iio: adc: add imx93 adc support

The ADC in i.mx93 is a total new ADC IP, add a driver to support
this ADC.

Currently, only support one shot normal conversion triggered by
software. For other mode, will add in future.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/20230117135137.1735536-2-haibo.chen@nxp.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

3 files changed, 495 insertions, 0 deletions

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 99468c64daf9..4a95c843a91b 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -566,6 +566,16 @@ config IMX8QXP_ADC
 	  This driver can also be built as a module. If so, the module will be
 	  called imx8qxp-adc.
 
+config IMX93_ADC
+	tristate "IMX93 ADC driver"
+	depends on ARCH_MXC || COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  Say yes here to build support for IMX93 ADC.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called imx93_adc.
+
 config LP8788_ADC
 	tristate "LP8788 ADC driver"
 	depends on MFD_LP8788
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 1e5bdf47a091..36c18177322a 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_HI8435) += hi8435.o
 obj-$(CONFIG_HX711) += hx711.o
 obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
 obj-$(CONFIG_IMX8QXP_ADC) += imx8qxp-adc.o
+obj-$(CONFIG_IMX93_ADC) += imx93_adc.o
 obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
 obj-$(CONFIG_INGENIC_ADC) += ingenic-adc.o
 obj-$(CONFIG_INTEL_MRFLD_ADC) += intel_mrfld_adc.o
diff --git a/drivers/iio/adc/imx93_adc.c b/drivers/iio/adc/imx93_adc.c
new file mode 100644
index 000000000000..d8de8284e13d
--- /dev/null
+++ b/drivers/iio/adc/imx93_adc.c
@@ -0,0 +1,484 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * NXP i.MX93 ADC driver
+ *
+ * Copyright 2023 NXP
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
+
+#define IMX93_ADC_DRIVER_NAME	"imx93-adc"
+
+/* Register map definition */
+#define IMX93_ADC_MCR		0x00
+#define IMX93_ADC_MSR		0x04
+#define IMX93_ADC_ISR		0x10
+#define IMX93_ADC_IMR		0x20
+#define IMX93_ADC_CIMR0		0x24
+#define IMX93_ADC_CTR0		0x94
+#define IMX93_ADC_NCMR0		0xA4
+#define IMX93_ADC_PCDR0		0x100
+#define IMX93_ADC_PCDR1		0x104
+#define IMX93_ADC_PCDR2		0x108
+#define IMX93_ADC_PCDR3		0x10c
+#define IMX93_ADC_PCDR4		0x110
+#define IMX93_ADC_PCDR5		0x114
+#define IMX93_ADC_PCDR6		0x118
+#define IMX93_ADC_PCDR7		0x11c
+#define IMX93_ADC_CALSTAT	0x39C
+
+/* ADC bit shift */
+#define IMX93_ADC_MCR_MODE_MASK			BIT(29)
+#define IMX93_ADC_MCR_NSTART_MASK		BIT(24)
+#define IMX93_ADC_MCR_CALSTART_MASK		BIT(14)
+#define IMX93_ADC_MCR_ADCLKSE_MASK		BIT(8)
+#define IMX93_ADC_MCR_PWDN_MASK			BIT(0)
+#define IMX93_ADC_MSR_CALFAIL_MASK		BIT(30)
+#define IMX93_ADC_MSR_CALBUSY_MASK		BIT(29)
+#define IMX93_ADC_MSR_ADCSTATUS_MASK		GENMASK(2, 0)
+#define IMX93_ADC_ISR_ECH_MASK			BIT(0)
+#define IMX93_ADC_ISR_EOC_MASK			BIT(1)
