Message-ID: <eb064f0873fd47e7cbd07f8e403f11dd6060ff34.camel@mediatek.com>
Date: Tue, 21 Jan 2025 06:25:48 +0000
From: Andy-ld Lu (卢东) <Andy-ld.Lu@...iatek.com>
To: "ansuelsmth@...il.com" <ansuelsmth@...il.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	"linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	Wenbin Mei (梅文彬) <Wenbin.Mei@...iatek.com>,
	Chaotian Jing (井朝天)
	<Chaotian.Jing@...iatek.com>, "conor+dt@...nel.org" <conor+dt@...nel.org>,
	"robh@...nel.org" <robh@...nel.org>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "matthias.bgg@...il.com"
	<matthias.bgg@...il.com>, "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
	"krzk+dt@...nel.org" <krzk+dt@...nel.org>, AngeloGioacchino Del Regno
	<angelogioacchino.delregno@...labora.com>, upstream <upstream@...oha.com>
Subject: Re: [PATCH 2/2] mmc: mtk-sd: add support for AN7581 MMC Host

On Mon, 2025-01-20 at 18:29 +0100, Christian Marangi wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On Thu, Jan 16, 2025 at 07:01:13AM +0000, Andy-ld Lu (卢东) wrote:
> > On Wed, 2025-01-15 at 08:29 +0100, Christian Marangi wrote:
> > > Add support for AN7581 MMC Host. The MMC Host controller is based
> > > on
> > > mt7622 with the difference of not having regulator supply and
> > > state_uhs
> > > pins and hclk clock.
> > > 
> > > Some minor fixes are applied to check if the state_uhs pins are
> > > defined
> > > and make hclk optional for the new airoha compatible.
> > > 
> > > Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
> > > ---
> > >  drivers/mmc/host/mtk-sd.c | 55 ++++++++++++++++++++++++++++++++-
> > > ----
> > > --
> > >  1 file changed, 46 insertions(+), 9 deletions(-)
> > > 
> > > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-
> > > sd.c
> > > index efb0d2d5716b..9d6868883c91 100644
> > > --- a/drivers/mmc/host/mtk-sd.c
> > > +++ b/drivers/mmc/host/mtk-sd.c
> > > @@ -666,6 +666,20 @@ static const struct mtk_mmc_compatible
> > > mt8196_compat = {
> > >     .support_new_rx = true,
> > >  };
> > > 
> > > +static const struct mtk_mmc_compatible an7581_compat = {
> > > +   .clk_div_bits = 12,
> > > +   .recheck_sdio_irq = true,
> > > +   .hs400_tune = false,
> > > +   .pad_tune_reg = MSDC_PAD_TUNE0,
> > > +   .async_fifo = true,
> > > +   .data_tune = true,
> > > +   .busy_check = true,
> > > +   .stop_clk_fix = true,
> > > +   .stop_dly_sel = 3,
> > > +   .enhance_rx = true,
> > > +   .support_64g = false,
> > > +};
> > > +
> > >  static const struct of_device_id msdc_of_ids[] = {
> > >     { .compatible = "mediatek,mt2701-mmc", .data =
> > > &mt2701_compat},
> > >     { .compatible = "mediatek,mt2712-mmc", .data =
> > > &mt2712_compat},
> > > @@ -680,7 +694,7 @@ static const struct of_device_id
> > > msdc_of_ids[] =
> > > {
> > >     { .compatible = "mediatek,mt8183-mmc", .data =
> > > &mt8183_compat},
> > >     { .compatible = "mediatek,mt8196-mmc", .data =
> > > &mt8196_compat},
> > >     { .compatible = "mediatek,mt8516-mmc", .data =
> > > &mt8516_compat},
> > > -
> > > +   { .compatible = "airoha,an7581-mmc", .data = &an7581_compat},
> > >     {}
> > >  };
> > >  MODULE_DEVICE_TABLE(of, msdc_of_ids);
> > > @@ -1600,6 +1614,10 @@ static int msdc_ops_switch_volt(struct
> > > mmc_host *mmc, struct mmc_ios *ios)
> > >     struct msdc_host *host = mmc_priv(mmc);
> > >     int ret;
> > > 
> > > +   /* Skip setting supply if not supported */
> > > +   if (!mmc->supply.vqmmc)
> > > +           return 0;
> > > +
> > 
> > Hi Christian,
> > 
> > I think here is no need. If you have not 'vqmmc' in the
> > dts, IS_ERR(mmc->supply.vqmmc) would be -ENODEV and the
> > corresponding
> > flow would not be executed.
> > 
> > And another question, host->pins_default is just selected here,
> > that
> > would be lost.
> > 
> > >     if (!IS_ERR(mmc->supply.vqmmc)) {
> > >             if (ios->signal_voltage != MMC_SIGNAL_VOLTAGE_330 &&
> > >                 ios->signal_voltage != MMC_SIGNAL_VOLTAGE_180) {
> > > @@ -1699,7 +1717,9 @@ static void msdc_enable_sdio_irq(struct
> > > mmc_host *mmc, int enb)
> > >                             dev_dbg(host->dev, "SDIO eint irq:
> > > %d!\n", host->eint_irq);
> > >                     }
> > > 
> > > -                   pinctrl_select_state(host->pinctrl, host-
> > > > pins_uhs);
> > > 
> > > +                   /* Skip setting uhs pins if not supported */
> > > +                   if (host->pins_uhs)
> > > +                           pinctrl_select_state(host->pinctrl,
> > > host->pins_uhs);
> > >             } else {
> > >                     dev_pm_clear_wake_irq(host->dev);
> > >             }
> > > @@ -2036,6 +2056,10 @@ static void msdc_ops_set_ios(struct
> > > mmc_host
> > > *mmc, struct mmc_ios *ios)
> > > 
> > >     msdc_set_buswidth(host, ios->bus_width);
> > > 
> > > +   /* Skip regulator if not supported */
> > > +   if (!mmc->supply.vmmc)
> > > +           goto skip_regulator;
> > > +
> > 
> > No need too.
> > 
> > >     /* Suspend/Resume will do power off/on */
> > >     switch (ios->power_mode) {
> > >     case MMC_POWER_UP:
> > > @@ -2071,6 +2095,7 @@ static void msdc_ops_set_ios(struct
> > > mmc_host
> > > *mmc, struct mmc_ios *ios)
> > >             break;
> > >     }
> > > 
> > > +skip_regulator:
> > >     if (host->mclk != ios->clock || host->timing != ios->timing)
> > >             msdc_set_mclk(host, ios->timing, ios->clock);
> > >  }
> > > @@ -2816,9 +2841,12 @@ static int msdc_of_clock_parse(struct
> > > platform_device *pdev,
> > >     if (IS_ERR(host->src_clk))
> > >             return PTR_ERR(host->src_clk);
> > > 
> > > -   host->h_clk = devm_clk_get(&pdev->dev, "hclk");
> > > -   if (IS_ERR(host->h_clk))
> > > -           return PTR_ERR(host->h_clk);
> > > +   /* AN7581 SoC doesn't have hclk */
> > > +   if (!device_is_compatible(&pdev->dev, "airoha,an7581-mmc")) {
> > > +           host->h_clk = devm_clk_get(&pdev->dev, "hclk");
> > > +           if (IS_ERR(host->h_clk))
> > > +                   return PTR_ERR(host->h_clk);
> > > +   }
> > 
> > devm_clk_get_optional could be used to instead here, no need to use
> > compatible to distinguish.
> > 
> 
> I can make the hclk optional but I think this would affect also every
> other compatible by hiding broken clock configuration.
> 
> > >     host->bus_clk = devm_clk_get_optional(&pdev->dev, "bus_clk");
> > >     if (IS_ERR(host->bus_clk))
> > > @@ -2926,10 +2954,13 @@ static int msdc_drv_probe(struct
> > > platform_device *pdev)
> > >             return PTR_ERR(host->pins_default);
> > >     }
> > > 
> > > -   host->pins_uhs = pinctrl_lookup_state(host->pinctrl,
> > > "state_uhs");
> > > -   if (IS_ERR(host->pins_uhs)) {
> > > -           dev_err(&pdev->dev, "Cannot find pinctrl uhs!\n");
> > > -           return PTR_ERR(host->pins_uhs);
> > > +   /* AN7581 doesn't have state_uhs pins */
> > > +   if (!device_is_compatible(&pdev->dev, "airoha,an7581-mmc")) {
> > > +           host->pins_uhs = pinctrl_lookup_state(host->pinctrl,
> > > "state_uhs");
> > > +           if (IS_ERR(host->pins_uhs)) {
> > > +                   dev_err(&pdev->dev, "Cannot find pinctrl
> > > uhs!\n");
> > > +                   return PTR_ERR(host->pins_uhs);
> > > +           }
> > >     }
> > 
> > Could you consider to set a dummy 'state_uhs' same as
> > 'state_default'
> > in the dts, that you could not use compatible to distinguish here.
> > 
> 
> This is problematic, correct me if I'm wrong, you are suggesting to
> assign the emmc pins to both default and uhs? This is problematic as
> the
> pinctrl driver would complain that such pins are already assigned to
> something. Also I don't think it's possible to assign these pins to a
> dummy pin.
> 
Maybe I have not expressed clearly...What I mean is that you could set
as below, and the content of &mmc_pins_uhs is just copied from
&mmc_pins_default.

mmc@...0e000 {
	...
	pinctrl-names = "default", "state_uhs";
	pinctrl-0 = <&mmc_pins_default>;
	pinctrl-1 = <&mmc_pins_uhs>;
}
> > > 
> > >     /* Support for SDIO eint irq ? */
> > > @@ -3010,6 +3041,12 @@ static int msdc_drv_probe(struct
> > > platform_device *pdev)
> > >             dev_err(&pdev->dev, "Cannot ungate clocks!\n");
> > >             goto release_clk;
> > >     }
> > > +
> > > +   /* AN7581 without regulator require tune to OCR values */
> > > +   if (device_is_compatible(&pdev->dev, "airoha,an7581-mmc") &&
> > > +       !mmc->ocr_avail)
> > > +           mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
> > > +
> > 
> > Maybe you could use regulator-fixed in the dts and configure
> > min/max
> > voltage to get ocr_avail, no need to set hard code here.
> > 
> 
> Also suggested by Wenbin Mei (梅文彬) and I just tried this.
> 
> This can't be done, fixed-regulator needs to have the same min and
> max
> voltage or they fail to probe sooo fixed-regulator saddly can't be
> used
> :(
> 
> I will send a new version of this with the other point corrected but
> I
> think a compatible and these additional if is a must :(
If use the fixed regulator such as below, you will get the same
ocr_avail as 'MMC_VDD_32_33 | MMC_VDD_33_34' through
mmc_regulator_get_ocrmask().

vmmc_3v3: regulator-vmmc-3v3 {
	compatible = "regulator-fixed";
	regulator-name = "vmmc";
	regulator-min-microvolt = <3300000>;
	regulator-max-microvolt = <3300000>;
	regulator-always-on;
}
> 
> > >     msdc_init_hw(host);
> > > 
> > >     if (mmc->caps2 & MMC_CAP2_CQE) {
> 
> --
>         Ansuel

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