0031-misc-add-gpevt-driver.patch

From 47877897dd1f70357c357f51c5f512c493b694c7 Mon Sep 17 00:00:00 2001
From: Matt Porter <mporter@ti.com>
Date: Wed, 17 Oct 2012 10:48:22 -0400
Subject: [PATCH 31/35] misc: add gpevt driver

Simply amazing...'nuff said.

Signed-off-by: Matt Porter <mporter@ti.com>
---
 drivers/misc/Kconfig  |   6 ++
 drivers/misc/Makefile |   1 +
 drivers/misc/gpevt.c  | 172 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 179 insertions(+)
 create mode 100644 drivers/misc/gpevt.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index b151b7c..cd43cbd 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -499,6 +499,12 @@ config USB_SWITCH_FSA9480
 	  stereo and mono audio, video, microphone and UART data to use
 	  a common connector port.
 
+config GPEVT
+	tristate "Amazing GPIO DMA Event Test Driver(tm)"
+	depends on TI_EDMA
+	help
+	  Simply amazing!
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 2129377..661d093 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -49,3 +49,4 @@ obj-y				+= carma/
 obj-$(CONFIG_USB_SWITCH_FSA9480) += fsa9480.o
 obj-$(CONFIG_ALTERA_STAPL)	+=altera-stapl/
 obj-$(CONFIG_INTEL_MEI)		+= mei/
+obj-$(CONFIG_GPEVT)		+= gpevt.o
diff --git a/drivers/misc/gpevt.c b/drivers/misc/gpevt.c
new file mode 100644
index 0000000..4fe256c
--- /dev/null
+++ b/drivers/misc/gpevt.c
@@ -0,0 +1,172 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/gpio.h>
+#include <linux/err.h>
+#include <linux/uaccess.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+
+#define GPEVT_MAGIC 0xdeadbeef
+
+static u32 *dst_fifo;
+static	dma_addr_t fifo_addr;
+
+static void gpevt_callback(void *data)
+{
+	struct device *dev = data;
+
+	dma_unmap_single(dev, fifo_addr, 32, DMA_FROM_DEVICE);
+
+	if (*dst_fifo == GPEVT_MAGIC)
+		dev_info(dev, "*** DMA transfer succeeded ***\n");
+	else
+		dev_info(dev, "*** DMA transfer failed ***\n");
+}
+
+static int __devinit gpevt_probe (struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct pinctrl *pinctrl;
+	struct dma_chan *chan;
+	struct dma_slave_config cfg;
+	struct dma_async_tx_descriptor *tx;
+	int gpio_evt = 0;
+	int ret;
+	u32 *src_buf;
+	struct scatterlist sg;
+
+	src_buf = devm_kzalloc(&pdev->dev, 32, GFP_KERNEL);
+	if (!src_buf) {
+		dev_err(&pdev->dev, "failed to allocate src buffer\n");
+		return -ENOMEM;
+	}
+
+	dst_fifo = devm_kzalloc(&pdev->dev, 32, GFP_KERNEL);
+	if (!dst_fifo) {
+		dev_err(&pdev->dev, "failed to allocate dst fifo\n");
+		return -ENOMEM;
+	}
+		
+	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
+	if (IS_ERR(pinctrl))
+		dev_warn(&pdev->dev,
+			"pins are not configured from the driver\n");
+
+        gpio_evt = of_get_named_gpio(np, "gpio-evt", 0);
+	if (gpio_evt < 0) {
+		dev_err(&pdev->dev, "failed to find gpio event signal!\n");
+		return -EINVAL;
+	}
+
+        ret = devm_gpio_request_one(&pdev->dev, gpio_evt,
+				    GPIOF_IN, "GPIO Event Pin");
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to claim gpio-evt pin\n");
+		return ret;
+	}
+
+	ret = request_irq(gpio_to_irq(gpio_evt), no_action,
+			  IRQ_TYPE_EDGE_FALLING, "gpevt", &pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to request falling edge irq/event\n");
+		return ret;
+	}
+
+	chan = dma_request_slave_channel(&pdev->dev, "gpioevt");
+	if (!chan) {
+		dev_err(&pdev->dev, "no gpio channel for gpevt\n");
+		return -EAGAIN;
+	}
+
+	fifo_addr = dma_map_single(&pdev->dev, dst_fifo, 32, DMA_FROM_DEVICE);
+	if (!fifo_addr) {
+		dev_err(&pdev->dev, "could not map dst fifo\n");
+		return -EIO;
+	}
+	cfg.dst_addr = fifo_addr;
+	cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	cfg.dst_maxburst = 1;
+
+	ret = dmaengine_slave_config(chan, &cfg);
+	if (ret)
+		return ret;
+
+	*src_buf = GPEVT_MAGIC;
+	sg_init_table(&sg, 1);
+	sg_dma_address(&sg) = dma_map_single(&pdev->dev, src_buf, 32, DMA_TO_DEVICE);
+	sg_dma_len(&sg) = 4;
+
+	tx = dmaengine_prep_slave_sg(chan, &sg, 1, DMA_MEM_TO_DEV,
+				     DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!tx) {
+		dev_err(&pdev->dev, "prep_slave_sg() failed\n");
+		return -EIO;
+	}
+
+	tx->callback = gpevt_callback;
+	tx->callback_param = &pdev->dev;
+	dmaengine_submit(tx);
+
+	dma_async_issue_pending(chan);
+		
+	dev_info(&pdev->dev, "Amazing GPIO DMA Event Test Driver(tm) engaged\n");
+
+	return 0;
+}
+
+static int __devexit gpevt_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static const struct of_device_id gpevt_dt_ids[] = {
+	{ .compatible = "gpevt", .data = (void *) NULL, },
+};
+MODULE_DEVICE_TABLE(of, gpevt_dt_ids);
+
+static struct platform_driver gpevt_driver = {
+	.driver = {
+		.name   = "gpevt",
+		.owner  = THIS_MODULE,
+		.of_match_table = gpevt_dt_ids,
+	},
+	.probe  = gpevt_probe,
+	.remove = __devexit_p(gpevt_remove),
+};
+
+static int __init gpevt_init(void)
+{
+	return platform_driver_register(&gpevt_driver);
+}
+
+static void __exit gpevt_exit(void)
+{
+	platform_driver_unregister(&gpevt_driver);
+}
+
+/* ------------------------------------------------------------------------- */
+
+module_init(gpevt_init);
+module_exit(gpevt_exit);
+
+MODULE_DESCRIPTION("Amazing GPIO DMA Event Test Driver(tm)");
+MODULE_AUTHOR("Matt Porter <mporter@ti.com>");
+MODULE_LICENSE("GPL");
-- 
1.8.2.1