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Message-Id: <20250113084503.228037-1-evepolonium@gmail.com>
Date: Mon, 13 Jan 2025 14:14:57 +0530
From: Atharva Tiwari <evepolonium@...il.com>
To:
Cc: evepolonium@...il.com,
Aun-Ali Zaidi <admin@...eit.net>,
Henrik Rydberg <rydberg@...math.org>,
Jean Delvare <jdelvare@...e.com>,
Guenter Roeck <linux@...ck-us.net>,
linux-kernel@...r.kernel.org,
linux-hwmon@...r.kernel.org
Subject: [PATCH v3] hwmon: Add T2 Mac fan control support in applesmc driver
This patch adds support for fan control on T2 Macs in the applesmc driver.
It introduces functions to handle floating-point fan speed values
(which are required by t2 chips).
The fan speed reading and writing are updated to support
both integer and floating-point values.
The fan manual control is also updated to handle T2 Mac-specific keys.
Guenter Roeck asked "Does this limit still apply?"
so yes the limit still applies.
Changes since v2:
--- fixed checkpatch issues
--- used function such as BIT(), FIELD_GET(), BIT_MASK()
in function "applesmc_float_to_u32" and "applesmc_u32_to_float"
for readability.
--- added error handling in function applesmc_show_fan_speed
--- used applesmc_write_entry instead of applesmc_write_key
in function applesmc_store_fan_speed
--- defined "F%dMd" as FAN_MANUAL_FMT
Co-developed-by: Aun-Ali Zaidi <admin@...eit.net>
Signed-off-by: Aun-Ali Zaidi <admin@...eit.net>
Signed-off-by: Atharva Tiwari <evepolonium@...il.com>
---
drivers/hwmon/applesmc.c | 122 ++++++++++++++++++++++++++++++++-------
1 file changed, 100 insertions(+), 22 deletions(-)
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index fc6d6a9053ce..e792d4283861 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -74,6 +74,7 @@
#define FAN_ID_FMT "F%dID" /* r-o char[16] */
#define TEMP_SENSOR_TYPE "sp78"
+#define FAN_MANUAL_FMT "F%dMd"
/* List of keys used to read/write fan speeds */
static const char *const fan_speed_fmt[] = {
@@ -511,6 +512,32 @@ static int applesmc_read_s16(const char *key, s16 *value)
return 0;
}
+static inline u32 applesmc_float_to_u32(u32 d)
+{
+ u8 sign = FIELD_GET(BIT(31), d);
+ s32 exp = FIELD_GET(BIT_MASK(8) << 23, d) - 0x7F;
+ u32 fr = d & ((1u << 23) - 1);
+
+ if (sign || exp < 0)
+ return 0;
+
+ return BIT(exp) + (fr >> (23 - exp));
+}
+
+static inline u32 applesmc_u32_to_float(u32 d)
+{
+ u32 dc = d, bc = 0, exp;
+
+ if (!d)
+ return 0;
+ while (dc >>= 1)
+ ++bc;
+ exp = 0x7F + bc;
+ return FIELD_PREP(BIT_MASK(8) << 23, exp) |
+ (d << (23 - (exp - 0x7F)) & BIT_MASK(23));
+
+}
+
/*
* applesmc_device_init - initialize the accelerometer. Can sleep.
