[PATCH] thinkpad_acpi: Add sysfs entry for lcdshadow feature

Nitin Joshi
2020-02-20T07:48:04Z

This feature is supported on some Thinkpad products like T490s, Thinkpad
X1 yoga 4th Gen etc . The lcdshadow feature can be enabled and disabled
when user press "Fn" + "D" key. Currently, no user feedback is given for
this action. Adding as sysfs entry allows userspace to show an On Screen
Display whenever the setting changes.

Summary of changes is mentioned below :

- Added TP_HKEY_EV_LCDSHADOW_CHANGED for consistency inside the driver
- Added unmapped LCDSHADOW to keymap
- Added lcdshadow_get function to read value using ACPI
- Added lcdshadow_refresh function to re-read value and send notification
- Added sysfs group creation to tpaci_lcdshadow_init
- Added lcdshadow_exit to remove sysfs group again
- Implemented lcdshadow_enable_show/lcdshadow_enable_store
- Added handler to tpacpi_driver_event to update refresh lcdshadow
- Explicitly call tpacpi_driver_event for extended keyset

Patch is tested on kernel 5.5 on Thinkpad X1 Yoga 4th Gen.

Co-developed-by: Benjamin Berg <bberg@redhat.com>
Signed-off-by: Benjamin Berg <bberg@redhat.com>
Reviewed-by: Mark Pearson <mpearson@lenovo.com>
Signed-off-by: Nitin Joshi <njoshi1@lenovo.com>
---
drivers/platform/x86/thinkpad_acpi.c | 117 +++++++++++++++++++++++----
1 file changed, 102 insertions(+), 15 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index da794dcfdd92..bd137cc7baee 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -155,6 +155,7 @@ enum tpacpi_hkey_event_t {
TP_HKEY_EV_VOL_UP = 0x1015, /* Volume up or unmute */
TP_HKEY_EV_VOL_DOWN = 0x1016, /* Volume down or unmute */
TP_HKEY_EV_VOL_MUTE = 0x1017, /* Mixer output mute */
+ TP_HKEY_EV_LCDSHADOW_CHANGED = 0x130f, /* Eprivacy status changed */

/* Reasons for waking up from S3/S4 */
TP_HKEY_EV_WKUP_S3_UNDOCK = 0x2304, /* undock requested, S3 */
@@ -1925,6 +1926,7 @@ enum { /* hot key scan codes (derived from ACPI DSDT) */

/* Lenovo extended keymap, starting at 0x1300 */
TP_ACPI_HOTKEYSCAN_EXTENDED_START,
+ TP_ACPI_HOTKEYSCAN_LCDSHADOW = 67,
/* first new observed key (star, favorites) is 0x1311 */
TP_ACPI_HOTKEYSCAN_STAR = 69,
TP_ACPI_HOTKEYSCAN_CLIPPING_TOOL2,
@@ -3342,7 +3344,7 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
- KEY_UNKNOWN, KEY_UNKNOWN
+ KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,

},

@@ -3444,7 +3446,8 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
- KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
+ KEY_UNKNOWN, KEY_UNKNOWN, KEY_UNKNOWN,
+ KEY_RESERVED, /* LCD Shadow/ePrivacy */
KEY_UNKNOWN,

KEY_BOOKMARKS, /* Favorite app, 0x311 */
@@ -3921,6 +3924,7 @@ static bool hotkey_notify_hotkey(const u32 hkey,
scancode -= (0x300 - TP_ACPI_HOTKEYSCAN_EXTENDED_START);
if (scancode >= TP_ACPI_HOTKEYSCAN_EXTENDED_START &&
scancode < TPACPI_HOTKEY_MAP_LEN) {
+ tpacpi_driver_event(hkey);
tpacpi_input_send_key(scancode);
return true;
}
@@ -9717,6 +9721,12 @@ static struct ibm_struct battery_driver_data = {

static int lcdshadow_state;

