--- /dev/null
+/*
+ * lpc32xx_adc.c - Support for ADC in LPC32XX
+ *
+ * 3-channel, 10-bit ADC
+ *
+ * Copyright (C) 2011, 2012 Roland Stigge <stigge@antcom.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; 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/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/completion.h>
+#include <linux/of.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+/*
+ * LPC32XX registers definitions
+ */
+#define LPC32XX_ADC_SELECT(x) ((x) + 0x04)
+#define LPC32XX_ADC_CTRL(x) ((x) + 0x08)
+#define LPC32XX_ADC_VALUE(x) ((x) + 0x48)
+
+/* Bit definitions for LPC32XX_ADC_SELECT: */
+#define AD_REFm 0x00000200 /* constant, always write this value! */
+#define AD_REFp 0x00000080 /* constant, always write this value! */
+#define AD_IN 0x00000010 /* multiple of this is the */
+ /* channel number: 0, 1, 2 */
+#define AD_INTERNAL 0x00000004 /* constant, always write this value! */
+
+/* Bit definitions for LPC32XX_ADC_CTRL: */
+#define AD_STROBE 0x00000002
+#define AD_PDN_CTRL 0x00000004
+
+/* Bit definitions for LPC32XX_ADC_VALUE: */
+#define ADC_VALUE_MASK 0x000003FF
+
+#define MOD_NAME "lpc32xx-adc"
+
+struct lpc32xx_adc_info {
+ void __iomem *adc_base;
+ struct clk *clk;
+ struct completion completion;
+
+ u32 value;
+};
+
+static int lpc32xx_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long mask)
+{
+ struct lpc32xx_adc_info *info = iio_priv(indio_dev);
+
+ if (mask == IIO_CHAN_INFO_RAW) {
+ mutex_lock(&indio_dev->mlock);
+ clk_enable(info->clk);
+ /* Measurement setup */
+ __raw_writel(AD_INTERNAL | (chan->address) | AD_REFp | AD_REFm,
+ LPC32XX_ADC_SELECT(info->adc_base));
+ /* Trigger conversion */
+ __raw_writel(AD_PDN_CTRL | AD_STROBE,
+ LPC32XX_ADC_CTRL(info->adc_base));
+ wait_for_completion(&info->completion); /* set by ISR */
+ clk_disable(info->clk);
+ *val = info->value;
+ mutex_unlock(&indio_dev->mlock);
+
+ return IIO_VAL_INT;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info lpc32xx_adc_iio_info = {
+ .read_raw = &lpc32xx_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+#define LPC32XX_ADC_CHANNEL(_index) { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = _index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .address = AD_IN * _index, \
+ .scan_index = _index, \
+}
+
+static const struct iio_chan_spec lpc32xx_adc_iio_channels[] = {
+ LPC32XX_ADC_CHANNEL(0),
+ LPC32XX_ADC_CHANNEL(1),
+ LPC32XX_ADC_CHANNEL(2),
+};
+
+static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id)
+{
+ struct lpc32xx_adc_info *info = dev_id;
+
+ /* Read value and clear irq */
+ info->value = __raw_readl(LPC32XX_ADC_VALUE(info->adc_base)) &
+ ADC_VALUE_MASK;
+ complete(&info->completion);
+
+ return IRQ_HANDLED;
+}
+
+static int lpc32xx_adc_probe(struct platform_device *pdev)
+{
+ struct lpc32xx_adc_info *info = NULL;
+ struct resource *res;
+ int retval = -ENODEV;
+ struct iio_dev *iodev = NULL;
+ int irq;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to get platform I/O memory\n");
+ return -EBUSY;
+ }
+
+ iodev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
+ if (!iodev)
+ return -ENOMEM;
+
+ info = iio_priv(iodev);
+
+ info->adc_base = devm_ioremap(&pdev->dev, res->start,
+ resource_size(res));
+ if (!info->adc_base) {
+ dev_err(&pdev->dev, "failed mapping memory\n");
+ return -EBUSY;
+ }
+
+ info->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(info->clk)) {
+ dev_err(&pdev->dev, "failed getting clock\n");
+ return PTR_ERR(info->clk);
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq <= 0) {
+ dev_err(&pdev->dev, "failed getting interrupt resource\n");
+ return -EINVAL;
+ }
+
+ retval = devm_request_irq(&pdev->dev, irq, lpc32xx_adc_isr, 0,
+ MOD_NAME, info);
+ if (retval < 0) {
+ dev_err(&pdev->dev, "failed requesting interrupt\n");
+ return retval;
+ }
+
+ platform_set_drvdata(pdev, iodev);
+
+ init_completion(&info->completion);
+
+ iodev->name = MOD_NAME;
+ iodev->dev.parent = &pdev->dev;
+ iodev->info = &lpc32xx_adc_iio_info;
+ iodev->modes = INDIO_DIRECT_MODE;
+ iodev->channels = lpc32xx_adc_iio_channels;
+ iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels);
+
+ retval = devm_iio_device_register(&pdev->dev, iodev);
+ if (retval)
+ return retval;
+
+ dev_info(&pdev->dev, "LPC32XX ADC driver loaded, IRQ %d\n", irq);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id lpc32xx_adc_match[] = {
+ { .compatible = "nxp,lpc3220-adc" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, lpc32xx_adc_match);
+#endif
+
+static struct platform_driver lpc32xx_adc_driver = {
+ .probe = lpc32xx_adc_probe,
+ .driver = {
+ .name = MOD_NAME,
+ .of_match_table = of_match_ptr(lpc32xx_adc_match),
+ },
+};
+
+module_platform_driver(lpc32xx_adc_driver);
+
+MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
+MODULE_DESCRIPTION("LPC32XX ADC driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff