[PATCH v4 2/3] iio: adc: sophgo-saradc: Add driver for Sophgo CV18XX series SARADC

Thomas Bonnefille
2024-08-12T15:01:20Z

This adds a driver for the common Sophgo SARADC.

Signed-off-by: Thomas Bonnefille <thomas.bonnefille@bootlin.com>
---
drivers/iio/adc/Kconfig | 10 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/sophgo-cv18xx-adc.c | 208 ++++++++++++++++++++++++++++++++++++
3 files changed, 219 insertions(+)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index f60fe85a30d5..b10bf26d8e86 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1156,6 +1156,16 @@ config SC27XX_ADC
This driver can also be built as a module. If so, the module
will be called sc27xx_adc.

+config SOPHGO_CV18XX_ADC
+ tristate "Sophgo CV18XX series SARADC"
+ depends on ARCH_SOPHGO || COMPILE_TEST
+ help
+ Say yes here to build support for the SARADC integrated inside
+ the Sophgo CV18XX series SoCs.
+
+ This driver can also be built as a module. If so, the module
+ will be called sophgo_cv18xx_adc.
+
config SPEAR_ADC
tristate "ST SPEAr ADC"
depends on PLAT_SPEAR || COMPILE_TEST
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index d370e066544e..24c241b12ef0 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -105,6 +105,7 @@ obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
obj-$(CONFIG_SD_ADC_MODULATOR) += sd_adc_modulator.o
+obj-$(CONFIG_SOPHGO_CV18XX_ADC) += sophgo-cv18xx-adc.o
obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
obj-$(CONFIG_STM32_ADC) += stm32-adc.o
diff --git a/drivers/iio/adc/sophgo-cv18xx-adc.c b/drivers/iio/adc/sophgo-cv18xx-adc.c
new file mode 100644
index 000000000000..ab7ee0f482cc
--- /dev/null
+++ b/drivers/iio/adc/sophgo-cv18xx-adc.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Sophgo CV18XX series SARADC Driver
+ *
+ * Copyright (C) Bootlin 2024
+ * Author: Thomas Bonnefille <thomas.bonnefille@bootlin.com>
+ */
+
+#include "linux/err.h"
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/dev_printk.h>
+#include <linux/interrupt.h>
+#include <linux/iio/iio.h>
+#include <linux/iopoll.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+
+#define CV18XX_ADC_CTRL_REG 0x04
+#define CV18XX_ADC_EN BIT(0)
+#define CV18XX_ADC_SEL(x) BIT((x) + 5)
+#define CV18XX_ADC_STATUS_REG 0x08
+#define CV18XX_ADC_BUSY BIT(0)
+#define CV18XX_ADC_CYC_SET_REG 0x0C
+/* The default cycle configuration is set to maximize the accuracy */
+#define CV18XX_ADC_DEF_STARTUP_CYCLE_MASK 0x1F
+#define CV18XX_ADC_DEF_SAMPLE_WINDOW_MASK 0xF00
+#define CV18XX_ADC_DEF_CLOCK_DIVIDER_MASK 0xF000
+#define CV18XX_ADC_DEF_COMPARE_CYCLE_MASK 0xF0000
+#define CV18XX_ADC_CH_RESULT_REG(x) (0x14 + 4 * (x))
+#define CV18XX_ADC_CH_RESULT GENMASK(11, 0)
+#define CV18XX_ADC_CH_VALID BIT(15)
+#define CV18XX_ADC_INTR_EN_REG 0x20
+#define CV18XX_ADC_INTR_CLR_REG 0x24
+#define CV18XX_ADC_INTR_CLR_BIT BIT(0)
+#define CV18XX_ADC_INTR_STA_REG 0x28
+#define CV18XX_ADC_INTR_STA_BIT BIT(0)
+
+#define CV18XX_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), \
+ .scan_index = index, \
+ }
+
+struct cv18xx_adc {
+ struct completion completion;
+ void __iomem *regs;
+ struct mutex lock; /* ADC Control and Result register */
+ int irq;
+};
+
+static const struct iio_chan_spec sophgo_channels[] = {
+ CV18XX_ADC_CHANNEL(0),
+ CV18XX_ADC_CHANNEL(1),
+ CV18XX_ADC_CHANNEL(2),
+};
+
+static void cv18xx_adc_start_measurement(struct cv18xx_adc *saradc,
