1 files changed, 167 insertions, 10 deletions

diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c
index 21d201befc2c..659308329308 100644
--- a/drivers/hwmon/ltc4245.c
+++ b/drivers/hwmon/ltc4245.c
@@ -21,6 +21,7 @@
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
+#include <linux/i2c/ltc4245.h>
 
 /* Here are names of the chip's registers (a.k.a. commands) */
 enum ltc4245_cmd {
@@ -60,8 +61,72 @@ struct ltc4245_data {
 
         /* Voltage registers */
         u8 vregs[0x0d];
+
+        /* GPIO ADC registers */
+        bool use_extra_gpios;
+        int gpios[3];
 };
 
+/*
+ * Update the readings from the GPIO pins. If the driver has been configured to
+ * sample all GPIO's as analog voltages, a round-robin sampling method is used.
+ * Otherwise, only the configured GPIO pin is sampled.
+ *
+ * LOCKING: must hold data->update_lock
+ */
+static void ltc4245_update_gpios(struct device *dev)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct ltc4245_data *data = i2c_get_clientdata(client);
+        u8 gpio_curr, gpio_next, gpio_reg;
+        int i;
+
+        /* no extra gpio support, we're basically done */
+        if (!data->use_extra_gpios) {
+                data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
+                return;
+        }
+
+        /*
+         * If the last reading was too long ago, then we mark all old GPIO
+         * readings as stale by setting them to -EAGAIN
+         */
+        if (time_after(jiffies, data->last_updated + 5 * HZ)) {
+                dev_dbg(&client->dev, "Marking GPIOs invalid\n");
+                for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
+                        data->gpios[i] = -EAGAIN;
+        }
+
+        /*
+         * Get the current GPIO pin
+         *
+         * The datasheet calls these GPIO[1-3], but we'll calculate the zero
+         * based array index instead, and call them GPIO[0-2]. This is much
+         * easier to think about.
+         */
+        gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
+        if (gpio_curr > 0)
+                gpio_curr -= 1;
+
+        /* Read the GPIO voltage from the GPIOADC register */
+        data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
+
+        /* Find the next GPIO pin to read */
+        gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
+
+        /*
+         * Calculate the correct setting for the GPIO register so it will
+         * sample the next GPIO pin
+         */
+        gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
+
+        /* Update the GPIO register */
+        i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
+
+        /* Update saved data */
+        data->cregs[LTC4245_GPIO] = gpio_reg;
+}
+
 static struct ltc4245_data *ltc4245_update_device(struct device *dev)
 {
         struct i2c_client *client = to_i2c_client(dev);
@@ -93,6 +158,9 @@ static struct ltc4245_data *ltc4245_update_device(struct device *dev)
                                 data->vregs[i] = val;
                 }
 
+                /* Update GPIO readings */
+                ltc4245_update_gpios(dev);
+
                 data->last_updated = jiffies;
                 data->valid = 1;
         }
@@ -233,6 +301,22 @@ static ssize_t ltc4245_show_alarm(struct device *dev,
         return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
 }
 
+static ssize_t ltc4245_show_gpio(struct device *dev,
+                                 struct device_attribute *da,
+                                 char *buf)
+{
+        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+        struct ltc4245_data *data = ltc4245_update_device(dev);
+        int val = data->gpios[attr->index];
+
+        /* handle stale GPIO's */
+        if (val < 0)
+                return val;
+
+        /* Convert to millivolts and print */
+        return snprintf(buf, PAGE_SIZE, "%u\n", val * 10);
+}
+
 /* These macros are used below in constructing device attribute objects
  * for use with sysfs_create_group() to make a sysfs device file
  * for each register.
@@ -254,6 +338,10 @@ static ssize_t ltc4245_show_alarm(struct device *dev,
         static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
         ltc4245_show_alarm, NULL, (mask), reg)
 
+#define LTC4245_GPIO_VOLTAGE(name, gpio_num) \
+        static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
+        ltc4245_show_gpio, NULL, gpio_num)
+
 /* Construct a sensor_device_attribute structure for each register */
 
 /* Input voltages */
@@ -293,7 +381,9 @@ LTC4245_ALARM(in7_min_alarm,	(1 << 2),	LTC4245_FAULT2);
 LTC4245_ALARM(in8_min_alarm,    (1 << 3),       LTC4245_FAULT2);
 
 /* GPIO voltages */
-LTC4245_VOLTAGE(in9_input,                      LTC4245_GPIOADC);
+LTC4245_GPIO_VOLTAGE(in9_input,                 0);
+LTC4245_GPIO_VOLTAGE(in10_input,                1);
+LTC4245_GPIO_VOLTAGE(in11_input,                2);
 
