[PATCH] iio: adc: Add imx8qxp adc driver support

[haibo.chen@nxp.com]

From: Haibo Chen <haibo.chen@nxp.com>

i.MX8QXP B0 and i.MX8QM has the same ADC IP, so add the
adc driver to support it.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
---
 drivers/iio/adc/Kconfig       |  10 +
 drivers/iio/adc/Makefile      |   1 +
 drivers/iio/adc/imx8qxp_adc.c | 723 ++++++++++++++++++++++++++++++++++
 3 files changed, 734 insertions(+)
 create mode 100644 drivers/iio/adc/imx8qxp_adc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 82e33082958c..10329fe5d8d4 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -480,6 +480,16 @@ config IMX7D_ADC
 	  This driver can also be built as a module. If so, the module will be
 	  called imx7d_adc.
 
+config IMX8QXP_ADC
+	tristate "IMX8QXP ADC driver"
+	depends on ARCH_MXC || COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  Say yes here to build support for IMX8QXP ADC.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called imx8qxp_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 919228900df9..480f76b628ca 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_FSL_MX25_ADC) += fsl-imx25-gcq.o
 obj-$(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_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/imx8qxp_adc.c b/drivers/iio/adc/imx8qxp_adc.c
new file mode 100644
index 000000000000..a6a9c42d08cd
--- /dev/null
+++ b/drivers/iio/adc/imx8qxp_adc.c
@@ -0,0 +1,723 @@
+/*
+ * NXP i.MX8QXP ADC driver
+ *
+ * Copyright (C) 2018 NXP
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/iio/sysfs.h>
+
+/* ADC register */
+#define IMX8QXP_REG_ADC_VERID		0x00
+#define IMX8QXP_REG_ADC_PARAM		0x04
+#define IMX8QXP_REG_ADC_CTRL		0x10
+#define IMX8QXP_REG_ADC_STAT		0x14
+#define IMX8QXP_REG_ADC_IE		0x18
+#define IMX8QXP_REG_ADC_DE		0x1c
+#define IMX8QXP_REG_ADC_CFG		0x20
+#define IMX8QXP_REG_ADC_PAUSE		0x24
+#define IMX8QXP_REG_ADC_FCTRL		0x30
+#define IMX8QXP_REG_ADC_SWTRIG		0x34
+#define IMX8QXP_REG_ADC_TCTRL0		0xc0
+#define IMX8QXP_REG_ADC_TCTRL1		0xc4
+#define IMX8QXP_REG_ADC_TCTRL2		0xc8
+#define IMX8QXP_REG_ADC_TCTRL3		0xcc
+#define IMX8QXP_REG_ADC_TCTRL4		0xd0
+#define IMX8QXP_REG_ADC_TCTRL5		0xd4
+#define IMX8QXP_REG_ADC_TCTRL6		0xd8
+#define IMX8QXP_REG_ADC_TCTRL7		0xdc
+#define IMX8QXP_REG_ADC_CMDL1		0x100
+#define IMX8QXP_REG_ADC_CMDH1		0x104
+#define IMX8QXP_REG_ADC_CMDL2		0x108
+#define IMX8QXP_REG_ADC_CMDH2		0x10c
+#define IMX8QXP_REG_ADC_CMDL3		0x110
+#define IMX8QXP_REG_ADC_CMDH3		0x114
+#define IMX8QXP_REG_ADC_CMDL4		0x118
+#define IMX8QXP_REG_ADC_CMDH4		0x11c
