[PATCH v2 2/2] iio: adc: sun4i_lradc: new driver
Alexandre Belloni
alexandre.belloni at free-electrons.com
Tue Jul 12 12:04:12 PDT 2016
Add an IIO driver for the Allwinner Low Resolution ADC. This ADC is usually
used for physical buttons connected using a resistor ladder.
Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
---
Changes in v2:
- prefixed defines with SUN4I_LRADC_
- removed sun4i_lradc_write_raw_get_fmt
- set indio_dev->dev.of_node
- pushed devm_iio_device_register() at the end of the probe function
- added a remove function to call regulator_disable()
drivers/iio/adc/Kconfig | 10 ++
drivers/iio/adc/Makefile | 3 +-
drivers/iio/adc/sun4i_lradc.c | 323 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 335 insertions(+), 1 deletion(-)
create mode 100644 drivers/iio/adc/sun4i_lradc.c
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 25378c5882e2..87aaac6a5f44 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -384,6 +384,16 @@ config ROCKCHIP_SARADC
To compile this driver as a module, choose M here: the
module will be called rockchip_saradc.
+config SUN4I_LRADC
+ tristate "Allwinner sun4i LRADC driver"
+ depends on ARCH_SUNXI || COMPILE_TEST
+ select IIO_TRIGGER
+ help
+ Say yes here to build support for the LRADC found on Allwinner SoCs.
+
+ To compile this driver as a module, choose M here: the module will be
+ called sun4i_lradc.
+
config TI_ADC081C
tristate "Texas Instruments ADC081C/ADC101C/ADC121C family"
depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 38638d46f972..a3b165af6bde 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -1,4 +1,4 @@
-#
+
# Makefile for IIO ADC drivers
#
@@ -37,6 +37,7 @@ obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_SUN4I_LRADC) += sun4i_lradc.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
diff --git a/drivers/iio/adc/sun4i_lradc.c b/drivers/iio/adc/sun4i_lradc.c
new file mode 100644
index 000000000000..cd42e1a994b9
--- /dev/null
+++ b/drivers/iio/adc/sun4i_lradc.c
@@ -0,0 +1,323 @@
+/*
+ * Driver for the LRADC present on the Allwinner sun4i
+ *
+ * Copyright 2016 Free Electrons
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/regulator/consumer.h>
+
+#define SUN4I_LRADC_CTRL 0x00
+#define SUN4I_LRADC_INTC 0x04
+#define SUN4I_LRADC_INTS 0x08
+#define SUN4I_LRADC_DATA0 0x0c
+#define SUN4I_LRADC_DATA1 0x10
+
+/* LRADC_CTRL bits */
+#define SUN4I_LRADC_FIRST_CONVERT_DLY(x) ((x) << 24) /* 8 bits */
+#define SUN4I_LRADC_CHAN_SELECT(x) ((x) << 22) /* 2 bits */
+#define SUN4I_LRADC_CONTINUE_TIME_SEL(x) ((x) << 16) /* 4 bits */
+#define SUN4I_LRADC_KEY_MODE_SEL(x) ((x) << 12) /* 2 bits */
+#define SUN4I_LRADC_LEVELA_B_CNT(x) ((x) << 8) /* 4 bits */
+#define SUN4I_LRADC_HOLD_EN BIT(6)
+#define SUN4I_LRADC_LEVELB_VOL(x) ((x) << 4) /* 2 bits */
+#define SUN4I_LRADC_SAMPLE_RATE(x) ((x) << 2) /* 2 bits */
+#define SUN4I_LRADC_EN BIT(0)
+
+/* LRADC_INTC and LRADC_INTS bits */
+#define SUN4I_LRADC_CHAN1_KEYUP_IRQ BIT(12)
+#define SUN4I_LRADC_CHAN1_ALRDY_HOLD_IRQ BIT(11)
+#define SUN4I_LRADC_CHAN1_HOLD_IRQ BIT(10)
+#define SUN4I_LRADC_CHAN1_KEYDOWN_IRQ BIT(9)
+#define SUN4I_LRADC_CHAN1_DATA_IRQ BIT(8)
+#define SUN4I_LRADC_CHAN0_KEYUP_IRQ BIT(4)
+#define SUN4I_LRADC_CHAN0_ALRDY_HOLD_IRQ BIT(3)
