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200 lines
4.6 KiB
200 lines
4.6 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* IIO DAC driver for NXP LPC18xx DAC |
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* |
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* Copyright (C) 2016 Joachim Eastwood <[email protected]> |
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* |
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* UNSUPPORTED hardware features: |
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* - Interrupts |
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* - DMA |
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*/ |
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#include <linux/clk.h> |
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#include <linux/err.h> |
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#include <linux/iio/iio.h> |
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#include <linux/iio/driver.h> |
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#include <linux/io.h> |
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#include <linux/iopoll.h> |
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#include <linux/module.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/mutex.h> |
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#include <linux/platform_device.h> |
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#include <linux/regulator/consumer.h> |
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/* LPC18XX DAC registers and bits */ |
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#define LPC18XX_DAC_CR 0x000 |
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#define LPC18XX_DAC_CR_VALUE_SHIFT 6 |
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#define LPC18XX_DAC_CR_VALUE_MASK 0x3ff |
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#define LPC18XX_DAC_CR_BIAS BIT(16) |
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#define LPC18XX_DAC_CTRL 0x004 |
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#define LPC18XX_DAC_CTRL_DMA_ENA BIT(3) |
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struct lpc18xx_dac { |
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struct regulator *vref; |
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void __iomem *base; |
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struct mutex lock; |
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struct clk *clk; |
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}; |
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static const struct iio_chan_spec lpc18xx_dac_iio_channels[] = { |
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{ |
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.type = IIO_VOLTAGE, |
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.output = 1, |
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | |
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BIT(IIO_CHAN_INFO_SCALE), |
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}, |
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}; |
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static int lpc18xx_dac_read_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *chan, |
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int *val, int *val2, long mask) |
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{ |
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struct lpc18xx_dac *dac = iio_priv(indio_dev); |
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u32 reg; |
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switch (mask) { |
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case IIO_CHAN_INFO_RAW: |
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reg = readl(dac->base + LPC18XX_DAC_CR); |
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*val = reg >> LPC18XX_DAC_CR_VALUE_SHIFT; |
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*val &= LPC18XX_DAC_CR_VALUE_MASK; |
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return IIO_VAL_INT; |
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case IIO_CHAN_INFO_SCALE: |
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*val = regulator_get_voltage(dac->vref) / 1000; |
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*val2 = 10; |
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return IIO_VAL_FRACTIONAL_LOG2; |
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} |
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return -EINVAL; |
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} |
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static int lpc18xx_dac_write_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *chan, |
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int val, int val2, long mask) |
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{ |
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struct lpc18xx_dac *dac = iio_priv(indio_dev); |
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u32 reg; |
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switch (mask) { |
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case IIO_CHAN_INFO_RAW: |
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if (val < 0 || val > LPC18XX_DAC_CR_VALUE_MASK) |
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return -EINVAL; |
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reg = LPC18XX_DAC_CR_BIAS; |
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reg |= val << LPC18XX_DAC_CR_VALUE_SHIFT; |
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mutex_lock(&dac->lock); |
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writel(reg, dac->base + LPC18XX_DAC_CR); |
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writel(LPC18XX_DAC_CTRL_DMA_ENA, dac->base + LPC18XX_DAC_CTRL); |
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mutex_unlock(&dac->lock); |
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return 0; |
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} |
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return -EINVAL; |
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} |
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static const struct iio_info lpc18xx_dac_info = { |
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.read_raw = lpc18xx_dac_read_raw, |
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.write_raw = lpc18xx_dac_write_raw, |
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}; |
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static int lpc18xx_dac_probe(struct platform_device *pdev) |
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{ |
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struct iio_dev *indio_dev; |
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struct lpc18xx_dac *dac; |
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int ret; |
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indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac)); |
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if (!indio_dev) |
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return -ENOMEM; |
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platform_set_drvdata(pdev, indio_dev); |
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dac = iio_priv(indio_dev); |
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mutex_init(&dac->lock); |
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dac->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(dac->base)) |
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return PTR_ERR(dac->base); |
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dac->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(dac->clk)) |
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return dev_err_probe(&pdev->dev, PTR_ERR(dac->clk), |
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"error getting clock\n"); |
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dac->vref = devm_regulator_get(&pdev->dev, "vref"); |
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if (IS_ERR(dac->vref)) |
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return dev_err_probe(&pdev->dev, PTR_ERR(dac->vref), |
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"error getting regulator\n"); |
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indio_dev->name = dev_name(&pdev->dev); |
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indio_dev->info = &lpc18xx_dac_info; |
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indio_dev->modes = INDIO_DIRECT_MODE; |
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indio_dev->channels = lpc18xx_dac_iio_channels; |
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indio_dev->num_channels = ARRAY_SIZE(lpc18xx_dac_iio_channels); |
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ret = regulator_enable(dac->vref); |
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if (ret) { |
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dev_err(&pdev->dev, "unable to enable regulator\n"); |
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return ret; |
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} |
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ret = clk_prepare_enable(dac->clk); |
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if (ret) { |
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dev_err(&pdev->dev, "unable to enable clock\n"); |
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goto dis_reg; |
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} |
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writel(0, dac->base + LPC18XX_DAC_CTRL); |
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writel(0, dac->base + LPC18XX_DAC_CR); |
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ret = iio_device_register(indio_dev); |
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if (ret) { |
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dev_err(&pdev->dev, "unable to register device\n"); |
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goto dis_clk; |
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} |
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return 0; |
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dis_clk: |
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clk_disable_unprepare(dac->clk); |
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dis_reg: |
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regulator_disable(dac->vref); |
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return ret; |
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} |
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static int lpc18xx_dac_remove(struct platform_device *pdev) |
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{ |
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struct iio_dev *indio_dev = platform_get_drvdata(pdev); |
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struct lpc18xx_dac *dac = iio_priv(indio_dev); |
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iio_device_unregister(indio_dev); |
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writel(0, dac->base + LPC18XX_DAC_CTRL); |
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clk_disable_unprepare(dac->clk); |
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regulator_disable(dac->vref); |
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return 0; |
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} |
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static const struct of_device_id lpc18xx_dac_match[] = { |
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{ .compatible = "nxp,lpc1850-dac" }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, lpc18xx_dac_match); |
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static struct platform_driver lpc18xx_dac_driver = { |
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.probe = lpc18xx_dac_probe, |
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.remove = lpc18xx_dac_remove, |
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.driver = { |
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.name = "lpc18xx-dac", |
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.of_match_table = lpc18xx_dac_match, |
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}, |
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}; |
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module_platform_driver(lpc18xx_dac_driver); |
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MODULE_DESCRIPTION("LPC18xx DAC driver"); |
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MODULE_AUTHOR("Joachim Eastwood <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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