From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH v2] mmc: sdhci_am654: Clear HISPD_ENA in some lower speed modes Date: Tue, 2 Apr 2019 10:42:22 +0300 Message-ID: <356a8af6-03ab-2827-03c9-a386c8cfaec8@intel.com> References: <20190401125804.5665-1-faiz_abbas@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190401125804.5665-1-faiz_abbas@ti.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Faiz Abbas , linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org Cc: ulf.hansson@linaro.org List-Id: linux-mmc@vger.kernel.org On 1/04/19 3:58 PM, Faiz Abbas wrote: > According to the AM654x Data Manual[1], the setup timing in lower speed > modes can only be met if the controller uses a falling edge data launch. > > To ensure this, the HIGH_SPEED_ENA (HOST_CONTROL[2]) bit should be > cleared in default speed, SD high speed, MMC high speed, SDR12 and SDR25 > speed modes. > > Use the sdhci writeb callback to implement this condition. > > [1] http://www.ti.com/lit/gpn/am6546 Section 5.10.5.16.1 > > Signed-off-by: Faiz Abbas Acked-by: Adrian Hunter > --- > > v2: Dropped QUIRK in favour of writeb callback > > drivers/mmc/host/Kconfig | 1 + > drivers/mmc/host/sdhci_am654.c | 22 ++++++++++++++++++++++ > 2 files changed, 23 insertions(+) > > diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig > index 28fcd8f580a1..6379fba8b122 100644 > --- a/drivers/mmc/host/Kconfig > +++ b/drivers/mmc/host/Kconfig > @@ -993,6 +993,7 @@ config MMC_SDHCI_OMAP > config MMC_SDHCI_AM654 > tristate "Support for the SDHCI Controller in TI's AM654 SOCs" > depends on MMC_SDHCI_PLTFM && OF > + select MMC_SDHCI_IO_ACCESSORS > help > This selects the Secure Digital Host Controller Interface (SDHCI) > support present in TI's AM654 SOCs. The controller supports > diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c > index eea183e90f1b..a91c0b45c48d 100644 > --- a/drivers/mmc/host/sdhci_am654.c > +++ b/drivers/mmc/host/sdhci_am654.c > @@ -158,6 +158,27 @@ static void sdhci_am654_set_power(struct sdhci_host *host, unsigned char mode, > sdhci_set_power_noreg(host, mode, vdd); > } > > +static void sdhci_am654_write_b(struct sdhci_host *host, u8 val, int reg) > +{ > + unsigned char timing = host->mmc->ios.timing; > + > + if (reg == SDHCI_HOST_CONTROL) { > + switch (timing) { > + /* > + * According to the data manual, HISPD bit > + * should not be set in these speed modes. > + */ > + case MMC_TIMING_SD_HS: > + case MMC_TIMING_MMC_HS: > + case MMC_TIMING_UHS_SDR12: > + case MMC_TIMING_UHS_SDR25: > + val &= ~SDHCI_CTRL_HISPD; > + } > + } > + > + writeb(val, host->ioaddr + reg); > +} > + > static struct sdhci_ops sdhci_am654_ops = { > .get_max_clock = sdhci_pltfm_clk_get_max_clock, > .get_timeout_clock = sdhci_pltfm_clk_get_max_clock, > @@ -165,6 +186,7 @@ static struct sdhci_ops sdhci_am654_ops = { > .set_bus_width = sdhci_set_bus_width, > .set_power = sdhci_am654_set_power, > .set_clock = sdhci_am654_set_clock, > + .write_b = sdhci_am654_write_b, > .reset = sdhci_reset, > }; > >