linux-kernel - Re: [PATCH v1 03/11] cpufreq: tegra20: Remove EMC clock usage

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Date:   Fri, 18 May 2018 07:24:50 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        linux-tegra@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Peter Geis <pgwipeout@...il.com>
Subject: Re: [PATCH v1 03/11] cpufreq: tegra20: Remove EMC clock usage

On 17-05-18, 21:00, Dmitry Osipenko wrote:
> The EMC driver has been gone 4 years ago, since the commit a7cbe92cef27
> ("ARM: tegra: remove tegra EMC scaling driver"). Remove the EMC clock
> usage as it does nothing. We may consider re-implementing the EMC scaling
> later, probably using PM Memory Bandwidth QoS API.
> 
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> ---
>  drivers/cpufreq/tegra20-cpufreq.c | 22 ----------------------
>  1 file changed, 22 deletions(-)
> 
> diff --git a/drivers/cpufreq/tegra20-cpufreq.c b/drivers/cpufreq/tegra20-cpufreq.c
> index dd8a76a64a8e..693f9067ba8a 100644
> --- a/drivers/cpufreq/tegra20-cpufreq.c
> +++ b/drivers/cpufreq/tegra20-cpufreq.c
> @@ -44,7 +44,6 @@ static struct cpufreq_frequency_table freq_table[] = {
>  static struct clk *cpu_clk;
>  static struct clk *pll_x_clk;
>  static struct clk *pll_p_clk;
> -static struct clk *emc_clk;
>  static bool pll_x_prepared;
>  
>  static unsigned int tegra_get_intermediate(struct cpufreq_policy *policy,
> @@ -95,17 +94,6 @@ static int tegra_target(struct cpufreq_policy *policy, unsigned int index)
>  	unsigned int ifreq = clk_get_rate(pll_p_clk) / 1000;
>  	int ret = 0;
>  
> -	/*
> -	 * Vote on memory bus frequency based on cpu frequency
> -	 * This sets the minimum frequency, display or avp may request higher
> -	 */
> -	if (rate >= 816000)
> -		clk_set_rate(emc_clk, 600000000); /* cpu 816 MHz, emc max */
> -	else if (rate >= 456000)
> -		clk_set_rate(emc_clk, 300000000); /* cpu 456 MHz, emc 150Mhz */
> -	else
> -		clk_set_rate(emc_clk, 100000000);  /* emc 50Mhz */
> -
>  	/*
>  	 * target freq == pll_p, don't need to take extra reference to pll_x_clk
>  	 * as it isn't used anymore.
> @@ -141,14 +129,12 @@ static int tegra_cpu_init(struct cpufreq_policy *policy)
>  	if (policy->cpu >= NUM_CPUS)
>  		return -EINVAL;
>  
> -	clk_prepare_enable(emc_clk);
>  	clk_prepare_enable(cpu_clk);
>  
>  	/* FIXME: what's the actual transition time? */
>  	ret = cpufreq_generic_init(policy, freq_table, 300 * 1000);
>  	if (ret) {
>  		clk_disable_unprepare(cpu_clk);
> -		clk_disable_unprepare(emc_clk);
>  		return ret;
>  	}
>  
> @@ -160,7 +146,6 @@ static int tegra_cpu_init(struct cpufreq_policy *policy)
>  static int tegra_cpu_exit(struct cpufreq_policy *policy)
>  {
>  	clk_disable_unprepare(cpu_clk);
> -	clk_disable_unprepare(emc_clk);
>  	return 0;
>  }
>  
> @@ -192,19 +177,12 @@ static int __init tegra_cpufreq_init(void)
>  	if (IS_ERR(pll_p_clk))
>  		return PTR_ERR(pll_p_clk);
>  
> -	emc_clk = clk_get_sys("cpu", "emc");
> -	if (IS_ERR(emc_clk)) {
> -		clk_put(cpu_clk);
> -		return PTR_ERR(emc_clk);
> -	}
> -
>  	return cpufreq_register_driver(&tegra_cpufreq_driver);
>  }
>  
>  static void __exit tegra_cpufreq_exit(void)
>  {
>  	cpufreq_unregister_driver(&tegra_cpufreq_driver);
> -	clk_put(emc_clk);
>  	clk_put(cpu_clk);
>  }

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh