Re: [PATCH] extcon: extcon-dra7xx: Add Extcon driver for DRA7xx

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On 06/15/2014 07:42 PM, George Cherian wrote:
This is the driver for the USB ID pin detection. This driver
handles only the USB ID pin changes generated by cable
insertion/removal.

Signed-off-by: George Cherian <george.cherian@xxxxxx>

Hi George,

Curious: Why can't you use extcon-gpio ?

Also, I thought that Linux specific bindings would be unacceptable.
"ti,dra7xx-extcon" looks very linux specific to me. Did the rules change ?

Thanks,
Guenter

---
  .../devicetree/bindings/extcon/extcon-dra7xx.txt   |  15 ++
  drivers/extcon/Kconfig                             |   5 +
  drivers/extcon/Makefile                            |   1 +
  drivers/extcon/extcon-dra7xx.c                     | 164 +++++++++++++++++++++
  4 files changed, 185 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt
  create mode 100644 drivers/extcon/extcon-dra7xx.c

diff --git a/Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt b/Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt
new file mode 100644
index 0000000..69c3804
--- /dev/null
+++ b/Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt
@@ -0,0 +1,15 @@
+EXTCON FOR DRA7xx USB
+
+Required Properties:
+ - compatible : Should be "ti,dra7xx-extcon"
+ - gpios : specifies the gpio pin used for ID pin detection.
+
+
+Please refer to ../gpio/gpio.txt for details of the common GPIO bindings
+
+Example:
+
+ dra7xx_extcon {
+                compatible = "ti,dra7xx-extcon";
+                gpios = <&gpio21 1 0>;
+        };
diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index aebde48..1481b7f 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -70,4 +70,9 @@ config EXTCON_PALMAS
  	  Say Y here to enable support for USB peripheral and USB host
  	  detection by palmas usb.

+config EXTCON_DRA7XX
+	tristate "DRA7xx USB ID detection EXTCON support"
+	help
+	  Say Y here to enable support for USB ID detection for DRA7xx.
+
  endif # MULTISTATE_SWITCH
diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
index bf7861e..b5f7cac 100644
--- a/drivers/extcon/Makefile
+++ b/drivers/extcon/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_EXTCON_MAX77693)	+= extcon-max77693.o
  obj-$(CONFIG_EXTCON_MAX8997)	+= extcon-max8997.o
  obj-$(CONFIG_EXTCON_ARIZONA)	+= extcon-arizona.o
  obj-$(CONFIG_EXTCON_PALMAS)	+= extcon-palmas.o
+obj-$(CONFIG_EXTCON_DRA7XX)	+= extcon-dra7xx.o
diff --git a/drivers/extcon/extcon-dra7xx.c b/drivers/extcon/extcon-dra7xx.c
new file mode 100644
index 0000000..2f80509
--- /dev/null
+++ b/drivers/extcon/extcon-dra7xx.c
@@ -0,0 +1,164 @@
+/*
+ * DRA7xx-Extcon  USB ID pin detection driver
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Author: George Cherian <george.cherian@xxxxxx>
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/extcon.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+struct dra7xx_extcon {
+	struct device *dev;
+	struct extcon_dev edev;
+
+	int id_gpio;
+	int id_irq;
+};
+
+static const char *dra7xx_extcon_cable[] = {
+	[1] = "USB-HOST",
+	NULL,
+};
+
+#define ID_GND		0
+
+static irqreturn_t id_irq_handler(int irq, void *data)
+{
+	struct dra7xx_extcon *dra7xx_extcon = (struct dra7xx_extcon *)data;
+	int id_current;
+
+	id_current = gpio_get_value_cansleep(dra7xx_extcon->id_gpio);
+	if (id_current == ID_GND)
+		extcon_set_cable_state(&dra7xx_extcon->edev, "USB-HOST", true);
+	else
+		extcon_set_cable_state(&dra7xx_extcon->edev, "USB-HOST", false);
+
+	return IRQ_HANDLED;
+}
+
+static void dra7xx_extcon_set_initial_state(struct dra7xx_extcon *dra7xx_extcon)
+{
+	int id_current;
+
+	id_current = gpio_get_value_cansleep(dra7xx_extcon->id_gpio);
+	if (id_current == ID_GND)
+		extcon_set_cable_state(&dra7xx_extcon->edev,
+				       "USB-HOST", true);
+	else
+		extcon_set_cable_state(&dra7xx_extcon->edev,
+				       "USB-HOST", false);
+}
+
+static int dra7xx_extcon_request_irq(struct dra7xx_extcon *dra7xx_extcon)
+{
+	int ret;
+
+	ret = devm_request_threaded_irq(dra7xx_extcon->dev,
+					dra7xx_extcon->id_irq,
+					NULL, id_irq_handler,
+					IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
+					dev_name(dra7xx_extcon->dev),
+					(void *)dra7xx_extcon);
+	if (ret) {
+		dev_err(dra7xx_extcon->dev, "failed to request id irq #%d\n",
+			dra7xx_extcon->id_irq);
+		return ret;
+	}
+	return ret;
+}
+
+static int dra7xx_extcon_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct dra7xx_extcon *dra7xx_extcon;
+	int ret, gpio;
+
+	dra7xx_extcon = devm_kzalloc(&pdev->dev, sizeof(*dra7xx_extcon),
+				     GFP_KERNEL);
+	if (!dra7xx_extcon)
+		return -ENOMEM;
+
+	dra7xx_extcon->dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, dra7xx_extcon);
+
+	dra7xx_extcon->edev.supported_cable = dra7xx_extcon_cable;
+
+	gpio = of_get_gpio(node, 0);
+	if (gpio_is_valid(gpio)) {
+		dra7xx_extcon->id_gpio = gpio;
+		ret = devm_gpio_request(&pdev->dev, dra7xx_extcon->id_gpio,
+					"id_gpio");
+		if (ret)
+			return ret;
+
+		dra7xx_extcon->id_irq = gpio_to_irq(dra7xx_extcon->id_gpio);
+	} else {
+		dev_err(&pdev->dev, "failed to get id gpio\n");
+		return -EPROBE_DEFER;
+	}
+
+	ret = dra7xx_extcon_request_irq(dra7xx_extcon);
+	if (ret)
+		return ret;
+
+	ret = extcon_dev_register(&dra7xx_extcon->edev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register extcon device\n");
+		return ret;
+	}
+
+	dra7xx_extcon_set_initial_state(dra7xx_extcon);
+
+	return 0;
+}
+
+static int dra7xx_extcon_remove(struct platform_device *pdev)
+{
+	struct dra7xx_extcon *dra7xx_extcon = platform_get_drvdata(pdev);
+
+	extcon_dev_unregister(&dra7xx_extcon->edev);
+	return 0;
+}
+
+static struct of_device_id of_dra7xx_extcon_match_tbl[] = {
+	{ .compatible = "ti,dra7xx-extcon", },
+	{ /* end */ }
+};
+
+static struct platform_driver dra7xx_extcon_driver = {
+	.probe = dra7xx_extcon_probe,
+	.remove = dra7xx_extcon_remove,
+	.driver = {
+		.name = "dra7xx-extcon",
+		.of_match_table = of_dra7xx_extcon_match_tbl,
+		.owner = THIS_MODULE,
+	},
+};
+
+module_platform_driver(dra7xx_extcon_driver);
+
+MODULE_ALIAS("platform:extcon-dra7xx");
+MODULE_AUTHOR("George Cherian <george.cherian@xxxxxx>");
+MODULE_DESCRIPTION("USB ID pin detection driver for DRA7xx");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, of_dra7xx_extcon_match_tbl);


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