+#define IMX8QXP_REG_ADC_CMDL5		0x120
+#define IMX8QXP_REG_ADC_CMDH5		0x124
+#define IMX8QXP_REG_ADC_CMDL6		0x128
+#define IMX8QXP_REG_ADC_CMDH6		0x12c
+#define IMX8QXP_REG_ADC_CMDL7		0x130
+#define IMX8QXP_REG_ADC_CMDH7		0x134
+#define IMX8QXP_REG_ADC_CMDL8		0x138
+#define IMX8QXP_REG_ADC_CMDH8		0x13c
+#define IMX8QXP_REG_ADC_CV1		0x200
+#define IMX8QXP_REG_ADC_CV2		0x204
+#define IMX8QXP_REG_ADC_CV3		0x208
+#define IMX8QXP_REG_ADC_CV4		0x20c
+#define IMX8QXP_REG_ADC_RESFIFO		0x300
+#define IMX8QXP_REG_ADC_TST		0xffc
+
+/* ADC IE bit shift */
+#define IMX8QXP_REG_ADC_IE_FOFIE_SHIFT		(1)
+#define IMX8QXP_REG_ADC_IE_FWMIE_SHIFT		(0)
+/* ADC CTRL bit shift*/
+#define IMX8QXP_REG_ADC_CTRL_FIFO_RESET_SHIFT		(8)
+#define IMX8QXP_REG_ADC_CTRL_SOFTWARE_RESET_SHIFT	(1)
+#define IMX8QXP_REG_ADC_CTRL_ADC_ENABLE			(0)
+/* ADC TCTRL bit shift*/
+#define IMX8QXP_REG_ADC_TCTRL_TCMD_SHIFT	(24)
+#define IMX8QXP_REG_ADC_TCTRL_TDLY_SHIFT	(16)
+#define IMX8QXP_REG_ADC_TCTRL_TPRI_SHIFT	(8)
+#define IMX8QXP_REG_ADC_TCTRL_HTEN_SHIFT	(0)
+/* ADC CMDL bit shift*/
+#define IMX8QXP_REG_ADC_CMDL_CSCALE_SHIFT	(8)
+#define IMX8QXP_REG_ADC_CMDL_MODE_SHIFT		(7)
+#define IMX8QXP_REG_ADC_CMDL_DIFF_SHIFT		(6)
+#define IMX8QXP_REG_ADC_CMDL_ABSEL_SHIFT	(5)
+#define IMX8QXP_REG_ADC_CMDL_ADCH_SHIFT		(0)
+/* ADC CMDH bit shift*/
+#define IMX8QXP_REG_ADC_CMDH_NEXT_SHIFT		(24)
+#define IMX8QXP_REG_ADC_CMDH_LOOP_SHIFT		(16)
+#define IMX8QXP_REG_ADC_CMDH_AVGS_SHIFT		(12)
+#define IMX8QXP_REG_ADC_CMDH_STS_SHIFT		(8)
+#define IMX8QXP_REG_ADC_CMDH_LWI_SHIFT		(7)
+#define IMX8QXP_REG_ADC_CMDH_CMPEN_SHIFT	(0)
+/* ADC CFG bit shift*/
+#define IMX8QXP_REG_ADC_CFG_PWREN_SHIFT		(28)
+#define IMX8QXP_REG_ADC_CFG_PUDLY_SHIFT		(16)
+#define IMX8QXP_REG_ADC_CFG_REFSEL_SHIFT	(6)
+#define IMX8QXP_REG_ADC_CFG_PWRSEL_SHIFT	(4)
+#define IMX8QXP_REG_ADC_CFG_TPRICTRL_SHIFT	(0)
+/* ADC FCTRL bit shift*/
+#define IMX8QXP_ADC_FCTRL_FWMARK_SHIFT		(16)
+#define IMX8QXP_ADC_FCTRL_FWMARK_MASK		(0x1f << 16)
+#define IMX8QXP_ADC_FCTRL_FCOUNT_MASK		(0x1f)
+/* ADC STAT bit shift*/
+#define IMX8QXP_REG_ADC_STAT_CMDACT_SHIFT	(24)
+#define IMX8QXP_REG_ADC_STAT_TRGACT_SHIFT	(16)
+#define IMX8QXP_REG_ADC_STAT_FOF_SHIFT		(1)
+#define IMX8QXP_REG_ADC_STAT_RDY_SHIFT		(0)
+
+/* ADC CMD PARAMETER*/
+#define IMX8QXP_REG_ADC_CMDL_CNANNEL_SCALE_DOWN		(0)
+#define IMX8QXP_REG_ADC_CMDL_CHANNEL_SCALE_FULL		(0x3f)
+#define IMX8QXP_REG_ADC_CMDL_SEL_A_A_B_CHANNEL		(0)
+#define IMX8QXP_REG_ADC_CMDL_SEL_B_B_A_CHANNEL		(1)
+#define IMX8QXP_REG_ADC_CMDL_STANDARD_RESOLUTION	(0)
+#define IMX8QXP_REG_ADC_CMDL_HIGH_RESOLUTION		(1)
