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Subject[PATCH v1 2/2] iio: adc: add NPCM ADC driver
Date
Add Nuvoton NPCM BMC Analog-to-Digital Converter(ADC) driver.

The NPCM ADC is a 10-bit converter for eight channel inputs.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
---
drivers/iio/adc/Kconfig | 10 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/npcm_adc.c | 336 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 347 insertions(+)
create mode 100644 drivers/iio/adc/npcm_adc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index a52fea8749a9..63a4204c5673 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -555,6 +555,16 @@ config NAU7802
To compile this driver as a module, choose M here: the
module will be called nau7802.

+config NPCM_ADC
+ tristate "Nuvoton NPCM ADC driver"
+ depends on ARCH_NPCM || COMPILE_TEST
+ depends on HAS_IOMEM
+ help
+ Say yes here to build support for Nuvoton NPCM ADC.
+
+ This driver can also be built as a module. If so, the module
+ will be called npcm_adc.
+
config PALMAS_GPADC
tristate "TI Palmas General Purpose ADC"
depends on MFD_PALMAS
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index a6e6a0b659e2..b0c3f3b73a5f 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
obj-$(CONFIG_MXS_LRADC_ADC) += mxs-lradc-adc.o
obj-$(CONFIG_NAU7802) += nau7802.o
+obj-$(CONFIG_NPCM_ADC) += npcm_adc.o
obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
obj-$(CONFIG_QCOM_SPMI_ADC5) += qcom-spmi-adc5.o
obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
diff --git a/drivers/iio/adc/npcm_adc.c b/drivers/iio/adc/npcm_adc.c
new file mode 100644
index 000000000000..4f7851472997
--- /dev/null
+++ b/drivers/iio/adc/npcm_adc.c
@@ -0,0 +1,336 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2016-2018 Nuvoton Technology corporation.
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/io.h>
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+
+struct npcm_adc {
+ u32 vref_mv;
+ bool int_status;
+ u32 adc_sample_hz;
+ struct device *dev;
+ void __iomem *regs;
+ struct clk *adc_clk;
+ wait_queue_head_t wq;
+ struct regulator *vref;
+ struct regmap *rst_regmap;
+};
+
+/* NPCM7xx reset module */
+#define IPSRST1_OFFSET 0x020
+#define IPSRST1_ADC_RST BIT(27)
+
+/* ADC registers */
+#define NPCM_ADCCON 0x00
+#define NPCM_ADCDATA 0x04
+
+/* ADCCON Register Bits */
+#define NPCM_ADCCON_ADC_INT_EN BIT(21)
+#define NPCM_ADCCON_REFSEL BIT(19)
+#define NPCM_ADCCON_ADC_INT_ST BIT(18)
+#define NPCM_ADCCON_ADC_EN BIT(17)
+#define NPCM_ADCCON_ADC_RST BIT(16)
+#define NPCM_ADCCON_ADC_CONV BIT(13)
+
+#define NPCM_ADCCON_CH_MASK GENMASK(27, 24)
+#define NPCM_ADCCON_CH(x) ((x) << 24)
+#define NPCM_ADCCON_DIV_SHIFT 1
+#define NPCM_ADCCON_DIV_MASK GENMASK(8, 1)
+#define NPCM_ADC_DATA_MASK(x) ((x) & GENMASK(9, 0))
+
+#define NPCM_ADC_ENABLE (NPCM_ADCCON_ADC_EN | NPCM_ADCCON_ADC_INT_EN)
+
+/* ADC General Definition */
+#define NPCM_RESOLUTION_BITS 10
+#define ADC_DEFAULT_SAMPLE_RATE 12500000
+#define INT_VREF_MV 2000
+
+#define NPCM_ADC_CHAN(ch) { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = ch, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+}
+
+static const struct iio_chan_spec npcm_adc_iio_channels[] = {
+ NPCM_ADC_CHAN(0),
+ NPCM_ADC_CHAN(1),
+ NPCM_ADC_CHAN(2),
+ NPCM_ADC_CHAN(3),
+ NPCM_ADC_CHAN(4),
+ NPCM_ADC_CHAN(5),
+ NPCM_ADC_CHAN(6),