+#define IMX93_ADC_ISR_EOC_ECH_MASK		(IMX93_ADC_ISR_EOC_MASK | \
+						 IMX93_ADC_ISR_ECH_MASK)
+#define IMX93_ADC_IMR_JEOC_MASK			BIT(3)
+#define IMX93_ADC_IMR_JECH_MASK			BIT(2)
+#define IMX93_ADC_IMR_EOC_MASK			BIT(1)
+#define IMX93_ADC_IMR_ECH_MASK			BIT(0)
+#define IMX93_ADC_PCDR_CDATA_MASK		GENMASK(11, 0)
+
+/* ADC status */
+#define IMX93_ADC_MSR_ADCSTATUS_IDLE			0
+#define IMX93_ADC_MSR_ADCSTATUS_POWER_DOWN		1
+#define IMX93_ADC_MSR_ADCSTATUS_WAIT_STATE		2
+#define IMX93_ADC_MSR_ADCSTATUS_BUSY_IN_CALIBRATION	3
+#define IMX93_ADC_MSR_ADCSTATUS_SAMPLE			4
+#define IMX93_ADC_MSR_ADCSTATUS_CONVERSION		6
+
+#define IMX93_ADC_TIMEOUT		msecs_to_jiffies(100)
+
+struct imx93_adc {
+	struct device *dev;
+	void __iomem *regs;
+	struct clk *ipg_clk;
+	int irq;
+	struct regulator *vref;
+	/* lock to protect against multiple access to the device */
+	struct mutex lock;
+	struct completion completion;
+};
+
+#define IMX93_ADC_CHAN(_idx) {					\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.channel = (_idx),					\
+	.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 imx93_adc_iio_channels[] = {
+	IMX93_ADC_CHAN(0),
+	IMX93_ADC_CHAN(1),
+	IMX93_ADC_CHAN(2),
+	IMX93_ADC_CHAN(3),
+};
+
+static void imx93_adc_power_down(struct imx93_adc *adc)
+{
+	u32 mcr, msr;
+	int ret;
+
+	mcr = readl(adc->regs + IMX93_ADC_MCR);
+	mcr |= FIELD_PREP(IMX93_ADC_MCR_PWDN_MASK, 1);
+	writel(mcr, adc->regs + IMX93_ADC_MCR);
+
+	ret = readl_poll_timeout(adc->regs + IMX93_ADC_MSR, msr,
+				 ((msr & IMX93_ADC_MSR_ADCSTATUS_MASK) ==
+				  IMX93_ADC_MSR_ADCSTATUS_POWER_DOWN),
+				 1, 50);
+	if (ret == -ETIMEDOUT)
+		dev_warn(adc->dev,
+			 "ADC do not in power down mode, current MSR is %x\n",
+			 msr);
+}
+
+static void imx93_adc_power_up(struct imx93_adc *adc)
+{
+	u32 mcr;
+
+	/* bring ADC out of power down state, in idle state */
+	mcr = readl(adc->regs + IMX93_ADC_MCR);
+	mcr &= ~FIELD_PREP(IMX93_ADC_MCR_PWDN_MASK, 1);
+	writel(mcr, adc->regs + IMX93_ADC_MCR);
+}
+
+static void imx93_adc_config_ad_clk(struct imx93_adc *adc)
+{
+	u32 mcr;
+
+	/* put adc in power down mode */
+	imx93_adc_power_down(adc);
+
+	/* config the AD_CLK equal to bus clock */
+	mcr = readl(adc->regs + IMX93_ADC_MCR);
+	mcr |= FIELD_PREP(IMX93_ADC_MCR_ADCLKSE_MASK, 1);
+	writel(mcr, adc->regs + IMX93_ADC_MCR);
+
+	imx93_adc_power_up(adc);
+}
+
+static int imx93_adc_calibration(struct imx93_adc *adc)
+{
+	u32 mcr, msr;
+	int ret;
+
+	/* make sure ADC in power down mode */
+	imx93_adc_power_down(adc);
+
+	/* config SAR controller operating clock */
+	mcr = readl(adc->regs + IMX93_ADC_MCR);
+	mcr &= ~FIELD_PREP(IMX93_ADC_MCR_ADCLKSE_MASK, 1);
+	writel(mcr, adc->regs + IMX93_ADC_MCR);
+
+	imx93_adc_power_up(adc);
+
+	/*
+	 * TODO: we use the default TSAMP/NRSMPL/AVGEN in MCR,
+	 * can add the setting of these bit if need in future.
