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    SubjectRe: [PATCH 3/7] mmc: dw_mmc: add device tree support
    On Tue, 1 May 2012, Thomas Abraham wrote:

    > Add device tree based discovery support.
    >
    > Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
    > ---
    > .../devicetree/bindings/mmc/synposis-dw-mshc.txt | 85 +++++++++
    > drivers/mmc/host/dw_mmc-pltfm.c | 24 +++
    > drivers/mmc/host/dw_mmc.c | 181 +++++++++++++++++++-
    > drivers/mmc/host/dw_mmc.h | 10 +
    > include/linux/mmc/dw_mmc.h | 2 +
    > 5 files changed, 296 insertions(+), 6 deletions(-)
    > create mode 100644 Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt
    >
    > diff --git a/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt
    > new file mode 100644
    > index 0000000..c1ed70e
    > --- /dev/null
    > +++ b/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt
    > @@ -0,0 +1,85 @@
    > +* Synopsis Designware Mobile Storage Host Controller
    > +
    > +The Synopsis designware mobile storage host controller is used to interface
    > +a SoC with storage medium such as eMMC or SD/MMC cards.
    > +
    > +Required Properties:
    > +
    > +* compatible: should be one of the following
    > + - synopsis,dw-mshc: for controllers compliant with synopsis dw-mshc.
    > +
    > +* reg: physical base address of the dw-mshc controller and size of its memory
    > + region.
    > +
    > +* interrupts: interrupt specifier for the controller. The format and value of
    > + the interrupt specifier depends on the interrupt parent for the controller.
    > +
    > +# Slots: The slot specific information are contained within child-nodes with
    > + each child-node representing a supported slot. There should be atleast one
    > + child node representing a card slot. The name of the slot child node should
    > + be 'slot{n}' where n is the unique number of the slot connnected to the
    > + controller. The following are optional properties which can be included in
    > + the slot child node.
    > +
    > + * bus-width: specifies the width of the data bus connected from the
    > + controller to the card slot. The value should be 1, 4 or 8. In case
    > + this property is not specified, a default value of 1 is assumed for
    > + this property.
    > +
    > + * cd-gpios: specifies the card detect gpio line. The format of the
    > + gpio specifier depends on the gpio controller.
    > +
    > + * wp-gpios: specifies the write protect gpio line. The format of the
    > + gpio specifier depends on the gpio controller.
    > +
    > + * gpios: specifies a list of gpios used for command, clock and data
    > + bus. The first gpio is the command line and the second gpio is the
    > + clock line. The rest of the gpios (depending on the bus-width
    > + property) are the data lines in no particular order. The format of
    > + the gpio specifier depends on the gpio controller.
    > +
    > +Optional properties:
    > +
    > +* fifo-depth: The maximum size of the tx/rx fifo's. If this property is not
    > + specified, the default value of the fifo size is determined from the
    > + controller registers.
    > +
    > +* card-detect-delay: Delay in milli-seconds before detecting card after card
    > + insert event. The default value is 0.
    > +
    > +* supports-highspeed: Enables support for high speed cards (upto 50MHz)
    > +
    > +* card-detection-broken: The card detection functionality is not available on
    > + any of the slots.
    > +
    > +* no-write-protect: The write protect pad of the controller is not connected
    > + to the write protect pin on the slot.

    What do you think about this patch

    http://www.spinics.net/lists/linux-sh/msg11259.html

    and about using mmc-generic OF properties instead of creating yet another
    copy of proprietary ones?

