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platform/x86: thinkpad_acpi: Add ThinkPad PrivacyGuard

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This feature is found optionally in T480s, T490, T490s.

The feature is called lcdshadow and visible via
/proc/acpi/ibm/lcdshadow.

The ACPI methods \_SB.PCI0.LPCB.EC.HKEY.{GSSS,SSSS,TSSS,CSSS} are
available in these machines. They get, set, toggle or change the state
apparently.

The patch was tested on a 5.0 series kernel on a T480s.

Signed-off-by: Alexander Schremmer <alex@alexanderweb.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This commit is contained in:
Alexander Schremmer
2019-08-22 13:48:33 +02:00
committed by Andy Shevchenko
parent ad0d315b4d
commit 110ea1d833
2 changed files with 128 additions and 0 deletions
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105
drivers/platform/x86/thinkpad_acpi.c
View File

@@ -9711,6 +9711,107 @@ static struct ibm_struct battery_driver_data = {
.exit = tpacpi_battery_exit,
};
/*************************************************************************
* LCD Shadow subdriver, for the Lenovo PrivacyGuard feature
*/
static int lcdshadow_state;
static int lcdshadow_on_off(bool state)
{
acpi_handle set_shadow_handle;
int output;
if (ACPI_FAILURE(acpi_get_handle(hkey_handle, "SSSS", &set_shadow_handle))) {
pr_warn("Thinkpad ACPI has no %s interface.\n", "SSSS");
return -EIO;
}
if (!acpi_evalf(set_shadow_handle, &output, NULL, "dd", (int)state))
return -EIO;
lcdshadow_state = state;
return 0;
}
static int lcdshadow_set(bool on)
{
if (lcdshadow_state < 0)
return lcdshadow_state;
if (lcdshadow_state == on)
return 0;
return lcdshadow_on_off(on);
}
static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)
{
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_evalf(get_shadow_handle, &output, NULL, "dd", 0)) {
lcdshadow_state = -EIO;
return -EIO;
}
if (!(output & 0x10000)) {
lcdshadow_state = -ENODEV;
return 0;
}
lcdshadow_state = output & 0x1;
return 0;
}
static void lcdshadow_resume(void)
{
if (lcdshadow_state >= 0)
lcdshadow_on_off(lcdshadow_state);
}
static int lcdshadow_read(struct seq_file *m)
{
if (lcdshadow_state < 0) {
seq_puts(m, "status:\t\tnot supported\n");
} else {
seq_printf(m, "status:\t\t%d\n", lcdshadow_state);
seq_puts(m, "commands:\t0, 1\n");
}
return 0;
}
static int lcdshadow_write(char *buf)
{
char *cmd;
int state = -1;
if (lcdshadow_state < 0)
return -ENODEV;
while ((cmd = next_cmd(&buf))) {
if (strlencmp(cmd, "0") == 0)
state = 0;
else if (strlencmp(cmd, "1") == 0)
state = 1;
}
if (state == -1)
return -EINVAL;
return lcdshadow_set(state);
}
static struct ibm_struct lcdshadow_driver_data = {
.name = "lcdshadow",
.resume = lcdshadow_resume,
.read = lcdshadow_read,
.write = lcdshadow_write,
};
/****************************************************************************
****************************************************************************
*
@@ -10192,6 +10293,10 @@ static struct ibm_init_struct ibms_init[] __initdata = {
.init = tpacpi_battery_init,
.data = &battery_driver_data,
},
{
.init = tpacpi_lcdshadow_init,
.data = &lcdshadow_driver_data,
},
};
static int __init set_ibm_param(const char *val, const struct kernel_param *kp)