On 06/03/16 11:13, Joachim Eastwood wrote: > Add base support for the 10-bit SAR ADC peripheral found > on NXP LPC18xx/43xx SoCs. > > This is a minimal driver that does not support burst mode, > interrupts, DMA or hardware triggers. > > User manual with register description can be found on: > LPC18xx: www.nxp.com/documents/user_manual/UM10430.pdf > LPC43xx: www.nxp.com/documents/user_manual/UM10503.pdf > > Signed-off-by: Joachim Eastwood <manabian@xxxxxxxxx> Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > --- > drivers/iio/adc/Kconfig | 10 ++ > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/lpc18xx_adc.c | 228 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 239 insertions(+) > create mode 100644 drivers/iio/adc/lpc18xx_adc.c > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index 932de1f9d1e7..85994e5889ec 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -234,6 +234,16 @@ config LP8788_ADC > To compile this driver as a module, choose M here: the module will be > called lp8788_adc. > > +config LPC18XX_ADC > + tristate "NXP LPC18xx ADC driver" > + depends on ARCH_LPC18XX || COMPILE_TEST > + depends on OF && HAS_IOMEM > + help > + Say yes here to build support for NXP LPC18XX ADC. > + > + To compile this driver as a module, choose M here: the module will be > + called lpc18xx_adc. > + > config MAX1027 > tristate "Maxim max1027 ADC driver" > depends on SPI > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index b1aa456e6af3..1a4ac4590857 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -24,6 +24,7 @@ obj-$(CONFIG_HI8435) += hi8435.o > obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o > obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o > obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o > +obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o > obj-$(CONFIG_MAX1027) += max1027.o > obj-$(CONFIG_MAX1363) += max1363.o > obj-$(CONFIG_MCP320X) += mcp320x.o > diff --git a/drivers/iio/adc/lpc18xx_adc.c b/drivers/iio/adc/lpc18xx_adc.c > new file mode 100644 > index 000000000000..fbe9b7a7e6b8 > --- /dev/null > +++ b/drivers/iio/adc/lpc18xx_adc.c > @@ -0,0 +1,228 @@ > +/* > + * IIO ADC driver for NXP LPC18xx ADC > + * > + * Copyright (C) 2016 Joachim Eastwood <manabian@xxxxxxxxx> > + * > + * 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: > + * - Hardware triggers > + * - Burst mode > + * - 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/of.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/regulator/consumer.h> > + > +/* LPC18XX ADC registers and bits */ > +#define LPC18XX_ADC_CR 0x000 > +#define LPC18XX_ADC_CR_CLKDIV_SHIFT 8 > +#define LPC18XX_ADC_CR_PDN BIT(21) > +#define LPC18XX_ADC_CR_START_NOW (0x1 << 24) > +#define LPC18XX_ADC_GDR 0x004 > + > +/* Data register bits */ > +#define LPC18XX_ADC_SAMPLE_SHIFT 6 > +#define LPC18XX_ADC_SAMPLE_MASK 0x3ff > +#define LPC18XX_ADC_CONV_DONE BIT(31) > + > +/* Clock should be 4.5 MHz or less */ > +#define LPC18XX_ADC_CLK_TARGET 4500000 > + > +struct lpc18xx_adc { > + void __iomem *base; > + struct device *dev; > + struct clk *clk; > + struct regulator *vref; > + u32 cr_reg; > +}; > + > +#define LPC18XX_ADC_CHAN(_idx) { \ > + .type = IIO_VOLTAGE, \ > + .indexed = 1, \ > + .channel = _idx, \ > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ > +} > + > +static const struct iio_chan_spec lpc18xx_adc_iio_channels[] = { > + LPC18XX_ADC_CHAN(0), > + LPC18XX_ADC_CHAN(1), > + LPC18XX_ADC_CHAN(2), > + LPC18XX_ADC_CHAN(3), > + LPC18XX_ADC_CHAN(4), > + LPC18XX_ADC_CHAN(5), > + LPC18XX_ADC_CHAN(6), > + LPC18XX_ADC_CHAN(7), > +}; > + > +static int lpc18xx_adc_read_chan(struct lpc18xx_adc *adc, unsigned int ch) > +{ > + int ret; > + u32 reg; > + > + reg = adc->cr_reg | BIT(ch) | LPC18XX_ADC_CR_START_NOW; > + writel(reg, adc->base + LPC18XX_ADC_CR); > + > + ret = readl_poll_timeout(adc->base + LPC18XX_ADC_GDR, reg, > + reg & LPC18XX_ADC_CONV_DONE, 3, 9); > + if (ret) { > + dev_warn(adc->dev, "adc read timed out\n"); > + return ret; > + } > + > + return (reg >> LPC18XX_ADC_SAMPLE_SHIFT) & LPC18XX_ADC_SAMPLE_MASK; > +} > + > +static int lpc18xx_adc_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct lpc18xx_adc *adc = iio_priv(indio_dev); > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + mutex_lock(&indio_dev->mlock); > + *val = lpc18xx_adc_read_chan(adc, chan->channel); > + mutex_unlock(&indio_dev->mlock); > + if (*val < 0) > + return *val; > + > + return IIO_VAL_INT; > + > + case IIO_CHAN_INFO_SCALE: > + *val = regulator_get_voltage(adc->vref) / 1000; > + *val2 = 10; > + > + return IIO_VAL_FRACTIONAL_LOG2; > + } > + > + return -EINVAL; > +} > + > +static const struct iio_info lpc18xx_adc_info = { > + .read_raw = lpc18xx_adc_read_raw, > + .driver_module = THIS_MODULE, > +}; > + > +static int lpc18xx_adc_probe(struct platform_device *pdev) > +{ > + struct iio_dev *indio_dev; > + struct lpc18xx_adc *adc; > + struct resource *res; > + unsigned int clkdiv; > + unsigned long rate; > + int ret; > + > + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc)); > + if (!indio_dev) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, indio_dev); > + adc = iio_priv(indio_dev); > + adc->dev = &pdev->dev; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + adc->base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(adc->base)) > + return PTR_ERR(adc->base); > + > + adc->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(adc->clk)) { > + dev_err(&pdev->dev, "error getting clock\n"); > + return PTR_ERR(adc->clk); > + } > + > + rate = clk_get_rate(adc->clk); > + clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET); > + > + adc->vref = devm_regulator_get(&pdev->dev, "vref"); > + if (IS_ERR(adc->vref)) { > + dev_err(&pdev->dev, "error getting regulator\n"); > + return PTR_ERR(adc->vref); > + } > + > + indio_dev->name = dev_name(&pdev->dev); > + indio_dev->dev.parent = &pdev->dev; > + indio_dev->info = &lpc18xx_adc_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = lpc18xx_adc_iio_channels; > + indio_dev->num_channels = ARRAY_SIZE(lpc18xx_adc_iio_channels); > + > + ret = regulator_enable(adc->vref); > + if (ret) { > + dev_err(&pdev->dev, "unable to enable regulator\n"); > + return ret; > + } > + > + ret = clk_prepare_enable(adc->clk); > + if (ret) { > + dev_err(&pdev->dev, "unable to enable clock\n"); > + goto dis_reg; > + } > + > + adc->cr_reg = (clkdiv << LPC18XX_ADC_CR_CLKDIV_SHIFT) | > + LPC18XX_ADC_CR_PDN; > + writel(adc->cr_reg, adc->base + LPC18XX_ADC_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: > + writel(0, adc->base + LPC18XX_ADC_CR); > + clk_disable_unprepare(adc->clk); > +dis_reg: > + regulator_disable(adc->vref); > + return ret; > +} > + > +static int lpc18xx_adc_remove(struct platform_device *pdev) > +{ > + struct iio_dev *indio_dev = platform_get_drvdata(pdev); > + struct lpc18xx_adc *adc = iio_priv(indio_dev); > + > + iio_device_unregister(indio_dev); > + > + writel(0, adc->base + LPC18XX_ADC_CR); > + clk_disable_unprepare(adc->clk); > + regulator_disable(adc->vref); > + > + return 0; > +} > + > +static const struct of_device_id lpc18xx_adc_match[] = { > + { .compatible = "nxp,lpc1850-adc" }, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, lpc18xx_adc_match); > + > +static struct platform_driver lpc18xx_adc_driver = { > + .probe = lpc18xx_adc_probe, > + .remove = lpc18xx_adc_remove, > + .driver = { > + .name = "lpc18xx-adc", > + .of_match_table = lpc18xx_adc_match, > + }, > +}; > +module_platform_driver(lpc18xx_adc_driver); > + > +MODULE_DESCRIPTION("LPC18xx ADC driver"); > +MODULE_AUTHOR("Joachim Eastwood <manabian@xxxxxxxxx>"); > +MODULE_LICENSE("GPL v2"); > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html