    Thanks
    Guennadi

    > +
    > +Example:
    > +
    > + The MSHC controller node can be split into two portions, SoC specific and
    > + board specific portions as listed below.
    > +
    > + dwmmc0@12200000 {
    > + compatible = "synopsis,dw-mshc";
    > + reg = <0x12200000 0x1000>;
    > + interrupts = <0 75 0>;
    > + };
    > +
    > + dwmmc0@12200000 {
    > + supports-highspeed;
    > + card-detection-broken;
    > + no-write-protect;
    > + fifo-depth = <0x80>;
    > + card-detect-delay = <200>;
    > +
    > + slot0 {
    > + bus-width = <8>;
    > + cd-gpios = <&gpc0 2 2 3 3>;
    > + gpios = <&gpc0 0 2 0 3>, <&gpc0 1 2 0 3>,
    > + <&gpc1 0 2 3 3>, <&gpc1 1 2 3 3>,
    > + <&gpc1 2 2 3 3>, <&gpc1 3 2 3 3>,
    > + <&gpc0 3 2 3 3>, <&gpc0 4 2 3 3>,
    > + <&gpc0 5 2 3 3>, <&gpc0 6 2 3 3>;
    > + };
    > + };
    > diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
    > index 92ec3eb..2b2c9bd 100644
    > --- a/drivers/mmc/host/dw_mmc-pltfm.c
    > +++ b/drivers/mmc/host/dw_mmc-pltfm.c
    > @@ -19,8 +19,24 @@
    > #include <linux/mmc/host.h>
    > #include <linux/mmc/mmc.h>
    > #include <linux/mmc/dw_mmc.h>
    > +#include <linux/of.h>
    > #include "dw_mmc.h"
    >
    > +#ifdef CONFIG_OF
    > +static struct dw_mci_drv_data synopsis_drv_data = {
    > + .ctrl_type = DW_MCI_TYPE_SYNOPSIS,
    > +};
    > +
    > +static const struct of_device_id dw_mci_pltfm_match[] = {
    > + { .compatible = "synopsis,dw-mshc",
    > + .data = (void *)&synopsis_drv_data, },
    > + {},
    > +};
    > +MODULE_DEVICE_TABLE(of, dw_mci_pltfm_match);
    > +#else
    > +static const struct of_device_id dw_mci_pltfm_match[];
    > +#endif
    > +
    > static int dw_mci_pltfm_probe(struct platform_device *pdev)
    > {
    > struct dw_mci *host;
    > @@ -51,6 +67,13 @@ static int dw_mci_pltfm_probe(struct platform_device *pdev)
    > if (!host->regs)
    > goto err_free;
    > platform_set_drvdata(pdev, host);
    > +
    > + if (pdev->dev.of_node) {
    > + const struct of_device_id *match;
    > + match = of_match_node(dw_mci_pltfm_match, pdev->dev.of_node);
    > + host->drv_data = match->data;
    > + }
    > +
    > ret = dw_mci_probe(host);
    > if (ret)
    > goto err_out;
    > @@ -111,6 +134,7 @@ static struct platform_driver dw_mci_pltfm_driver = {
    > .remove = __exit_p(dw_mci_pltfm_remove),
    > .driver = {
    > .name = "dw_mmc",
    > + .of_match_table = of_match_ptr(dw_mci_pltfm_match),
    > .pm = &dw_mci_pltfm_pmops,
    > },
    > };
    > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
    > index 38cb7f8..bcf66d7 100644
    > --- a/drivers/mmc/host/dw_mmc.c
    > +++ b/drivers/mmc/host/dw_mmc.c
    > @@ -33,9 +33,13 @@
    > #include <linux/bitops.h>
    > #include <linux/regulator/consumer.h>
    > #include <linux/workqueue.h>
    > +#include <linux/of.h>
    > +#include <linux/of_gpio.h>
    >
    > #include "dw_mmc.h"
    >
    > +#define NUM_PINS(x) (x + 2)
    > +
    > /* Common flag combinations */
    > #define DW_MCI_DATA_ERROR_FLAGS (SDMMC_INT_DTO | SDMMC_INT_DCRC | \
    > SDMMC_INT_HTO | SDMMC_INT_SBE | \
    > @@ -86,6 +90,8 @@ struct idmac_desc {
    > struct dw_mci_slot {
    > struct mmc_host *mmc;
    > struct dw_mci *host;
    > + int wp_gpio;
    > + int cd_gpio;
    >
    > u32 ctype;
    >
    > @@ -816,6 +822,8 @@ static int dw_mci_get_ro(struct mmc_host *mmc)
    > read_only = 0;
    > else if (brd->get_ro)
    > read_only = brd->get_ro(slot->id);
    > + else if (gpio_is_valid(slot->wp_gpio))
    > + read_only = gpio_get_value(slot->wp_gpio);
    > else
    > read_only =
    > mci_readl(slot->host, WRTPRT) & (1 << slot->id) ? 1 : 0;
    > @@ -837,6 +845,8 @@ static int dw_mci_get_cd(struct mmc_host *mmc)
    > present = 1;
    > else if (brd->get_cd)
    > present = !brd->get_cd(slot->id);
    > + else if (gpio_is_valid(slot->cd_gpio))
    > + present = gpio_get_value(slot->cd_gpio);
    > else
    > present = (mci_readl(slot->host, CDETECT) & (1 << slot->id))
    > == 0 ? 1 : 0;
    > @@ -1747,6 +1757,96 @@ static void dw_mci_work_routine_card(struct work_struct *work)
    > }
    > }
    >
    > +#ifdef CONFIG_OF
    > +static struct device_node *dw_mci_of_find_slot_node(struct device *dev, u8 slot)
    > +{
