--- /dev/null
+/*
+ * IIO DAC driver for NXP LPC18xx DAC
+ *
+ * Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * UNSUPPORTED hardware features:
+ * - Interrupts
+ * - DMA
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+/* LPC18XX DAC registers and bits */
+#define LPC18XX_DAC_CR 0x000
+#define LPC18XX_DAC_CR_VALUE_SHIFT 6
+#define LPC18XX_DAC_CR_VALUE_MASK 0x3ff
+#define LPC18XX_DAC_CR_BIAS BIT(16)
+#define LPC18XX_DAC_CTRL 0x004
+#define LPC18XX_DAC_CTRL_DMA_ENA BIT(3)
+
+struct lpc18xx_dac {
+ struct regulator *vref;
+ void __iomem *base;
+ struct mutex lock;
+ struct clk *clk;
+};
+
+static const struct iio_chan_spec lpc18xx_dac_iio_channels[] = {
+ {
+ .type = IIO_VOLTAGE,
+ .output = 1,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ },
+};
+
+static int lpc18xx_dac_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct lpc18xx_dac *dac = iio_priv(indio_dev);
+ u32 reg;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ reg = readl(dac->base + LPC18XX_DAC_CR);
+ *val = reg >> LPC18XX_DAC_CR_VALUE_SHIFT;
+ *val &= LPC18XX_DAC_CR_VALUE_MASK;
+
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = regulator_get_voltage(dac->vref) / 1000;
+ *val2 = 10;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ }
+
+ return -EINVAL;
+}
+
+static int lpc18xx_dac_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct lpc18xx_dac *dac = iio_priv(indio_dev);
+ u32 reg;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (val < 0 || val > LPC18XX_DAC_CR_VALUE_MASK)
+ return -EINVAL;
+
+ reg = LPC18XX_DAC_CR_BIAS;
+ reg |= val << LPC18XX_DAC_CR_VALUE_SHIFT;
+
+ mutex_lock(&dac->lock);
+ writel(reg, dac->base + LPC18XX_DAC_CR);
+ writel(LPC18XX_DAC_CTRL_DMA_ENA, dac->base + LPC18XX_DAC_CTRL);
+ mutex_unlock(&dac->lock);
+
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info lpc18xx_dac_info = {
+ .read_raw = lpc18xx_dac_read_raw,
+ .write_raw = lpc18xx_dac_write_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int lpc18xx_dac_probe(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev;
+ struct lpc18xx_dac *dac;
+ struct resource *res;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, indio_dev);
+ dac = iio_priv(indio_dev);
+ mutex_init(&dac->lock);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ dac->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(dac->base))
+ return PTR_ERR(dac->base);
+
+ dac->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(dac->clk)) {
+ dev_err(&pdev->dev, "error getting clock\n");
+ return PTR_ERR(dac->clk);
+ }
+
+ dac->vref = devm_regulator_get(&pdev->dev, "vref");
+ if (IS_ERR(dac->vref)) {
+ dev_err(&pdev->dev, "error getting regulator\n");
+ return PTR_ERR(dac->vref);
+ }
+
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->info = &lpc18xx_dac_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = lpc18xx_dac_iio_channels;
+ indio_dev->num_channels = ARRAY_SIZE(lpc18xx_dac_iio_channels);
+
+ ret = regulator_enable(dac->vref);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to enable regulator\n");
+ return ret;
+ }
+
+ ret = clk_prepare_enable(dac->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to enable clock\n");
+ goto dis_reg;
+ }
+
+ writel(0, dac->base + LPC18XX_DAC_CTRL);
+ writel(0, dac->base + LPC18XX_DAC_CR);
+
+ ret = iio_device_register(indio_dev);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to register device\n");
+ goto dis_clk;
+ }
+
+ return 0;
+
+dis_clk:
+ clk_disable_unprepare(dac->clk);
+dis_reg:
+ regulator_disable(dac->vref);
+ return ret;
+}
+
+static int lpc18xx_dac_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct lpc18xx_dac *dac = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+
+ writel(0, dac->base + LPC18XX_DAC_CTRL);
+ clk_disable_unprepare(dac->clk);
+ regulator_disable(dac->vref);
+
+ return 0;
+}
+
+static const struct of_device_id lpc18xx_dac_match[] = {
+ { .compatible = "nxp,lpc1850-dac" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, lpc18xx_dac_match);
+
+static struct platform_driver lpc18xx_dac_driver = {
+ .probe = lpc18xx_dac_probe,
+ .remove = lpc18xx_dac_remove,
+ .driver = {
+ .name = "lpc18xx-dac",
+ .of_match_table = lpc18xx_dac_match,
+ },
+};
+module_platform_driver(lpc18xx_dac_driver);
+
+MODULE_DESCRIPTION("LPC18xx DAC driver");
+MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
+MODULE_LICENSE("GPL v2");
projects / linux.git / commitdiff