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hwmon: (dell-smm) Make fan/temp sensor number a u8
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Right now, we only use bits 0 to 7 of the fan/temp sensor number
by doing number & 0xff. Passing the value as a u8 makes this
step unnecessary. Also add checks to the ioctl handler since
users might get confused when passing 0x00000101 does the same
as passing 0x00000001.

Tested on a Dell Inspiron 3505.

Signed-off-by: Armin Wolf <[email protected]>
Reviewed-by: Pali Rohár <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>
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@Wer-Wolf @groeck
Wer-Wolf authored and groeck committed Feb 28, 2022
1 parent ec3db1e commit 4d9983d
Showing 1 changed file with 45 additions and 23 deletions.
68 changes: 45 additions & 23 deletions drivers/hwmon/dell-smm-hwmon.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
#include <linux/errno.h>
#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
Expand Down Expand Up @@ -250,46 +251,52 @@ static int i8k_smm(struct smm_regs *regs)
/*
* Read the fan status.
*/
static int i8k_get_fan_status(const struct dell_smm_data *data, int fan)
static int i8k_get_fan_status(const struct dell_smm_data *data, u8 fan)
{
struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
struct smm_regs regs = {
.eax = I8K_SMM_GET_FAN,
.ebx = fan,
};

if (data->disallow_fan_support)
return -EINVAL;

regs.ebx = fan & 0xff;
return i8k_smm(&regs) ? : regs.eax & 0xff;
}

/*
* Read the fan speed in RPM.
*/
static int i8k_get_fan_speed(const struct dell_smm_data *data, int fan)
static int i8k_get_fan_speed(const struct dell_smm_data *data, u8 fan)
{
struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
struct smm_regs regs = {
.eax = I8K_SMM_GET_SPEED,
.ebx = fan,
};

if (data->disallow_fan_support)
return -EINVAL;

regs.ebx = fan & 0xff;
return i8k_smm(&regs) ? : (regs.eax & 0xffff) * data->i8k_fan_mult;
}

/*
* Read the fan type.
*/
static int _i8k_get_fan_type(const struct dell_smm_data *data, int fan)
static int _i8k_get_fan_type(const struct dell_smm_data *data, u8 fan)
{
struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
struct smm_regs regs = {
.eax = I8K_SMM_GET_FAN_TYPE,
.ebx = fan,
};

if (data->disallow_fan_support || data->disallow_fan_type_call)
return -EINVAL;

regs.ebx = fan & 0xff;
return i8k_smm(&regs) ? : regs.eax & 0xff;
}

static int i8k_get_fan_type(struct dell_smm_data *data, int fan)
static int i8k_get_fan_type(struct dell_smm_data *data, u8 fan)
{
/* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
if (data->fan_type[fan] == INT_MIN)
Expand All @@ -301,14 +308,16 @@ static int i8k_get_fan_type(struct dell_smm_data *data, int fan)
/*
* Read the fan nominal rpm for specific fan speed.
*/
static int __init i8k_get_fan_nominal_speed(const struct dell_smm_data *data, int fan, int speed)
static int __init i8k_get_fan_nominal_speed(const struct dell_smm_data *data, u8 fan, int speed)
{
struct smm_regs regs = { .eax = I8K_SMM_GET_NOM_SPEED, };
struct smm_regs regs = {
.eax = I8K_SMM_GET_NOM_SPEED,
.ebx = fan | (speed << 8),
};

if (data->disallow_fan_support)
return -EINVAL;

regs.ebx = (fan & 0xff) | (speed << 8);
return i8k_smm(&regs) ? : (regs.eax & 0xffff) * data->i8k_fan_mult;
}

Expand All @@ -329,41 +338,43 @@ static int i8k_enable_fan_auto_mode(const struct dell_smm_data *data, bool enabl
/*
* Set the fan speed (off, low, high, ...).
*/
static int i8k_set_fan(const struct dell_smm_data *data, int fan, int speed)
static int i8k_set_fan(const struct dell_smm_data *data, u8 fan, int speed)
{
struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };

if (data->disallow_fan_support)
return -EINVAL;

speed = (speed < 0) ? 0 : ((speed > data->i8k_fan_max) ? data->i8k_fan_max : speed);
regs.ebx = (fan & 0xff) | (speed << 8);
regs.ebx = fan | (speed << 8);

return i8k_smm(&regs);
}

static int __init i8k_get_temp_type(int sensor)
static int __init i8k_get_temp_type(u8 sensor)
{
struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP_TYPE, };
struct smm_regs regs = {
.eax = I8K_SMM_GET_TEMP_TYPE,
.ebx = sensor,
};

regs.ebx = sensor & 0xff;
return i8k_smm(&regs) ? : regs.eax & 0xff;
}

/*
* Read the cpu temperature.
*/
static int _i8k_get_temp(int sensor)
static int _i8k_get_temp(u8 sensor)
{
struct smm_regs regs = {
.eax = I8K_SMM_GET_TEMP,
.ebx = sensor & 0xff,
.ebx = sensor,
};

return i8k_smm(&regs) ? : regs.eax & 0xff;
}

static int i8k_get_temp(int sensor)
static int i8k_get_temp(u8 sensor)
{
int temp = _i8k_get_temp(sensor);

Expand Down Expand Up @@ -496,13 +507,19 @@ static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
if (copy_from_user(&val, argp, sizeof(int)))
return -EFAULT;

if (val > U8_MAX || val < 0)
return -EINVAL;

val = i8k_get_fan_speed(data, val);
break;

case I8K_GET_FAN:
if (copy_from_user(&val, argp, sizeof(int)))
return -EFAULT;

if (val > U8_MAX || val < 0)
return -EINVAL;

val = i8k_get_fan_status(data, val);
break;

Expand All @@ -513,6 +530,9 @@ static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
if (copy_from_user(&val, argp, sizeof(int)))
return -EFAULT;

if (val > U8_MAX || val < 0)
return -EINVAL;

if (copy_from_user(&speed, argp + 1, sizeof(int)))
return -EFAULT;

Expand Down Expand Up @@ -920,7 +940,8 @@ static int __init dell_smm_init_hwmon(struct device *dev)
{
struct dell_smm_data *data = dev_get_drvdata(dev);
struct device *dell_smm_hwmon_dev;
int i, state, err;
int state, err;
u8 i;

for (i = 0; i < DELL_SMM_NO_TEMP; i++) {
data->temp_type[i] = i8k_get_temp_type(i);
Expand Down Expand Up @@ -1236,7 +1257,8 @@ static int __init dell_smm_probe(struct platform_device *pdev)
{
struct dell_smm_data *data;
const struct dmi_system_id *id, *fan_control;
int fan, ret;
int ret;
u8 fan;

data = devm_kzalloc(&pdev->dev, sizeof(struct dell_smm_data), GFP_KERNEL);
if (!data)
Expand Down

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