linux-kernel - Re: [PATCH v2 16/20] extcon: intel-cht-wc: Use new intel_cht_wc_get

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Date:   Wed, 17 Nov 2021 15:47:00 +0900
From:   Chanwoo Choi <cwchoi00@...il.com>
To:     Hans de Goede <hdegoede@...hat.com>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Mark Gross <markgross@...nel.org>,
        Andy Shevchenko <andy@...radead.org>,
        Wolfram Sang <wsa@...-dreams.de>,
        Sebastian Reichel <sre@...nel.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Ard Biesheuvel <ardb@...nel.org>
Cc:     Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
        Yauhen Kharuzhy <jekhor@...il.com>,
        Tsuchiya Yuto <kitakar@...il.com>,
        platform-driver-x86@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-efi@...r.kernel.org
Subject: Re: [PATCH v2 16/20] extcon: intel-cht-wc: Use new
 intel_cht_wc_get_model() helper

On 21. 11. 15. 오전 2:03, Hans de Goede wrote:
> The CHT_WC_VBUS_GPIO_CTLO GPIO actually driving an external 5V Vboost
> converter for Vbus depends on the board on which the Cherry Trail -
> Whiskey Cove PMIC is actually used.
> 
> Since the information about the exact PMIC setup is necessary in other
> places too, the drivers/mfd/intel_soc_pmic_chtwc.c code now has a new
> intel_cht_wc_get_model() helper.
> 
> Only poke the CHT_WC_VBUS_GPIO_CTLO GPIO if this new helper returns
> INTEL_CHT_WC_GPD_WIN_POCKET, which indicates the Type-C (with PD and
> DP-altmode) setup used on the GPD pocket and GPD win; and on which
> this GPIO actually controls an external 5V Vboost converter.
> 
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> ---
>   drivers/extcon/extcon-intel-cht-wc.c | 35 +++++++++++++++++-----------
>   1 file changed, 21 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/extcon/extcon-intel-cht-wc.c b/drivers/extcon/extcon-intel-cht-wc.c
> index 771f6f4cf92e..a5aeeecc44fb 100644
> --- a/drivers/extcon/extcon-intel-cht-wc.c
> +++ b/drivers/extcon/extcon-intel-cht-wc.c
> @@ -14,6 +14,7 @@
>   #include <linux/module.h>
>   #include <linux/mod_devicetable.h>
>   #include <linux/platform_device.h>
> +#include <linux/property.h>
>   #include <linux/regmap.h>
>   #include <linux/slab.h>
>   
> @@ -358,20 +359,26 @@ static int cht_wc_extcon_probe(struct platform_device *pdev)
>   	if (IS_ERR(ext->edev))
>   		return PTR_ERR(ext->edev);
>   
> -	/*
> -	 * When a host-cable is detected the BIOS enables an external 5v boost
> -	 * converter to power connected devices there are 2 problems with this:
> -	 * 1) This gets seen by the external battery charger as a valid Vbus
> -	 *    supply and it then tries to feed Vsys from this creating a
> -	 *    feedback loop which causes aprox. 300 mA extra battery drain
> -	 *    (and unless we drive the external-charger-disable pin high it
> -	 *    also tries to charge the battery causing even more feedback).
> -	 * 2) This gets seen by the pwrsrc block as a SDP USB Vbus supply
> -	 * Since the external battery charger has its own 5v boost converter
> -	 * which does not have these issues, we simply turn the separate
> -	 * external 5v boost converter off and leave it off entirely.
> -	 */
> -	cht_wc_extcon_set_5v_boost(ext, false);
> +	switch (intel_cht_wc_get_model()) {

intel_cht_wc_get_model() is defined in driver/mfd/intel_soc_pmic_chtwc.c

Usually, mfd drivers share the data structure such as struct 
intel_soc_pmic. But, didn't call the exported function for only
specific driver between linux kernel framework (extcon vs. mfd).

So that I think that you better to update the mode information
to 'struct intel_soc_pmic' data structure and then use it
instead of using the exported function which may make the confusion.

> +	case INTEL_CHT_WC_GPD_WIN_POCKET:
> +		/*
> +		 * When a host-cable is detected the BIOS enables an external 5v boost
> +		 * converter to power connected devices there are 2 problems with this:
> +		 * 1) This gets seen by the external battery charger as a valid Vbus
> +		 *    supply and it then tries to feed Vsys from this creating a
> +		 *    feedback loop which causes aprox. 300 mA extra battery drain
> +		 *    (and unless we drive the external-charger-disable pin high it
> +		 *    also tries to charge the battery causing even more feedback).
> +		 * 2) This gets seen by the pwrsrc block as a SDP USB Vbus supply
> +		 * Since the external battery charger has its own 5v boost converter
> +		 * which does not have these issues, we simply turn the separate
> +		 * external 5v boost converter off and leave it off entirely.
> +		 */
> +		cht_wc_extcon_set_5v_boost(ext, false);
> +		break;
> +	default:
> +		break;
> +	}
>   
>   	/* Enable sw control */
>   	ret = cht_wc_extcon_sw_control(ext, true);
> 


-- 
Best Regards,
Samsung Electronics
Chanwoo Choi