0125-cape-Added-support-for-IIO-helper-cape.patch

From ab0813154582de151e9c7d3a9bbdfc6143e78392 Mon Sep 17 00:00:00 2001
From: Matt Ranostay <mranostay@gmail.com>
Date: Tue, 19 Mar 2013 17:06:03 +0000
Subject: [PATCH 125/184] cape: Added support for IIO helper cape

Since we currently can't export the IIO channels from the
ADCs this patch exposes an sysfs entry to read a respective
channel.

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
---
 drivers/misc/cape/beaglebone/Kconfig           |   7 +
 drivers/misc/cape/beaglebone/Makefile          |   1 +
 drivers/misc/cape/beaglebone/bone-iio-helper.c | 175 +++++++++++++++++++++++++
 3 files changed, 183 insertions(+)
 create mode 100644 drivers/misc/cape/beaglebone/bone-iio-helper.c

diff --git a/drivers/misc/cape/beaglebone/Kconfig b/drivers/misc/cape/beaglebone/Kconfig
index 9bf5ac0..4937577 100644
--- a/drivers/misc/cape/beaglebone/Kconfig
+++ b/drivers/misc/cape/beaglebone/Kconfig
@@ -9,6 +9,13 @@ config BEAGLEBONE_PINMUX_HELPER
 	help
 	  Say Y here to include support for the pinmux helper
 
+config BEAGLEBONE_IIO_HELPER
+	tristate "Beaglebone AM335x TSCADC Helper"
+	depends on ARCH_OMAP2PLUS && OF && MFD_TI_AM335X_TSCADC
+	default n
+	help
+	  Say Y here to include support for the IIO helper
+
 config CAPE_BEAGLEBONE
 	tristate "Beaglebone cape support"
 	depends on ARCH_OMAP2PLUS && OF && I2C
diff --git a/drivers/misc/cape/beaglebone/Makefile b/drivers/misc/cape/beaglebone/Makefile
index 508b931..e32550d 100644
--- a/drivers/misc/cape/beaglebone/Makefile
+++ b/drivers/misc/cape/beaglebone/Makefile
@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_BEAGLEBONE_PINMUX_HELPER)	+= bone-pinmux-helper.o
+obj-$(CONFIG_BEAGLEBONE_IIO_HELPER)	+= bone-iio-helper.o
 
 obj-$(CONFIG_CAPE_BEAGLEBONE)		+= capemgr.o
 obj-$(CONFIG_CAPE_BEAGLEBONE_GEIGER)	+= cape-bone-geiger.o
diff --git a/drivers/misc/cape/beaglebone/bone-iio-helper.c b/drivers/misc/cape/beaglebone/bone-iio-helper.c
new file mode 100644
index 0000000..d2c76e1
--- /dev/null
+++ b/drivers/misc/cape/beaglebone/bone-iio-helper.c
@@ -0,0 +1,175 @@
+/*
+ * Industrial IO helper driver
+ *
+ * Copyright (C) 2013 Matt Ranostay <mranostay@gmail.com>
+ *
+ * Based on original work by
+ *  Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/math64.h>
+#include <linux/input/ti_am335x_tsc.h>
+#include <linux/platform_data/ti_am335x_adc.h>
+#include <linux/mfd/ti_am335x_tscadc.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/machine.h>
+#include <linux/iio/consumer.h>
+
+static const struct of_device_id bone_iio_helper_of_match[] = {
+	{
+		.compatible = "bone-iio-helper",
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bone_iio_helper_of_match);
+
+struct iio_helper_info {
+	struct platform_device *pdev;
+	const char *vsense_name;
+	unsigned int vsense_scale;
+	struct iio_channel *vsense_channel;
+};
+
+static ssize_t iio_helper_show_mvolts(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct iio_helper_info *info = platform_get_drvdata(pdev);
+	int ret, val;
+	u32 mvolts;
+
+	ret = iio_read_channel_raw(info->vsense_channel, &val);
+	if (ret < 0)
+		return ret;
+
+	/* volts = ((1800 / 4096) * val * scale) = (1.8 * val * scale /4096) */
+	mvolts = div_u64(1800 * info->vsense_scale * (u64)val, 4096 * 100);
+
+	return sprintf(buf, "%d\n", mvolts);
+}
+
+static DEVICE_ATTR(mvolts, S_IRUGO,
+		iio_helper_show_mvolts, NULL);
+
+static int iio_helper_sysfs_register(struct platform_device *pdev)
+{
+	return device_create_file(&pdev->dev, &dev_attr_mvolts);
+}
+
+static int bone_iio_helper_probe(struct platform_device *pdev)
+{
+	struct iio_helper_info *info;
+	struct device_node *pnode = pdev->dev.of_node;
+	int err;
+
+	/* we only support OF */
+	if (pnode == NULL) {
+		dev_err(&pdev->dev, "No platform of_node!\n");
+		return -ENODEV;
+	}
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (info == NULL) {
+		dev_err(&pdev->dev, "Failed to allocate info\n");
+		err = -ENOMEM;
+		goto err_no_mem;
+	}
+	platform_set_drvdata(pdev, info);
+	info->pdev = pdev;
+
+	if (of_property_read_string(pnode, "vsense-name", &info->vsense_name) != 0) {
+		dev_err(&pdev->dev, "Could not read vsense-name property.");
+		err = -EINVAL;
+		goto err_no_vsense;
+	}
+
+	if (of_property_read_u32(pnode, "vsense-scale", &info->vsense_scale) != 0) {
+		dev_err(&pdev->dev, "Could not read vsense-scale property");
+		err = -EINVAL;
+		goto err_no_vsense;
+	}
+
+	if (info->vsense_scale == 0) {
+		dev_err(&pdev->dev, "Invalid vsense-scale property");
+		err = -EINVAL;
+		goto err_no_vsense;
+	}
+
+	info->vsense_channel = iio_channel_get(NULL, info->vsense_name);
+	if (IS_ERR(info->vsense_channel)) {
+		dev_err(&pdev->dev, "Could not get %s analog input\n",
+					info->vsense_name);
+		err = PTR_ERR(info->vsense_channel);
+		goto err_no_vsense;
+	}
+
+	err = iio_helper_sysfs_register(pdev);
+	if (err != 0) {
+		dev_err(&pdev->dev, "unable to register sysfs\n");
+		goto err_no_sysfs;
+	}
+
+	dev_info(&pdev->dev, "ready\n");
+
+	return 0;
+
+err_no_sysfs:
+	/* fall-through */
+err_no_vsense:
+	kfree(info);
+err_no_mem:
+	return err;
+}
+
+
+static int bone_iio_helper_remove(struct platform_device *pdev)
+{
+	struct iio_helper_info *info = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+
+	iio_channel_release(info->vsense_channel);
+	device_remove_file(dev, &dev_attr_mvolts);
+	kfree(info->vsense_name);
+	devm_kfree(dev, info);
+
+	return 0;
+}
+
+struct platform_driver bone_iio_helper_driver = {
+	.probe		= bone_iio_helper_probe,
+	.remove		= bone_iio_helper_remove,
+	.driver	= {
+		.name		= "bone-iio-helper",
+		.owner		= THIS_MODULE,
+		.of_match_table	= bone_iio_helper_of_match,
+	},
+};
+
+module_platform_driver(bone_iio_helper_driver);
+
+MODULE_AUTHOR("Matt Ranostay");
+MODULE_DESCRIPTION("Beaglebone IIO helper driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:bone-iio-helper");
-- 
1.8.2.1