Input: trackpoint - only expose supported controls for Elan, ALPS and NXP

The newer trackpoints from ALPS, Elan and NXP implement a very limited
subset of extended commands and controls that the original trackpoints
implemented, so we should not be exposing not working controls in sysfs.
The newer trackpoints also do not implement "Power On Reset" or "Read
Extended Button Status", so we should not be using these commands during
initialization.

While we are at it, let's change "unsigned char" to u8 for byte data or
bool for booleans and use better suited error codes instead of -1.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

2 files changed, 172 insertions, 110 deletions

diff --git a/drivers/input/mouse/trackpoint.c b/drivers/input/mouse/trackpoint.c
index 92a8898682a6..bbd29220dbe9 100644
--- a/drivers/input/mouse/trackpoint.c
+++ b/drivers/input/mouse/trackpoint.c
@@ -19,6 +19,13 @@
 #include "psmouse.h"
 #include "trackpoint.h"
 
+static const char * const trackpoint_variants[] = {
+        [TP_VARIANT_IBM]        = "IBM",
+        [TP_VARIANT_ALPS]       = "ALPS",
+        [TP_VARIANT_ELAN]       = "Elan",
+        [TP_VARIANT_NXP]        = "NXP",
+};
+
 /*
  * Power-on Reset: Resets all trackpoint parameters, including RAM values,
  * to defaults.
@@ -26,7 +33,7 @@
  */
 static int trackpoint_power_on_reset(struct ps2dev *ps2dev)
 {
-        unsigned char results[2];
+        u8 results[2];
         int tries = 0;
 
         /* Issue POR command, and repeat up to once if 0xFC00 received */
@@ -38,7 +45,7 @@ static int trackpoint_power_on_reset(struct ps2dev *ps2dev)
 
         /* Check for success response -- 0xAA00 */
         if (results[0] != 0xAA || results[1] != 0x00)
-                return -1;
+                return -ENODEV;
 
         return 0;
 }
@@ -46,8 +53,7 @@ static int trackpoint_power_on_reset(struct ps2dev *ps2dev)
 /*
  * Device IO: read, write and toggle bit
  */
-static int trackpoint_read(struct ps2dev *ps2dev,
-                           unsigned char loc, unsigned char *results)
+static int trackpoint_read(struct ps2dev *ps2dev, u8 loc, u8 *results)
 {
         if (ps2_command(ps2dev, NULL, MAKE_PS2_CMD(0, 0, TP_COMMAND)) ||
             ps2_command(ps2dev, results, MAKE_PS2_CMD(0, 1, loc))) {
@@ -57,8 +63,7 @@ static int trackpoint_read(struct ps2dev *ps2dev,
         return 0;
 }
 
-static int trackpoint_write(struct ps2dev *ps2dev,
-                            unsigned char loc, unsigned char val)
+static int trackpoint_write(struct ps2dev *ps2dev, u8 loc, u8 val)
 {
         if (ps2_command(ps2dev, NULL, MAKE_PS2_CMD(0, 0, TP_COMMAND)) ||
             ps2_command(ps2dev, NULL, MAKE_PS2_CMD(0, 0, TP_WRITE_MEM)) ||
@@ -70,8 +75,7 @@ static int trackpoint_write(struct ps2dev *ps2dev,
         return 0;
 }
 
-static int trackpoint_toggle_bit(struct ps2dev *ps2dev,
-                                 unsigned char loc, unsigned char mask)
+static int trackpoint_toggle_bit(struct ps2dev *ps2dev, u8 loc, u8 mask)
 {
         /* Bad things will happen if the loc param isn't in this range */
         if (loc < 0x20 || loc >= 0x2F)
@@ -87,11 +91,11 @@ static int trackpoint_toggle_bit(struct ps2dev *ps2dev,
         return 0;
 }
 
-static int trackpoint_update_bit(struct ps2dev *ps2dev, unsigned char loc,
-                                 unsigned char mask, unsigned char value)
+static int trackpoint_update_bit(struct ps2dev *ps2dev,
+                                 u8 loc, u8 mask, u8 value)
 {
         int retval = 0;
-        unsigned char data;
+        u8 data;
 
         trackpoint_read(ps2dev, loc, &data);
         if (((data & mask) == mask) != !!value)
@@ -105,17 +109,18 @@ static int trackpoint_update_bit(struct ps2dev *ps2dev, unsigned char loc,
  */
 struct trackpoint_attr_data {
         size_t field_offset;
-        unsigned char command;
-        unsigned char mask;
-        unsigned char inverted;
-        unsigned char power_on_default;
+        u8 command;
+        u8 mask;
+        bool inverted;
+        u8 power_on_default;
 };
 
