From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751786AbeFEJhH (ORCPT ); Tue, 5 Jun 2018 05:37:07 -0400 Received: from mga05.intel.com ([192.55.52.43]:57779 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751502AbeFEJhF (ORCPT ); Tue, 5 Jun 2018 05:37:05 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,478,1520924400"; d="scan'208";a="54857045" Subject: Re: [PATCH] mmc: tegra: Use sdhci_pltfm_clk_get_max_clock To: Aapo Vienamo , Ulf Hansson , Thierry Reding , Jonathan Hunter , linux-mmc@vger.kernel.org, linux-tegra@vger.kernel.org Cc: linux-kernel@vger.kernel.org References: <1528126540-27004-1-git-send-email-avienamo@nvidia.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <0c9cb398-07ac-360b-c661-31670f64fe06@intel.com> Date: Tue, 5 Jun 2018 12:35:45 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <1528126540-27004-1-git-send-email-avienamo@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/06/18 18:35, Aapo Vienamo wrote: > The sdhci get_max_clock callback is set to sdhci_pltfm_clk_get_max_clock > and tegra_sdhci_get_max_clock is removed. It appears that the > shdci-tegra specific callback was originally introduced due to the > requirement that the host clock has to be twice the bus clock on DDR50 > mode. As far as I can tell the only effect the removal has on DDR50 mode > is in cases where the parent clock is unable to supply the requested > clock rate, causing the DDR50 mode to run at a lower frequency. > Currently the DDR50 mode isn't enabled on any of the SoCs and would also > require configuring the SDHCI clock divider register to function > properly. > > The problem with tegra_sdhci_get_max_clock is that it divides the clock > rate by two and thus artificially limits the maximum frequency of faster > signaling modes which don't have the host-bus frequency ratio requirement > of DDR50 such as SDR104 and HS200. Furthermore, the call to > clk_round_rate() may return an error which isn't handled by > tegra_sdhci_get_max_clock. > > Signed-off-by: Aapo Vienamo Acked-by: Adrian Hunter > --- > drivers/mmc/host/sdhci-tegra.c | 15 ++------------- > 1 file changed, 2 insertions(+), 13 deletions(-) > > diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c > index 970d38f6..c8745b5 100644 > --- a/drivers/mmc/host/sdhci-tegra.c > +++ b/drivers/mmc/host/sdhci-tegra.c > @@ -234,17 +234,6 @@ static void tegra_sdhci_set_uhs_signaling(struct sdhci_host *host, > sdhci_set_uhs_signaling(host, timing); > } > > -static unsigned int tegra_sdhci_get_max_clock(struct sdhci_host *host) > -{ > - struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); > - > - /* > - * DDR modes require the host to run at double the card frequency, so > - * the maximum rate we can support is half of the module input clock. > - */ > - return clk_round_rate(pltfm_host->clk, UINT_MAX) / 2; > -} > - > static void tegra_sdhci_set_tap(struct sdhci_host *host, unsigned int tap) > { > u32 reg; > @@ -309,7 +298,7 @@ static const struct sdhci_ops tegra_sdhci_ops = { > .platform_execute_tuning = tegra_sdhci_execute_tuning, > .set_uhs_signaling = tegra_sdhci_set_uhs_signaling, > .voltage_switch = tegra_sdhci_voltage_switch, > - .get_max_clock = tegra_sdhci_get_max_clock, > + .get_max_clock = sdhci_pltfm_clk_get_max_clock, > }; > > static const struct sdhci_pltfm_data sdhci_tegra20_pdata = { > @@ -357,7 +346,7 @@ static const struct sdhci_ops tegra114_sdhci_ops = { > .platform_execute_tuning = tegra_sdhci_execute_tuning, > .set_uhs_signaling = tegra_sdhci_set_uhs_signaling, > .voltage_switch = tegra_sdhci_voltage_switch, > - .get_max_clock = tegra_sdhci_get_max_clock, > + .get_max_clock = sdhci_pltfm_clk_get_max_clock, > }; > > static const struct sdhci_pltfm_data sdhci_tegra114_pdata = { >