+static void lcdshadow_notify_change(void)
+{
+ sysfs_notify(&tpacpi_pdev->dev.kobj, NULL,
+ "lcdshadow_enable");
+}
+
static int lcdshadow_on_off(bool state)
{
acpi_handle set_shadow_handle;
@@ -9731,6 +9741,7 @@ static int lcdshadow_on_off(bool state)
return -EIO;

lcdshadow_state = state;
+ lcdshadow_notify_change();
return 0;
}

@@ -9743,27 +9754,90 @@ static int lcdshadow_set(bool on)
return lcdshadow_on_off(on);
}

-static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)
+static int lcdshadow_get(void)
{
acpi_handle get_shadow_handle;
int output;

- if (ACPI_FAILURE(acpi_get_handle(hkey_handle, "GSSS", &get_shadow_handle))) {
- lcdshadow_state = -ENODEV;
- return 0;
- }
+ if (ACPI_FAILURE(acpi_get_handle(hkey_handle, "GSSS",
+ &get_shadow_handle)))
+ return -ENODEV;

- if (!acpi_evalf(get_shadow_handle, &output, NULL, "dd", 0)) {
- lcdshadow_state = -EIO;
+ if (!acpi_evalf(get_shadow_handle, &output, NULL, "dd", 0))
return -EIO;
+
+ if (!(output & 0x10000))
+ return -ENODEV;
+
+ return output & 0x1;
+}
+
+static void lcdshadow_refresh(void)
+{
+ int new_state;
+
+ new_state = lcdshadow_get();
+
+ if (lcdshadow_state != new_state) {
+ lcdshadow_state = new_state;
+ lcdshadow_notify_change();
}
- if (!(output & 0x10000)) {
- lcdshadow_state = -ENODEV;
- return 0;
- }
- lcdshadow_state = output & 0x1;
+}

- return 0;
+
+/* sysfs lcdshadow entry */
+static ssize_t lcdshadow_enable_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ if (lcdshadow_state < 0)
+ return lcdshadow_state;
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", lcdshadow_state);
+}
+
+static ssize_t lcdshadow_enable_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long t;
+ int res;
+
+ if (parse_strtoul(buf, 1, &t))
+ return -EINVAL;
+
+ tpacpi_disclose_usertask(attr->attr.name, "set to %ld\n", t);
+
+ res = lcdshadow_set(!!t);
+
+ return (res < 0) ? res : count;
+}
+
+static DEVICE_ATTR_RW(lcdshadow_enable);
+
+static struct attribute *lcdshadow_attributes[] = {
+ &dev_attr_lcdshadow_enable.attr,
+ NULL
+};
+
+static const struct attribute_group lcdshadow_attr_group = {
+ .attrs = lcdshadow_attributes,
+};
+
+
+static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)
+{
+ int res;
+
+ lcdshadow_state = lcdshadow_get();
+
+ if (lcdshadow_state < 0 && lcdshadow_state != -ENODEV)
+ return lcdshadow_state;
+
+ res = sysfs_create_group(&tpacpi_pdev->dev.kobj,
+ &lcdshadow_attr_group);
+
+ return res;
}

static void lcdshadow_resume(void)
@@ -9805,11 +9879,18 @@ static int lcdshadow_write(char *buf)
return lcdshadow_set(state);
}

+static void lcdshadow_exit(void)
+{
+ sysfs_remove_group(&tpacpi_pdev->dev.kobj,
+ &lcdshadow_attr_group);
+}
+
static struct ibm_struct lcdshadow_driver_data = {
.name = "lcdshadow",
.resume = lcdshadow_resume,
.read = lcdshadow_read,
.write = lcdshadow_write,
+ .exit = lcdshadow_exit,
};

/****************************************************************************
@@ -9859,6 +9940,12 @@ static void tpacpi_driver_event(const unsigned int hkey_event)

mutex_unlock(&kbdlight_mutex);
}
+ if (lcdshadow_state >= 0) {
+ switch (hkey_event) {
+ case TP_HKEY_EV_LCDSHADOW_CHANGED:
+ lcdshadow_refresh();
+ }
+ }
}

static void hotkey_driver_event(const unsigned int scancode)
--
2.17.1