-static ssize_t trackpoint_show_int_attr(struct psmouse *psmouse, void *data, char *buf)
+static ssize_t trackpoint_show_int_attr(struct psmouse *psmouse,
+                                        void *data, char *buf)
 {
         struct trackpoint_data *tp = psmouse->private;
         struct trackpoint_attr_data *attr = data;
-        unsigned char value = *(unsigned char *)((char *)tp + attr->field_offset);
+        u8 value = *(u8 *)((void *)tp + attr->field_offset);
 
         if (attr->inverted)
                 value = !value;
@@ -128,8 +133,8 @@ static ssize_t trackpoint_set_int_attr(struct psmouse *psmouse, void *data,
 {
         struct trackpoint_data *tp = psmouse->private;
         struct trackpoint_attr_data *attr = data;
-        unsigned char *field = (unsigned char *)((char *)tp + attr->field_offset);
-        unsigned char value;
+        u8 *field = (void *)tp + attr->field_offset;
+        u8 value;
         int err;
 
         err = kstrtou8(buf, 10, &value);
@@ -157,17 +162,14 @@ static ssize_t trackpoint_set_bit_attr(struct psmouse *psmouse, void *data,
 {
         struct trackpoint_data *tp = psmouse->private;
         struct trackpoint_attr_data *attr = data;
-        unsigned char *field = (unsigned char *)((char *)tp + attr->field_offset);
-        unsigned int value;
+        bool *field = (void *)tp + attr->field_offset;
+        bool value;
         int err;
 
-        err = kstrtouint(buf, 10, &value);
+        err = kstrtobool(buf, &value);
         if (err)
                 return err;
 
-        if (value > 1)
-                return -EINVAL;
-
         if (attr->inverted)
                 value = !value;
 
@@ -193,30 +195,6 @@ PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,				\
                     &trackpoint_attr_##_name,                           \
                     trackpoint_show_int_attr, trackpoint_set_bit_attr)
 
-#define TRACKPOINT_UPDATE_BIT(_psmouse, _tp, _name)                     \
-do {                                                                    \
-        struct trackpoint_attr_data *_attr = &trackpoint_attr_##_name;  \
-                                                                        \
-        trackpoint_update_bit(&_psmouse->ps2dev,                        \
-                        _attr->command, _attr->mask, _tp->_name);       \
-} while (0)
-
-#define TRACKPOINT_UPDATE(_power_on, _psmouse, _tp, _name)              \
-do {                                                                    \
-        if (!_power_on ||                                               \
-            _tp->_name != trackpoint_attr_##_name.power_on_default) {   \
-                if (!trackpoint_attr_##_name.mask)                      \
-                        trackpoint_write(&_psmouse->ps2dev,             \
-                                 trackpoint_attr_##_name.command,       \
-                                 _tp->_name);                           \
-                else                                                    \
-                        TRACKPOINT_UPDATE_BIT(_psmouse, _tp, _name);    \
-        }                                                               \
-} while (0)
-
-#define TRACKPOINT_SET_POWER_ON_DEFAULT(_tp, _name)                             \
-        (_tp->_name = trackpoint_attr_##_name.power_on_default)
-
 TRACKPOINT_INT_ATTR(sensitivity, TP_SENS, TP_DEF_SENS);
 TRACKPOINT_INT_ATTR(speed, TP_SPEED, TP_DEF_SPEED);
 TRACKPOINT_INT_ATTR(inertia, TP_INERTIA, TP_DEF_INERTIA);
@@ -229,13 +207,33 @@ TRACKPOINT_INT_ATTR(ztime, TP_Z_TIME, TP_DEF_Z_TIME);
 TRACKPOINT_INT_ATTR(jenks, TP_JENKS_CURV, TP_DEF_JENKS_CURV);
 TRACKPOINT_INT_ATTR(drift_time, TP_DRIFT_TIME, TP_DEF_DRIFT_TIME);
 
