Input: elants_i2c - use DMA safe i2c when possible

To avoid bounce buffer when an i2c controller decides to use DMA for a
transaction, let's make out buffer that we use for reads DMA-safe and let
the master know that DMAing into it is safe.

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index d21ca39..f2cb231 100644 (file)
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -147,10 +147,11 @@ struct elants_data {
        u8 cmd_resp[HEADER_SIZE];
        struct completion cmd_done;
 
-       u8 buf[MAX_PACKET_SIZE];
-
        bool wake_irq_enabled;
        bool keep_power_in_suspend;
+
+       /* Must be last to be used for DMA operations */
+       u8 buf[MAX_PACKET_SIZE] ____cacheline_aligned;
 };
 
 static int elants_i2c_send(struct i2c_client *client,
@@ -863,7 +864,7 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev)
        int i;
        int len;
 
-       len = i2c_master_recv(client, ts->buf, sizeof(ts->buf));
+       len = i2c_master_recv_dmasafe(client, ts->buf, sizeof(ts->buf));
        if (len < 0) {
                dev_err(&client->dev, "%s: failed to read data: %d\n",
                        __func__, len);