+ int channel)
+{
+ writel(0, saradc->regs + CV18XX_ADC_CTRL_REG);
+ writel(CV18XX_ADC_SEL(channel) | CV18XX_ADC_EN,
+ saradc->regs + CV18XX_ADC_CTRL_REG);
+}
+
+static int cv18xx_adc_wait(struct cv18xx_adc *saradc)
+{
+ if (saradc->irq < 0) {
+ u32 reg;
+
+ return readl_poll_timeout(saradc->regs + CV18XX_ADC_STATUS_REG,
+ reg, !(reg & CV18XX_ADC_BUSY),
+ 500, 1000000);
+ }
+ return wait_for_completion_timeout(&saradc->completion,
+ msecs_to_jiffies(1000)) > 0
+ ? 0 : -ETIMEDOUT;
+}
+
+static int cv18xx_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:{
+ struct cv18xx_adc *saradc = iio_priv(indio_dev);
+ u32 sample;
+
+ scoped_guard(mutex, &saradc->lock) {
+ int ret;
+
+ cv18xx_adc_start_measurement(saradc, chan->scan_index);
+ ret = cv18xx_adc_wait(saradc);
+ if (ret < 0)
+ return ret;
+
+ sample = readl(saradc->regs + CV18XX_ADC_CH_RESULT_REG(chan->scan_index));
+ }
+ if (!(sample & CV18XX_ADC_CH_VALID))
+ return -ENODATA;
+
+ *val = sample & CV18XX_ADC_CH_RESULT;
+ return IIO_VAL_INT;
+ }
+ case IIO_CHAN_INFO_SCALE:
+ *val = 3300;
+ *val2 = 12;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static irqreturn_t cv18xx_adc_interrupt_handler(int irq, void *private)
+{
+ struct cv18xx_adc *saradc = private;
+
+ if (!(FIELD_GET(CV18XX_ADC_INTR_STA_BIT,
+ readl(saradc->regs + CV18XX_ADC_INTR_STA_REG))))
+ return IRQ_NONE;
+
+ writel(CV18XX_ADC_INTR_CLR_BIT, saradc->regs + CV18XX_ADC_INTR_CLR_REG);
+ complete(&saradc->completion);
+ return IRQ_HANDLED;
+}
+
+static const struct iio_info cv18xx_adc_info = {
+ .read_raw = &cv18xx_adc_read_raw,
+};
+
+static int cv18xx_adc_probe(struct platform_device *pdev)
+{
+ struct cv18xx_adc *saradc;
+ struct iio_dev *indio_dev;
+ struct clk *clk;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*saradc));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ saradc = iio_priv(indio_dev);
+ indio_dev->name = "sophgo-cv18xx-adc";
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &cv18xx_adc_info;
+ indio_dev->num_channels = ARRAY_SIZE(sophgo_channels);
+ indio_dev->channels = sophgo_channels;
+
+ clk = devm_clk_get_enabled(&pdev->dev, NULL);
+ if (IS_ERR(clk))
+ return PTR_ERR(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(&pdev->dev, saradc->irq,
+ cv18xx_adc_interrupt_handler, 0,
+ dev_name(&pdev->dev), saradc);
+ if (ret)
+ return ret;
+
+ writel(1, saradc->regs + CV18XX_ADC_INTR_EN_REG);
+ }
+
+ ret = devm_mutex_init(&pdev->dev, &saradc->lock);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, indio_dev);
+ writel(FIELD_PREP(CV18XX_ADC_DEF_STARTUP_CYCLE_MASK, 0xF) |
+ FIELD_PREP(CV18XX_ADC_DEF_SAMPLE_WINDOW_MASK, 0xF) |
+ FIELD_PREP(CV18XX_ADC_DEF_CLOCK_DIVIDER_MASK, 0x1) |
+ FIELD_PREP(CV18XX_ADC_DEF_COMPARE_CYCLE_MASK, 0xF),
+ saradc->regs + CV18XX_ADC_CYC_SET_REG);
+
+ return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+static const struct of_device_id cv18xx_adc_match[] = {
+ { .compatible = "sophgo,cv1800b-saradc", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, cv18xx_adc_match);
+
+static struct platform_driver cv18xx_adc_driver = {
+ .driver = {
+ .name = "sophgo-cv18xx-saradc",
+ .of_match_table = cv18xx_adc_match,
+ },
+ .probe = cv18xx_adc_probe,
+};
+module_platform_driver(cv18xx_adc_driver);
+
+MODULE_AUTHOR("Thomas Bonnefille <thomas.bonnefille@bootlin.com>");
+MODULE_DESCRIPTION("Sophgo CV18XX series SARADC driver");
+MODULE_LICENSE("GPL");

--
2.46.0