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SubjectRe: [PATCH 03/14] mmc: mmci: Add support for setting pad type via pinctrl
On 12 January 2018 at 13:15,  <patrice.chotard@st.com> wrote:
> From: Patrice Chotard <patrice.chotard@st.com>
>
> The STM32 variant hasn't the control bit to switch pads in opendrain mode.
> In this case we can achieve the same result by asking to the pinmux driver
> to configure pins for us.
>
> This patch make the mmci driver able to do this whenever needed.
>
> Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
> ---
> drivers/mmc/host/mmci.c | 54 ++++++++++++++++++++++++++++++++++++++++---------
> drivers/mmc/host/mmci.h | 5 +++++
> 2 files changed, 50 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index 7e56f85..38e8c20 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -85,6 +85,8 @@
> * @mmcimask1: true if variant have a MMCIMASK1 register.
> * @start_err: true is the variant has STARTBITERR bit inside MMCISTATUS
> * register.
> + * @opendrain: true if variant have dedicated bit for opendrain pins
> + * configuration.
> */
> struct variant_data {
> unsigned int clkreg;
> @@ -116,6 +118,7 @@ struct variant_data {
> bool reversed_irq_handling;
> bool mmcimask1;
> bool start_err;
> + bool opendrain;

Similar comment as for patch2.

To be consistent with how we implement support for similar variant
variations, I would prefer to have this being a u32. Something along
the lines of how the "busy_detect_flag" is being used.

[...]

> @@ -1394,9 +1405,11 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> {
> struct mmci_host *host = mmc_priv(mmc);
> struct variant_data *variant = host->variant;
> + struct pinctrl_state *pins;
> u32 pwr = 0;
> unsigned long flags;
> int ret;
> + bool is_opendrain;
>
> if (host->plat->ios_handler &&
> host->plat->ios_handler(mmc_dev(mmc), ios))
> @@ -1455,16 +1468,31 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> ~MCI_ST_DATA2DIREN);
> }
>
> - if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN) {
> - if (host->hw_designer != AMBA_VENDOR_ST)
> - pwr |= MCI_ROD;
> - else {
> - /*
> - * The ST Micro variant use the ROD bit for something
> - * else and only has OD (Open Drain).
> - */
> - pwr |= MCI_OD;

Seems like you should actually split this change into two parts.

One that adds the variant flag for the open drain bit, when then can
clean up this code. Then a patch on top that starts using pinctrl in
case there is no open drain bit set.

Does that sounds reasonable?

> + if (host->variant->opendrain) {
> + if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN) {
> + if (host->hw_designer != AMBA_VENDOR_ST) {
> + pwr |= MCI_ROD;
> + } else {
> + /*
> + * The ST Micro variant use the ROD bit for
> + * something else and only has OD (Open Drain).
> + */
> + pwr |= MCI_OD;
> + }
> }
> + } else {
> + /*
> + * If the variant cannot configure the pads by its own, then we
> + * expect the pinctrl to be able to do that for us
> + */
> + is_opendrain = (ios->bus_mode == MMC_BUSMODE_OPENDRAIN);
> + pins = pinctrl_lookup_state(host->pinctrl, is_opendrain ?

How about doing the lookup in ->probe() instead? Then just select the
state here, if supported?

> + MMCI_PINCTRL_STATE_OPENDRAIN :
> + MMCI_PINCTRL_STATE_PUSHPULL);
> + if (IS_ERR(pins))
> + dev_warn(mmc_dev(mmc), "Cannot select pin drive type via pinctrl\n");
> + else
> + pinctrl_select_state(host->pinctrl, pins);
> }
>
> /*
> @@ -1609,6 +1637,14 @@ static int mmci_probe(struct amba_device *dev,
> host = mmc_priv(mmc);
> host->mmc = mmc;
>
> + if (!variant->opendrain) {
> + host->pinctrl = devm_pinctrl_get(&dev->dev);
> + if (IS_ERR(host->pinctrl)) {
> + dev_err(&dev->dev, "failed to get pinctrl");
> + goto host_free;
> + }
> + }
> +
> host->hw_designer = amba_manf(dev);
> host->hw_revision = amba_rev(dev);
> dev_dbg(mmc_dev(mmc), "designer ID = 0x%02x\n", host->hw_designer);
> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
> index 83160a9..de3d0b3 100644
> --- a/drivers/mmc/host/mmci.h
> +++ b/drivers/mmc/host/mmci.h
> @@ -192,6 +192,10 @@
>
> #define NR_SG 128
>
> +/* pinctrl configs */
> +#define MMCI_PINCTRL_STATE_PUSHPULL "default"

Seems like we should be able to cope fine without having to add a
separate define for the PUSHPULL, but rather just select the default
state instead.

> +#define MMCI_PINCTRL_STATE_OPENDRAIN "opendrain"
> +
> struct clk;
> struct variant_data;
> struct dma_chan;
> @@ -227,6 +231,7 @@ struct mmci_host {
> bool vqmmc_enabled;
> struct mmci_platform_data *plat;
> struct variant_data *variant;
> + struct pinctrl *pinctrl;
>
> u8 hw_designer;
> u8 hw_revision:4;
> --
> 1.9.1
>

Kind regards
Uffe

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