| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * IIO DAC driver for NXP LPC18xx DAC |
| * |
| * Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com> |
| * |
| * 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, |
| }; |
| |
| 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"); |