Input: elantech - add support for SMBus devices
Many of the Elantech devices are connected through PS/2 and a different
bus (SMBus or plain I2C).
To not break any existing device, we only enable SMBus based
on a module parameter. If some laptops require the quirk to
be set, we will have to rely on a list of PNPIds or MDI matching
to individually expose those hardware over SMBus.
the parameter mentioned above is elantech_smbus from the psmouse
module.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: KT Liao <kt.liao@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index a2a14a3..510e7c06 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -14,13 +14,16 @@
#include <linux/dmi.h>
#include <linux/slab.h>
#include <linux/module.h>
+#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
+#include <linux/platform_device.h>
#include <linux/serio.h>
#include <linux/libps2.h>
#include <asm/unaligned.h>
#include "psmouse.h"
#include "elantech.h"
+#include "elan_i2c.h"
#define elantech_debug(fmt, ...) \
do { \
@@ -1084,7 +1087,8 @@ static unsigned int elantech_convert_res(unsigned int val)
static int elantech_get_resolution_v4(struct psmouse *psmouse,
unsigned int *x_res,
- unsigned int *y_res)
+ unsigned int *y_res,
+ unsigned int *bus)
{
unsigned char param[3];
@@ -1093,6 +1097,7 @@ static int elantech_get_resolution_v4(struct psmouse *psmouse,
*x_res = elantech_convert_res(param[1] & 0x0f);
*y_res = elantech_convert_res((param[1] & 0xf0) >> 4);
+ *bus = param[2];
return 0;
}
@@ -1474,6 +1479,12 @@ static void elantech_disconnect(struct psmouse *psmouse)
{
struct elantech_data *etd = psmouse->private;
+ /*
+ * We might have left a breadcrumb when trying to
+ * set up SMbus companion.
+ */
+ psmouse_smbus_cleanup(psmouse);
+
if (etd->tp_dev)
input_unregister_device(etd->tp_dev);
sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
@@ -1659,6 +1670,8 @@ static int elantech_query_info(struct psmouse *psmouse,
{
unsigned char param[3];
+ memset(info, 0, sizeof(*info));
+
/*
* Do the version query again so we can store the result
*/
@@ -1717,7 +1730,8 @@ static int elantech_query_info(struct psmouse *psmouse,
if (info->hw_version == 4) {
if (elantech_get_resolution_v4(psmouse,
&info->x_res,
- &info->y_res)) {
+ &info->y_res,
+ &info->bus)) {
psmouse_warn(psmouse,
"failed to query resolution data.\n");
}
@@ -1726,6 +1740,129 @@ static int elantech_query_info(struct psmouse *psmouse,
return 0;
}
+#if defined(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)
+
+/*
+ * The newest Elantech device can use a secondary bus (over SMBus) which
+ * provides a better bandwidth and allow a better control of the touchpads.
+ * This is used to decide if we need to use this bus or not.
+ */
+enum {
+ ELANTECH_SMBUS_NOT_SET = -1,
+ ELANTECH_SMBUS_OFF,
+ ELANTECH_SMBUS_ON,
+};
+
+static int elantech_smbus = IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_SMBUS) ?
+ ELANTECH_SMBUS_NOT_SET : ELANTECH_SMBUS_OFF;
+module_param_named(elantech_smbus, elantech_smbus, int, 0644);
+MODULE_PARM_DESC(elantech_smbus, "Use a secondary bus for the Elantech device.");
+
+static int elantech_create_smbus(struct psmouse *psmouse,
+ struct elantech_device_info *info,
+ bool leave_breadcrumbs)
+{
+ const struct property_entry i2c_properties[] = {
+ PROPERTY_ENTRY_BOOL("elan,trackpoint"),
+ { },
+ };
+ struct i2c_board_info smbus_board = {
+ I2C_BOARD_INFO("elan_i2c", 0x15),
+ .flags = I2C_CLIENT_HOST_NOTIFY,
+ };
+
+ if (info->has_trackpoint)
+ smbus_board.properties = i2c_properties;
+
+ return psmouse_smbus_init(psmouse, &smbus_board, NULL, 0,
+ leave_breadcrumbs);
+}
+
+/**
+ * elantech_setup_smbus - called once the PS/2 devices are enumerated
+ * and decides to instantiate a SMBus InterTouch device.