+ NPCM_ADC_CHAN(7),
+};
+
+static irqreturn_t npcm_adc_isr(int irq, void *data)
+{
+ u32 regtemp = 0;
+ struct iio_dev *indio_dev = data;
+ struct npcm_adc *info = iio_priv(indio_dev);
+
+ regtemp = ioread32(info->regs + NPCM_ADCCON);
+ if (regtemp & NPCM_ADCCON_ADC_INT_ST) {
+ iowrite32(regtemp, info->regs + NPCM_ADCCON);
+ wake_up_interruptible(&info->wq);
+ info->int_status = true;
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int npcm_adc_read(struct npcm_adc *info, int *val, u8 channel)
+{
+ int ret;
+ u32 regtemp = 0;
+
+ /* Select ADC channal */
+ regtemp = ioread32(info->regs + NPCM_ADCCON);
+ regtemp &= ~NPCM_ADCCON_CH_MASK;
+ iowrite32(regtemp | NPCM_ADCCON_CH(channel) |
+ NPCM_ADCCON_ADC_CONV, info->regs + NPCM_ADCCON);
+
+ info->int_status = false;
+ ret = wait_event_interruptible_timeout(info->wq, info->int_status,
+ msecs_to_jiffies(10));
+ if (ret == 0) {
+ regtemp = ioread32(info->regs + NPCM_ADCCON);
+ if ((regtemp & NPCM_ADCCON_ADC_CONV) && info->rst_regmap) {
+ /* if conversion failed - reset ADC module */
+ regmap_write(info->rst_regmap, IPSRST1_OFFSET,
+ IPSRST1_ADC_RST);
+ msleep(100);
+ regmap_write(info->rst_regmap, IPSRST1_OFFSET, 0x0);
+ msleep(100);
+
+ /* Enable ADC and start conversion Module */
+ iowrite32(NPCM_ADC_ENABLE | NPCM_ADCCON_ADC_CONV,
+ info->regs + NPCM_ADCCON);
+ dev_err(info->dev, "RESET ADC Complete\n");
+ }
+ return -ETIMEDOUT;
+ }
+ if (ret < 0)
+ return ret;
+
+ *val = NPCM_ADC_DATA_MASK(ioread32(info->regs + NPCM_ADCDATA));
+
+ return 0;
+}
+
+static int npcm_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ int ret;
+ struct npcm_adc *info = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&indio_dev->mlock);
+ ret = npcm_adc_read(info, val, chan->channel);
+ if (ret) {
+ dev_err(info->dev, "NPCM ADC read failed\n");
+ mutex_unlock(&indio_dev->mlock);
+ return ret;
+ }
+ mutex_unlock(&indio_dev->mlock);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = info->vref_mv;
+ *val2 = NPCM_RESOLUTION_BITS;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = info->adc_sample_hz;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static const struct iio_info npcm_adc_iio_info = {
+ .read_raw = &npcm_adc_read_raw,
+};
+
+static const struct of_device_id npcm_adc_match[] = {
+ { .compatible = "nuvoton,npcm750-adc", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, npcm_adc_match);
+
+static int npcm_adc_probe(struct platform_device *pdev)
+{
+ int ret;
+ int irq;
+ u32 div;
+ u32 reg_con;
+ struct resource *res;
+ struct npcm_adc *info;
+ struct iio_dev *indio_dev;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = pdev->dev.of_node;
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
+ if (!indio_dev)
+ return -ENOMEM;
+ info = iio_priv(indio_dev);
+
+ info->dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ info->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(info->regs))
+ return PTR_ERR(info->regs);
+
+ info->adc_clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(info->adc_clk)) {
+ dev_warn(&pdev->dev, "ADC clock failed: can't read clk, Assuming ADC clock Rate 12.5MHz\n");
+ info->adc_sample_hz = ADC_DEFAULT_SAMPLE_RATE;
+ } else {
+ /* calculate ADC clock sample rate */
+ reg_con = ioread32(info->regs + NPCM_ADCCON);
+ div = reg_con & NPCM_ADCCON_DIV_MASK;
+ div = div >> NPCM_ADCCON_DIV_SHIFT;
