2c_client *client,
 		}
 	}
 
+	pdata = client->dev.platform_data;
+	data->slpz_gpio = pdata ? pdata->slpz_gpio : -1;
+
+	if (data->slpz_gpio >= 0) {
+		err = gpio_request_one(data->slpz_gpio, GPIOF_OUT_INIT_HIGH,
+				       "ds2482.slpz");
+		if (err < 0)
+			goto exit_w1_remove;
+	}
+
 	return 0;
 
 exit_w1_remove:
@@ -539,6 +579,11 @@ static int ds2482_remove(struct i2c_client *client)
 			w1_remove_master_device(&data->w1_ch[idx].w1_bm);
 	}
 
+	if (data->slpz_gpio >= 0) {
+		gpio_set_value(data->slpz_gpio, 0);
+		gpio_free(data->slpz_gpio);
+	}
+
 	/* Free the memory */
 	kfree(data);
 	return 0;
diff --git a/include/linux/platform_data/ds2482.h b/include/linux/platform_data/ds2482.h
new file mode 100644
index 00000000000..5a6879e2a09
--- /dev/null
+++ b/include/linux/platform_data/ds2482.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2012 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#ifndef __PLATFORM_DATA_DS2482__
+#define __PLATFORM_DATA_DS2482__
+
+struct ds2482_platform_data {
+	int		slpz_gpio;
+};
+
+#endif /* __PLATFORM_DATA_DS2482__ */