-TRACKPOINT_BIT_ATTR(press_to_select, TP_TOGGLE_PTSON, TP_MASK_PTSON, 0,
+TRACKPOINT_BIT_ATTR(press_to_select, TP_TOGGLE_PTSON, TP_MASK_PTSON, false,
                     TP_DEF_PTSON);
-TRACKPOINT_BIT_ATTR(skipback, TP_TOGGLE_SKIPBACK, TP_MASK_SKIPBACK, 0,
+TRACKPOINT_BIT_ATTR(skipback, TP_TOGGLE_SKIPBACK, TP_MASK_SKIPBACK, false,
                     TP_DEF_SKIPBACK);
-TRACKPOINT_BIT_ATTR(ext_dev, TP_TOGGLE_EXT_DEV, TP_MASK_EXT_DEV, 1,
+TRACKPOINT_BIT_ATTR(ext_dev, TP_TOGGLE_EXT_DEV, TP_MASK_EXT_DEV, true,
                     TP_DEF_EXT_DEV);
 
+static bool trackpoint_is_attr_available(struct psmouse *psmouse,
+                                         struct attribute *attr)
+{
+        struct trackpoint_data *tp = psmouse->private;
+
+        return tp->variant_id == TP_VARIANT_IBM ||
+                attr == &psmouse_attr_sensitivity.dattr.attr ||
+                attr == &psmouse_attr_press_to_select.dattr.attr;
+}
+
+static umode_t trackpoint_is_attr_visible(struct kobject *kobj,
+                                          struct attribute *attr, int n)
+{
+        struct device *dev = container_of(kobj, struct device, kobj);
+        struct serio *serio = to_serio_port(dev);
+        struct psmouse *psmouse = serio_get_drvdata(serio);
+
+        return trackpoint_is_attr_available(psmouse, attr) ? attr->mode : 0;
+}
+
 static struct attribute *trackpoint_attrs[] = {
         &psmouse_attr_sensitivity.dattr.attr,
         &psmouse_attr_speed.dattr.attr,
@@ -255,24 +253,56 @@ static struct attribute *trackpoint_attrs[] = {
 };
 
 static struct attribute_group trackpoint_attr_group = {
-        .attrs = trackpoint_attrs,
+        .is_visible     = trackpoint_is_attr_visible,
+        .attrs          = trackpoint_attrs,
 };
 
-static int trackpoint_start_protocol(struct psmouse *psmouse, unsigned char *firmware_id)
-{
-        unsigned char param[2] = { 0 };
+#define TRACKPOINT_UPDATE(_power_on, _psmouse, _tp, _name)              \
+do {                                                                    \
+        struct trackpoint_attr_data *_attr = &trackpoint_attr_##_name;  \
+                                                                        \
+        if ((!_power_on || _tp->_name != _attr->power_on_default) &&    \
+            trackpoint_is_attr_available(_psmouse,                      \
+                                &psmouse_attr_##_name.dattr.attr)) {    \
+                if (!_attr->mask)                                       \
+                        trackpoint_write(&_psmouse->ps2dev,             \
+                                         _attr->command, _tp->_name);   \
+                else                                                    \
+                        trackpoint_update_bit(&_psmouse->ps2dev,        \
+                                        _attr->command, _attr->mask,    \
+                                        _tp->_name);                    \
+        }                                                               \
+} while (0)
 
-        if (ps2_command(&psmouse->ps2dev, param, MAKE_PS2_CMD(0, 2, TP_READ_ID)))
-                return -1;
+#define TRACKPOINT_SET_POWER_ON_DEFAULT(_tp, _name)                     \
+do {                                                                    \
+        _tp->_name = trackpoint_attr_##_name.power_on_default;          \
+} while (0)
 
-        /* add new TP ID. */
-        if (!(param[0] & TP_MAGIC_IDENT))
-                return -1;
+static int trackpoint_start_protocol(struct psmouse *psmouse,
+                                     u8 *variant_id, u8 *firmware_id)
+{
+        u8 param[2] = { 0 };
+        int error;
 
