ENGR00306134-1: hwmon: mag3110 Enable mag3110 driver for i.MX6SX-SDB platform

The mag3110 driver can support irq mode and polling mode. On i.MX6SX-SDB platorm,
mag3110 sensor and other sensor share the same GPIO interrutp line. The main modification:

* Modify the driver to support irq working mode.
* Add shared interrupt support in the driver.
* Fix the clear interrupt flag issue.

Signed-off-by: Luwei Zhou <b45643@freescale.com>

1 files changed, 44 insertions, 15 deletions

diff --git a/drivers/hwmon/mag3110.c b/drivers/hwmon/mag3110.c
index 9d7f617bcaef..a8d80fa46dfe 100755
--- a/drivers/hwmon/mag3110.c
+++ b/drivers/hwmon/mag3110.c
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright (C) 2011-2013 Freescale Semiconductor, Inc.
+ * Copyright (C) 2011-2014 Freescale Semiconductor, Inc.
  *
  * 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
@@ -37,12 +37,11 @@
 #define MAG3110_ID              0xC4
 #define MAG3110_XYZ_DATA_LEN    6
 #define MAG3110_STATUS_ZYXDR    0x08
-
+#define MAG3110_IRQ_USED        1
 #define MAG3110_AC_MASK         (0x01)
 #define MAG3110_AC_OFFSET       0
 #define MAG3110_DR_MODE_MASK    (0x7 << 5)
 #define MAG3110_DR_MODE_OFFSET  5
-#define MAG3110_IRQ_USED   0
 
 #define POLL_INTERVAL_MAX       500
 #define POLL_INTERVAL           100
@@ -182,9 +181,11 @@ static int mag3110_init_client(struct i2c_client *client)
 static int mag3110_read_data(short *x, short *y, short *z)
 {
         struct mag3110_data *data;
-        int retry = 3;
         u8 tmp_data[MAG3110_XYZ_DATA_LEN];
+#if !MAG3110_IRQ_USED
+        int retry = 3;
         int result;
+#endif
         if (!mag3110_pdata || mag3110_pdata->active == MAG_STANDBY)
                 return -EINVAL;
 
@@ -210,10 +211,12 @@ static int mag3110_read_data(short *x, short *y, short *z)
 
         data->data_ready = 0;
 
-        if (mag3110_read_block_data(data->client,
+        while (i2c_smbus_read_byte_data(data->client, MAG3110_DR_STATUS)) {
+                if (mag3110_read_block_data(data->client,
                                     MAG3110_OUT_X_MSB, MAG3110_XYZ_DATA_LEN,
                                     tmp_data) < 0)
-                return -1;
+                        return -1;
+        }
 
         *x = ((tmp_data[0] << 8) & 0xff00) | tmp_data[1];
         *y = ((tmp_data[2] << 8) & 0xff00) | tmp_data[3];
@@ -248,8 +251,26 @@ static void mag3110_dev_poll(struct input_polled_dev *dev)
 #if MAG3110_IRQ_USED
 static irqreturn_t mag3110_irq_handler(int irq, void *dev_id)
 {
+        int result;
+        u8 tmp_data[MAG3110_XYZ_DATA_LEN];
+        result = i2c_smbus_read_byte_data(mag3110_pdata->client,
+                                                  MAG3110_DR_STATUS);
+        if (!(result & MAG3110_STATUS_ZYXDR))
+                return IRQ_NONE;
+
         mag3110_pdata->data_ready = 1;
-        wake_up_interruptible(&mag3110_pdata->waitq);
+
+        if (mag3110_pdata->active == MAG_STANDBY)
+                /*
+                 * Since the mode will be changed, sometimes irq will
+                 * be handled in StandBy mode because of interrupt latency.
+                 * So just clear the interrutp flag via reading block data.
+                 */
+                mag3110_read_block_data(mag3110_pdata->client,
+                                        MAG3110_OUT_X_MSB,
+                                        MAG3110_XYZ_DATA_LEN, tmp_data);
+        else
+                wake_up_interruptible(&mag3110_pdata->waitq);
 
         return IRQ_HANDLED;
 }
@@ -284,6 +305,7 @@ static ssize_t mag3110_enable_store(struct device *dev,
 
         mutex_lock(&mag3110_lock);
         client = mag3110_pdata->client;
+
         reg = mag3110_read_reg(client, MAG3110_CTRL_REG1);
         if (enable && mag3110_pdata->active == MAG_STANDBY) {
                 reg |= MAG3110_AC_MASK;
@@ -297,12 +319,10 @@ static ssize_t mag3110_enable_store(struct device *dev,
                         mag3110_pdata->active = MAG_STANDBY;
         }
 
-        if (mag3110_pdata->active == MAG_ACTIVED) {
-                msleep(100);
-                /* Read out MSB data to clear interrupt flag automatically */
-                mag3110_read_block_data(client, MAG3110_OUT_X_MSB,
+        /* Read out MSB data to clear interrupt flag */
+        msleep(100);
+        mag3110_read_block_data(mag3110_pdata->client, MAG3110_OUT_X_MSB,
                                         MAG3110_XYZ_DATA_LEN, tmp_data);
-        }
         mutex_unlock(&mag3110_lock);
         return count;
 }
@@ -402,6 +422,11 @@ static int mag3110_probe(struct i2c_client *client,
         struct regulator *vdd, *vdd_io;
         u32 pos = 0;
         struct device_node *of_node = client->dev.of_node;
+#if MAG3110_IRQ_USED
+        struct irq_data *irq_data = irq_get_irq_data(client->irq);
+        u32 irq_flag;
+        bool shared_irq = of_property_read_bool(of_node, "shared-interrupt");
+#endif
         vdd = NULL;
         vdd_io = NULL;
 
@@ -484,10 +509,14 @@ static int mag3110_probe(struct i2c_client *client,
                 ret = -EINVAL;
                 goto error_rm_poll_dev;
         }
-        /* set irq type to edge rising */
+
 #if MAG3110_IRQ_USED
-        ret = request_irq(client->irq, mag3110_irq_handler,
-                          IRQF_TRIGGER_RISING, client->dev.driver->name, idev);
+        irq_flag = irqd_get_trigger_type(irq_data);
+        irq_flag |= IRQF_ONESHOT;
+        if (shared_irq)
+                irq_flag |= IRQF_SHARED;
+        ret = request_threaded_irq(client->irq, NULL, mag3110_irq_handler,
+                          irq_flag, client->dev.driver->name, idev);
         if (ret < 0) {
                 dev_err(&client->dev, "failed to register irq %d!\n",
                         client->irq);