+	 */
+
+	/* run calibration */
+	mcr = readl(adc->regs + IMX93_ADC_MCR);
+	mcr |= FIELD_PREP(IMX93_ADC_MCR_CALSTART_MASK, 1);
+	writel(mcr, adc->regs + IMX93_ADC_MCR);
+
+	/* wait calibration to be finished */
+	ret = readl_poll_timeout(adc->regs + IMX93_ADC_MSR, msr,
+		!(msr & IMX93_ADC_MSR_CALBUSY_MASK), 1000, 2000000);
+	if (ret == -ETIMEDOUT) {
+		dev_warn(adc->dev, "ADC do not finish calibration in 2 min!\n");
+		imx93_adc_power_down(adc);
+		return ret;
+	}
+
+	/* check whether calbration is success or not */
+	msr = readl(adc->regs + IMX93_ADC_MSR);
+	if (msr & IMX93_ADC_MSR_CALFAIL_MASK) {
+		dev_warn(adc->dev, "ADC calibration failed!\n");
+		imx93_adc_power_down(adc);
+		return -EAGAIN;
+	}
+
+	return 0;
+}
+
+static int imx93_adc_read_channel_conversion(struct imx93_adc *adc,
+						int channel_number,
+						int *result)
+{
+	u32 channel;
+	u32 imr, mcr, pcda;
+	long ret;
+
+	reinit_completion(&adc->completion);
+
+	/* config channel mask register */
+	channel = 1 << channel_number;
+	writel(channel, adc->regs + IMX93_ADC_NCMR0);
+
+	/* TODO: can config desired sample time in CTRn if need */
+
+	/* config interrupt mask */
+	imr = FIELD_PREP(IMX93_ADC_IMR_EOC_MASK, 1);
+	writel(imr, adc->regs + IMX93_ADC_IMR);
+	writel(channel, adc->regs + IMX93_ADC_CIMR0);
+
+	/* config one-shot mode */
+	mcr = readl(adc->regs + IMX93_ADC_MCR);
+	mcr &= ~FIELD_PREP(IMX93_ADC_MCR_MODE_MASK, 1);
+	writel(mcr, adc->regs + IMX93_ADC_MCR);
+
+	/* start normal conversion */
+	mcr = readl(adc->regs + IMX93_ADC_MCR);
+	mcr |= FIELD_PREP(IMX93_ADC_MCR_NSTART_MASK, 1);
+	writel(mcr, adc->regs + IMX93_ADC_MCR);
+
+	ret = wait_for_completion_interruptible_timeout(&adc->completion,
+							IMX93_ADC_TIMEOUT);
+	if (ret == 0)
+		return -ETIMEDOUT;
+
+	if (ret < 0)
+		return ret;
+
+	pcda = readl(adc->regs + IMX93_ADC_PCDR0 + channel_number * 4);
+
+	*result = FIELD_GET(IMX93_ADC_PCDR_CDATA_MASK, pcda);
+
+	return ret;
+}
+
+static int imx93_adc_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct imx93_adc *adc = iio_priv(indio_dev);
+	struct device *dev = adc->dev;
+	long ret;
+	u32 vref_uv;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		pm_runtime_get_sync(dev);
+		mutex_lock(&adc->lock);
+		ret = imx93_adc_read_channel_conversion(adc, chan->channel, val);
+		mutex_unlock(&adc->lock);
+		pm_runtime_mark_last_busy(dev);
+		pm_runtime_put_sync_autosuspend(dev);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		ret = vref_uv = regulator_get_voltage(adc->vref);
+		if (ret < 0)
+			return ret;
+		*val = vref_uv / 1000;
+		*val2 = 12;
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = clk_get_rate(adc->ipg_clk);
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static irqreturn_t imx93_adc_isr(int irq, void *dev_id)
+{
+	struct imx93_adc *adc = dev_id;
+	u32 isr, eoc, unexpected;
+
+	isr = readl(adc->regs + IMX93_ADC_ISR);
+
+	if (FIELD_GET(IMX93_ADC_ISR_EOC_ECH_MASK, isr)) {
+		eoc = isr & IMX93_ADC_ISR_EOC_ECH_MASK;
+		writel(eoc, adc->regs + IMX93_ADC_ISR);
+		complete(&adc->completion);
+	}
+
+	unexpected = isr & ~IMX93_ADC_ISR_EOC_ECH_MASK;
+	if (unexpected) {
+		writel(unexpected, adc->regs + IMX93_ADC_ISR);
+		dev_err(adc->dev, "Unexpected interrupt 0x%08x.\n", unexpected);
+		return IRQ_NONE;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_info imx93_adc_iio_info = {
+	.read_raw = &imx93_adc_read_raw,
+};
+
+static int imx93_adc_probe(struct platform_device *pdev)
+{
+	struct imx93_adc *adc;
+	struct iio_dev *indio_dev;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
+	if (!indio_dev)
+		return dev_err_probe(dev, -ENOMEM,
+				     "Failed allocating iio device\n");
+
+	adc = iio_priv(indio_dev);
+	adc->dev = dev;
+
+	mutex_init(&adc->lock);
+	adc->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(adc->regs))
+		return dev_err_probe(dev, PTR_ERR(adc->regs),
+				     "Failed geting ioremap resource\n");
+
