[PATCH v2 1/3] iio: adc: rn5t618: Add ADC driver for RN5T618/RC5T619

Andreas Kemnade
2020-01-20T21:21:32Z

Both chips have an A/D converter capable of measuring
things like VBAT, VUSB and analog inputs.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
Changes in v2:
- enum for channels
- bulk read instead of single byte read for conversion
result
- fix get_virq error handling
- use devm for registering device and requesting IRQ

drivers/iio/adc/Kconfig | 10 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/rn5t618-adc.c | 253 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 264 insertions(+)
create mode 100644 drivers/iio/adc/rn5t618-adc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index f0af3a42f53c..9ea9489e3f0a 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -735,6 +735,16 @@ config RCAR_GYRO_ADC
To compile this driver as a module, choose M here: the
module will be called rcar-gyroadc.

+config RN5T618_ADC
+ tristate "ADC for the RN5T618/RC5T619 family of chips"
+ depends on MFD_RN5T618
+ help
+ Say yes here to build support for the integrated ADC inside the
+ RN5T618/619 series PMICs:
+
+ This driver can also be built as a module. If so, the module
+ will be called rn5t618-adc.
+
config ROCKCHIP_SARADC
tristate "Rockchip SARADC driver"
depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index ef9cc485fb67..2aea70556ed0 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_QCOM_VADC_COMMON) += qcom-vadc-common.o
obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
+obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
diff --git a/drivers/iio/adc/rn5t618-adc.c b/drivers/iio/adc/rn5t618-adc.c
new file mode 100644
index 000000000000..667bd814569d
--- /dev/null
+++ b/drivers/iio/adc/rn5t618-adc.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ADC driver for the RICOH RN5T618 power management chip family
+ *
+ * Copyright (C) 2019 Andreas Kemnade
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mfd/rn5t618.h>
+#include <linux/platform_device.h>
+#include <linux/completion.h>
+#include <linux/regmap.h>
+#include <linux/iio/iio.h>
+#include <linux/slab.h>
+#include <linux/irqdomain.h>
+
+#define RN5T618_ADC_CONVERSION_TIMEOUT (msecs_to_jiffies(500))
+#define REFERENCE_VOLT 2500
+
+/* mask for selecting channels for single conversion */
+#define ADCCNT3_CHANNEL_MASK 0x7
+/* average 4-time conversion mode */
+#define ADCCNT3_AVG BIT(3)
+/* set for starting a single conversion, gets cleared by hw when done */
+#define ADCCNT3_GODONE BIT(4)
+/* automatic conversion, period is in ADCCNT2, selected channels are
+ * in ADCCNT1
+ */
+#define ADCCNT3_AUTO BIT(5)
+#define ADCEND_IRQ BIT(0)
+
+struct rn5t618_adc_data {
+ struct device *dev;
+ struct rn5t618 *rn5t618;
+ struct completion conv_completion;
+ int irq;
+};
+
+struct rn5t618_channel_ratios {
+ u16 numerator;
+ u16 denominator;
+};
+
+enum rn5t618_channels {
+ LIMMON = 0,
+ VBAT,
+ VADP,
+ VUSB,
+ VSYS,
+ VTHM,
+ AIN1,
+ AIN0
+};
+
+static const struct rn5t618_channel_ratios rn5t618_ratios[8] = {
+ [LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
+ [VBAT] = {2, 1},
+ [VADP] = {3, 1},
+ [VUSB] = {3, 1},
+ [VSYS] = {3, 1},
+ [VTHM] = {1, 1},
+ [AIN1] = {1, 1},
+ [AIN0] = {1, 1},
+};
+
+static int rn5t618_read_adc_reg(struct rn5t618 *rn5t618, int reg, u16 *val)
+{
+ u8 data[2];
+ int ret;
+
+ ret = regmap_bulk_read(rn5t618->regmap, reg, data, sizeof(data));
+ if (ret < 0)
+ return ret;
+
+ *val = (data[0] << 4) | (data[1] & 0xF);
+
+ return 0;
+}
+
+static irqreturn_t rn5t618_adc_irq(int irq, void *data)
+{
+ struct rn5t618_adc_data *adc = data;
+ unsigned int r = 0;
+ int ret;
+
+ /* clear low & high threshold irqs */
+ regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC1, 0);
+ regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC2, 0);
+
+ ret = regmap_read(adc->rn5t618->regmap, RN5T618_IR_ADC3, &r);
+ if (ret < 0)
+ dev_err(adc->dev, "failed to read IRQ status: %d\n", ret);
+
+ regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC3, 0);