    > + struct device_node *np;
    > + char name[7];
    > +
    > + if (!dev || !dev->of_node)
    > + return NULL;
    > +
    > + for_each_child_of_node(dev->of_node, np) {
    > + sprintf(name, "slot%d", slot);
    > + if (!strcmp(name, np->name))
    > + return np;
    > + }
    > + return NULL;
    > +}
    > +
    > +static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
    > +{
    > + struct device_node *np = dw_mci_of_find_slot_node(dev, slot);
    > + u32 bus_wd = 1;
    > +
    > + if (!np)
    > + return 1;
    > +
    > + if (of_property_read_u32(np, "bus-width", &bus_wd))
    > + dev_err(dev, "bus-width property not found, assuming width"
    > + " as 1\n");
    > + return bus_wd;
    > +}
    > +
    > +static int dw_mci_of_setup_bus(struct dw_mci *host, u8 slot, u32 bus_wd)
    > +{
    > + struct device_node *np = dw_mci_of_find_slot_node(&host->dev, slot);
    > + int idx, gpio, ret;
    > +
    > + for (idx = 0; idx < NUM_PINS(bus_wd); idx++) {
    > + gpio = of_get_gpio(np, idx);
    > + if (!gpio_is_valid(gpio)) {
    > + dev_err(&host->dev, "invalid gpio: %d\n", gpio);
    > + return -EINVAL;
    > + }
    > +
    > + ret = devm_gpio_request(&host->dev, gpio, "dw-mci-bus");
    > + if (ret) {
    > + dev_err(&host->dev, "gpio [%d] request failed\n", gpio);
    > + return -EBUSY;
    > + }
    > + }
    > +
    > + host->slot[slot]->wp_gpio = -1;
    > + gpio = of_get_named_gpio(np, "wp_gpios", 0);
    > + if (!gpio_is_valid(gpio)) {
    > + dev_info(&host->dev, "wp gpio not available");
    > + } else {
    > + ret = devm_gpio_request(&host->dev, gpio, "dw-mci-wp");
    > + if (ret)
    > + dev_info(&host->dev, "gpio [%d] request failed\n",
    > + gpio);
    > + else
    > + host->slot[slot]->wp_gpio = gpio;
    > + }
    > +
    > + host->slot[slot]->cd_gpio = -1;
    > + gpio = of_get_named_gpio(np, "cd-gpios", 0);
    > + if (!gpio_is_valid(gpio)) {
    > + dev_info(&host->dev, "cd gpio not available");
    > + } else {
    > + ret = devm_gpio_request(&host->dev, gpio, "dw-mci-cd");
    > + if (ret)
    > + dev_err(&host->dev, "gpio [%d] request failed\n", gpio);
    > + else
    > + host->slot[slot]->cd_gpio = gpio;
    > + }
    > +
    > + return 0;
    > +}
    > +
    > +#else /* CONFIG_OF */
    > +static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
    > +{
    > + return 1;
    > +}
    > +
    > +static int dw_mci_of_setup_bus(struct dw_mci *host, u8 slot, u32 bus_wd)
    > +{
    > + return -EINVAL;
    > +}
    > +#endif /* CONFIG_OF */
    > +
    > static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
    > {
    > struct mmc_host *mmc;
    > @@ -1760,6 +1860,7 @@ static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
    > slot->id = id;
    > slot->mmc = mmc;
    > slot->host = host;
    > + host->slot[id] = slot;
    >
    > mmc->ops = &dw_mci_ops;
    > mmc->f_min = DIV_ROUND_UP(host->bus_hz, 510);
    > @@ -1780,12 +1881,21 @@ static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
    > if (host->pdata->caps)
    > mmc->caps = host->pdata->caps;
    >
    > + mmc->caps |= host->drv_data->caps;
    > +
    > if (host->pdata->caps2)
    > mmc->caps2 = host->pdata->caps2;
    >
    > - if (host->pdata->get_bus_wd)
    > + if (host->pdata->get_bus_wd) {
    > if (host->pdata->get_bus_wd(slot->id) >= 4)
    > mmc->caps |= MMC_CAP_4_BIT_DATA;
    > + } else if (host->dev.of_node) {
    > + unsigned int bus_width;
    > + bus_width = dw_mci_of_get_bus_wd(&host->dev, slot->id);
    > + if (bus_width >= 4)
    > + mmc->caps |= MMC_CAP_4_BIT_DATA;
    > + dw_mci_of_setup_bus(host, slot->id, bus_width);
    > + }
    >
    > if (host->pdata->quirks & DW_MCI_QUIRK_HIGHSPEED)
    > mmc->caps |= MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED;
    > @@ -1830,7 +1940,6 @@ static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
    > else
    > clear_bit(DW_MMC_CARD_PRESENT, &slot->flags);
    >
    > - host->slot[id] = slot;
    > mmc_add_host(mmc);
    >
    > #if defined(CONFIG_DEBUG_FS)
    > @@ -1923,15 +2032,75 @@ static bool mci_wait_reset(struct device *dev, struct dw_mci *host)
    > return false;
    > }
    >
    > +#ifdef CONFIG_OF
    > +static struct dw_mci_of_quirks {
    > + char *quirk;
    > + int id;
