iio: adc: Add MEN 16z188 ADC driver

Add support for MEN 16z188 ADC IP Core on MCB FPGAs.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@men.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/iio/adc/Kconfig

@@ -155,6 +155,16 @@ config MCP3422
 	  This driver can also be built as a module. If so, the module will be
 	  called mcp3422.
 
+config MEN_Z188_ADC
+	tristate "MEN 16z188 ADC IP Core support"
+	depends on MCB
+	help
+	  Say yes here to enable support for the MEN 16z188 ADC IP-Core on a MCB
+	  carrier.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called men_z188_adc.
+
 config NAU7802
 	tristate "Nuvoton NAU7802 ADC driver"
 	depends on I2C

drivers/iio/adc/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
 obj-$(CONFIG_MAX1363) += max1363.o
 obj-$(CONFIG_MCP320X) += mcp320x.o
 obj-$(CONFIG_MCP3422) += mcp3422.o
+obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
 obj-$(CONFIG_NAU7802) += nau7802.o
 obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
 obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o

drivers/iio/adc/men_z188_adc.c

@@ -0,0 +1,171 @@
+/*
+ * MEN 16z188 Analog to Digial Converter
+ *
+ * Copyright (C) 2014 MEN Mikroelektronik GmbH (www.men.de)
+ * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
+ *
+ * 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; version 2 of the License.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mcb.h>
+#include <linux/iio/iio.h>
+
+#define Z188_ADC_MAX_CHAN	8
+#define Z188_ADC_GAIN		0x0700000
+#define Z188_MODE_VOLTAGE	BIT(27)
+#define Z188_CFG_AUTO		0x1
+#define Z188_CTRL_REG		0x40
+
+#define ADC_DATA(x) (((x) >> 2) & 0x7ffffc)
+#define ADC_OVR(x) ((x) & 0x1)
+
+struct z188_adc {
+	struct resource *mem;
+	void __iomem *base;
+};
+
+#define Z188_ADC_CHANNEL(idx) {					\
+		.type = IIO_VOLTAGE,				\
+		.indexed = 1,					\
+		.channel = (idx),				\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
+}
+
+static const struct iio_chan_spec z188_adc_iio_channels[] = {
+	Z188_ADC_CHANNEL(0),
+	Z188_ADC_CHANNEL(1),
+	Z188_ADC_CHANNEL(2),
+	Z188_ADC_CHANNEL(3),
+	Z188_ADC_CHANNEL(4),
+	Z188_ADC_CHANNEL(5),
+	Z188_ADC_CHANNEL(6),
+	Z188_ADC_CHANNEL(7),
+};
+
+static int z188_iio_read_raw(struct iio_dev *iio_dev,
+			struct iio_chan_spec const *chan,
+			int *val,
+			int *val2,
+			long info)
+{
+	struct z188_adc *adc = iio_priv(iio_dev);
+	int ret;
+	u16 tmp;
+
+	switch (info) {
+	case IIO_CHAN_INFO_RAW:
+		tmp = readw(adc->base + chan->channel * 4);
+
+		if (ADC_OVR(tmp)) {
+			dev_info(&iio_dev->dev,
+				"Oversampling error on ADC channel %d\n",
+				chan->channel);
+			return -EIO;
+		}
+		*val = ADC_DATA(tmp);
+		ret = IIO_VAL_INT;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static struct iio_info z188_adc_info = {
+	.read_raw = &z188_iio_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static void men_z188_config_channels(void __iomem *addr)
+{
+	int i;
+	u32 cfg;
+	u32 ctl;
+
+	ctl = readl(addr + Z188_CTRL_REG);
+	ctl |= Z188_CFG_AUTO;
+	writel(ctl, addr + Z188_CTRL_REG);
+
+	for (i = 0; i < Z188_ADC_MAX_CHAN; i++) {
+		cfg = readl(addr + i);
+		cfg &= ~Z188_ADC_GAIN;
+		cfg |= Z188_MODE_VOLTAGE;
+		writel(cfg, addr + i);
+	}
+}
+
+static int men_z188_probe(struct mcb_device *dev,
+			const struct mcb_device_id *id)
+{
+	struct z188_adc *adc;
+	struct iio_dev *indio_dev;
+	struct resource *mem;
+
+	indio_dev = devm_iio_device_alloc(&dev->dev, sizeof(struct z188_adc));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	adc = iio_priv(indio_dev);
+	indio_dev->name = "z188-adc";
+	indio_dev->dev.parent = &dev->dev;
+	indio_dev->info = &z188_adc_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = z188_adc_iio_channels;
+	indio_dev->num_channels = ARRAY_SIZE(z188_adc_iio_channels);
+
+	mem = mcb_request_mem(dev, "z188-adc");
+	if (!mem)
+		return -ENOMEM;
+
+	adc->base = ioremap(mem->start, resource_size(mem));
+	if (adc->base == NULL)
+		goto err;
+
+	men_z188_config_channels(adc->base);
+
+	adc->mem = mem;
+	mcb_set_drvdata(dev, indio_dev);
+
+	return iio_device_register(indio_dev);
+
+err:
+	mcb_release_mem(mem);
+	return -ENXIO;
+}
+
+static void men_z188_remove(struct mcb_device *dev)
+{
+	struct iio_dev *indio_dev  = mcb_get_drvdata(dev);
+	struct z188_adc *adc = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	iounmap(adc->base);
+	mcb_release_mem(adc->mem);
+}
+
+static const struct mcb_device_id men_z188_ids[] = {
+	{ .device = 0xbc },
+};
+MODULE_DEVICE_TABLE(mcb, men_z188_ids);
+
+static struct mcb_driver men_z188_driver = {
+	.driver = {
+		.name = "z188-adc",
+		.owner = THIS_MODULE,
+	},
+	.probe = men_z188_probe,
+	.remove = men_z188_remove,
+	.id_table = men_z188_ids,
+};
+module_mcb_driver(men_z188_driver);
+
+MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("IIO ADC driver for MEN 16z188 ADC Core");
+MODULE_ALIAS("mcb:16z188");