Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelv...

[pandora-kernel.git] / drivers / hwmon / max1111.c

diff --git a/drivers/hwmon/max1111.c b/drivers/hwmon/max1111.c
index 12a54aa..c97b78e 100644 (file)
--- a/drivers/hwmon/max1111.c
+++ b/drivers/hwmon/max1111.c
@@ -38,8 +38,10 @@ struct max1111_data {
        struct device           *hwmon_dev;
        struct spi_message      msg;
        struct spi_transfer     xfer[2];
-       uint8_t *tx_buf;
-       uint8_t *rx_buf;
+       uint8_t tx_buf[MAX1111_TX_BUF_SIZE];
+       uint8_t rx_buf[MAX1111_RX_BUF_SIZE];
+       struct mutex            drvdata_lock;
+       /* protect msg, xfer and buffers from multiple access */
 };
 
 static int max1111_read(struct device *dev, int channel)
@@ -48,6 +50,9 @@ static int max1111_read(struct device *dev, int channel)
        uint8_t v1, v2;
        int err;
 
+       /* writing to drvdata struct is not thread safe, wait on mutex */
+       mutex_lock(&data->drvdata_lock);
+
        data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) |
                MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
                MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
@@ -55,12 +60,15 @@ static int max1111_read(struct device *dev, int channel)
        err = spi_sync(data->spi, &data->msg);
        if (err < 0) {
                dev_err(dev, "spi_sync failed with %d\n", err);
+               mutex_unlock(&data->drvdata_lock);
                return err;
        }
 
        v1 = data->rx_buf[0];
        v2 = data->rx_buf[1];
 
+       mutex_unlock(&data->drvdata_lock);
+
        if ((v1 & 0xc0) || (v2 & 0x3f))
                return -EINVAL;
 
@@ -123,33 +131,23 @@ static const struct attribute_group max1111_attr_group = {
        .attrs  = max1111_attributes,
 };
 
-static int setup_transfer(struct max1111_data *data)
+static int __devinit setup_transfer(struct max1111_data *data)
 {
        struct spi_message *m;
        struct spi_transfer *x;
 
-       data->tx_buf = kmalloc(MAX1111_TX_BUF_SIZE, GFP_KERNEL);
-       if (!data->tx_buf)
-               return -ENOMEM;
-
-       data->rx_buf = kmalloc(MAX1111_RX_BUF_SIZE, GFP_KERNEL);
-       if (!data->rx_buf) {
-               kfree(data->tx_buf);
-               return -ENOMEM;
-       }
-
        m = &data->msg;
        x = &data->xfer[0];
 
        spi_message_init(m);
 
        x->tx_buf = &data->tx_buf[0];
-       x->len = 1;
+       x->len = MAX1111_TX_BUF_SIZE;
        spi_message_add_tail(x, m);
 
        x++;
        x->rx_buf = &data->rx_buf[0];
-       x->len = 2;
+       x->len = MAX1111_RX_BUF_SIZE;
        spi_message_add_tail(x, m);
 
        return 0;
@@ -176,13 +174,15 @@ static int __devinit max1111_probe(struct spi_device *spi)
        if (err)
                goto err_free_data;
 
+       mutex_init(&data->drvdata_lock);
+
        data->spi = spi;
        spi_set_drvdata(spi, data);
 
        err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
        if (err) {
                dev_err(&spi->dev, "failed to create attribute group\n");
-               goto err_free_all;
+               goto err_free_data;
        }
 
        data->hwmon_dev = hwmon_device_register(&spi->dev);
@@ -199,9 +199,6 @@ static int __devinit max1111_probe(struct spi_device *spi)
 
 err_remove:
        sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
-err_free_all:
-       kfree(data->rx_buf);
-       kfree(data->tx_buf);
 err_free_data:
        kfree(data);
        return err;
@@ -213,8 +210,7 @@ static int __devexit max1111_remove(struct spi_device *spi)
 
        hwmon_device_unregister(data->hwmon_dev);
        sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
-       kfree(data->rx_buf);
-       kfree(data->tx_buf);
+       mutex_destroy(&data->drvdata_lock);
        kfree(data);
        return 0;
 }