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

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Le 05/22/2012 04:08 PM, Jean-Christophe PLAGNIOL-VILLARD a écrit :
On 12:09 Tue 22 May     , ludovic.desroches@xxxxxxxxx wrote:
From: Ludovic Desroches<ludovic.desroches@xxxxxxxxx>

Signed-off-by: Ludovic Desroches<ludovic.desroches@xxxxxxxxx>
---
  .../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


It's a property from the common mmc binding so why not using it?

+- 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

ok

+
+		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


Sorry but what do you mean? The node is checked into atmci_of_init and the return is checked:

+	if (!pdata) {
+		pdata = atmci_of_init(pdev);
+		if (IS_ERR(pdata)) {
+			dev_err(&pdev->dev, "platform data not available\n");
+			return -EINVAL;
+		}
+	}


Regards

Ludovic


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