 /* Power Consumption (virtual) */
 LTC4245_POWER(power1_input,                     LTC4245_12VSENSE);
@@ -304,7 +394,7 @@ LTC4245_POWER(power4_input,			LTC4245_VEESENSE);
 /* Finally, construct an array of pointers to members of the above objects,
  * as required for sysfs_create_group()
  */
-static struct attribute *ltc4245_attributes[] = {
+static struct attribute *ltc4245_std_attributes[] = {
         &sensor_dev_attr_in1_input.dev_attr.attr,
         &sensor_dev_attr_in2_input.dev_attr.attr,
         &sensor_dev_attr_in3_input.dev_attr.attr,
@@ -345,10 +435,77 @@ static struct attribute *ltc4245_attributes[] = {
         NULL,
 };
 
-static const struct attribute_group ltc4245_group = {
-        .attrs = ltc4245_attributes,
+static struct attribute *ltc4245_gpio_attributes[] = {
+        &sensor_dev_attr_in10_input.dev_attr.attr,
+        &sensor_dev_attr_in11_input.dev_attr.attr,
+        NULL,
+};
+
+static const struct attribute_group ltc4245_std_group = {
+        .attrs = ltc4245_std_attributes,
+};
+
+static const struct attribute_group ltc4245_gpio_group = {
+        .attrs = ltc4245_gpio_attributes,
 };
 
+static int ltc4245_sysfs_create_groups(struct i2c_client *client)
+{
+        struct ltc4245_data *data = i2c_get_clientdata(client);
+        struct device *dev = &client->dev;
+        int ret;
+
+        /* register the standard sysfs attributes */
+        ret = sysfs_create_group(&dev->kobj, &ltc4245_std_group);
+        if (ret) {
+                dev_err(dev, "unable to register standard attributes\n");
+                return ret;
+        }
+
+        /* if we're using the extra gpio support, register it's attributes */
+        if (data->use_extra_gpios) {
+                ret = sysfs_create_group(&dev->kobj, &ltc4245_gpio_group);
+                if (ret) {
+                        dev_err(dev, "unable to register gpio attributes\n");
+                        sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
+                        return ret;
+                }
+        }
+
+        return 0;
+}
+
+static void ltc4245_sysfs_remove_groups(struct i2c_client *client)
+{
+        struct ltc4245_data *data = i2c_get_clientdata(client);
+        struct device *dev = &client->dev;
+
+        if (data->use_extra_gpios)
+                sysfs_remove_group(&dev->kobj, &ltc4245_gpio_group);
+
+        sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
+}
+
+static bool ltc4245_use_extra_gpios(struct i2c_client *client)
+{
+        struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
+#ifdef CONFIG_OF
+        struct device_node *np = client->dev.of_node;
+#endif
+
+        /* prefer platform data */
+        if (pdata)
+                return pdata->use_extra_gpios;
+
+#ifdef CONFIG_OF
+        /* fallback on OF */
+        if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
+                return true;
+#endif
+
+        return false;
+}
+
 static int ltc4245_probe(struct i2c_client *client,
                          const struct i2c_device_id *id)
 {
@@ -367,15 +524,16 @@ static int ltc4245_probe(struct i2c_client *client,
 
         i2c_set_clientdata(client, data);
         mutex_init(&data->update_lock);
+        data->use_extra_gpios = ltc4245_use_extra_gpios(client);
 
         /* Initialize the LTC4245 chip */
         i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
         i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
 
         /* Register sysfs hooks */
-        ret = sysfs_create_group(&client->dev.kobj, &ltc4245_group);
+        ret = ltc4245_sysfs_create_groups(client);
         if (ret)
-                goto out_sysfs_create_group;
+                goto out_sysfs_create_groups;
 
         data->hwmon_dev = hwmon_device_register(&client->dev);
         if (IS_ERR(data->hwmon_dev)) {
@@ -386,8 +544,8 @@ static int ltc4245_probe(struct i2c_client *client,
         return 0;
 
 out_hwmon_device_register:
-        sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
-out_sysfs_create_group:
+        ltc4245_sysfs_remove_groups(client);
+out_sysfs_create_groups:
         kfree(data);
 out_kzalloc:
         return ret;
@@ -398,8 +556,7 @@ static int ltc4245_remove(struct i2c_client *client)
         struct ltc4245_data *data = i2c_get_clientdata(client);
 
         hwmon_device_unregister(data->hwmon_dev);
-        sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
-
+        ltc4245_sysfs_remove_groups(client);
         kfree(data);
 
         return 0;