+#define IMX8QXP_REG_ADC_CMDL_MODE_SINGLE		(0)
+#define IMX8QXP_REG_ADC_CMDL_MODE_DIFF			(1)
+
+#define IMX8QXP_REG_ADC_CMDH_LWI_INCREMENT_ENABLE	(1)
+#define IMX8QXP_REG_ADC_CMDH_LWI_INCREMENT_DISABLE	(0)
+#define IMX8QXP_REG_ADC_CMDH_CMPEN_DISABLE		(0)
+#define IMX8QXP_REG_ADC_CMDH_CMPEN_ENABLE_TRUE		(2)
+#define IMX8QXP_REG_ADC_CMDH_CMPEN_ENABLE_UNTILE_TRUE	(0x3)
+
+/* ADC PAUSE PARAMETER*/
+#define IMX8QXP_REG_ADC_PAUSE_ENABLE		(0x80000000)
+/* ADC TRIGGER PARAMETER*/
+#define IMX8QXP_REG_ADC_TCTRL_TPRI_PRIORITY_HIGH	(0)
+#define IMX8QXP_REG_ADC_TCTRL_TPRI_PRIORITY_LOW	(1)
+
+#define IMX8QXP_REG_ADC_TCTRL_HTEN_HARDWARE_TIRGGER_DISABLE	(0)
+#define IMX8QXP_REG_ADC_TCTRC_HTEN_HARDWARE_TIRGGER_ENABLE	(1)
+
+#define MAX_CMD (8)
+#define MAX_TRIG (8)
+
+#define IMX8QXP_ADC_TIMEOUT		msecs_to_jiffies(100)
+
+struct imx8qxp_adc_trigger_ctrl {
+	u32 tcmd;
+	u32 tdly;
+	u32 tpri;
+	u32 hten;
+};
+
+struct imx8qxp_adc_cmd_l {
+	u32 scale;
+	u32 mode;
+	u32 diff;
+	u32 absel;
+	u32 adch;
+};
+
+struct imx8qxp_adc_cmd_h {
+	u32 next;
+	u32 loop;
+	u32 avgs;
+	u32 sts;
+	u32 lwi;
+	u32 cmpen;
+};
+
+struct imx8qxp_adc_cfg {
+	u32 pwren;
+	u32 pudly;
+	u32 refsel;
+	u32 pwrsel;
+	u32 tprictrl;
+};
+
+struct imx8qxp_adc {
+	struct device *dev;
+	void __iomem *regs;
+	struct clk *clk;
+	struct clk *ipg_clk;
+
+	u32 vref_uv;
+	u32 value;
+	u32 channel_id;
+	u32 trigger_id;
+	u32 cmd_id;
+
+	struct regulator *vref;
+	struct imx8qxp_adc_cmd_l adc_cmd_l[MAX_CMD + 1];
+	struct imx8qxp_adc_cmd_h adc_cmd_h[MAX_CMD + 1];
+	struct imx8qxp_adc_trigger_ctrl adc_trigger_ctrl[MAX_TRIG + 1];
+	struct imx8qxp_adc_cfg adc_cfg;
+	struct completion completion;
+};
+
+#define IMX8QXP_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 imx8qxp_adc_iio_channels[] = {
+	IMX8QXP_ADC_CHAN(0),
+	IMX8QXP_ADC_CHAN(1),
+	IMX8QXP_ADC_CHAN(2),
+	IMX8QXP_ADC_CHAN(3),
+	IMX8QXP_ADC_CHAN(4),
+	IMX8QXP_ADC_CHAN(5),
+	IMX8QXP_ADC_CHAN(6),
+	IMX8QXP_ADC_CHAN(7),
+};
+
+static void imx8qxp_adc_feature_prepare(struct imx8qxp_adc *adc)
+{
+	u32 i;
+
+	adc->trigger_id = 0;
+	adc->cmd_id = 0;
+	adc->channel_id = 0;
+
+	for (i = 0; i < MAX_CMD + 1; i++) {
+		adc->adc_cmd_l[i].scale = 1;
+		adc->adc_cmd_l[i].mode = 0;
+		adc->adc_cmd_l[i].diff = 0;
+		adc->adc_cmd_l[i].absel = 0;
+		adc->adc_cmd_l[i].adch = 0;
+		adc->adc_cmd_h[i].next = 0;
+		adc->adc_cmd_h[i].loop = 0;
+		adc->adc_cmd_h[i].avgs = 0;
+		adc->adc_cmd_h[i].sts = 0;
+		adc->adc_cmd_h[i].lwi = 0;
+		adc->adc_cmd_h[i].cmpen = 0;
+	}
+
+	for (i = 0; i < MAX_TRIG; i++) {
+		adc->adc_trigger_ctrl[i].tcmd = 0;
