From: Sowjanya Komatineni <skomatineni@nvidia.com>
To: Adrian Hunter <adrian.hunter@intel.com>, <ulf.hansson@linaro.org>,
<thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
<robh+dt@kernel.org>
Cc: <devicetree@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-mmc@vger.kernel.org>
Subject: Re: [PATCH v2 6/6] sdhci: tegra: Add missing TMCLK for data timeout
Date: Wed, 5 Aug 2020 17:07:10 -0700 [thread overview]
Message-ID: <8e8f3742-f80e-c58b-4d7b-99b5a455b157@nvidia.com> (raw)
In-Reply-To: <d131fc8c-fa1f-cb67-fe6a-955d3582d1d6@intel.com>
On 8/5/20 1:06 AM, Adrian Hunter wrote:
> On 4/08/20 7:29 am, Sowjanya Komatineni wrote:
>> commit b5a84ecf025a ("mmc: tegra: Add Tegra210 support")
> So that could be a Fixes tag also?
Thanks Adrian. Will resend with fixes tag.
Sowjanya
>
>> Tegra210 and later has a separate sdmmc_legacy_tm (TMCLK) used by Tegra
>> SDMMC hawdware for data timeout to achive better timeout than using
>> SDCLK and using TMCLK is recommended.
>>
>> USE_TMCLK_FOR_DATA_TIMEOUT bit in Tegra SDMMC register
>> SDHCI_TEGRA_VENDOR_SYS_SW_CTRL can be used to choose either TMCLK or
>> SDCLK for data timeout.
>>
>> Default USE_TMCLK_FOR_DATA_TIMEOUT bit is set to 1 and TMCLK is used
>> for data timeout by Tegra SDMMC hardware and having TMCLK not enabled
>> is not recommended.
>>
>> So, this patch fixes it.
>>
>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> Acked-by: Adrian Hunter <adrian.hunter@intel.com>
>
>> ---
>> drivers/mmc/host/sdhci-tegra.c | 41 +++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 41 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
>> index 31ed321..c0b9405 100644
>> --- a/drivers/mmc/host/sdhci-tegra.c
>> +++ b/drivers/mmc/host/sdhci-tegra.c
>> @@ -140,6 +140,7 @@ struct sdhci_tegra_autocal_offsets {
>> struct sdhci_tegra {
>> const struct sdhci_tegra_soc_data *soc_data;
>> struct gpio_desc *power_gpio;
>> + struct clk *tmclk;
>> bool ddr_signaling;
>> bool pad_calib_required;
>> bool pad_control_available;
>> @@ -1611,6 +1612,44 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
>> goto err_power_req;
>> }
>>
>> + /*
>> + * Tegra210 has a separate SDMMC_LEGACY_TM clock used for host
>> + * timeout clock and SW can choose TMCLK or SDCLK for hardware
>> + * data timeout through the bit USE_TMCLK_FOR_DATA_TIMEOUT of
>> + * the register SDHCI_TEGRA_VENDOR_SYS_SW_CTRL.
>> + *
>> + * USE_TMCLK_FOR_DATA_TIMEOUT bit default is set to 1 and SDMMC uses
>> + * 12Mhz TMCLK which is advertised in host capability register.
>> + * With TMCLK of 12Mhz provides maximum data timeout period that can
>> + * be achieved is 11s better than using SDCLK for data timeout.
>> + *
>> + * So, TMCLK is set to 12Mhz and kept enabled all the time on SoC's
>> + * supporting SDR104 mode and when not using SDCLK for data timeout.
>> + */
>> +
>> + if ((soc_data->nvquirks & NVQUIRK_ENABLE_SDR104) &&
>> + !(soc_data->pdata->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK)) {
>> + clk = devm_clk_get(&pdev->dev, "tmclk");
>> + if (IS_ERR(clk)) {
>> + rc = PTR_ERR(clk);
>> + if (rc == -EPROBE_DEFER)
>> + goto err_power_req;
>> +
>> + dev_warn(&pdev->dev, "failed to get tmclk: %d\n", rc);
>> + clk = NULL;
>> + }
>> +
>> + clk_set_rate(clk, 12000000);
>> + rc = clk_prepare_enable(clk);
>> + if (rc) {
>> + dev_err(&pdev->dev,
>> + "failed to enable tmclk: %d\n", rc);
>> + goto err_power_req;
>> + }
>> +
>> + tegra_host->tmclk = clk;
>> + }
>> +
>> clk = devm_clk_get(mmc_dev(host->mmc), NULL);
>> if (IS_ERR(clk)) {
>> rc = PTR_ERR(clk);
>> @@ -1654,6 +1693,7 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
>> err_rst_get:
>> clk_disable_unprepare(pltfm_host->clk);
>> err_clk_get:
>> + clk_disable_unprepare(tegra_host->tmclk);
>> err_power_req:
>> err_parse_dt:
>> sdhci_pltfm_free(pdev);
>> @@ -1671,6 +1711,7 @@ static int sdhci_tegra_remove(struct platform_device *pdev)
>> reset_control_assert(tegra_host->rst);
>> usleep_range(2000, 4000);
>> clk_disable_unprepare(pltfm_host->clk);
>> + clk_disable_unprepare(tegra_host->tmclk);
>>
>> sdhci_pltfm_free(pdev);
>>
>>
prev parent reply other threads:[~2020-08-06 0:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-04 4:29 [PATCH v2 0/6] Fix timeout clock used by hardware data timeout Sowjanya Komatineni
2020-08-04 4:29 ` [PATCH v2 1/6] sdhci: tegra: Remove SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK for Tegra210 Sowjanya Komatineni
2020-08-05 7:48 ` Adrian Hunter
2020-08-04 4:29 ` [PATCH v2 2/6] sdhci: tegra: Remove SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK for Tegra186 Sowjanya Komatineni
2020-08-05 7:52 ` Adrian Hunter
2020-08-04 4:29 ` [PATCH v2 3/6] arm64: tegra: Add missing timeout clock to Tegra210 SDMMC Sowjanya Komatineni
2020-08-04 4:29 ` [PATCH v2 4/6] arm64: tegra: Add missing timeout clock to Tegra186 SDMMC nodes Sowjanya Komatineni
2020-08-04 4:29 ` [PATCH v2 5/6] arm64: tegra: Add missing timeout clock to Tegra194 " Sowjanya Komatineni
2020-08-04 4:29 ` [PATCH v2 6/6] sdhci: tegra: Add missing TMCLK for data timeout Sowjanya Komatineni
2020-08-05 8:06 ` Adrian Hunter
2020-08-06 0:07 ` Sowjanya Komatineni [this message]
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