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>

diff --git a/drivers/input/touchscreen/wacom_w8001.c b/drivers/input/touchscreen/wacom_w8001.c
index 2f33a01..56dc35c 100644 (file)
--- 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);