+		adc->adc_trigger_ctrl[i].tdly = 0;
+		adc->adc_trigger_ctrl[i].tpri = 0;
+		adc->adc_trigger_ctrl[i].hten = 0;
+	}
+
+	adc->adc_cfg.pwren = 0;
+	adc->adc_cfg.pudly = 0;
+	adc->adc_cfg.refsel = 0;
+	adc->adc_cfg.pwrsel = 0;
+	adc->adc_cfg.tprictrl = 0;
+}
+
+static void imx8qxp_adc_reset(struct imx8qxp_adc *adc)
+{
+	u32 ctrl;
+
+	/*software reset, need to clear the set bit*/
+	ctrl = readl(adc->regs + IMX8QXP_REG_ADC_CTRL);
+	ctrl |= 1 << IMX8QXP_REG_ADC_CTRL_SOFTWARE_RESET_SHIFT;
+	writel(ctrl, adc->regs + IMX8QXP_REG_ADC_CTRL);
+	udelay(10);
+	ctrl &= ~(1 << IMX8QXP_REG_ADC_CTRL_SOFTWARE_RESET_SHIFT);
+	writel(ctrl, adc->regs + IMX8QXP_REG_ADC_CTRL);
+
+	/* reset the fifo */
+	ctrl |= 1 << IMX8QXP_REG_ADC_CTRL_FIFO_RESET_SHIFT;
+	writel(ctrl, adc->regs + IMX8QXP_REG_ADC_CTRL);
+}
+
+static void imx8qxp_adc_reg_config(struct imx8qxp_adc *adc)
+{
+	u32 adc_cfg, adc_tctrl, adc_cmdl, adc_cmdh;
+	u32 t_id, c_id;
+
+	adc_cfg = adc->adc_cfg.pwren << IMX8QXP_REG_ADC_CFG_PWREN_SHIFT
+			| adc->adc_cfg.pudly << IMX8QXP_REG_ADC_CFG_PUDLY_SHIFT
+			| adc->adc_cfg.refsel << IMX8QXP_REG_ADC_CFG_REFSEL_SHIFT
+			| adc->adc_cfg.pwrsel << IMX8QXP_REG_ADC_CFG_PWRSEL_SHIFT
+			| adc->adc_cfg.tprictrl << IMX8QXP_REG_ADC_CFG_TPRICTRL_SHIFT;
+	writel(adc_cfg, adc->regs + IMX8QXP_REG_ADC_CFG);
+
+	t_id = adc->trigger_id;
+	adc_tctrl = adc->adc_trigger_ctrl[t_id].tcmd << IMX8QXP_REG_ADC_TCTRL_TCMD_SHIFT
+			| adc->adc_trigger_ctrl[t_id].tdly << IMX8QXP_REG_ADC_TCTRL_TDLY_SHIFT
+			| adc->adc_trigger_ctrl[t_id].tpri << IMX8QXP_REG_ADC_TCTRL_TPRI_SHIFT
+			| adc->adc_trigger_ctrl[t_id].hten << IMX8QXP_REG_ADC_TCTRL_HTEN_SHIFT;
+	writel(adc_tctrl, adc->regs + IMX8QXP_REG_ADC_TCTRL0 + t_id * 4);
+
+	c_id = adc->cmd_id - 1;
+	adc_cmdl = adc->adc_cmd_l[c_id].scale << IMX8QXP_REG_ADC_CMDL_CSCALE_SHIFT
+			| adc->adc_cmd_l[c_id].mode << IMX8QXP_REG_ADC_CMDL_MODE_SHIFT
+			| adc->adc_cmd_l[c_id].diff << IMX8QXP_REG_ADC_CMDL_DIFF_SHIFT
+			| adc->adc_cmd_l[c_id].absel << IMX8QXP_REG_ADC_CMDL_ABSEL_SHIFT
+			| adc->adc_cmd_l[c_id].adch << IMX8QXP_REG_ADC_CMDL_ADCH_SHIFT;
+	writel(adc_cmdl, adc->regs + IMX8QXP_REG_ADC_CMDL1 + c_id * 8);
+
+	adc_cmdh = adc->adc_cmd_h[c_id].next << IMX8QXP_REG_ADC_CMDH_NEXT_SHIFT
+			| adc->adc_cmd_h[c_id].loop << IMX8QXP_REG_ADC_CMDH_LOOP_SHIFT
+			| adc->adc_cmd_h[c_id].avgs << IMX8QXP_REG_ADC_CMDH_AVGS_SHIFT
+			| adc->adc_cmd_h[c_id].sts << IMX8QXP_REG_ADC_CMDH_STS_SHIFT
+			| adc->adc_cmd_h[c_id].lwi << IMX8QXP_REG_ADC_CMDH_LWI_SHIFT
+			| adc->adc_cmd_h[c_id].cmpen << IMX8QXP_REG_ADC_CMDH_CMPEN_SHIFT;
