Re: [PATCH v3 1/3] mmc: atmel-mci: add device tree support

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 12:09 Tue 22 May     , ludovic.desroches@atmel.com wrote:
> From: Ludovic Desroches <ludovic.desroches@atmel.com>
> 
> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
> ---
>  .../devicetree/bindings/mmc/atmel-hsmci.txt        |   67 +++++++++++++++
>  drivers/mmc/host/atmel-mci.c                       |   89 +++++++++++++++++++-
>  2 files changed, 154 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/mmc/atmel-hsmci.txt
> 
> diff --git a/Documentation/devicetree/bindings/mmc/atmel-hsmci.txt b/Documentation/devicetree/bindings/mmc/atmel-hsmci.txt
> new file mode 100644
> index 0000000..81c20cc
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mmc/atmel-hsmci.txt
> @@ -0,0 +1,67 @@
> +* Atmel High Speed MultiMedia Card Interface
> +
> +This controller on atmel products provides an interface for MMC, SD and SDIO
> +types of memory cards.
> +
> +1) MCI node
> +
> +Required properties:
> +- compatible: no blank "atmel,hsmci"
> +- reg: should contain HSMCI registers location and length
> +- interrupts: should contain HSMCI interrupt number
> +- #address-cells: should be one. The cell is the slot id.
> +- #size-cells: should be zero.
> +- at least one slot node
> +
> +The node contains child nodes for each slot that the platform uses
> +
> +Example MCI node:
> +
> +mmc0: mmc@f0008000 {
> +	compatible = "atmel,hsmci";
> +	reg = <0xf0008000 0x600>;
> +	interrupts = <12 4>;
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	[ child node definitions...]
> +};
> +
> +2) slot nodes
> +
> +Required properties:
> +- reg: should contain the slot id.
> +- bus-width: number of data lines connected to the controller
> +
> +Optional properties:
> +- cd-gpios: specify GPIOs for card detection
> +- cd-inverted: invert the value of external card detect gpio line
why this

no need you can use the third field and OF_GPIO_ACTIVE_LOW
as done on ohci-at91.c

> +- wp-gpios: specify GPIOs for write protection
> +
> +Example slot node:
> +
> +slot@0 {
> +	reg = <0>;
> +	bus-width = <4>;
> +	cd-gpios = <&pioD 15 0>
> +	cd-inverted;
> +};
> +
> +Example full MCI node:
> +mmc0: mmc@f0008000 {
> +	compatible = "atmel,hsmci";
> +	reg = <0xf0008000 0x600>;
> +	interrupts = <12 4>;
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +	slot@0 {
> +		reg = <0>;
> +		bus-width = <4>;
> +		cd-gpios = <&pioD 15 0>
> +		cd-inverted;
> +	};
> +	slot@1 {
> +		reg = <1>;
> +		bus-width = <4>;
> +	};
> +};
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index 556d384..43f98fc 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -19,6 +19,9 @@
>  #include <linux/interrupt.h>
>  #include <linux/ioport.h>
>  #include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_gpio.h>
>  #include <linux/platform_device.h>
>  #include <linux/scatterlist.h>
>  #include <linux/seq_file.h>
> @@ -493,6 +496,74 @@ err:
>  	dev_err(&mmc->class_dev, "failed to initialize debugfs for slot\n");
>  }
>  
> +#if defined(CONFIG_OF)
> +static const struct of_device_id atmci_dt_ids[] = {
> +	{ .compatible = "atmel,hsmci" },
> +	{ /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, atmci_dt_ids);
> +
> +static struct mci_platform_data __devinit*
> +atmci_of_init(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct device_node *cnp;
> +	struct mci_platform_data *pdata;
> +	unsigned int slot_id;
> +	const __be32 *reg;
> +
> +	if (!np) {
> +		dev_err(&pdev->dev, "device node not found\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata) {
> +		dev_err(&pdev->dev, "could not allocate memory for pdata\n");
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	for_each_child_of_node(np, cnp) {
> +		reg = of_get_property(cnp, "reg", NULL);
> +		if (!reg) {
> +			dev_warn(&pdev->dev, "reg property is missing for %s\n",
> +				 cnp->full_name);
> +			continue;
> +		}
> +
> +		slot_id = be32_to_cpu(reg[0]);
read_u32
> +
> +		if (slot_id > (ATMCI_MAX_NR_SLOTS-1)) {
> +			dev_warn(&pdev->dev, "can't have more than %d slots\n",
> +			         ATMCI_MAX_NR_SLOTS);
> +			break;
> +		}
> +
> +		if (of_property_read_u32(cnp, "bus-width",
> +		                         &pdata->slot[slot_id].bus_width))
> +			pdata->slot[slot_id].bus_width = 1;
> +
> +		pdata->slot[slot_id].detect_pin =
> +			of_get_named_gpio(cnp, "cd-gpios", 0);
> +
> +		if (of_find_property(cnp, "cd-inverted", NULL))
> +			pdata->slot[slot_id].detect_is_active_high = true;
> +
> +		pdata->slot[slot_id].wp_pin =
> +			of_get_named_gpio(cnp, "wp-gpios", 0);
> +	}
> +
> +	return pdata;
> +}
> +#else /* CONFIG_OF */
> +static inline struct mci_platform_data*
> +atmci_of_init(struct platform_device *dev)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +#endif
> +
>  static inline unsigned int atmci_get_version(struct atmel_mci *host)
>  {
>  	return atmci_readl(host, ATMCI_VERSION) & 0x00000fff;
> @@ -2038,6 +2109,13 @@ static int __init atmci_init_slot(struct atmel_mci *host,
>  	slot->sdc_reg = sdc_reg;
>  	slot->sdio_irq = sdio_irq;
>  
> +	dev_dbg(&mmc->class_dev,
> +	        "slot[%u]: bus_width=%u, detect_pin=%d, "
> +		"detect_is_active_high=%s, wp_pin=%d\n",
> +		id, slot_data->bus_width, slot_data->detect_pin,
> +		slot_data->detect_is_active_high ? "true" : "false",
> +		slot_data->wp_pin);
> +
>  	mmc->ops = &atmci_ops;
>  	mmc->f_min = DIV_ROUND_UP(host->bus_hz, 512);
>  	mmc->f_max = host->bus_hz / 2;
> @@ -2258,8 +2336,14 @@ static int __init atmci_probe(struct platform_device *pdev)
>  	if (!regs)
>  		return -ENXIO;
>  	pdata = pdev->dev.platform_data;
> -	if (!pdata)
> -		return -ENXIO;
check the node and then check the return

Best Regards,
J.