[PATCH AUTOSEL 6.13 15/31] platform/x86: thinkpad_acpi: Fix invalid fan speed on ThinkPad X120e

Sasha Levin
2025-02-18T20:25:27Z

From: Sybil Isabel Dorsett <sybdorsett@proton.me>

[ Upstream commit 1046cac109225eda0973b898e053aeb3d6c10e1d ]

On ThinkPad X120e, fan speed is reported in ticks per revolution
rather than RPM.

Recalculate the fan speed value reported for ThinkPad X120e
to RPM based on a 22.5 kHz clock.

Based on the information on
https://www.thinkwiki.org/wiki/How_to_control_fan_speed,
the same problem is highly likely to be relevant to at least Edge11,
but Edge11 is not addressed in this patch.

Signed-off-by: Sybil Isabel Dorsett <sybdorsett@proton.me>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250203163255.5525-1-sybdorsett@proton.me
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/platform/x86/thinkpad_acpi.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 2cfb2ac3f465a..05d77f87e235e 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -7883,6 +7883,7 @@ static struct ibm_struct volume_driver_data = {

#define FAN_NS_CTRL_STATUS BIT(2) /* Bit which determines control is enabled or not */
#define FAN_NS_CTRL BIT(4) /* Bit which determines control is by host or EC */
+#define FAN_CLOCK_TPM (22500*60) /* Ticks per minute for a 22.5 kHz clock */

enum { /* Fan control constants */
fan_status_offset = 0x2f, /* EC register 0x2f */
@@ -7938,6 +7939,7 @@ static int fan_watchdog_maxinterval;

static bool fan_with_ns_addr;
static bool ecfw_with_fan_dec_rpm;
+static bool fan_speed_in_tpr;

static struct mutex fan_mutex;

@@ -8140,8 +8142,11 @@ static int fan_get_speed(unsigned int *speed)
!acpi_ec_read(fan_rpm_offset + 1, &hi)))
return -EIO;

- if (likely(speed))
+ if (likely(speed)) {
*speed = (hi << 8) | lo;
+ if (fan_speed_in_tpr && *speed != 0)
+ *speed = FAN_CLOCK_TPM / *speed;
+ }
break;
case TPACPI_FAN_RD_TPEC_NS:
if (!acpi_ec_read(fan_rpm_status_ns, &lo))
@@ -8174,8 +8179,11 @@ static int fan2_get_speed(unsigned int *speed)
if (rc)
return -EIO;

- if (likely(speed))
+ if (likely(speed)) {
*speed = (hi << 8) | lo;
+ if (fan_speed_in_tpr && *speed != 0)
+ *speed = FAN_CLOCK_TPM / *speed;
+ }
break;

case TPACPI_FAN_RD_TPEC_NS:
@@ -8786,6 +8794,7 @@ static const struct attribute_group fan_driver_attr_group = {
#define TPACPI_FAN_NOFAN 0x0008 /* no fan available */
#define TPACPI_FAN_NS 0x0010 /* For EC with non-Standard register addresses */
#define TPACPI_FAN_DECRPM 0x0020 /* For ECFW's with RPM in register as decimal */
+#define TPACPI_FAN_TPR 0x0040 /* Fan speed is in Ticks Per Revolution */

static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
TPACPI_QEC_IBM('1', 'Y', TPACPI_FAN_Q1),
@@ -8815,6 +8824,7 @@ static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
TPACPI_Q_LNV3('R', '0', 'V', TPACPI_FAN_NS), /* 11e Gen5 KL-Y */
TPACPI_Q_LNV3('N', '1', 'O', TPACPI_FAN_NOFAN), /* X1 Tablet (2nd gen) */
TPACPI_Q_LNV3('R', '0', 'Q', TPACPI_FAN_DECRPM),/* L480 */
+ TPACPI_Q_LNV('8', 'F', TPACPI_FAN_TPR), /* ThinkPad x120e */
};

static int __init fan_init(struct ibm_init_struct *iibm)
@@ -8885,6 +8895,8 @@ static int __init fan_init(struct ibm_init_struct *iibm)

if (quirks & TPACPI_FAN_Q1)
fan_quirk1_setup();
+ if (quirks & TPACPI_FAN_TPR)
+ fan_speed_in_tpr = true;
/* Try and probe the 2nd fan */
tp_features.second_fan = 1; /* needed for get_speed to work */
res = fan2_get_speed(&speed);
--
2.39.5