Re: [PATCH 1/2] platform/x86: thinkpad_acpi: Simplify thermal mode checking

[Ilpo Järvinen]

On Wed, 14 Feb 2024, Vishnu Sankar wrote:

Thanks for doing this, it's major improvement to readability already as
is, and even more of after the second patch!!

> Add a thermal_read_mode_check helper function to make the code

thermal_read_mode_check()

remove "function" as it's obvious.

> simpler during init.
> This helps particularly when the new TPEC_12 mode is added in
> the next patch.

Flow the paragraph normally without the premature line break.

> Suggested-by: Ilpo Jarvinen <ilpo.jarvinen@xxxxxxxxx>

This is not my email address, please use

Suggested-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>

> Signed-off-by: Vishnu Sankar <vishnuocv@xxxxxxxxx>
> ---
>  drivers/platform/x86/thinkpad_acpi.c | 136 +++++++++++++--------------
>  1 file changed, 66 insertions(+), 70 deletions(-)
> 
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index c4895e9bc714..2428c8bd0fa2 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -6147,6 +6147,71 @@ struct ibm_thermal_sensors_struct {
>  static enum thermal_access_mode thermal_read_mode;
>  static bool thermal_use_labels;
>  
> +/* Function to check thermal read mode */
> +static enum thermal_access_mode thermal_read_mode_check(void)
> +{
> +	u8 t, ta1, ta2, ver = 0;
> +	int i;
> +
> +	if (thinkpad_id.ec_model) {
> +		/*
> +		 * Direct EC access mode: sensors at registers
> +		 * 0x78-0x7F, 0xC0-0xC7.  Registers return 0x00 for

While this comment is touches, lets make minor improvements to it.

Remove the double space, they are not needed in kernel comments.

> +		 * non-implemented, thermal sensors return 0x80 when
> +		 * not available

Please add the missing .

Perhaps add an empty line here to break the comment into two paragraphs?

> +		 * The above rule is unfortunately flawed. This has been seen with
> +		 * 0xC2 (power supply ID) causing thermal control problems.
> +		 * The EC version can be determined by offset 0xEF and at least for
> +		 * version 3 the Lenovo firmware team confirmed that registers 0xC0-0xC7
> +		 * are not thermal registers.

Please reflow the entire comment to 80 chars.

> +		 */
> +		if (!acpi_ec_read(TP_EC_FUNCREV, &ver))
> +			pr_warn("Thinkpad ACPI EC unable to access EC version\n");
> +
> +		ta1 = ta2 = 0;
> +		for (i = 0; i < 8; i++) {
> +			if (acpi_ec_read(TP_EC_THERMAL_TMP0 + i, &t)) {
> +				ta1 |= t;
> +			} else {
> +				ta1 = 0;
> +				break;
> +			}
> +			if (ver < 3) {
> +				if (acpi_ec_read(TP_EC_THERMAL_TMP8 + i, &t)) {
> +					ta2 |= t;
> +				} else {
> +					ta1 = 0;
> +					break;
> +				}
> +			}
> +		}
> +
> +		if (ta1 == 0) {
> +			pr_err("ThinkPad ACPI EC access misbehaving, disabling thermal sensors access\n");
> +			return TPACPI_THERMAL_NONE;
> +		}
> +
> +		if (ver >= 3) {
> +			thermal_use_labels = true;
> +			return TPACPI_THERMAL_TPEC_8;
> +		}
> +
> +		return (ta2 != 0) ? TPACPI_THERMAL_TPEC_16 : TPACPI_THERMAL_TPEC_8;
> +	}
> +
> +	if (acpi_evalf(ec_handle, NULL, "TMP7", "qv")) {
> +		if (tpacpi_is_ibm() &&
> +		    acpi_evalf(ec_handle, NULL, "UPDT", "qv"))

Put this to single line and retain the braces please (I know it will be 
>80 char but nothing important is lost).