+	writel(adc_cmdh, adc->regs + IMX8QXP_REG_ADC_CMDH1 + c_id * 8);
+}
+
+static void imx8qxp_adc_mode_config(struct imx8qxp_adc *adc)
+{
+	u32 cmd_id, trigger_id, channel_id;
+
+	channel_id = adc->channel_id;
+	cmd_id = adc->cmd_id - 1;
+	trigger_id = adc->trigger_id;
+
+	/* config the cmd */
+	adc->adc_cmd_l[cmd_id].scale = IMX8QXP_REG_ADC_CMDL_CHANNEL_SCALE_FULL;
+	adc->adc_cmd_l[cmd_id].mode = IMX8QXP_REG_ADC_CMDL_STANDARD_RESOLUTION;
+	adc->adc_cmd_l[cmd_id].diff = IMX8QXP_REG_ADC_CMDL_MODE_SINGLE;
+	adc->adc_cmd_l[cmd_id].absel = IMX8QXP_REG_ADC_CMDL_SEL_A_A_B_CHANNEL;
+	adc->adc_cmd_l[cmd_id].adch = channel_id;
+
+	adc->adc_cmd_h[cmd_id].next = 0;
+	adc->adc_cmd_h[cmd_id].loop = 0;
+	adc->adc_cmd_h[cmd_id].avgs = 7;  // 128 times conversion
+	adc->adc_cmd_h[cmd_id].sts = 0;
+	adc->adc_cmd_h[cmd_id].lwi = IMX8QXP_REG_ADC_CMDH_LWI_INCREMENT_DISABLE;
+	adc->adc_cmd_h[cmd_id].cmpen = IMX8QXP_REG_ADC_CMDH_CMPEN_DISABLE;
+
+	/* config the trigger control */
+	adc->adc_trigger_ctrl[trigger_id].tcmd = adc->cmd_id;  //point to cmd1
+	adc->adc_trigger_ctrl[trigger_id].tdly = 0;
+	adc->adc_trigger_ctrl[trigger_id].tpri = IMX8QXP_REG_ADC_TCTRL_TPRI_PRIORITY_HIGH;
+	adc->adc_trigger_ctrl[trigger_id].hten = IMX8QXP_REG_ADC_TCTRL_HTEN_HARDWARE_TIRGGER_DISABLE;
+
+	/* ADC configuration */
+	adc->adc_cfg.pwren = 1;
+	adc->adc_cfg.pudly = 0x80;
+	adc->adc_cfg.refsel = 0;
+	adc->adc_cfg.pwrsel = 3;
+	adc->adc_cfg.tprictrl = 0;
+
+	imx8qxp_adc_reg_config(adc);
+}
+
+static void imx8qxp_adc_fifo_config(struct imx8qxp_adc *adc)
+{
+	u32 fifo_ctrl, interrupt_en;
+
+	fifo_ctrl = readl(adc->regs + IMX8QXP_REG_ADC_FCTRL);
+	fifo_ctrl &= ~IMX8QXP_ADC_FCTRL_FWMARK_MASK;
+	/* set the watermark level to 1 */
+	fifo_ctrl |= 0 << IMX8QXP_ADC_FCTRL_FWMARK_SHIFT;
+	writel(fifo_ctrl, adc->regs + IMX8QXP_REG_ADC_FCTRL);
+
+	/* FIFO Watermark Interrupt Enable */
+	interrupt_en = readl(adc->regs + IMX8QXP_REG_ADC_IE);
+	interrupt_en |= 1 << IMX8QXP_REG_ADC_IE_FWMIE_SHIFT;
+	writel(interrupt_en, adc->regs + IMX8QXP_REG_ADC_IE);
+}
+
+static void imx8qxp_adc_disable(struct imx8qxp_adc *adc)
+{
+	u32 ctrl;
+
+	ctrl = readl(adc->regs + IMX8QXP_REG_ADC_CTRL);
+	ctrl &=  ~(1 << IMX8QXP_REG_ADC_CTRL_ADC_ENABLE);
+	writel(ctrl, adc->regs + IMX8QXP_REG_ADC_CTRL);
+}
+
+static void imx8qxp_adc_enable(struct imx8qxp_adc *adc)
+{
+	u32 ctrl;
+
+	ctrl = readl(adc->regs + IMX8QXP_REG_ADC_CTRL);
+	ctrl |= 1 << IMX8QXP_REG_ADC_CTRL_ADC_ENABLE;
+	writel(ctrl, adc->regs + IMX8QXP_REG_ADC_CTRL);
+
+}
+
+static void imx8qxp_adc_start_trigger(struct imx8qxp_adc *adc)
+{
