Input: wacom_w8001 - simplify querying logic

There is no need for locking when we send query and start commands
to the touchscreen since there is no concurrency.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 40 insertions, 81 deletions

diff --git a/drivers/input/touchscreen/wacom_w8001.c b/drivers/input/touchscreen/wacom_w8001.c
index 2f33a0167644..56dc35c94bb1 100644
--- a/drivers/input/touchscreen/wacom_w8001.c
+++ b/drivers/input/touchscreen/wacom_w8001.c
@@ -25,18 +25,16 @@ MODULE_AUTHOR("Jaya Kumar <jayakumar.lkml@gmail.com>");
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");
 
-/*
- * Definitions & global arrays.
- */
-
 #define W8001_MAX_LENGTH        11
-#define W8001_PACKET_LEN        11
-#define W8001_LEAD_MASK 0x80
-#define W8001_LEAD_BYTE 0x80
-#define W8001_TAB_MASK 0x40
-#define W8001_TAB_BYTE 0x40
+#define W8001_LEAD_MASK         0x80
+#define W8001_LEAD_BYTE         0x80
+#define W8001_TAB_MASK          0x40
+#define W8001_TAB_BYTE          0x40
 
-#define W8001_QUERY_PACKET 0x20
+#define W8001_QUERY_PACKET      0x20
+
+#define W8001_CMD_START         '1'
+#define W8001_CMD_QUERY         '*'
 
 struct w8001_coord {
         u8 rdy;
@@ -57,18 +55,19 @@ struct w8001_coord {
 struct w8001 {
         struct input_dev *dev;
         struct serio *serio;
-        struct mutex cmd_mutex;
         struct completion cmd_done;
         int id;
         int idx;
-        unsigned char expected_packet;
+        unsigned char response_type;
+        unsigned char response[W8001_MAX_LENGTH];
         unsigned char data[W8001_MAX_LENGTH];
-        unsigned char response[W8001_PACKET_LEN];
         char phys[32];
 };
 
-static int parse_data(u8 *data, struct w8001_coord *coord)
+static void parse_data(u8 *data, struct w8001_coord *coord)
 {
+        memset(coord, 0, sizeof(*coord));
+
         coord->rdy = data[0] & 0x20;
         coord->tsw = data[0] & 0x01;
         coord->f1 = data[0] & 0x02;
@@ -87,15 +86,15 @@ static int parse_data(u8 *data, struct w8001_coord *coord)
 
         coord->tilt_x = data[7] & 0x7F;
         coord->tilt_y = data[8] & 0x7F;
-
-        return 0;
 }
 
-static void w8001_process_data(struct w8001 *w8001, unsigned char data)
+static irqreturn_t w8001_interrupt(struct serio *serio,
+                                   unsigned char data, unsigned int flags)
 {
+        struct w8001 *w8001 = serio_get_drvdata(serio);
         struct input_dev *dev = w8001->dev;
-        u8 tmp;
         struct w8001_coord coord;
+        unsigned char tmp;
 
         w8001->data[w8001->idx] = data;
         switch (w8001->idx++) {
@@ -105,12 +104,13 @@ static void w8001_process_data(struct w8001 *w8001, unsigned char data)
                         w8001->idx = 0;
                 }
                 break;
+
         case 8:
                 tmp = w8001->data[0] & W8001_TAB_MASK;
                 if (unlikely(tmp == W8001_TAB_BYTE))
                         break;
+
                 w8001->idx = 0;
-                memset(&coord, 0, sizeof(coord));
                 parse_data(w8001->data, &coord);
                 input_report_abs(dev, ABS_X, coord.x);
                 input_report_abs(dev, ABS_Y, coord.y);
@@ -118,86 +118,48 @@ static void w8001_process_data(struct w8001 *w8001, unsigned char data)
                 input_report_key(dev, BTN_TOUCH, coord.tsw);
                 input_sync(dev);
                 break;
+
         case 10:
                 w8001->idx = 0;
-                memcpy(w8001->response, &w8001->data, W8001_PACKET_LEN);
-                w8001->expected_packet = W8001_QUERY_PACKET;
+                memcpy(w8001->response, w8001->data, W8001_MAX_LENGTH);
+                w8001->response_type = W8001_QUERY_PACKET;
                 complete(&w8001->cmd_done);
                 break;
         }
-}
-
-
-static irqreturn_t w8001_interrupt(struct serio *serio,
-                unsigned char data, unsigned int flags)
-{
-        struct w8001 *w8001 = serio_get_drvdata(serio);
-
-        w8001_process_data(w8001, data);
 