> +			/* 600e/x, 770e, 770x */
> +			return TPACPI_THERMAL_ACPI_UPDT;
> +		/* IBM/LENOVO DSDT EC.TMPx access, max 8 sensors */
> +		return TPACPI_THERMAL_ACPI_TMP07;
> +	}
> +
> +	/* temperatures not supported on 570, G4x, R30, R31, R32 */
> +	return TPACPI_THERMAL_NONE;
> +}
> +
>  /* idx is zero-based */
>  static int thermal_get_sensor(int idx, s32 *value)
>  {
> @@ -6375,78 +6440,9 @@ static const struct attribute_group temp_label_attr_group = {
>  
>  static int __init thermal_init(struct ibm_init_struct *iibm)
>  {
> -	u8 t, ta1, ta2, ver = 0;
> -	int i;
> -	int acpi_tmp7;
> -
>  	vdbg_printk(TPACPI_DBG_INIT, "initializing thermal subdriver\n");
>  
> -	acpi_tmp7 = acpi_evalf(ec_handle, NULL, "TMP7", "qv");
> -
> -	if (thinkpad_id.ec_model) {
> -		/*
> -		 * Direct EC access mode: sensors at registers
> -		 * 0x78-0x7F, 0xC0-0xC7.  Registers return 0x00 for
> -		 * non-implemented, thermal sensors return 0x80 when
> -		 * not available
> -		 * The above rule is unfortunately flawed. This has been seen with
> -		 * 0xC2 (power supply ID) causing thermal control problems.
> -		 * The EC version can be determined by offset 0xEF and at least for
> -		 * version 3 the Lenovo firmware team confirmed that registers 0xC0-0xC7
> -		 * are not thermal registers.
> -		 */
> -		if (!acpi_ec_read(TP_EC_FUNCREV, &ver))
> -			pr_warn("Thinkpad ACPI EC unable to access EC version\n");
> -
> -		ta1 = ta2 = 0;
> -		for (i = 0; i < 8; i++) {
> -			if (acpi_ec_read(TP_EC_THERMAL_TMP0 + i, &t)) {
> -				ta1 |= t;
> -			} else {
> -				ta1 = 0;
> -				break;
> -			}
> -			if (ver < 3) {
> -				if (acpi_ec_read(TP_EC_THERMAL_TMP8 + i, &t)) {
> -					ta2 |= t;
> -				} else {
> -					ta1 = 0;
> -					break;
> -				}
> -			}
> -		}
> -		if (ta1 == 0) {
> -			/* This is sheer paranoia, but we handle it anyway */
> -			if (acpi_tmp7) {
> -				pr_err("ThinkPad ACPI EC access misbehaving, falling back to ACPI TMPx access mode\n");
> -				thermal_read_mode = TPACPI_THERMAL_ACPI_TMP07;

Eh, where did this go in the new helper?

-- 
 i.

> -			} else {
> -				pr_err("ThinkPad ACPI EC access misbehaving, disabling thermal sensors access\n");
> -				thermal_read_mode = TPACPI_THERMAL_NONE;
> -			}
> -		} else {
> -			if (ver >= 3) {
> -				thermal_read_mode = TPACPI_THERMAL_TPEC_8;
> -				thermal_use_labels = true;
> -			} else {
> -				thermal_read_mode =
> -					(ta2 != 0) ?
> -					TPACPI_THERMAL_TPEC_16 : TPACPI_THERMAL_TPEC_8;
> -			}
> -		}
> -	} else if (acpi_tmp7) {
> -		if (tpacpi_is_ibm() &&
> -		    acpi_evalf(ec_handle, NULL, "UPDT", "qv")) {
> -			/* 600e/x, 770e, 770x */
> -			thermal_read_mode = TPACPI_THERMAL_ACPI_UPDT;
> -		} else {
> -			/* IBM/LENOVO DSDT EC.TMPx access, max 8 sensors */
> -			thermal_read_mode = TPACPI_THERMAL_ACPI_TMP07;
> -		}
> -	} else {
> -		/* temperatures not supported on 570, G4x, R30, R31, R32 */
> -		thermal_read_mode = TPACPI_THERMAL_NONE;
> -	}
> +	thermal_read_mode = thermal_read_mode_check();
>  
>  	vdbg_printk(TPACPI_DBG_INIT, "thermal is %s, mode %d\n",
>  		str_supported(thermal_read_mode != TPACPI_THERMAL_NONE),
>