+	writel(1 << adc->trigger_id, adc->regs + IMX8QXP_REG_ADC_SWTRIG);
+}
+
+static u32 imx8qxp_adc_get_sample_rate(struct imx8qxp_adc *adc)
+{
+
+	u32 input_clk;
+
+	input_clk = clk_get_rate(adc->clk);
+
+	return input_clk / 3;
+}
+
+static int imx8qxp_adc_read_raw(struct iio_dev *indio_dev,
+			struct iio_chan_spec const *chan,
+			int *val,
+			int *val2,
+			long mask)
+{
+
+	struct imx8qxp_adc *adc = iio_priv(indio_dev);
+
+	u32 channel;
+	long ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		pm_runtime_get_sync(adc->dev);
+
+		mutex_lock(&indio_dev->mlock);
+		reinit_completion(&adc->completion);
+
+		channel = chan->channel & 0x07;
+		adc->channel_id = channel;
+		adc->cmd_id = 1;
+		adc->trigger_id = 0;
+		imx8qxp_adc_mode_config(adc);
+
+		imx8qxp_adc_fifo_config(adc);
+
+		imx8qxp_adc_enable(adc);
+
+		imx8qxp_adc_start_trigger(adc);
+
+		ret = wait_for_completion_interruptible_timeout
+				(&adc->completion, IMX8QXP_ADC_TIMEOUT);
+
+		pm_runtime_mark_last_busy(adc->dev);
+		pm_runtime_put_sync_autosuspend(adc->dev);
+
+		if (ret == 0) {
+			mutex_unlock(&indio_dev->mlock);
+			return -ETIMEDOUT;
+		}
+		if (ret < 0) {
+			mutex_unlock(&indio_dev->mlock);
+			return ret;
+		}
+
+		*val = adc->value;
+		mutex_unlock(&indio_dev->mlock);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		adc->vref_uv = regulator_get_voltage(adc->vref);
+		*val = adc->vref_uv / 1000;
+		*val2 = 12;
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = imx8qxp_adc_get_sample_rate(adc);
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int imx8qxp_adc_read_data(struct imx8qxp_adc *adc)
+{
+	u32 value;
+
+	value = readl(adc->regs + IMX8QXP_REG_ADC_RESFIFO);
+	value &= 0xffff;
+	return (value >> 3);
+}
+
+static irqreturn_t imx8qxp_adc_isr(int irq, void *dev_id)
+{
+	struct imx8qxp_adc *adc = (struct imx8qxp_adc *)dev_id;
+
+	u32 fifo_count;
+
+	fifo_count = readl(adc->regs + IMX8QXP_REG_ADC_FCTRL)
+			& IMX8QXP_ADC_FCTRL_FCOUNT_MASK;
+
+	if (fifo_count) {
+		adc->value = imx8qxp_adc_read_data(adc);
+		complete(&adc->completion);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int imx8qxp_adc_reg_access(struct iio_dev *indio_dev,
+			unsigned int reg, unsigned int writeval,
+			unsigned int *readval)
+{
+	struct imx8qxp_adc *adc = iio_priv(indio_dev);
+
+	if (!readval || reg % 4 || reg > IMX8QXP_REG_ADC_TST)
+		return -EINVAL;
+
+	pm_runtime_get_sync(adc->dev);
+
+	*readval = readl(adc->regs + reg);
+
+	pm_runtime_mark_last_busy(adc->dev);
+	pm_runtime_put_sync_autosuspend(adc->dev);
+
+	return 0;
+}
+
+static const struct iio_info imx8qxp_adc_iio_info = {
