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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * IIO DAC driver for NXP LPC18xx DAC4 *5 * Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>6 *7 * UNSUPPORTED hardware features:8 * - Interrupts9 * - DMA10 */11 12#include <linux/clk.h>13#include <linux/err.h>14#include <linux/iio/iio.h>15#include <linux/iio/driver.h>16#include <linux/io.h>17#include <linux/iopoll.h>18#include <linux/module.h>19#include <linux/mod_devicetable.h>20#include <linux/mutex.h>21#include <linux/platform_device.h>22#include <linux/regulator/consumer.h>23 24/* LPC18XX DAC registers and bits */25#define LPC18XX_DAC_CR 0x00026#define LPC18XX_DAC_CR_VALUE_SHIFT 627#define LPC18XX_DAC_CR_VALUE_MASK 0x3ff28#define LPC18XX_DAC_CR_BIAS BIT(16)29#define LPC18XX_DAC_CTRL 0x00430#define LPC18XX_DAC_CTRL_DMA_ENA BIT(3)31 32struct lpc18xx_dac {33 struct regulator *vref;34 void __iomem *base;35 struct mutex lock;36 struct clk *clk;37};38 39static const struct iio_chan_spec lpc18xx_dac_iio_channels[] = {40 {41 .type = IIO_VOLTAGE,42 .output = 1,43 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |44 BIT(IIO_CHAN_INFO_SCALE),45 },46};47 48static int lpc18xx_dac_read_raw(struct iio_dev *indio_dev,49 struct iio_chan_spec const *chan,50 int *val, int *val2, long mask)51{52 struct lpc18xx_dac *dac = iio_priv(indio_dev);53 u32 reg;54 55 switch (mask) {56 case IIO_CHAN_INFO_RAW:57 reg = readl(dac->base + LPC18XX_DAC_CR);58 *val = reg >> LPC18XX_DAC_CR_VALUE_SHIFT;59 *val &= LPC18XX_DAC_CR_VALUE_MASK;60 61 return IIO_VAL_INT;62 63 case IIO_CHAN_INFO_SCALE:64 *val = regulator_get_voltage(dac->vref) / 1000;65 *val2 = 10;66 67 return IIO_VAL_FRACTIONAL_LOG2;68 }69 70 return -EINVAL;71}72 73static int lpc18xx_dac_write_raw(struct iio_dev *indio_dev,74 struct iio_chan_spec const *chan,75 int val, int val2, long mask)76{77 struct lpc18xx_dac *dac = iio_priv(indio_dev);78 u32 reg;79 80 switch (mask) {81 case IIO_CHAN_INFO_RAW:82 if (val < 0 || val > LPC18XX_DAC_CR_VALUE_MASK)83 return -EINVAL;84 85 reg = LPC18XX_DAC_CR_BIAS;86 reg |= val << LPC18XX_DAC_CR_VALUE_SHIFT;87 88 mutex_lock(&dac->lock);89 writel(reg, dac->base + LPC18XX_DAC_CR);90 writel(LPC18XX_DAC_CTRL_DMA_ENA, dac->base + LPC18XX_DAC_CTRL);91 mutex_unlock(&dac->lock);92 93 return 0;94 }95 96 return -EINVAL;97}98 99static const struct iio_info lpc18xx_dac_info = {100 .read_raw = lpc18xx_dac_read_raw,101 .write_raw = lpc18xx_dac_write_raw,102};103 104static int lpc18xx_dac_probe(struct platform_device *pdev)105{106 struct iio_dev *indio_dev;107 struct lpc18xx_dac *dac;108 int ret;109 110 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));111 if (!indio_dev)112 return -ENOMEM;113 114 platform_set_drvdata(pdev, indio_dev);115 dac = iio_priv(indio_dev);116 mutex_init(&dac->lock);117 118 dac->base = devm_platform_ioremap_resource(pdev, 0);119 if (IS_ERR(dac->base))120 return PTR_ERR(dac->base);121 122 dac->clk = devm_clk_get(&pdev->dev, NULL);123 if (IS_ERR(dac->clk))124 return dev_err_probe(&pdev->dev, PTR_ERR(dac->clk),125 "error getting clock\n");126 127 dac->vref = devm_regulator_get(&pdev->dev, "vref");128 if (IS_ERR(dac->vref))129 return dev_err_probe(&pdev->dev, PTR_ERR(dac->vref),130 "error getting regulator\n");131 132 indio_dev->name = dev_name(&pdev->dev);133 indio_dev->info = &lpc18xx_dac_info;134 indio_dev->modes = INDIO_DIRECT_MODE;135 indio_dev->channels = lpc18xx_dac_iio_channels;136 indio_dev->num_channels = ARRAY_SIZE(lpc18xx_dac_iio_channels);137 138 ret = regulator_enable(dac->vref);139 if (ret) {140 dev_err(&pdev->dev, "unable to enable regulator\n");141 return ret;142 }143 144 ret = clk_prepare_enable(dac->clk);145 if (ret) {146 dev_err(&pdev->dev, "unable to enable clock\n");147 goto dis_reg;148 }149 150 writel(0, dac->base + LPC18XX_DAC_CTRL);151 writel(0, dac->base + LPC18XX_DAC_CR);152 153 ret = iio_device_register(indio_dev);154 if (ret) {155 dev_err(&pdev->dev, "unable to register device\n");156 goto dis_clk;157 }158 159 return 0;160 161dis_clk:162 clk_disable_unprepare(dac->clk);163dis_reg:164 regulator_disable(dac->vref);165 return ret;166}167 168static void lpc18xx_dac_remove(struct platform_device *pdev)169{170 struct iio_dev *indio_dev = platform_get_drvdata(pdev);171 struct lpc18xx_dac *dac = iio_priv(indio_dev);172 173 iio_device_unregister(indio_dev);174 175 writel(0, dac->base + LPC18XX_DAC_CTRL);176 clk_disable_unprepare(dac->clk);177 regulator_disable(dac->vref);178}179 180static const struct of_device_id lpc18xx_dac_match[] = {181 { .compatible = "nxp,lpc1850-dac" },182 { /* sentinel */ }183};184MODULE_DEVICE_TABLE(of, lpc18xx_dac_match);185 186static struct platform_driver lpc18xx_dac_driver = {187 .probe = lpc18xx_dac_probe,188 .remove_new = lpc18xx_dac_remove,189 .driver = {190 .name = "lpc18xx-dac",191 .of_match_table = lpc18xx_dac_match,192 },193};194module_platform_driver(lpc18xx_dac_driver);195 196MODULE_DESCRIPTION("LPC18xx DAC driver");197MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");198MODULE_LICENSE("GPL v2");199