    > +} of_quriks[] = {
    > + {
    > + .quirk = "supports-highspeed",
    > + .id = DW_MCI_QUIRK_HIGHSPEED,
    > + }, {
    > + .quirk = "card-detection-broken",
    > + .id = DW_MCI_QUIRK_BROKEN_CARD_DETECTION,
    > + }, {
    > + .quirk = "no-write-protect",
    > + .id = DW_MCI_QUIRK_NO_WRITE_PROTECT,
    > + },
    > + { }
    > +};
    > +
    > +static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
    > +{
    > + struct dw_mci_board *pdata;
    > + struct device *dev = &host->dev;
    > + struct device_node *np = dev->of_node, *slot;
    > + u32 timing[3];
    > + int idx, cnt;
    > +
    > + pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
    > + if (!pdata) {
    > + dev_err(dev, "could not allocate memory for pdata\n");
    > + return ERR_PTR(-ENOMEM);
    > + }
    > +
    > + /* find out number of slots supported */
    > + for_each_child_of_node(np, slot)
    > + pdata->num_slots++;
    > +
    > + /* get quirks */
    > + cnt = sizeof(of_quriks) / sizeof(struct dw_mci_of_quirks);
    > + for (idx = 0; idx < cnt; idx++)
    > + if (of_get_property(np, of_quriks[idx].quirk, NULL))
    > + pdata->quirks |= of_quriks[idx].id;
    > +
    > + if (of_property_read_u32(np, "fifo-depth", &pdata->fifo_depth))
    > + dev_info(dev, "fifo-depth property not found, using "
    > + "value of FIFOTH register as default\n");
    > +
    > + of_property_read_u32(np, "card-detect-delay", &pdata->detect_delay_ms);
    > +
    > + return pdata;
    > +}
    > +
    > +#else /* CONFIG_OF */
    > +static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
    > +{
    > + return ERR_PTR(-EINVAL);
    > +}
    > +#endif /* CONFIG_OF */
    > +
    > int dw_mci_probe(struct dw_mci *host)
    > {
    > int width, i, ret = 0;
    > u32 fifo_size;
    >
    > - if (!host->pdata || !host->pdata->init) {
    > - dev_err(&host->dev,
    > - "Platform data must supply init function\n");
    > - return -ENODEV;
    > + if (!host->pdata) {
    > + host->pdata = dw_mci_parse_dt(host);
    > + if (IS_ERR(host->pdata)) {
    > + dev_err(&host->dev, "platform data not available\n");
    > + return -EINVAL;
    > + }
    > }
    >
    > if (!host->pdata->select_slot && host->pdata->num_slots > 1) {
    > diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
    > index 15c27e1..8b8862b 100644
    > --- a/drivers/mmc/host/dw_mmc.h
    > +++ b/drivers/mmc/host/dw_mmc.h
    > @@ -182,4 +182,14 @@ extern int dw_mci_suspend(struct dw_mci *host);
    > extern int dw_mci_resume(struct dw_mci *host);
    > #endif
    >
    > +/* Variations in the dw_mci controller */
    > +#define DW_MCI_TYPE_SYNOPSIS 0
    > +#define DW_MCI_TYPE_EXYNOS5250 1 /* Samsung Exynos5250 Extensions */
    > +
    > +/* dw_mci platform driver data */
    > +struct dw_mci_drv_data {
    > + unsigned long ctrl_type;
    > + unsigned long caps;
    > +};
    > +
    > #endif /* _DW_MMC_H_ */
    > diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
    > index fb51a5f..71d2b56 100644
    > --- a/include/linux/mmc/dw_mmc.h
    > +++ b/include/linux/mmc/dw_mmc.h
    > @@ -78,6 +78,7 @@ struct mmc_data;
    > * @data_offset: Set the offset of DATA register according to VERID.
    > * @dev: Device associated with the MMC controller.
    > * @pdata: Platform data associated with the MMC controller.
    > + * @drv_data: Driver specific data for identified variant of the controller
    > * @biu_clk: Pointer to bus interface unit clock instance.
    > * @ciu_clk: Pointer to card interface unit clock instance.
    > * @slot: Slots sharing this MMC controller.
    > @@ -160,6 +161,7 @@ struct dw_mci {
    > u16 data_offset;
    > struct device dev;
    > struct dw_mci_board *pdata;
    > + struct dw_mci_drv_data *drv_data;
    > struct clk *biu_clk;
    > struct clk *ciu_clk;
    > struct dw_mci_slot *slot[MAX_MCI_SLOTS];
    > --
    > 1.7.5.4
    >
    >
    > _______________________________________________
    > linux-arm-kernel mailing list
    > linux-arm-kernel@lists.infradead.org
    > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
    >

    ---
    Guennadi Liakhovetski, Ph.D.
    Freelance Open-Source Software Developer
    http://www.open-technology.de/


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