*/
@@ -841,16 +868,33 @@ static ssize_t applesmc_show_fan_speed(struct device *dev,
int ret;
unsigned int speed = 0;
char newkey[5];
- u8 buffer[2];
+ u8 buffer[4] = {0};
+ const struct applesmc_entry *entry;
+ bool is_float = false;
scnprintf(newkey, sizeof(newkey), fan_speed_fmt[to_option(attr)],
to_index(attr));
- ret = applesmc_read_key(newkey, buffer, 2);
+ entry = applesmc_get_entry_by_key(newkey);
+ if (IS_ERR(entry))
+ return PTR_ERR(entry);
+
+ if (!strcmp(entry->type, "flt"))
+ is_float = true;
+
+ if (is_float) {
+ ret = applesmc_read_entry(entry, buffer, 4);
+ if (ret)
+ return ret;
+ speed = applesmc_float_to_u32(*(u32 *)buffer);
+ } else {
+ ret = applesmc_read_entry(entry, buffer, 2);
+ if (ret)
+ return ret;
+ speed = ((buffer[0] << 8 | buffer[1]) >> 2);
+ }
if (ret)
return ret;
-
- speed = ((buffer[0] << 8 | buffer[1]) >> 2);
return sysfs_emit(sysfsbuf, "%u\n", speed);
}
@@ -861,7 +905,9 @@ static ssize_t applesmc_store_fan_speed(struct device *dev,
int ret;
unsigned long speed;
char newkey[5];
- u8 buffer[2];
+ u8 buffer[4];
+ const struct applesmc_entry *entry;
+ bool is_float = false;
if (kstrtoul(sysfsbuf, 10, &speed) < 0 || speed >= 0x4000)
return -EINVAL; /* Bigger than a 14-bit value */
@@ -869,9 +915,20 @@ static ssize_t applesmc_store_fan_speed(struct device *dev,
scnprintf(newkey, sizeof(newkey), fan_speed_fmt[to_option(attr)],
to_index(attr));
- buffer[0] = (speed >> 6) & 0xff;
- buffer[1] = (speed << 2) & 0xff;
- ret = applesmc_write_key(newkey, buffer, 2);
+ entry = applesmc_get_entry_by_key(newkey);
+ if (IS_ERR(entry))
+ return PTR_ERR(entry);
+ if (!strcmp(entry->type, "flt"))
+ is_float = true;
+
+ if (is_float) {
+ *(u32 *)buffer = applesmc_u32_to_float(speed);
+ ret = applesmc_write_entry(entry, buffer, 4);
+ } else {
+ buffer[0] = (speed >> 6) & 0xff;
+ buffer[1] = (speed << 2) & 0xff;
+ ret = applesmc_write_entry((const struct applesmc_entry *)newkey, buffer, 2);
+ }
if (ret)
return ret;
@@ -885,12 +942,23 @@ static ssize_t applesmc_show_fan_manual(struct device *dev,
int ret;
u16 manual = 0;
u8 buffer[2];
+ char newkey[5];
+ bool has_newkey = false;
+
+ scnprintf(newkey, sizeof(newkey), FAN_MANUAL_FMT, to_index(attr));
+
+ ret = applesmc_has_key(newkey, &has_newkey);
+ if (has_newkey) {
+ ret = applesmc_read_key(newkey, buffer, 1);
+ manual = buffer[0] & 0x01;
+ } else {
+ ret = applesmc_read_key(FANS_MANUAL, buffer, 2);
+ manual = ((buffer[0] << 8 | buffer[1]) >> to_index(attr)) & 0x01;
+ }
- ret = applesmc_read_key(FANS_MANUAL, buffer, 2);
if (ret)
return ret;
- manual = ((buffer[0] << 8 | buffer[1]) >> to_index(attr)) & 0x01;
return sysfs_emit(sysfsbuf, "%d\n", manual);
}
@@ -900,28 +968,38 @@ static ssize_t applesmc_store_fan_manual(struct device *dev,
{
int ret;
u8 buffer[2];
+ char newkey[5];
+ bool has_newkey = false;
unsigned long input;
u16 val;
if (kstrtoul(sysfsbuf, 10, &input) < 0)
return -EINVAL;
- ret = applesmc_read_key(FANS_MANUAL, buffer, 2);
- if (ret)
- goto out;
-
- val = (buffer[0] << 8 | buffer[1]);
+ scnprintf(newkey, sizeof(newkey), FAN_MANUAL_FMT, to_index(attr));
- if (input)
- val = val | (0x01 << to_index(attr));
- else
- val = val & ~(0x01 << to_index(attr));
+ ret = applesmc_has_key(newkey, &has_newkey);
+ if (ret)
+ return ret;
+ if (has_newkey) {
+ buffer[0] = (input != 0x00);
+ ret = applesmc_write_key(newkey, buffer, 1);
+ } else {
+ ret = applesmc_read_key(FANS_MANUAL, buffer, 2);
+ val = (buffer[0] << 8 | buffer[1]);
+ if (ret)
+ goto out;
- buffer[0] = (val >> 8) & 0xFF;
- buffer[1] = val & 0xFF;
+ if (input)
+ val = val | (0x01 << to_index(attr));
+ else
+ val = val & ~(0x01 << to_index(attr));
- ret = applesmc_write_key(FANS_MANUAL, buffer, 2);
+ buffer[0] = (val >> 8) & 0xFF;
+ buffer[1] = val & 0xFF;
+ ret = applesmc_write_key(FANS_MANUAL, buffer, 2);
+ }
out:
if (ret)
return ret;
--
2.39.5
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