         return IRQ_HANDLED;
 }
 
-static int w8001_async_command(struct w8001 *w8001, unsigned char *packet,
-                                        int len)
-{
-        int rc = -1;
-        int i;
-
-        mutex_lock(&w8001->cmd_mutex);
-
-        for (i = 0; i < len; i++) {
-                if (serio_write(w8001->serio, packet[i]))
-                        goto out;
-        }
-        rc = 0;
-
-out:
-        mutex_unlock(&w8001->cmd_mutex);
-        return rc;
-}
-
-static int w8001_command(struct w8001 *w8001, unsigned char *packet, int len)
+static int w8001_command(struct w8001 *w8001, unsigned char command,
+                         bool wait_response)
 {
-        int rc = -1;
-        int i;
+        int rc;
 
-        mutex_lock(&w8001->cmd_mutex);
-
-        serio_pause_rx(w8001->serio);
+        w8001->response_type = 0;
         init_completion(&w8001->cmd_done);
-        serio_continue_rx(w8001->serio);
-
-        for (i = 0; i < len; i++) {
-                if (serio_write(w8001->serio, packet[i]))
-                        goto out;
-        }
 
-        wait_for_completion_timeout(&w8001->cmd_done, HZ);
+        rc = serio_write(w8001->serio, command);
+        if (rc == 0 && wait_response) {
 
-        if (w8001->expected_packet == W8001_QUERY_PACKET) {
-                /* We are back in reporting mode, the query was ACKed */
-                memcpy(packet, w8001->response, W8001_PACKET_LEN);
-                rc = 0;
+                wait_for_completion_timeout(&w8001->cmd_done, HZ);
+                if (w8001->response_type != W8001_QUERY_PACKET)
+                        rc = -EIO;
         }
 
-out:
-        mutex_unlock(&w8001->cmd_mutex);
         return rc;
 }
 
 static int w8001_setup(struct w8001 *w8001)
 {
-        struct w8001_coord coord;
         struct input_dev *dev = w8001->dev;
-        unsigned char start[1] = { '1' };
-        unsigned char query[11] = { '*' };
+        struct w8001_coord coord;
+        int error;
 
-        if (w8001_command(w8001, query, 1))
-                return -1;
+        error = w8001_command(w8001, W8001_CMD_QUERY, true);
+        if (error)
+                return error;
 
-        memset(&coord, 0, sizeof(coord));
-        parse_data(query, &coord);
+        parse_data(w8001->response, &coord);
 
         input_set_abs_params(dev, ABS_X, 0, coord.x, 0, 0);
         input_set_abs_params(dev, ABS_Y, 0, coord.y, 0, 0);
@@ -205,10 +167,7 @@ static int w8001_setup(struct w8001 *w8001)
         input_set_abs_params(dev, ABS_TILT_X, 0, coord.tilt_x, 0, 0);
         input_set_abs_params(dev, ABS_TILT_Y, 0, coord.tilt_y, 0, 0);
 
-        if (w8001_async_command(w8001, start, 1))
-                return -1;
-
-        return 0;
+        return w8001_command(w8001, W8001_CMD_START, false);
 }
 
 /*
@@ -249,7 +208,6 @@ static int w8001_connect(struct serio *serio, struct serio_driver *drv)
         w8001->serio = serio;
         w8001->id = serio->id.id;
         w8001->dev = input_dev;
-        mutex_init(&w8001->cmd_mutex);
         init_completion(&w8001->cmd_done);
         snprintf(w8001->phys, sizeof(w8001->phys), "%s/input0", serio->phys);
 
@@ -269,7 +227,8 @@ static int w8001_connect(struct serio *serio, struct serio_driver *drv)
         if (err)
                 goto fail2;
 
-        if (w8001_setup(w8001))
+        err = w8001_setup(w8001);
+        if (err)
                 goto fail3;
 
         err = input_register_device(w8001->dev);