--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Sophgo CV1800B SARADC Driver
+ *
+ * Copyright (C) Bootlin 2024
+ * Author: Thomas Bonnefille <thomas.bonnefille@bootlin.com>
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#include <linux/iio/iio.h>
+
+#define CV1800B_ADC_CTRL_REG 0x04
+#define CV1800B_ADC_EN BIT(0)
+#define CV1800B_ADC_SEL(x) BIT((x) + 5)
+#define CV1800B_ADC_STATUS_REG 0x08
+#define CV1800B_ADC_BUSY BIT(0)
+#define CV1800B_ADC_CYC_SET_REG 0x0C
+#define CV1800B_MASK_STARTUP_CYCLE GENMASK(4, 0)
+#define CV1800B_MASK_SAMPLE_WINDOW GENMASK(11, 8)
+#define CV1800B_MASK_CLKDIV GENMASK(15, 12)
+#define CV1800B_MASK_COMPARE_CYCLE GENMASK(19, 16)
+#define CV1800B_ADC_CH_RESULT_REG(x) (0x14 + 4 * (x))
+#define CV1800B_ADC_CH_RESULT GENMASK(11, 0)
+#define CV1800B_ADC_CH_VALID BIT(15)
+#define CV1800B_ADC_INTR_EN_REG 0x20
+#define CV1800B_ADC_INTR_CLR_REG 0x24
+#define CV1800B_ADC_INTR_CLR_BIT BIT(0)
+#define CV1800B_ADC_INTR_STA_REG 0x28
+#define CV1800B_ADC_INTR_STA_BIT BIT(0)
+#define CV1800B_READ_TIMEOUT_MS 1000
+#define CV1800B_READ_TIMEOUT_US (CV1800B_READ_TIMEOUT_MS * 1000)
+
+#define CV1800B_ADC_CHANNEL(index) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
+ .scan_index = index, \
+ }
+
+struct cv1800b_adc {
+ struct completion completion;
+ void __iomem *regs;
+ struct mutex lock; /* ADC Control and Result register */
+ struct clk *clk;
+ int irq;
+};
+
+static const struct iio_chan_spec sophgo_channels[] = {
+ CV1800B_ADC_CHANNEL(0),
+ CV1800B_ADC_CHANNEL(1),
+ CV1800B_ADC_CHANNEL(2),
+};
+
+static void cv1800b_adc_start_measurement(struct cv1800b_adc *saradc,
+ int channel)
+{
+ writel(0, saradc->regs + CV1800B_ADC_CTRL_REG);
+ writel(CV1800B_ADC_SEL(channel) | CV1800B_ADC_EN,
+ saradc->regs + CV1800B_ADC_CTRL_REG);
+}
+
+static int cv1800b_adc_wait(struct cv1800b_adc *saradc)
+{
+ if (saradc->irq < 0) {
+ u32 reg;
+
+ return readl_poll_timeout(saradc->regs + CV1800B_ADC_STATUS_REG,
+ reg, !(reg & CV1800B_ADC_BUSY),
+ 500, CV1800B_READ_TIMEOUT_US);
+ }
+
+ return wait_for_completion_timeout(&saradc->completion,
+ msecs_to_jiffies(CV1800B_READ_TIMEOUT_MS)) > 0 ?
