Message-ID: <Pine.LNX.4.64.1205040047280.18111@axis700.grange>
Date:	Fri, 4 May 2012 00:48:34 +0200 (CEST)
From:	Guennadi Liakhovetski <g.liakhovetski@....de>
To:	Thomas Abraham <thomas.abraham@...aro.org>
cc:	linux-mmc@...r.kernel.org, devicetree-discuss@...ts.ozlabs.org,
	linux-samsung-soc@...r.kernel.org, patches@...aro.org,
	linux-kernel@...r.kernel.org, rob.herring@...xeda.com,
	grant.likely@...retlab.ca, kgene.kim@...sung.com, cjb@...top.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [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@...aro.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@...00000 {
> +		compatible = "synopsis,dw-mshc";
> +		reg = <0x12200000 0x1000>;
> +		interrupts = <0 75 0>;
> +	};
> +
> +	dwmmc0@...00000 {
> +		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@...ts.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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