From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [RESEDN PATCH v2 3/4] mmc: sdhci: Don't try to switch to unsupported voltage Date: Fri, 23 Sep 2016 10:12:43 +0300 Message-ID: <785df157-dadc-4dd3-76e9-aea3a0f031a5@intel.com> References: <1474589577-11193-1-git-send-email-shawn.lin@rock-chips.com> <1474589577-11193-3-git-send-email-shawn.lin@rock-chips.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1474589577-11193-3-git-send-email-shawn.lin@rock-chips.com> Sender: linux-mmc-owner@vger.kernel.org To: Shawn Lin Cc: Ulf Hansson , Jaehoon Chung , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, Ziyuan Xu List-Id: linux-rockchip.vger.kernel.org On 23/09/16 03:12, Shawn Lin wrote: > From: Ziyuan Xu > > Sdhci shouldn't switch to the unsupported voltage if claiming > that it can not support the requested voltage. Let's fix it. > > Signed-off-by: Ziyuan Xu > Signed-off-by: Shawn Lin > --- > > Changes in v2: None > > drivers/mmc/host/sdhci.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 4805566..b1f1edd 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -1845,7 +1845,8 @@ static int sdhci_start_signal_voltage_switch(struct mmc_host *mmc, > > switch (ios->signal_voltage) { > case MMC_SIGNAL_VOLTAGE_330: > - if (!(host->flags & SDHCI_SIGNALING_330)) > + if (!(host->flags & SDHCI_SIGNALING_330) || > + !(host->caps & SDHCI_CAN_VDD_330)) You are mixing signal voltage and supply voltage here. Note, I don't believe all drivers set the capabilities correctly when they are using regulators, but in any case this is not the place in the code to make such assumptions. Better for the driver to remove SDHCI_SIGNALING_330 from flags when it is not supported. > return -EINVAL; > /* Set 1.8V Signal Enable in the Host Control2 register to 0 */ > ctrl &= ~SDHCI_CTRL_VDD_180; > @@ -1872,7 +1873,8 @@ static int sdhci_start_signal_voltage_switch(struct mmc_host *mmc, > > return -EAGAIN; > case MMC_SIGNAL_VOLTAGE_180: > - if (!(host->flags & SDHCI_SIGNALING_180)) > + if (!(host->flags & SDHCI_SIGNALING_180) || > + !(host->caps & SDHCI_CAN_VDD_180)) You are mixing signal voltage and supply voltage here, and this is not correct: not being able to do 1.8V supply does not mean you can't do 1.8V signaling. The SDHCI way of determining supported signal voltages is based on supported transfer modes. If the driver can't get the transfer modes correct (e.g. we still don't have MMC_CAP2_3_3V_ONLY_DDR or equivalent), remove SDHCI_SIGNALING_180 from the flags. > return -EINVAL; > if (!IS_ERR(mmc->supply.vqmmc)) { > ret = mmc_regulator_set_vqmmc(mmc, ios); >