-        if (firmware_id)
-                *firmware_id = param[1];
+        error = ps2_command(&psmouse->ps2dev,
+                            param, MAKE_PS2_CMD(0, 2, TP_READ_ID));
+        if (error)
+                return error;
+
+        switch (param[0]) {
+        case TP_VARIANT_IBM:
+        case TP_VARIANT_ALPS:
+        case TP_VARIANT_ELAN:
+        case TP_VARIANT_NXP:
+                if (variant_id)
+                        *variant_id = param[0];
+                if (firmware_id)
+                        *firmware_id = param[1];
+                return 0;
+        }
 
-        return 0;
+        return -ENODEV;
 }
 
 /*
@@ -285,7 +315,7 @@ static int trackpoint_sync(struct psmouse *psmouse, bool in_power_on_state)
 {
         struct trackpoint_data *tp = psmouse->private;
 
-        if (!in_power_on_state) {
+        if (!in_power_on_state && tp->variant_id == TP_VARIANT_IBM) {
                 /*
                  * Disable features that may make device unusable
                  * with this driver.
@@ -347,7 +377,8 @@ static void trackpoint_defaults(struct trackpoint_data *tp)
 
 static void trackpoint_disconnect(struct psmouse *psmouse)
 {
-        sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj, &trackpoint_attr_group);
+        device_remove_group(&psmouse->ps2dev.serio->dev,
+                            &trackpoint_attr_group);
 
         kfree(psmouse->private);
         psmouse->private = NULL;
@@ -355,14 +386,20 @@ static void trackpoint_disconnect(struct psmouse *psmouse)
 
 static int trackpoint_reconnect(struct psmouse *psmouse)
 {
-        int reset_fail;
+        struct trackpoint_data *tp = psmouse->private;
+        int error;
+        bool was_reset;
 
-        if (trackpoint_start_protocol(psmouse, NULL))
-                return -1;
+        error = trackpoint_start_protocol(psmouse, NULL, NULL);
+        if (error)
+                return error;
 
-        reset_fail = trackpoint_power_on_reset(&psmouse->ps2dev);
-        if (trackpoint_sync(psmouse, !reset_fail))
-                return -1;
+        was_reset = tp->variant_id == TP_VARIANT_IBM &&
+                    trackpoint_power_on_reset(&psmouse->ps2dev) == 0;
+
+        error = trackpoint_sync(psmouse, was_reset);
+        if (error)
+                return error;
 
         return 0;
 }
@@ -370,49 +407,66 @@ static int trackpoint_reconnect(struct psmouse *psmouse)
 int trackpoint_detect(struct psmouse *psmouse, bool set_properties)
 {
         struct ps2dev *ps2dev = &psmouse->ps2dev;
-        unsigned char firmware_id;
-        unsigned char button_info;
+        struct trackpoint_data *tp;
+        u8 variant_id;
+        u8 firmware_id;
+        u8 button_info;
         int error;
 
-        if (trackpoint_start_protocol(psmouse, &firmware_id))
-                return -1;
+        error = trackpoint_start_protocol(psmouse, &variant_id, &firmware_id);
+        if (error)
+                return error;
 
         if (!set_properties)
                 return 0;
 
-        if (trackpoint_read(ps2dev, TP_EXT_BTN, &button_info)) {
-                psmouse_warn(psmouse, "failed to get extended button data, assuming 3 buttons\n");
-                button_info = 0x33;
-        } else if (!button_info) {
-                psmouse_warn(psmouse, "got 0 in extended button data, assuming 3 buttons\n");
-                button_info = 0x33;
-        }
-
-        psmouse->private = kzalloc(sizeof(struct trackpoint_data), GFP_KERNEL);
-        if (!psmouse->private)
+        tp = kzalloc(sizeof(*tp), GFP_KERNEL);
+        if (!tp)
                 return -ENOMEM;
 
-        psmouse->vendor = "IBM";
+        trackpoint_defaults(tp);
+        tp->variant_id = variant_id;
+        tp->firmware_id = firmware_id;
+
+        psmouse->private = tp;
+
+        psmouse->vendor = trackpoint_variants[variant_id];
         psmouse->name = "TrackPoint";
 
         psmouse->reconnect = trackpoint_reconnect;
         psmouse->disconnect = trackpoint_disconnect;
 
