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>

diff --git a/drivers/w1/masters/ds2482.c b/drivers/w1/masters/ds2482.c
index b05e8fefbabd98d379797b6dfc05744ad248a584..03b2f8f416073afb41faa4f13c117589dc7d34c6 100644 (file)
--- 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)
@@ -95,9 +98,15 @@ static const struct i2c_device_id ds2482_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, ds2482_id);
 
+static const struct dev_pm_ops ds2482_pm_ops = {
+       .suspend = ds2482_suspend,
+       .resume = ds2482_resume,
+};
+
 static struct i2c_driver ds2482_driver = {
        .driver = {
                .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 (file)
index 0000000..5a6879e
--- /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__ */