+ info->adc_sample_hz = clk_get_rate(info->adc_clk) /
+ ((div + 1) * 2);
+ }
+
+ if (of_device_is_compatible(np, "nuvoton,npcm750-adc")) {
+ info->rst_regmap = syscon_regmap_lookup_by_compatible
+ ("nuvoton,npcm750-rst");
+ if (IS_ERR(info->rst_regmap)) {
+ dev_err(&pdev->dev, "Failed to find nuvoton,npcm750-rst\n");
+ ret = PTR_ERR(info->rst_regmap);
+ goto err_disable_clk;
+ }
+ }
+
+ reg_con = ioread32(info->regs + NPCM_ADCCON);
+ info->vref = devm_regulator_get_optional(&pdev->dev, "vref");
+ if (!IS_ERR(info->vref)) {
+ ret = regulator_enable(info->vref);
+ if (ret) {
+ dev_err(&pdev->dev, "Can't enable ADC reference voltage\n");
+ goto err_disable_clk;
+ }
+
+ ret = regulator_get_voltage(info->vref);
+ if (ret < 0)
+ goto err_disable_vref_reg;
+
+ info->vref_mv = ret / 1000;
+ iowrite32(reg_con & ~NPCM_ADCCON_REFSEL,
+ info->regs + NPCM_ADCCON);
+ } else {
+ /* Any other error indicates that the regulator does exist */
+ if (PTR_ERR(info->vref) != -ENODEV) {
+ goto err_disable_clk;
+ return PTR_ERR(info->vref);
+ }
+
+ /* Use internal reference */
+ info->vref_mv = INT_VREF_MV;
+ iowrite32(reg_con | NPCM_ADCCON_REFSEL,
+ info->regs + NPCM_ADCCON);
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq <= 0) {
+ dev_err(dev, "failed getting interrupt resource\n");
+ ret = -EINVAL;
+ goto err_disable_vref_reg;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, npcm_adc_isr, 0,
+ "NPCM_ADC", indio_dev);
+ if (ret < 0) {
+ dev_err(dev, "failed requesting interrupt\n");
+ goto err_disable_vref_reg;
+ }
+
+ init_waitqueue_head(&info->wq);
+
+ platform_set_drvdata(pdev, indio_dev);
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->info = &npcm_adc_iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = npcm_adc_iio_channels;
+ indio_dev->num_channels = ARRAY_SIZE(npcm_adc_iio_channels);
+
+ ret = iio_device_register(indio_dev);
+ if (ret) {
+ dev_err(&pdev->dev, "Couldn't register the device.\n");
+ goto err_disable_vref_reg;
+ }
+
+ reg_con = ioread32(info->regs + NPCM_ADCCON);
+ reg_con |= NPCM_ADC_ENABLE;
+
+ /* Enable the ADC Module */
+ iowrite32(reg_con, info->regs + NPCM_ADCCON);
+
+ /* Start ADC conversion */
+ iowrite32(reg_con | NPCM_ADCCON_ADC_CONV, info->regs + NPCM_ADCCON);
+
+ pr_info("NPCM ADC driver probed, sample Rate %dHz\n",
+ info->adc_sample_hz);
+
+ return 0;
+
+err_disable_vref_reg:
+ if (!IS_ERR(info->vref))
+ regulator_disable(info->vref);
+err_disable_clk:
+ clk_disable_unprepare(info->adc_clk);
+
+ return ret;
+}
+
+static int npcm_adc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct npcm_adc *info = iio_priv(indio_dev);
+ u32 regtemp = 0;
+
+ regtemp = ioread32(info->regs + NPCM_ADCCON);
+
+ /* Disable the ADC Module */
+ iowrite32(regtemp & ~NPCM_ADCCON_ADC_EN, info->regs + NPCM_ADCCON);
+
+ iio_device_unregister(indio_dev);
+ clk_disable_unprepare(info->adc_clk);
+ if (!IS_ERR(info->vref))
+ regulator_disable(info->vref);
+
+ return 0;
+}
+
+static struct platform_driver npcm_adc_driver = {
+ .probe = npcm_adc_probe,
+ .remove = npcm_adc_remove,
+ .driver = {
+ .name = "npcm_adc",
+ .of_match_table = npcm_adc_match,
+ },
+};
+
+module_platform_driver(npcm_adc_driver);
+
+MODULE_DESCRIPTION("Nuvoton NPCM ADC Sensor Driver");
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
+MODULE_LICENSE("GPL v2");
--
2.14.1
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