+        if (variant_id != TP_VARIANT_IBM) {
+                /* Newer variants do not support extended button query. */
+                button_info = 0x33;
+        } else {
+                error = trackpoint_read(ps2dev, TP_EXT_BTN, &button_info);
+                if (error) {
+                        psmouse_warn(psmouse,
+                                     "failed to get extended button data, assuming 3 buttons\n");
+                        button_info = 0x33;
+                } else if (!button_info) {
+                        psmouse_warn(psmouse,
+                                     "got 0 in extended button data, assuming 3 buttons\n");
+                        button_info = 0x33;
+                }
+        }
+
         if ((button_info & 0x0f) >= 3)
-                __set_bit(BTN_MIDDLE, psmouse->dev->keybit);
+                input_set_capability(psmouse->dev, EV_KEY, BTN_MIDDLE);
 
         __set_bit(INPUT_PROP_POINTER, psmouse->dev->propbit);
         __set_bit(INPUT_PROP_POINTING_STICK, psmouse->dev->propbit);
 
-        trackpoint_defaults(psmouse->private);
-
-        error = trackpoint_power_on_reset(ps2dev);
-
-        /* Write defaults to TP only if reset fails. */
-        if (error)
+        if (variant_id != TP_VARIANT_IBM ||
+            trackpoint_power_on_reset(ps2dev) != 0) {
+                /*
+                 * Write defaults to TP if we did not reset the trackpoint.
+                 */
                 trackpoint_sync(psmouse, false);
+        }
 
-        error = sysfs_create_group(&ps2dev->serio->dev.kobj, &trackpoint_attr_group);
+        error = device_add_group(&ps2dev->serio->dev, &trackpoint_attr_group);
         if (error) {
                 psmouse_err(psmouse,
                             "failed to create sysfs attributes, error: %d\n",
@@ -423,8 +477,8 @@ int trackpoint_detect(struct psmouse *psmouse, bool set_properties)
         }
 
         psmouse_info(psmouse,
-                     "IBM TrackPoint firmware: 0x%02x, buttons: %d/%d\n",
-                     firmware_id,
+                     "%s TrackPoint firmware: 0x%02x, buttons: %d/%d\n",
+                     psmouse->vendor, firmware_id,
                      (button_info & 0xf0) >> 4, button_info & 0x0f);
 
         return 0;
diff --git a/drivers/input/mouse/trackpoint.h b/drivers/input/mouse/trackpoint.h
index 88055755f82e..10a039148234 100644
--- a/drivers/input/mouse/trackpoint.h
+++ b/drivers/input/mouse/trackpoint.h
@@ -21,10 +21,16 @@
 #define TP_COMMAND              0xE2    /* Commands start with this */
 
 #define TP_READ_ID              0xE1    /* Sent for device identification */
-#define TP_MAGIC_IDENT          0x03    /* Sent after a TP_READ_ID followed */
-                                        /* by the firmware ID */
-                                        /* Firmware ID includes 0x1, 0x2, 0x3 */
 
+/*
+ * Valid first byte responses to the "Read Secondary ID" (0xE1) command.
+ * 0x01 was the original IBM trackpoint, others implement very limited
+ * subset of trackpoint features.
+ */
+#define TP_VARIANT_IBM          0x01
+#define TP_VARIANT_ALPS         0x02
+#define TP_VARIANT_ELAN         0x03
+#define TP_VARIANT_NXP          0x04
 
 /*
  * Commands
@@ -136,18 +142,20 @@
 
 #define MAKE_PS2_CMD(params, results, cmd) ((params<<12) | (results<<8) | (cmd))
 
-struct trackpoint_data
-{
-        unsigned char sensitivity, speed, inertia, reach;
-        unsigned char draghys, mindrag;
-        unsigned char thresh, upthresh;
-        unsigned char ztime, jenks;
-        unsigned char drift_time;
+struct trackpoint_data {
+        u8 variant_id;
+        u8 firmware_id;
+
+        u8 sensitivity, speed, inertia, reach;
+        u8 draghys, mindrag;
+        u8 thresh, upthresh;
+        u8 ztime, jenks;
+        u8 drift_time;
 
         /* toggles */
-        unsigned char press_to_select;
-        unsigned char skipback;
-        unsigned char ext_dev;
+        bool press_to_select;
+        bool skipback;
+        bool ext_dev;
 };
 
 #ifdef CONFIG_MOUSE_PS2_TRACKPOINT