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From: Stephen Boyd <sboyd@kernel.org>
To: Sowjanya Komatineni <skomatineni@nvidia.com>,
	jason@lakedaemon.net, jonathanh@nvidia.com,
	linus.walleij@linaro.org, marc.zyngier@arm.com,
	mark.rutland@arm.com, stefan@agner.ch, tglx@linutronix.de,
	thierry.reding@gmail.com
Cc: pdeschrijver@nvidia.com, pgaikwad@nvidia.com,
	linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org,
	jckuo@nvidia.com, josephl@nvidia.com, talho@nvidia.com,
	skomatineni@nvidia.com, linux-tegra@vger.kernel.org,
	linux-kernel@vger.kernel.org, mperttunen@nvidia.com,
	spatra@nvidia.com, robh+dt@kernel.org, digetx@gmail.com,
	devicetree@vger.kernel.org, rjw@rjwysocki.net,
	viresh.kumar@linaro.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH v9 07/22] clk: Add API to get index of the clock parent
Date: Wed, 06 Nov 2019 15:10:05 -0800
Message-ID: <20191106231005.F2CD820869@mail.kernel.org> (raw)
In-Reply-To: <1565984527-5272-8-git-send-email-skomatineni@nvidia.com>

Quoting Sowjanya Komatineni (2019-08-16 12:41:52)
> This patch adds an API clk_hw_get_parent_index to get index of the
> clock parent to use during the clock restore operations on system
> resume.

Is there a reason we can't save the clk hw index at suspend time by
reading the hardware to understand the current parent? The parent index
typically doesn't matter unless we're trying to communicate something
from the framework to the provider driver. Put another way, I would
think the provider driver can figure out the index itself without having
to go through the framework to do so.

> 
> Reviewed-by: Thierry Reding <treding@nvidia.com>
> Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index cbcc333aec84..12ad0e9b8591 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1645,6 +1645,23 @@ static int clk_fetch_parent_index(struct clk_core *core,
>         return i;
>  }
>  
> +/**
> + * clk_hw_get_parent_index - return the index of parent clock
> + * @hw: clk_hw associated with the clk being consumed
> + * @parent_hw: clk_hw associated with the parent of clk
> + *
> + * Fetches and returns the index of parent clock.
> + * If hw or parent_hw is NULL, returns -EINVAL.
> + */
> +int clk_hw_get_parent_index(struct clk_hw *hw, struct clk_hw *parent_hw)
> +{
> +       if (!hw || !parent_hw)
> +               return -EINVAL;

The caller should be ashamed if they call this with NULL arguments.
I'd prefer we skip this check and we get an oops.

> +
> +       return clk_fetch_parent_index(hw->core, parent_hw->core);
> +}
> +EXPORT_SYMBOL_GPL(clk_hw_get_parent_index);
> +
>  /*
>   * Update the orphan status of @core and all its children.
>   */

  reply index

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16 19:41 [PATCH v9 00/22] SC7 entry and exit support for Tegra210 Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 01/22] pinctrl: tegra: Fix write barrier placement in pmx_writel Sowjanya Komatineni
2019-08-18 22:20   ` Linus Walleij
2019-08-16 19:41 ` [PATCH v9 02/22] pinctrl: tegra: Flush pinctrl writes during resume Sowjanya Komatineni
2019-08-18 22:20   ` Linus Walleij
2019-08-16 19:41 ` [PATCH v9 03/22] clk: tegra: divider: Save and restore divider rate Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 04/22] clk: tegra: pllout: Save and restore pllout context Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 05/22] clk: tegra: pll: Save and restore pll context Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 06/22] clk: tegra: Support for OSC context save and restore Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 07/22] clk: Add API to get index of the clock parent Sowjanya Komatineni
2019-11-06 23:10   ` Stephen Boyd [this message]
2019-11-07  0:54     ` Dmitry Osipenko
2019-11-07 15:21       ` Thierry Reding
2019-11-07 19:19         ` Stephen Boyd
2019-11-08 10:11           ` Thierry Reding
2019-11-08 18:12             ` Stephen Boyd
2019-11-08 18:55               ` Thierry Reding
2019-11-08 21:15                 ` Stephen Boyd
2019-08-16 19:41 ` [PATCH v9 08/22] clk: tegra: periph: Add restore_context support Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 09/22] clk: tegra: clk-super: Fix to enable PLLP branches to CPU Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 10/22] clk: tegra: clk-super: Add restore-context support Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 11/22] clk: tegra: clk-dfll: Add suspend and resume support Sowjanya Komatineni
2019-11-08 21:20   ` Stephen Boyd
2019-11-08 23:38     ` Dmitry Osipenko
2019-08-16 19:41 ` [PATCH v9 12/22] cpufreq: tegra124: " Sowjanya Komatineni
2019-11-02 14:42   ` Thierry Reding
2019-08-16 19:41 ` [PATCH v9 13/22] clk: tegra210: Use fence_udelay during PLLU init Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 14/22] clk: tegra: Share clk and rst register defines with Tegra clock driver Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 15/22] clk: tegra210: Add suspend and resume support Sowjanya Komatineni
2019-08-19 16:47   ` Dmitry Osipenko
2019-08-16 19:42 ` [PATCH v9 16/22] soc/tegra: pmc: Allow to support more tegras wake Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 17/22] soc/tegra: pmc: Add pmc wake support for tegra210 Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 18/22] arm64: tegra: Enable wake from deep sleep on RTC alarm Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 19/22] soc/tegra: pmc: Configure core power request polarity Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 20/22] soc/tegra: pmc: Configure deep sleep control settings Sowjanya Komatineni
2019-08-19 16:48   ` Dmitry Osipenko
2019-08-19 18:20     ` Sowjanya Komatineni
2019-08-19 19:07       ` Sowjanya Komatineni
2019-08-19 19:33         ` Dmitry Osipenko
2019-08-16 19:42 ` [PATCH v9 21/22] arm64: dts: tegra210-p2180: Jetson TX1 SC7 timings Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 22/22] arm64: dts: tegra210-p3450: Jetson Nano " Sowjanya Komatineni

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