drivers: k230: Add adc driver

arch/riscv/boot/dts/canaan/k230.dtsi

@@ -515,6 +515,12 @@
 			clocks = <&wdt1>;
 		};
 
+		adc: adc@9140d000 {
+			compatible = "canaan,k230-adc";
+			reg = <0x0 0x9140d000 0x0 0x1000>;
+			clocks = <&adc_clk>;
+		};
+
 		vpu: vpu@0x90400000 {
 			status              = "okay";
 			compatible          = "canaan,vpu";

arch/riscv/configs/k230_defconfig

@@ -214,7 +214,7 @@ CONFIG_RPMSG_CHAR=y
 CONFIG_RPMSG_CTRL=y
 CONFIG_RPMSG_VIRTIO=y
 CONFIG_IIO=y
-CONFIG_XUANTIE_TH1520_ADC=m
+CONFIG_K230_ADC=y
 CONFIG_PWM=y
 CONFIG_PWM_XUANTIE=m
 CONFIG_PHY_SUN4I_USB=m

drivers/iio/adc/Kconfig

@@ -1454,4 +1454,16 @@ config XUANTIE_TH1520_ADC
 	  This driver can also be built as a module. If so, the module will be
 	  called xuantie-th1520-adc.
 
+config K230_ADC
+	tristate "Canaan K230 ADC driver"
+	depends on OF
+	depends on ARCH_CANAAN
+	default ARCH_CANAAN
+	help
+	  Say yes here to support for Canaan K230 analog-to-digital
+	  converter.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called k230-adc.
+
 endmenu

drivers/iio/adc/Makefile

@@ -130,3 +130,4 @@ obj-$(CONFIG_XILINX_XADC) += xilinx-xadc.o
 obj-$(CONFIG_XILINX_AMS) += xilinx-ams.o
 obj-$(CONFIG_SD_ADC_MODULATOR) += sd_adc_modulator.o
 obj-$(CONFIG_XUANTIE_TH1520_ADC) += th1520-adc.o
+obj-$(CONFIG_K230_ADC) += k230-adc.o

drivers/iio/adc/k230-adc.c

@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023, Canaan Bright Sight Co., Ltd
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#define ADC_MAX_CHANNEL     6
+#define ADC_MAX_DMA_CHN     3
+
+struct k230_adc_regs {
+	uint32_t trim_reg;
+	uint32_t cfg_reg;
+	uint32_t mode_reg;
+	uint32_t thsd_reg;
+	uint32_t dma_intr_reg;
+	uint32_t data_reg[ADC_MAX_CHANNEL];
+	uint32_t data_dma[ADC_MAX_DMA_CHN];
+};
+
+struct k230_adc_priv {
+	void __iomem *base;
+	struct clk *clk;
+	struct mutex lock;
+};
+
+#define K230_ADC_CHANNEL(n)						\
+	{								\
+		.channel		= n,				\
+		.datasheet_name		= "channel"#n,			\
+		.type			= IIO_VOLTAGE,			\
+		.indexed		= 1,				\
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW),	\
+	}
+
+static const struct iio_chan_spec k230_adc_channels[] = {
+	K230_ADC_CHANNEL(0),
+	K230_ADC_CHANNEL(1),
+	K230_ADC_CHANNEL(2),
+	K230_ADC_CHANNEL(3),
+	K230_ADC_CHANNEL(4),
+	K230_ADC_CHANNEL(5),
+};
+
+static int k230_adc_init(struct k230_adc_priv *dev)
+{
+	struct k230_adc_regs *regs = dev->base;
+	uint32_t data;
+
+	data = readl(&regs->trim_reg);
+	data &= ~(0x1);
+	writel(data, &regs->trim_reg);
+	data |= (0x1) | (0x1 << 20);
+	writel(data, &regs->trim_reg);
+	fsleep(1000);
+	data &= ~(0x1 << 20);
+	writel(data, &regs->trim_reg);
+
+	writel(0x0, &regs->mode_reg);
+	mutex_init(&dev->lock);
+
+	return 0;
+}
+
+static int k230_adc_read(struct k230_adc_priv *dev, int channel)
+{
+	struct k230_adc_regs *regs = dev->base;
+	int ret = -ETIMEDOUT, timeout;
+
+	mutex_lock(&dev->lock);
+
+	writel(channel | 0x10, &regs->cfg_reg);
+	for (timeout = 0; timeout < 1000; timeout++) {
+		if ((readl(&regs->cfg_reg) & 0x10100) == 0x10000) {
+			ret = readl(&regs->data_reg[channel]);
+			break;
+		}
+		fsleep(1);
+	}
+
+	mutex_unlock(&dev->lock);
+
+	return ret;
+}
+
+static int k230_adc_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, int *val,
+			     int *val2, long mask)
+{
+	struct k230_adc_priv *priv = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type != IIO_VOLTAGE)
+			return -EINVAL;
+
+		*val = k230_adc_read(priv, chan->channel);
+		if (*val < 0)
+			return *val;
+
+		return IIO_VAL_INT;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info k230_adc_info = {
+	.read_raw = k230_adc_read_raw,
+};
+
+static int k230_adc_probe(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev;
+	struct k230_adc_priv *priv;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+	if (!indio_dev) {
+		dev_err(dev, "Failed allocating iio device\n");
+		return -ENOMEM;
+	}
+
+	priv = iio_priv(indio_dev);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "Failed getting clock\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		dev_err(dev, "Could not prepare or enable clock.\n");
+		return ret;
+	}
+
+	k230_adc_init(priv);
+
+	indio_dev->name = dev_name(dev);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &k230_adc_info;
+	indio_dev->channels = k230_adc_channels;
+	indio_dev->num_channels = ARRAY_SIZE(k230_adc_channels);
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret)
+		dev_err(dev, "could not register k230-adc");
+
+	return ret;
+}
+
+static const struct of_device_id k230_adc_match[] = {
+	{ .compatible = "canaan,k230-adc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, k230_adc_match);
+
+static struct platform_driver k230_adc_driver = {
+	.driver	= {
+		.name = "k230-adc",
+		.of_match_table	= k230_adc_match,
+	},
+	.probe	= k230_adc_probe,
+};
+module_platform_driver(k230_adc_driver);
+
+MODULE_AUTHOR("Canaan SDK Team");
+MODULE_DESCRIPTION("Canaan Kendyte K230 chip ADC Driver");
+MODULE_LICENSE("GPL");