+#define SUN4I_LRADC_CHAN0_HOLD_IRQ BIT(2)
+#define SUN4I_LRADC_CHAN0_KEYDOWN_IRQ BIT(1)
+#define SUN4I_LRADC_CHAN0_DATA_IRQ BIT(0)
+
+#define NUM_SUN4I_LRADC_CHANS 2
+
+struct sun4i_lradc_state {
+ void __iomem *base;
+ struct regulator *vref_supply;
+ u32 vref_mv;
+ struct completion data_ok[NUM_SUN4I_LRADC_CHANS];
+ spinlock_t lock;
+};
+
+#define SUN4I_LRADC_CHANNEL(chan) { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = (chan), \
+ .scan_index = (chan), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_SAMP_FREQ) \
+}
+
+static const struct iio_chan_spec sun4i_lradc_chan_array[] = {
+ SUN4I_LRADC_CHANNEL(0),
+ SUN4I_LRADC_CHANNEL(1),
+};
+
+static const struct {
+ int val;
+ int val2;
+} sun4i_lradc_sample_freq_avail[] = {
+ {250, 0},
+ {125, 0},
+ {62, 500000},
+ {32, 250000},
+};
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("32.25 62.5 125 250");
+
+static struct attribute *sun4i_lradc_attributes[] = {
+ &iio_const_attr_sampling_frequency_available.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group sun4i_lradc_attribute_group = {
+ .attrs = sun4i_lradc_attributes,
+};
+
+static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
+{
+ struct iio_dev *indio_dev = dev_id;
+ struct sun4i_lradc_state *st = iio_priv(indio_dev);
+ u32 ints, intc;
+
+ spin_lock(&st->lock);
+
+ ints = readl(st->base + SUN4I_LRADC_INTS);
+ intc = readl(st->base + SUN4I_LRADC_INTC);
+
+ if (ints & SUN4I_LRADC_CHAN0_DATA_IRQ)
+ complete_all(&st->data_ok[0]);
+
+ if (ints & SUN4I_LRADC_CHAN1_DATA_IRQ)
+ complete_all(&st->data_ok[1]);
+
+ intc &= ~ints;
+ writel(intc, st->base + SUN4I_LRADC_INTC);
+ writel(ints, st->base + SUN4I_LRADC_INTS);
+
+ spin_unlock(&st->lock);
+
+ return IRQ_HANDLED;
+}
+
+static int sun4i_lradc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct sun4i_lradc_state *st = iio_priv(indio_dev);
+ int ret, tmp, idx;
+ unsigned long flags;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ reinit_completion(&st->data_ok[chan->channel]);
+ spin_lock_irqsave(&st->lock, flags);
+ tmp = readl(st->base + SUN4I_LRADC_INTC);
+
+ if (chan->channel)
+ tmp |= SUN4I_LRADC_CHAN1_DATA_IRQ;
+ else
+ tmp |= SUN4I_LRADC_CHAN0_DATA_IRQ;
+
+ writel(tmp, st->base + SUN4I_LRADC_INTC);
+ spin_unlock_irqrestore(&st->lock, flags);
+
+ ret = wait_for_completion_interruptible_timeout(
+ &st->data_ok[chan->channel],
+ msecs_to_jiffies(1000));
+ if (ret == 0)
+ return -ETIMEDOUT;
+
+ if (chan->channel)
+ *val = readl(st->base + SUN4I_LRADC_DATA1);
+ else
+ *val = readl(st->base + SUN4I_LRADC_DATA0);
+
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = st->vref_mv;
+ *val2 = 6;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ tmp = readl(st->base + SUN4I_LRADC_CTRL);
+ idx = (tmp >> 2) & 0x3;
+ *val = sun4i_lradc_sample_freq_avail[idx].val;
+ *val2 = sun4i_lradc_sample_freq_avail[idx].val2;
+ return IIO_VAL_INT_PLUS_MICRO;
+
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
+static int sun4i_lradc_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct sun4i_lradc_state *st = iio_priv(indio_dev);
+ u32 ctrl;
+ int i;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ for (i = 0; i < ARRAY_SIZE(sun4i_lradc_sample_freq_avail); i++)