+
+ if (r & ADCEND_IRQ)
+ complete(&adc->conv_completion);
+
+ return IRQ_HANDLED;
+}
+
+static int rn5t618_adc_read(struct iio_dev *iio_dev,
+ const struct iio_chan_spec *chan,
+ int *val, int *val2, long mask)
+{
+ struct rn5t618_adc_data *adc = iio_priv(iio_dev);
+ u16 raw;
+ int ret;
+
+ /* select channel */
+ ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
+ ADCCNT3_CHANNEL_MASK,
+ chan->channel);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(adc->rn5t618->regmap, RN5T618_EN_ADCIR3, ADCEND_IRQ);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
+ ADCCNT3_AVG,
+ mask == IIO_CHAN_INFO_AVERAGE_RAW ?
+ ADCCNT3_AVG : 0);
+ if (ret < 0)
+ return ret;
+
+ init_completion(&adc->conv_completion);
+ /* single conversion */
+ ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
+ ADCCNT3_GODONE, ADCCNT3_GODONE);
+ if (ret < 0)
+ return ret;
+
+ ret = wait_for_completion_timeout(&adc->conv_completion,
+ RN5T618_ADC_CONVERSION_TIMEOUT);
+ if (ret == 0) {
+ dev_warn(adc->dev, "timeout waiting for adc result\n");
+ return -ETIMEDOUT;
+ }
+
+ ret = rn5t618_read_adc_reg(adc->rn5t618,
+ RN5T618_ILIMDATAH + 2 * chan->channel,
+ &raw);
+ if (ret < 0)
+ return ret;
+
+ *val = raw;
+ if (mask == IIO_CHAN_INFO_PROCESSED)
+ *val = *val * REFERENCE_VOLT *
+ rn5t618_ratios[chan->channel].numerator /
+ rn5t618_ratios[chan->channel].denominator / 4095;
+
+ return IIO_VAL_INT;
+}
+
+static const struct iio_info rn5t618_adc_iio_info = {
+ .read_raw = &rn5t618_adc_read,
+};
+
+#define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
+ .type = _type, \
+ .channel = _channel, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
+ BIT(IIO_CHAN_INFO_PROCESSED), \
+ .datasheet_name = _name, \
+ .indexed = 1. \
+}
+
+static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
+ RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
+ RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
+ RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
+ RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
+ RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
+ RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
+ RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
+ RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
+};
+
+static int rn5t618_adc_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct iio_dev *iio_dev;
+ struct rn5t618_adc_data *adc;
+ struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
+
+ iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
+ if (!iio_dev) {
+ dev_err(&pdev->dev, "failed allocating iio device\n");
+ return -ENOMEM;
+ }
+
+ adc = iio_priv(iio_dev);
+ adc->dev = &pdev->dev;
+ adc->rn5t618 = rn5t618;
+
+ if (rn5t618->irq_data)
+ adc->irq = regmap_irq_get_virq(rn5t618->irq_data,
+ RN5T618_IRQ_ADC);
+
+ if (adc->irq <= 0) {
+ dev_err(&pdev->dev, "get virq failed\n");
+ return -EINVAL;
+ }
+
+ init_completion(&adc->conv_completion);
+
+ iio_dev->name = dev_name(&pdev->dev);
+ iio_dev->dev.parent = &pdev->dev;
+ iio_dev->info = &rn5t618_adc_iio_info;
+ iio_dev->modes = INDIO_DIRECT_MODE;
+ iio_dev->channels = rn5t618_adc_iio_channels;
+ iio_dev->num_channels = ARRAY_SIZE(rn5t618_adc_iio_channels);
+
+ /* stop any auto-conversion */
+ ret = regmap_write(rn5t618->regmap, RN5T618_ADCCNT3, 0);
+ if (ret < 0)
+ return ret;
+
+ platform_set_drvdata(pdev, iio_dev);
+
+ ret = devm_request_threaded_irq(adc->dev, adc->irq, NULL,
+ rn5t618_adc_irq,
+ IRQF_ONESHOT, dev_name(adc->dev),
+ adc);
+ if (ret < 0) {
+ dev_err(adc->dev, "request irq %d failed: %d\n", adc->irq, ret);
+ return ret;
+ }
+
+ ret = devm_iio_device_register(adc->dev, iio_dev);
+
+ return ret;
+}
+
+static struct platform_driver rn5t618_adc_driver = {
+ .driver = {
+ .name = "rn5t618-adc",
+ },
+ .probe = rn5t618_adc_probe,
+};
+
+module_platform_driver(rn5t618_adc_driver);
+MODULE_ALIAS("platform:rn5t618-adc");
+MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
+MODULE_LICENSE("GPL");
--
2.11.0