Input: resistive-adc-touch - rework mapping of channels

Instead of iterating over channels establish and use channel map to
retrieve data. As a side effect this will silence "uninitialized variable"
warnings.

Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/YLXR2brkc4H54xtK@google.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/resistive-adc-touch.c b/drivers/input/touchscreen/resistive-adc-touch.c
index ea1884f..ea7dd9d 100644 (file)
--- a/drivers/input/touchscreen/resistive-adc-touch.c
+++ b/drivers/input/touchscreen/resistive-adc-touch.c
@@ -25,12 +25,12 @@
 #define GRTS_MAX_CHANNELS                              4
 
 enum grts_ch_type {
-       GRTS_CH_NONE = 0,
        GRTS_CH_X,
        GRTS_CH_Y,
        GRTS_CH_PRESSURE,
        GRTS_CH_Z1,
        GRTS_CH_Z2,
+       GRTS_CH_MAX = GRTS_CH_Z2 + 1
 };
 
 /**
@@ -42,7 +42,7 @@ enum grts_ch_type {
  * @iio_cb:            iio_callback buffer for the data
  * @input:             the input device structure that we register
  * @prop:              touchscreen properties struct
- * @ch:                        channels that are defined for the touchscreen
+ * @ch_map:            map of channels that are defined for the touchscreen
  */
 struct grts_state {
        u32                             x_plate_ohms;
@@ -52,37 +52,25 @@ struct grts_state {
        struct iio_cb_buffer            *iio_cb;
        struct input_dev                *input;
        struct touchscreen_properties   prop;
-       u8                              ch[GRTS_MAX_CHANNELS];
+       u8                              ch_map[GRTS_CH_MAX];
 };
 
 static int grts_cb(const void *data, void *private)
 {
        const u16 *touch_info = data;
        struct grts_state *st = private;
-       unsigned int x, y, press = 0, z1 = 0, z2;
-       unsigned int Rt, i;
-
-       for (i = 0; i < ARRAY_SIZE(st->ch) && st->ch[i] != GRTS_CH_NONE; i++) {
-               switch (st->ch[i]) {
-               case GRTS_CH_X:
-                       x = touch_info[i];
-                       break;
-               case GRTS_CH_Y:
-                       y = touch_info[i];
-                       break;
-               case GRTS_CH_PRESSURE:
-                       press = touch_info[i];
-                       break;
-               case GRTS_CH_Z1:
-                       z1 = touch_info[i];
-                       break;
-               case GRTS_CH_Z2:
-                       z2 = touch_info[i];
-                       break;
-               }
-       }
+       unsigned int x, y, press;
+
+       x = touch_info[st->ch_map[GRTS_CH_X]];
+       y = touch_info[st->ch_map[GRTS_CH_Y]];
+
+       if (st->ch_map[GRTS_CH_PRESSURE] < GRTS_MAX_CHANNELS) {
+               press = touch_info[st->ch_map[GRTS_CH_PRESSURE]];
+       } else if (st->ch_map[GRTS_CH_Z1] < GRTS_MAX_CHANNELS) {
+               unsigned int z1 = touch_info[st->ch_map[GRTS_CH_Z1]];
+               unsigned int z2 = touch_info[st->ch_map[GRTS_CH_Z2]];
+               unsigned int Rt;
 
-       if (z1) {
                Rt = z2;
                Rt -= z1;
                Rt *= st->x_plate_ohms;
@@ -142,60 +130,59 @@ static void grts_disable(void *data)
        iio_channel_release_all_cb(data);
 }
 
-static int grts_get_properties(struct grts_state *st, struct device *dev)
+static int grts_map_channel(struct grts_state *st, struct device *dev,
+                           enum grts_ch_type type, const char *name,
+                           bool optional)
 {
-       int idx, error;
-
-       idx = device_property_match_string(dev, "io-channel-names", "x");
-       if (idx < 0)
-               return idx;
-
-       if (idx >= ARRAY_SIZE(st->ch))
+       int idx;
+
+       idx = device_property_match_string(dev, "io-channel-names", name);
+       if (idx < 0) {
+               if (!optional)
+                       return idx;
+               idx = GRTS_MAX_CHANNELS;
+       } else if (idx >= GRTS_MAX_CHANNELS) {
                return -EOVERFLOW;
+       }
 
-       st->ch[idx] = GRTS_CH_X;
+       st->ch_map[type] = idx;
+       return 0;
+}
 
-       idx = device_property_match_string(dev, "io-channel-names", "y");
-       if (idx < 0)
-               return idx;
+static int grts_get_properties(struct grts_state *st, struct device *dev)
+{
+       int error;
 
-       if (idx >= ARRAY_SIZE(st->ch))
-               return -EOVERFLOW;
+       error = grts_map_channel(st, dev, GRTS_CH_X, "x", false);
+       if (error)
+               return error;
 
-       st->ch[idx] = GRTS_CH_Y;
+       error = grts_map_channel(st, dev, GRTS_CH_Y, "y", false);
+       if (error)
+               return error;
 
        /* pressure is optional */
-       idx = device_property_match_string(dev, "io-channel-names", "pressure");
-       if (idx >= 0) {
-               if (idx >= ARRAY_SIZE(st->ch))
-                       return -EOVERFLOW;
+       error = grts_map_channel(st, dev, GRTS_CH_PRESSURE, "pressure", true);
+       if (error)
+               return error;
 
-               st->ch[idx] = GRTS_CH_PRESSURE;
+       if (st->ch_map[GRTS_CH_PRESSURE] < GRTS_MAX_CHANNELS) {
                st->pressure = true;
-
                return 0;
        }
 
        /* if no pressure is defined, try optional z1 + z2 */
-       idx = device_property_match_string(dev, "io-channel-names", "z1");
-       if (idx < 0)
-               return 0;
-
-       if (idx >= ARRAY_SIZE(st->ch))
-               return -EOVERFLOW;
+       error = grts_map_channel(st, dev, GRTS_CH_Z1, "z1", true);
+       if (error)
+               return error;
 
-       st->ch[idx] = GRTS_CH_Z1;
+       if (st->ch_map[GRTS_CH_Z1] >= GRTS_MAX_CHANNELS)
+               return 0;
 
        /* if z1 is provided z2 is not optional */
-       idx = device_property_match_string(dev, "io-channel-names", "z2");
-       if (idx < 0)
-               return idx;
-
-       if (idx >= ARRAY_SIZE(st->ch))
-               return -EOVERFLOW;
-
-       st->ch[idx] = GRTS_CH_Z2;
-       st->pressure = true;
+       error = grts_map_channel(st, dev, GRTS_CH_Z2, "z2", true);
+       if (error)
+               return error;
 
        error = device_property_read_u32(dev,
                                         "touchscreen-x-plate-ohms",
@@ -205,6 +192,7 @@ static int grts_get_properties(struct grts_state *st, struct device *dev)
                return error;
        }
 
+       st->pressure = true;
        return 0;
 }