+ if (sun4i_lradc_sample_freq_avail[i].val == val &&
+ sun4i_lradc_sample_freq_avail[i].val2 == val2)
+ break;
+ if (i == ARRAY_SIZE(sun4i_lradc_sample_freq_avail))
+ return -EINVAL;
+
+ ctrl = readl(st->base + SUN4I_LRADC_CTRL);
+ ctrl &= ~SUN4I_LRADC_SAMPLE_RATE(0x3);
+ writel(ctrl | SUN4I_LRADC_SAMPLE_RATE(i),
+ st->base + SUN4I_LRADC_CTRL);
+
+ return 0;
+
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info sun4i_lradc_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = sun4i_lradc_read_raw,
+ .write_raw = sun4i_lradc_write_raw,
+ .attrs = &sun4i_lradc_attribute_group,
+};
+
+static int sun4i_lradc_probe(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev;
+ struct device *dev = &pdev->dev;
+ struct sun4i_lradc_state *st;
+ int err;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+
+ platform_set_drvdata(pdev, indio_dev);
+
+ indio_dev->dev.parent = dev;
+ indio_dev->dev.of_node = dev->of_node;
+ indio_dev->name = dev_name(dev);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &sun4i_lradc_info;
+
+ st->vref_supply = devm_regulator_get(dev, "vref");
+ if (IS_ERR(st->vref_supply))
+ return PTR_ERR(st->vref_supply);
+
+ st->base = devm_ioremap_resource(dev,
+ platform_get_resource(pdev, IORESOURCE_MEM, 0));
+ if (IS_ERR(st->base))
+ return PTR_ERR(st->base);
+
+ /* Disable then clear all interrupts */
+ writel(0, st->base + SUN4I_LRADC_INTC);
+ writel(0xffffffff, st->base + SUN4I_LRADC_INTS);
+
+ err = devm_request_irq(dev, platform_get_irq(pdev, 0),
+ sun4i_lradc_irq, 0,
+ "sun4i-a10-lradc", indio_dev);
+ if (err)
+ return err;
+
+ /* Setup the ADC channels available on the board */
+ indio_dev->num_channels = ARRAY_SIZE(sun4i_lradc_chan_array);
+ indio_dev->channels = sun4i_lradc_chan_array;
+
+ err = regulator_enable(st->vref_supply);
+ if (err)
+ return err;
+
+ /* lradc Vref internally is divided by 2/3 */
+ st->vref_mv = regulator_get_voltage(st->vref_supply) * 2 / 3000;
+
+ init_completion(&st->data_ok[0]);
+ init_completion(&st->data_ok[1]);
+ spin_lock_init(&st->lock);
+
+ /* Continuous mode on both channels */
+ writel(SUN4I_LRADC_CHAN_SELECT(0x3) | SUN4I_LRADC_KEY_MODE_SEL(0x2) |
+ SUN4I_LRADC_SAMPLE_RATE(0x00) | SUN4I_LRADC_EN,
+ st->base + SUN4I_LRADC_CTRL);
+
+ err = devm_iio_device_register(dev, indio_dev);
+ if (err < 0) {
+ dev_err(dev, "Couldn't register the device.\n");
+ return err;
+ }
+
+ return 0;
+}
+
+static int sun4i_lradc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct sun4i_lradc_state *st = iio_priv(indio_dev);
+
+ regulator_disable(st->vref_supply);
+
+ return 0;
+}
+
+static const struct of_device_id sun4i_lradc_of_match[] = {
+ { .compatible = "allwinner,sun4i-a10-lradc", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
+
+static struct platform_driver sun4i_lradc_driver = {
+ .probe = sun4i_lradc_probe,
+ .remove = sun4i_lradc_remove,
+ .driver = {
+ .name = "sun4i-a10-lradc",
+ .of_match_table = of_match_ptr(sun4i_lradc_of_match),
+ },
+};
+
+module_platform_driver(sun4i_lradc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Allwinner sun4i low resolution ADC driver");
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni at free-electrons.com>");
--
2.8.1
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