+	/* The third irq is for ADC conversion usage */
+	adc->irq = platform_get_irq(pdev, 2);
+	if (adc->irq < 0)
+		return adc->irq;
+
+	adc->ipg_clk = devm_clk_get(dev, "ipg");
+	if (IS_ERR(adc->ipg_clk))
+		return dev_err_probe(dev, PTR_ERR(adc->ipg_clk),
+				     "Failed getting clock.\n");
+
+	adc->vref = devm_regulator_get(dev, "vref");
+	if (IS_ERR(adc->vref))
+		return dev_err_probe(dev, PTR_ERR(adc->vref),
+				     "Failed getting reference voltage.\n");
+
+	ret = regulator_enable(adc->vref);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to enable reference voltage.\n");
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	init_completion(&adc->completion);
+
+	indio_dev->name = "imx93-adc";
+	indio_dev->info = &imx93_adc_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = imx93_adc_iio_channels;
+	indio_dev->num_channels = ARRAY_SIZE(imx93_adc_iio_channels);
+
+	ret = clk_prepare_enable(adc->ipg_clk);
+	if (ret) {
+		dev_err_probe(dev, ret,
+			      "Failed to enable ipg clock.\n");
+		goto error_regulator_disable;
+	}
+
+	ret = request_irq(adc->irq, imx93_adc_isr, 0, IMX93_ADC_DRIVER_NAME, adc);
+	if (ret < 0) {
+		dev_err_probe(dev, ret,
+			      "Failed requesting irq, irq = %d\n", adc->irq);
+		goto error_ipg_clk_disable;
+	}
+
+	ret = imx93_adc_calibration(adc);
+	if (ret < 0)
+		goto error_free_adc_irq;
+
+	imx93_adc_config_ad_clk(adc);
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err_probe(dev, ret,
+			      "Failed to register this iio device.\n");
+		goto error_adc_power_down;
+	}
+
+	pm_runtime_set_active(dev);
+	pm_runtime_set_autosuspend_delay(dev, 50);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_enable(dev);
+
+	return 0;
+
+error_adc_power_down:
+	imx93_adc_power_down(adc);
+error_free_adc_irq:
+	free_irq(adc->irq, adc);
+error_ipg_clk_disable:
+	clk_disable_unprepare(adc->ipg_clk);
+error_regulator_disable:
+	regulator_disable(adc->vref);
+
+	return ret;
+}
+
+static int imx93_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct imx93_adc *adc = iio_priv(indio_dev);
+	struct device *dev = adc->dev;
+
+	/* adc power down need clock on */
+	pm_runtime_get_sync(dev);
+
+	pm_runtime_disable(dev);
+	pm_runtime_dont_use_autosuspend(dev);
+	pm_runtime_put_noidle(dev);
+
+	iio_device_unregister(indio_dev);
+	imx93_adc_power_down(adc);
+	free_irq(adc->irq, adc);
+	clk_disable_unprepare(adc->ipg_clk);
+	regulator_disable(adc->vref);
+
+	return 0;
+}
+
+static int imx93_adc_runtime_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct imx93_adc *adc = iio_priv(indio_dev);
+
+	imx93_adc_power_down(adc);
+	clk_disable_unprepare(adc->ipg_clk);
+	regulator_disable(adc->vref);
+
+	return 0;
+}
+
+static int imx93_adc_runtime_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct imx93_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	ret = regulator_enable(adc->vref);
+	if (ret) {
+		dev_err(dev,
+			"Can't enable adc reference top voltage, err = %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(adc->ipg_clk);
+	if (ret) {
+		dev_err(dev, "Could not prepare or enable clock.\n");
+		goto err_disable_reg;
+	}
+
+	imx93_adc_power_up(adc);
+
+	return 0;
+
+err_disable_reg:
+	regulator_disable(adc->vref);
+
+	return ret;
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(imx93_adc_pm_ops,
+				 imx93_adc_runtime_suspend,
+				 imx93_adc_runtime_resume, NULL);
+
+static const struct of_device_id imx93_adc_match[] = {
+	{ .compatible = "nxp,imx93-adc", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx93_adc_match);
+
+static struct platform_driver imx93_adc_driver = {
+	.probe		= imx93_adc_probe,
+	.remove		= imx93_adc_remove,
+	.driver		= {
+		.name	= IMX93_ADC_DRIVER_NAME,
+		.of_match_table = imx93_adc_match,
+		.pm	= pm_ptr(&imx93_adc_pm_ops),
+	},
+};
+
+module_platform_driver(imx93_adc_driver);
+
+MODULE_DESCRIPTION("NXP i.MX93 ADC driver");
+MODULE_AUTHOR("Haibo Chen <haibo.chen@nxp.com>");
+MODULE_LICENSE("GPL");