diff options
Diffstat (limited to 'drivers/iio/adc/lpc32xx_adc.c')
| -rw-r--r-- | drivers/iio/adc/lpc32xx_adc.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/drivers/iio/adc/lpc32xx_adc.c b/drivers/iio/adc/lpc32xx_adc.c new file mode 100644 index 000000000..b56ce1525 --- /dev/null +++ b/drivers/iio/adc/lpc32xx_adc.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * lpc32xx_adc.c - Support for ADC in LPC32XX + * + * 3-channel, 10-bit ADC + * + * Copyright (C) 2011, 2012 Roland Stigge <stigge@antcom.de> + */ + +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/err.h> +#include <linux/iio/iio.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/regulator/consumer.h> + +/* + * LPC32XX registers definitions + */ +#define LPC32XXAD_SELECT(x) ((x) + 0x04) +#define LPC32XXAD_CTRL(x) ((x) + 0x08) +#define LPC32XXAD_VALUE(x) ((x) + 0x48) + +/* Bit definitions for LPC32XXAD_SELECT: */ +/* constant, always write this value! */ +#define LPC32XXAD_REFm 0x00000200 +/* constant, always write this value! */ +#define LPC32XXAD_REFp 0x00000080 + /* multiple of this is the channel number: 0, 1, 2 */ +#define LPC32XXAD_IN 0x00000010 +/* constant, always write this value! */ +#define LPC32XXAD_INTERNAL 0x00000004 + +/* Bit definitions for LPC32XXAD_CTRL: */ +#define LPC32XXAD_STROBE 0x00000002 +#define LPC32XXAD_PDN_CTRL 0x00000004 + +/* Bit definitions for LPC32XXAD_VALUE: */ +#define LPC32XXAD_VALUE_MASK 0x000003FF + +#define LPC32XXAD_NAME "lpc32xx-adc" + +struct lpc32xx_adc_state { + void __iomem *adc_base; + struct clk *clk; + struct completion completion; + struct regulator *vref; + + 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_state *st = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&indio_dev->mlock); + ret = clk_prepare_enable(st->clk); + if (ret) { + mutex_unlock(&indio_dev->mlock); + return ret; + } + /* Measurement setup */ + __raw_writel(LPC32XXAD_INTERNAL | (chan->address) | + LPC32XXAD_REFp | LPC32XXAD_REFm, + LPC32XXAD_SELECT(st->adc_base)); + /* Trigger conversion */ + __raw_writel(LPC32XXAD_PDN_CTRL | LPC32XXAD_STROBE, + LPC32XXAD_CTRL(st->adc_base)); + wait_for_completion(&st->completion); /* set by ISR */ + clk_disable_unprepare(st->clk); + *val = st->value; + mutex_unlock(&indio_dev->mlock); + + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + *val = regulator_get_voltage(st->vref) / 1000; + *val2 = 10; + + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } +} + +static const struct iio_info lpc32xx_adc_iio_info = { + .read_raw = &lpc32xx_read_raw, +}; + +#define LPC32XX_ADC_CHANNEL_BASE(_index) \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = _index, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .address = LPC32XXAD_IN * _index, \ + .scan_index = _index, + +#define LPC32XX_ADC_CHANNEL(_index) { \ + LPC32XX_ADC_CHANNEL_BASE(_index) \ +} + +#define LPC32XX_ADC_SCALE_CHANNEL(_index) { \ + LPC32XX_ADC_CHANNEL_BASE(_index) \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ +} + +static const struct iio_chan_spec lpc32xx_adc_iio_channels[] = { + LPC32XX_ADC_CHANNEL(0), + LPC32XX_ADC_CHANNEL(1), + LPC32XX_ADC_CHANNEL(2), +}; + +static const struct iio_chan_spec lpc32xx_adc_iio_scale_channels[] = { + LPC32XX_ADC_SCALE_CHANNEL(0), + LPC32XX_ADC_SCALE_CHANNEL(1), + LPC32XX_ADC_SCALE_CHANNEL(2), +}; + +static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id) +{ + struct lpc32xx_adc_state *st = dev_id; + + /* Read value and clear irq */ + st->value = __raw_readl(LPC32XXAD_VALUE(st->adc_base)) & + LPC32XXAD_VALUE_MASK; + complete(&st->completion); + + return IRQ_HANDLED; +} + +static int lpc32xx_adc_probe(struct platform_device *pdev) +{ + struct lpc32xx_adc_state *st = 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 -ENXIO; + } + + iodev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); + if (!iodev) + return -ENOMEM; + + st = iio_priv(iodev); + + st->adc_base = devm_ioremap(&pdev->dev, res->start, + resource_size(res)); + if (!st->adc_base) { + dev_err(&pdev->dev, "failed mapping memory\n"); + return -EBUSY; + } + + st->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(st->clk)) { + dev_err(&pdev->dev, "failed getting clock\n"); + return PTR_ERR(st->clk); + } + + irq = platform_get_irq(pdev, 0); + if (irq <= 0) + return -ENXIO; + + retval = devm_request_irq(&pdev->dev, irq, lpc32xx_adc_isr, 0, + LPC32XXAD_NAME, st); + if (retval < 0) { + dev_err(&pdev->dev, "failed requesting interrupt\n"); + return retval; + } + + st->vref = devm_regulator_get(&pdev->dev, "vref"); + if (IS_ERR(st->vref)) { + iodev->channels = lpc32xx_adc_iio_channels; + dev_info(&pdev->dev, + "Missing vref regulator: No scaling available\n"); + } else { + iodev->channels = lpc32xx_adc_iio_scale_channels; + } + + platform_set_drvdata(pdev, iodev); + + init_completion(&st->completion); + + iodev->name = LPC32XXAD_NAME; + iodev->info = &lpc32xx_adc_iio_info; + iodev->modes = INDIO_DIRECT_MODE; + 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; +} + +static const struct of_device_id lpc32xx_adc_match[] = { + { .compatible = "nxp,lpc3220-adc" }, + {}, +}; +MODULE_DEVICE_TABLE(of, lpc32xx_adc_match); + +static struct platform_driver lpc32xx_adc_driver = { + .probe = lpc32xx_adc_probe, + .driver = { + .name = LPC32XXAD_NAME, + .of_match_table = lpc32xx_adc_match, + }, +}; + +module_platform_driver(lpc32xx_adc_driver); + +MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); +MODULE_DESCRIPTION("LPC32XX ADC driver"); +MODULE_LICENSE("GPL"); |