+	.read_raw = &imx8qxp_adc_read_raw,
+	.debugfs_reg_access = &imx8qxp_adc_reg_access,
+};
+
+static const struct of_device_id imx8qxp_adc_match[] = {
+	{ .compatible = "fsl,imx8qxp-adc", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx8qxp_adc_match);
+
+static int imx8qxp_adc_probe(struct platform_device *pdev)
+{
+	struct imx8qxp_adc *adc;
+	struct iio_dev *indio_dev;
+	struct resource *mem;
+	int irq;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
+	if (!indio_dev) {
+		dev_err(&pdev->dev, "Failed allocating iio device\n");
+		return -ENOMEM;
+	}
+
+	adc = iio_priv(indio_dev);
+	adc->dev = &pdev->dev;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	adc->regs = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(adc->regs)) {
+		ret = PTR_ERR(adc->regs);
+		dev_err(&pdev->dev,
+			"Failed to remap adc memory, err = %d\n", ret);
+		return ret;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "No irq resource?\n");
+		return irq;
+	}
+
+	adc->clk = devm_clk_get(&pdev->dev, "per");
+	if (IS_ERR(adc->clk)) {
+		ret = PTR_ERR(adc->clk);
+		dev_err(&pdev->dev, "Failed getting clock, err = %d\n", ret);
+		return ret;
+	}
+
+	adc->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
+	if (IS_ERR(adc->ipg_clk)) {
+		ret = PTR_ERR(adc->ipg_clk);
+		dev_err(&pdev->dev, "Failed getting clock, err = %d\n", ret);
+		return ret;
+	}
+
+	adc->vref = devm_regulator_get(&pdev->dev, "vref");
+	if (IS_ERR(adc->vref)) {
+		ret = PTR_ERR(adc->vref);
+		dev_err(&pdev->dev,
+			"Failed getting reference voltage, err = %d\n", ret);
+		return ret;
+	}
+
+	ret = regulator_enable(adc->vref);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Can't enable adc reference top voltage, err = %d\n",
+			ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	init_completion(&adc->completion);
+
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->info = &imx8qxp_adc_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = imx8qxp_adc_iio_channels;
+	indio_dev->num_channels = ARRAY_SIZE(imx8qxp_adc_iio_channels);
+
+	ret = clk_prepare_enable(adc->clk);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Could not prepare or enable the clock.\n");
+		goto error_adc_clk_enable;
+	}
+
+	ret = clk_prepare_enable(adc->ipg_clk);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Could not prepare or enable the clock.\n");
+		goto error_adc_ipg_clk_enable;
+	}
+
+	ret = devm_request_irq(adc->dev, irq,
+				imx8qxp_adc_isr, 0,
+				dev_name(&pdev->dev), adc);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed requesting irq, irq = %d\n", irq);