+ 0 : -ETIMEDOUT;
+}
+
+static int cv1800b_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct cv1800b_adc *saradc = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW: {
+ u32 sample;
+
+ scoped_guard(mutex, &saradc->lock) {
+ int ret;
+
+ cv1800b_adc_start_measurement(saradc, chan->scan_index);
+ ret = cv1800b_adc_wait(saradc);
+ if (ret < 0)
+ return ret;
+
+ sample = readl(saradc->regs + CV1800B_ADC_CH_RESULT_REG(chan->scan_index));
+ }
+ if (!(sample & CV1800B_ADC_CH_VALID))
+ return -ENODATA;
+
+ *val = sample & CV1800B_ADC_CH_RESULT;
+ return IIO_VAL_INT;
+ }
+ case IIO_CHAN_INFO_SCALE:
+ *val = 3300;
+ *val2 = 12;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_SAMP_FREQ: {
+ u32 status_reg = readl(saradc->regs + CV1800B_ADC_CYC_SET_REG);
+ unsigned int clk_div = (1 + FIELD_GET(CV1800B_MASK_CLKDIV, status_reg));
+ unsigned int freq = clk_get_rate(saradc->clk) / clk_div;
+ unsigned int nb_startup_cycle = 1 + FIELD_GET(CV1800B_MASK_STARTUP_CYCLE, status_reg);
+ unsigned int nb_sample_cycle = 1 + FIELD_GET(CV1800B_MASK_SAMPLE_WINDOW, status_reg);
+ unsigned int nb_compare_cycle = 1 + FIELD_GET(CV1800B_MASK_COMPARE_CYCLE, status_reg);
+
+ *val = freq / (nb_startup_cycle + nb_sample_cycle + nb_compare_cycle);
+ return IIO_VAL_INT;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static irqreturn_t cv1800b_adc_interrupt_handler(int irq, void *private)
+{
+ struct cv1800b_adc *saradc = private;
+ u32 reg = readl(saradc->regs + CV1800B_ADC_INTR_STA_REG);
+
+ if (!(FIELD_GET(CV1800B_ADC_INTR_STA_BIT, reg)))
+ return IRQ_NONE;
+
+ writel(CV1800B_ADC_INTR_CLR_BIT, saradc->regs + CV1800B_ADC_INTR_CLR_REG);
+ complete(&saradc->completion);
+
+ return IRQ_HANDLED;
+}
+
+static const struct iio_info cv1800b_adc_info = {
+ .read_raw = &cv1800b_adc_read_raw,
+};
+
+static int cv1800b_adc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cv1800b_adc *saradc;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*saradc));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ saradc = iio_priv(indio_dev);
+ indio_dev->name = "sophgo-cv1800b-adc";
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &cv1800b_adc_info;
+ indio_dev->num_channels = ARRAY_SIZE(sophgo_channels);
+ indio_dev->channels = sophgo_channels;
+
+ saradc->clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(saradc->clk))
+ return PTR_ERR(saradc->clk);
+
+ saradc->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(saradc->regs))
+ return PTR_ERR(saradc->regs);
+
+ saradc->irq = platform_get_irq_optional(pdev, 0);
+ if (saradc->irq > 0) {
+ init_completion(&saradc->completion);
+ ret = devm_request_irq(dev, saradc->irq,
+ cv1800b_adc_interrupt_handler, 0,
+ dev_name(dev), saradc);
+ if (ret)
+ return ret;
+
+ writel(1, saradc->regs + CV1800B_ADC_INTR_EN_REG);
+ }
+
+ ret = devm_mutex_init(dev, &saradc->lock);
+ if (ret)
+ return ret;
+
+ writel(FIELD_PREP(CV1800B_MASK_STARTUP_CYCLE, 15) |
+ FIELD_PREP(CV1800B_MASK_SAMPLE_WINDOW, 15) |
+ FIELD_PREP(CV1800B_MASK_CLKDIV, 1) |
+ FIELD_PREP(CV1800B_MASK_COMPARE_CYCLE, 15),
+ saradc->regs + CV1800B_ADC_CYC_SET_REG);
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id cv1800b_adc_match[] = {
+ { .compatible = "sophgo,cv1800b-saradc", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, cv1800b_adc_match);
+
+static struct platform_driver cv1800b_adc_driver = {
+ .driver = {
+ .name = "sophgo-cv1800b-saradc",
+ .of_match_table = cv1800b_adc_match,
+ },
+ .probe = cv1800b_adc_probe,
+};
+module_platform_driver(cv1800b_adc_driver);
+
+MODULE_AUTHOR("Thomas Bonnefille <thomas.bonnefille@bootlin.com>");
+MODULE_DESCRIPTION("Sophgo CV1800B SARADC driver");
+MODULE_LICENSE("GPL");
projects / linux-block.git / commitdiff