[PATCH v2 7/9] Input: elantech - add support for SMBus devices

From: Benjamin Tissoires
Date: Mon Apr 09 2018 - 05:12:06 EST

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@xxxxxxxxxx>

---
changes in v2:
- use of device property instead of platform data
---
drivers/input/mouse/Kconfig | 12 +++
drivers/input/mouse/elantech.c | 188 +++++++++++++++++++++++++++++++++++-
drivers/input/mouse/elantech.h | 24 +++++
drivers/input/mouse/psmouse-base.c | 21 +++-
drivers/input/mouse/psmouse-smbus.c | 11 ++-
drivers/input/mouse/psmouse.h | 1 +
6 files changed, 246 insertions(+), 11 deletions(-)

diff --git a/drivers/input/mouse/Kconfig b/drivers/input/mouse/Kconfig
index 89ebb8f39fee..f27f23f2d99a 100644
--- a/drivers/input/mouse/Kconfig
+++ b/drivers/input/mouse/Kconfig
@@ -133,6 +133,18 @@ config MOUSE_PS2_ELANTECH

If unsure, say N.

+config MOUSE_PS2_ELANTECH_SMBUS
+ bool "Elantech PS/2 SMbus companion" if EXPERT
+ default y
+ depends on MOUSE_PS2 && MOUSE_PS2_ELANTECH
+ depends on I2C=y || I2C=MOUSE_PS2
+ select MOUSE_PS2_SMBUS
+ help
+ Say Y here if you have a Elantech touchpad connected to
+ to an SMBus, but enumerated through PS/2.
+
+ If unsure, say Y.
+
config MOUSE_PS2_SENTELIC
bool "Sentelic Finger Sensing Pad PS/2 protocol extension"
depends on MOUSE_PS2
diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index a2a14a31edb5..510e7c0622d3 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;
+}
diff --git a/drivers/input/mouse/elantech.h b/drivers/input/mouse/elantech.h
index 851df4ce6232..f9b1c485e8d9 100644
--- a/drivers/input/mouse/elantech.h
+++ b/drivers/input/mouse/elantech.h
@@ -106,6 +106,15 @@
*/
#define ETP_WEIGHT_VALUE 5

+/*
+ * Bus information on 3rd byte of query ETP_RESOLUTION_QUERY(0x04)
+ */
+#define ETP_BUS_PS2_ONLY 0
+#define ETP_BUS_SMB_ALERT_ONLY 1
+#define ETP_BUS_SMB_HST_NTFY_ONLY 2
+#define ETP_BUS_PS2_SMB_ALERT 3
+#define ETP_BUS_PS2_SMB_HST_NTFY 4
+
/*
* The base position for one finger, v4 hardware
*/
@@ -122,6 +131,7 @@ struct elantech_device_info {
unsigned int fw_version;
unsigned int x_res;
unsigned int y_res;
+ unsigned int bus;
bool paritycheck;
bool jumpy_cursor;
bool reports_pressure;
@@ -156,6 +166,7 @@ struct elantech_data {

#ifdef CONFIG_MOUSE_PS2_ELANTECH
int elantech_detect(struct psmouse *psmouse, bool set_properties);
+int elantech_init_ps2(struct psmouse *psmouse);
int elantech_init(struct psmouse *psmouse);
#else
static inline int elantech_detect(struct psmouse *psmouse, bool set_properties)
@@ -166,6 +177,19 @@ static inline int elantech_init(struct psmouse *psmouse)
{
return -ENOSYS;
}
+static inline int elantech_init_ps2(struct psmouse *psmouse)
+{
+ return -ENOSYS;
+}
#endif /* CONFIG_MOUSE_PS2_ELANTECH */

+#if defined(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)
+int elantech_init_smbus(struct psmouse *psmouse);
+#else
+static inline int elantech_init_smbus(struct psmouse *psmouse)
+{
+ return -ENOSYS;
+}
+#endif /* CONFIG_MOUSE_PS2_ELANTECH_SMBUS */
+
#endif
diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index 8900c3166ebf..5ff5b1952be0 100644
--- a/drivers/input/mouse/psmouse-base.c
+++ b/drivers/input/mouse/psmouse-base.c
@@ -856,7 +856,17 @@ static const struct psmouse_protocol psmouse_protocols[] = {
.name = "ETPS/2",
.alias = "elantech",
.detect = elantech_detect,
- .init = elantech_init,
+ .init = elantech_init_ps2,
+ },
+#endif
+#ifdef CONFIG_MOUSE_PS2_ELANTECH_SMBUS
+ {
+ .type = PSMOUSE_ELANTECH_SMBUS,
+ .name = "ETSMBus",
+ .alias = "elantech-smbus",
+ .detect = elantech_detect,
+ .init = elantech_init_smbus,
+ .smbus_companion = true,
},
#endif
#ifdef CONFIG_MOUSE_PS2_SENTELIC
@@ -1158,8 +1168,13 @@ static int psmouse_extensions(struct psmouse *psmouse,
/* Try Elantech touchpad */
if (max_proto > PSMOUSE_IMEX &&
psmouse_try_protocol(psmouse, PSMOUSE_ELANTECH,
- &max_proto, set_properties, true)) {
- return PSMOUSE_ELANTECH;
+ &max_proto, set_properties, false)) {
+ if (!set_properties)
+ return PSMOUSE_ELANTECH;
+
+ ret = elantech_init(psmouse);
+ if (ret >= 0)
+ return ret;
}

if (max_proto > PSMOUSE_IMEX) {
diff --git a/drivers/input/mouse/psmouse-smbus.c b/drivers/input/mouse/psmouse-smbus.c
index c7ac24d119c1..c8a3b1f35ce3 100644
--- a/drivers/input/mouse/psmouse-smbus.c
+++ b/drivers/input/mouse/psmouse-smbus.c
@@ -237,10 +237,13 @@ int psmouse_smbus_init(struct psmouse *psmouse,
smbdev->psmouse = psmouse;
smbdev->board = *board;

- smbdev->board.platform_data = kmemdup(pdata, pdata_size, GFP_KERNEL);
- if (!smbdev->board.platform_data) {
- kfree(smbdev);
- return -ENOMEM;
+ if (pdata) {
+ smbdev->board.platform_data = kmemdup(pdata, pdata_size,
+ GFP_KERNEL);
+ if (!smbdev->board.platform_data) {
+ kfree(smbdev);
+ return -ENOMEM;
+ }
}

psmouse->private = smbdev;
diff --git a/drivers/input/mouse/psmouse.h b/drivers/input/mouse/psmouse.h
index 71ac50082c8b..dd4ec1f602d7 100644
--- a/drivers/input/mouse/psmouse.h
+++ b/drivers/input/mouse/psmouse.h
@@ -68,6 +68,7 @@ enum psmouse_type {
PSMOUSE_VMMOUSE,
PSMOUSE_BYD,
PSMOUSE_SYNAPTICS_SMBUS,
+ PSMOUSE_ELANTECH_SMBUS,
PSMOUSE_AUTO /* This one should always be last */
};

--
2.14.3