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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-04 12:31:05 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-04 12:31:05 -0700
commiteb7bfed901b9fea6e48bec10009dc8c8641e36e7 (patch)
treee03df0b64ecdfc3c51bf0bbdd2f96cd2a6348a7a /drivers/iio/adc/lpc18xx_adc.c
parent56d118c243fbc62d95a79183bb6bcfc38a398da5 (diff)
parent486294f184c05cff116160bb731cbb679f047621 (diff)
Merge tag 'iio-for-4.7a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next
Jonathan writes: First round of IIO new device support, features and cleanups for the 4.7 cycle. New core support * UV light modifier (for intensity) * UV light index channel type. New device support * hp206c barometer and altimeter - new driver. * mcp4131 potentiometer - new driver supporting lots of parts from Microchip. * mma8452 - FXLS8471Q support - NXP LPC18XX SOC ADC - new driver. - NXP LPC18XX SOC DAC - new driver. - rockchip_saradc - support rk3399 * st accel - h3lis331dl support Staging driver removals * adis16204 - obsolete part making it hard to get parts to test the driver in order to clean it up. * adis16220 - obsolete part making it hard to get the parts test the driver in order to clean it up. Features * core - convenience functions to claim / release direct access to the device. Makes more consistent handling of this corner easier. Used in ad7192 driver. * ak8975 - power regulator support. * at91-sama5d2 - differential channel support. * mma8452 - runtime pm support - drop device specific autosleep and use the runtime pm one instead. * ms5611 - DT bindings - oversampling ratio support Cleanups and minor fixes * MAINTAINERS - Peter got married - hence name change! * Documentation - Fix a typo in in_proximity_raw description. - Add some missing docs for iio_buffer_access_funcs. * Tools - update iio_event_monitor names to match new stuff. - make generic_buffer look for triggers ending in -trigger as we let these in for a number of drivers a long time back and now it is a fairly common option. Drivers * staging wide - convert bare unsigned usage to unsigned int to comply with coding style. * non staging wide: - since boiler plate gpio handling of interrupts has been moved into the ACPI core we don't need to include gpio/consumer.h in a load of drivers so drop it. * ad7606 - fix an endian casting sparse warning. * ak8975 - fix a possible unitialized warning from gcc. - drop and unused field left over from earlier cleanups - fix a missing regulator_disable on exit. * at91-sama5d2 - typo and indentation - missing IOMEM dependency. - cleanup mode register usage by avoidling erasing whole thing when changing the sampling frequency. * bmc150 - use the core demux and available_scan_masks to simplify buffer handling - optimize the transfers in the trigger handler now we have a magic function to emulate bulk reads (under circumstances met here). This matters with some rather dumb i2c adapters in particular. - use a single regmap_conf for all bus types as they were all the same. * bmg160 - use the core demux and available_scan_masks to simplify the buffer handling - optimize the transfers in the trigger handler now we have a magic funciton to emulate bulk rads (under circumstances met here). - drop gpio interrupt probing from the driver (ACPI) as now handled by the ACPI core. * ina2xx-adc - update the CALIB register when RShunt changes. - fix scale for VShunt - in reality this error canceled out when used. * isl29028 - use regmap to retrieve the struct device instead of carrying a second copy of it around. * kxcjk-1013 - use core demux - optimize i2c transfers in the trigger handler. * mcp4531 - refactor to use a pointer to access model parameters instead of indexing into the array each time. * mma8452 - style fixes - avoid swtiching to active whenever the config changes - add missin i2c_device_id for mma8451 * mpu6050 - fix possible NULL dereference. - fix the name / chip_id used when ACPI used (otherwise reports as NULL). * ms5611 - fix a missing regulator_disable that left the regulator on during removal. * mxc4005 - drop gpio interrupt handling for ACPI case from driver as the core now handles this case. * st-sensors - note that there are only ever a maximum of 3 axis on current st-sensors so just allocate a fixed sized buffer big enough for that. * tpl0102 - change the i2c_check_functionality condition to bring it inline with other IIO users as EOPNOTSUPP. * tsl2563 - replace deprecated flush_scheduled_work
Diffstat (limited to 'drivers/iio/adc/lpc18xx_adc.c')
-rw-r--r--drivers/iio/adc/lpc18xx_adc.c231
1 files changed, 231 insertions, 0 deletions
diff --git a/drivers/iio/adc/lpc18xx_adc.c b/drivers/iio/adc/lpc18xx_adc.c
new file mode 100644
index 000000000000..3ef18f4b27f0
--- /dev/null
+++ b/drivers/iio/adc/lpc18xx_adc.c
@@ -0,0 +1,231 @@
+/*
+ * IIO ADC driver for NXP LPC18xx ADC
+ *
+ * Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>
+ *
+ * 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/mutex.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 {
+ struct regulator *vref;
+ void __iomem *base;
+ struct device *dev;
+ struct mutex lock;
+ struct clk *clk;
+ 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(&adc->lock);
+ *val = lpc18xx_adc_read_chan(adc, chan->channel);
+ mutex_unlock(&adc->lock);
+ 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;
+ mutex_init(&adc->lock);
+
+ 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@gmail.com>");
+MODULE_LICENSE("GPL v2");