linux-kernel - Re: [PATCH v2 3/6] clk: qcom: branch: Add BRANCH_HALT

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Date:   Fri, 14 Oct 2022 17:20:06 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Marc Zyngier <maz@...nel.org>,
        Melody Olvera <quic_molvera@...cinc.com>,
        Michael Turquette <mturquette@...libre.com>,
        Rob Herring <robh+dt@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Imran Shaik <quic_imrashai@...cinc.com>,
        Melody Olvera <quic_molvera@...cinc.com>
Subject: Re: [PATCH v2 3/6] clk: qcom: branch: Add BRANCH_HALT_INVERT flag support for branch clocks

Quoting Melody Olvera (2022-10-14 15:10:08)
> diff --git a/drivers/clk/qcom/clk-branch.c b/drivers/clk/qcom/clk-branch.c
> index f869fc6aaed6..b5dc1f4ef277 100644
> --- a/drivers/clk/qcom/clk-branch.c
> +++ b/drivers/clk/qcom/clk-branch.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: GPL-2.0
>  /*
>   * Copyright (c) 2013, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved.
>   */
>  
>  #include <linux/kernel.h>
> @@ -56,6 +57,10 @@ static bool clk_branch2_check_halt(const struct clk_branch *br, bool enabling)
>  
>         if (enabling) {
>                 val &= mask;
> +
> +               if (br->halt_check == BRANCH_HALT_INVERT)
> +                       return (val & BRANCH_CLK_OFF) == BRANCH_CLK_OFF;
> +
>                 return (val & BRANCH_CLK_OFF) == 0 ||
>                         val == BRANCH_NOC_FSM_STATUS_ON;
>         } else {
> diff --git a/drivers/clk/qcom/clk-branch.h b/drivers/clk/qcom/clk-branch.h
> index 17a58119165e..4ac1debeb91e 100644
> --- a/drivers/clk/qcom/clk-branch.h
> +++ b/drivers/clk/qcom/clk-branch.h
> @@ -1,5 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0 */
>  /* Copyright (c) 2013, The Linux Foundation. All rights reserved. */
> +/* Copyright (c) 2022, Qualcomm Innovation Center, Inc. All rights reserved. */
>  
>  #ifndef __QCOM_CLK_BRANCH_H__
>  #define __QCOM_CLK_BRANCH_H__
> @@ -33,6 +34,7 @@ struct clk_branch {
>  #define BRANCH_HALT_ENABLE_VOTED       (BRANCH_HALT_ENABLE | BRANCH_VOTED)
>  #define BRANCH_HALT_DELAY              2 /* No bit to check; just delay */
>  #define BRANCH_HALT_SKIP               3 /* Don't check halt bit */
> +#define BRANCH_HALT_INVERT             4 /* Invert logic for halt bit */

How is it different from BRANCH_HALT vs. BRANCH_HALT_ENABLE?