+ */
+static int elantech_setup_smbus(struct psmouse *psmouse,
+ struct elantech_device_info *info,
+ bool leave_breadcrumbs)
+{
+ int error;
+
+ if (elantech_smbus == ELANTECH_SMBUS_OFF)
+ return -ENXIO;
+
+ if (elantech_smbus == ELANTECH_SMBUS_NOT_SET) {
+ /*
+ * FIXME:
+ * constraint the I2C capable devices by using FW version,
+ * board version, or by using DMI matching
+ */
+ return -ENXIO;
+ }
+
+ psmouse_info(psmouse, "Trying to set up SMBus access\n");
+
+ error = elantech_create_smbus(psmouse, info, leave_breadcrumbs);
+ if (error) {
+ if (error == -EAGAIN)
+ psmouse_info(psmouse, "SMbus companion is not ready yet\n");
+ else
+ psmouse_err(psmouse, "unable to create intertouch device\n");
+
+ return error;
+ }
+
+ return 0;
+}
+
+static bool elantech_use_host_notify(struct psmouse *psmouse,
+ struct elantech_device_info *info)
+{
+ switch (info->bus) {
+ case ETP_BUS_PS2_ONLY:
+ /* expected case */
+ break;
+ case ETP_BUS_SMB_ALERT_ONLY:
+ /* fall-through */
+ case ETP_BUS_PS2_SMB_ALERT:
+ psmouse_dbg(psmouse, "Ignoring SMBus provider through alert protocol.\n");
+ break;
+ case ETP_BUS_SMB_HST_NTFY_ONLY:
+ /* fall-through */
+ case ETP_BUS_PS2_SMB_HST_NTFY:
+ return true;
+ default:
+ psmouse_dbg(psmouse,
+ "Ignoring SMBus bus provider %d.\n",
+ info->bus);
+ }
+
+ return false;
+}
+
+int elantech_init_smbus(struct psmouse *psmouse)
+{
+ struct elantech_device_info info;
+ int error = -EINVAL;
+
+ psmouse_reset(psmouse);
+
+ error = elantech_query_info(psmouse, &info);
+ if (error)
+ goto init_fail;
+
+ if (info.hw_version < 4) {
+ error = -ENXIO;
+ goto init_fail;
+ }
+
+ return elantech_create_smbus(psmouse, &info, false);
+ init_fail:
+ psmouse_reset(psmouse);
+ return error;
+}
+#endif /* CONFIG_MOUSE_PS2_ELANTECH_SMBUS */
+
/*
* Initialize the touchpad and create sysfs entries
*/
@@ -1734,7 +1871,7 @@ static int elantech_setup_ps2(struct psmouse *psmouse,
{
struct elantech_data *etd;
int i;
- int error;
+ int error = -EINVAL;
struct input_dev *tp_dev;
psmouse->private = etd = kzalloc(sizeof(*etd), GFP_KERNEL);
@@ -1821,7 +1958,7 @@ static int elantech_setup_ps2(struct psmouse *psmouse,
return error;
}
-int elantech_init(struct psmouse *psmouse)
+int elantech_init_ps2(struct psmouse *psmouse)
{
struct elantech_device_info info;
int error = -EINVAL;
@@ -1841,3 +1978,46 @@ int elantech_init(struct psmouse *psmouse)
psmouse_reset(psmouse);
return error;
}
+
+int elantech_init(struct psmouse *psmouse)
+{
+ struct elantech_device_info info;
+ int error = -EINVAL;
+
+ psmouse_reset(psmouse);
+
+ error = elantech_query_info(psmouse, &info);
+ if (error)
+ goto init_fail;
+
+#if defined(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)
+
+ if (elantech_use_host_notify(psmouse, &info)) {
+ if (!IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_SMBUS) ||
+ !IS_ENABLED(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)) {
+ psmouse_warn(psmouse,
+ "The touchpad can support a better bus than the too old PS/2 protocol. "
+ "Make sure MOUSE_PS2_ELANTECH_SMBUS and MOUSE_ELAN_I2C_SMBUS are enabled to get a better touchpad experience.\n");
+ }
+ error = elantech_setup_smbus(psmouse, &info, true);
+ if (!error)
+ return PSMOUSE_ELANTECH_SMBUS;
+ }
+
+#endif /* CONFIG_MOUSE_PS2_ELANTECH_SMBUS */
+
+ error = elantech_setup_ps2(psmouse, &info);
+ if (error < 0) {
+ /*
+ * Not using any flavor of Elantech support, so clean up
+ * SMbus breadcrumbs, if any.
+ */
+ psmouse_smbus_cleanup(psmouse);
+ goto init_fail;
+ }
+
+ return PSMOUSE_ELANTECH;
+ init_fail:
+ psmouse_reset(psmouse);
+ return error;
+}