+		goto error_iio_device_register;
+	}
+
+	imx8qxp_adc_feature_prepare(adc);
+	imx8qxp_adc_reset(adc);
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		imx8qxp_adc_disable(adc);
+		dev_err(&pdev->dev, "Couldn't register the device.\n");
+		goto error_iio_device_register;
+	}
+
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	return 0;
+
+error_iio_device_register:
+	clk_disable_unprepare(adc->ipg_clk);
+error_adc_ipg_clk_enable:
+	clk_disable_unprepare(adc->clk);
+error_adc_clk_enable:
+	regulator_disable(adc->vref);
+
+	return ret;
+}
+
+static int imx8qxp_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct imx8qxp_adc *adc = iio_priv(indio_dev);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	iio_device_unregister(indio_dev);
+
+	imx8qxp_adc_disable(adc);
+
+	clk_disable_unprepare(adc->clk);
+	clk_disable_unprepare(adc->ipg_clk);
+	regulator_disable(adc->vref);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
+
+	return 0;
+}
+
+static int imx8qxp_adc_runtime_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct imx8qxp_adc *adc = iio_priv(indio_dev);
+
+	imx8qxp_adc_disable(adc);
+
+	clk_disable_unprepare(adc->clk);
+	clk_disable_unprepare(adc->ipg_clk);
+	regulator_disable(adc->vref);
+
+	return 0;
+}
+
+static int imx8qxp_adc_runtime_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct imx8qxp_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	ret = regulator_enable(adc->vref);
+	if (ret) {
+		dev_err(adc->dev,
+			"Can't enable adc reference top voltage, err = %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(adc->clk);
+	if (ret) {
+		dev_err(adc->dev,
+			"Could not prepare or enable clock.\n");
+		regulator_disable(adc->vref);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(adc->ipg_clk);
+	if (ret) {
+		dev_err(adc->dev,
+			"Could not prepare or enable clock.\n");
+		clk_disable_unprepare(adc->clk);
+		regulator_disable(adc->vref);
+		return ret;
+	}
+	imx8qxp_adc_reset(adc);
+
+	return 0;
+}
+
+static const struct dev_pm_ops imx8qxp_adc_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(imx8qxp_adc_runtime_suspend, imx8qxp_adc_runtime_resume, NULL)
+};
+
+static struct platform_driver imx8qxp_adc_driver = {
+	.probe		= imx8qxp_adc_probe,
+	.remove		= imx8qxp_adc_remove,
+	.driver		= {
+		.name	= "imx8qxp_adc",
+		.of_match_table = imx8qxp_adc_match,
+		.pm	= &imx8qxp_adc_pm_ops,
+	},
+};
+
+module_platform_driver(imx8qxp_adc_driver);
+
+MODULE_AUTHOR("Haibo Chen <haibo.chen@nxp.com>");
+MODULE_DESCRIPTION("NXP IMX8QXP ADC driver");
+MODULE_LICENSE("GPL v2");
-- 
2.17.1