[PATCH 1/2] dm: adc: add iMX93 ADC support

Luca Ellero
2023-07-05T12:56:38Z

This commit adds driver for iMX93 ADC.

The driver is implemented using driver model and provides
ADC uclass's methods for ADC single channel operations:
- adc_start_channel()
- adc_channel_data()
- adc_stop()

ADC features:
- channels: 4
- resolution: 12-bit

Signed-off-by: Luca Ellero <l.ellero@asem.it>
---
drivers/adc/Kconfig | 8 ++
drivers/adc/Makefile | 1 +
drivers/adc/imx93-adc.c | 290 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 299 insertions(+)
create mode 100644 drivers/adc/imx93-adc.c

diff --git a/drivers/adc/Kconfig b/drivers/adc/Kconfig
index e719c38bb3..4336732dee 100644
--- a/drivers/adc/Kconfig
+++ b/drivers/adc/Kconfig
@@ -63,3 +63,11 @@ config STM32_ADC
- core driver to deal with common resources
- child driver to deal with individual ADC resources (declare ADC
device and associated channels, start/stop conversions)
+
+config ADC_IMX93
+ bool "Enable NXP IMX93 ADC driver"
+ help
+ This enables basic driver for NXP IMX93 ADC.
+ It provides:
+ - 4 analog input channels
+ - 12-bit resolution
diff --git a/drivers/adc/Makefile b/drivers/adc/Makefile
index c1387f3a34..5336c82097 100644
--- a/drivers/adc/Makefile
+++ b/drivers/adc/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_ADC_SANDBOX) += sandbox.o
obj-$(CONFIG_SARADC_ROCKCHIP) += rockchip-saradc.o
obj-$(CONFIG_SARADC_MESON) += meson-saradc.o
obj-$(CONFIG_STM32_ADC) += stm32-adc.o stm32-adc-core.o
+obj-$(CONFIG_ADC_IMX93) += imx93-adc.o
diff --git a/drivers/adc/imx93-adc.c b/drivers/adc/imx93-adc.c
new file mode 100644
index 0000000000..41d04e0426
--- /dev/null
+++ b/drivers/adc/imx93-adc.c
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023 ASEM Srl
+ * Author: Luca Ellero <l.ellero@asem.it>
+ *
+ * Originally based on NXP linux-imx kernel v5.15 drivers/iio/adc/imx93_adc.c
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <dm.h>
+#include <linux/bitfield.h>
+#include <linux/iopoll.h>
+#include <clk.h>
+#include <adc.h>
+
+#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
+
+#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_EOC_MASK BIT(1)
+
+#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)
+
+#define IDLE 0
+#define POWER_DOWN 1
+#define WAIT_STATE 2
+#define BUSY_IN_CALIBRATION 3
+#define SAMPLE 4
+#define CONVERSION 6
+
+#define IMX93_ADC_MAX_CHANNEL 3
+#define IMX93_ADC_DAT_MASK 0xfff
+#define IMX93_ADC_TIMEOUT 100000
+
+struct imx93_adc_priv {
+ int active_channel;
+ void __iomem *regs;
+ struct clk ipg_clk;
+};
+
+static void imx93_adc_power_down(struct imx93_adc_priv *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) == POWER_DOWN), 50);
+ if (ret == -ETIMEDOUT)
+ pr_warn("ADC not in power down mode, current MSR: %x\n", msr);
+}
+
+static void imx93_adc_power_up(struct imx93_adc_priv *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_priv *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);
+
+ /* bring ADC out of power down state, in idle state */
+ imx93_adc_power_up(adc);
+}
+
+static int imx93_adc_calibration(struct imx93_adc_priv *adc)
+{
+ u32 mcr, msr;
+ int ret;
+
+ /* make sure ADC is 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);
+
+ /* bring ADC out of power down state */
+ imx93_adc_power_up(adc);
+
+ /*
+ * we use the default TSAMP/NRSMPL/AVGEN in MCR,
+ * can add the setting of these bit if need
+ */
+
+ /* 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), 2000000);
+ if (ret == -ETIMEDOUT) {
+ pr_warn("ADC calibration timeout\n");
+ return ret;
+ }
+
+ /* check whether calbration is successful or not */
+ msr = readl(adc->regs + IMX93_ADC_MSR);
+ if (msr & IMX93_ADC_MSR_CALFAIL_MASK) {
+ pr_warn("ADC calibration failed!\n");
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
+static int imx93_adc_channel_data(struct udevice *dev, int channel,
+ unsigned int *data)
+{
+ struct imx93_adc_priv *adc = dev_get_priv(dev);
+ u32 isr, pcda;
+ int ret;
+
+ if (channel != adc->active_channel) {
+ pr_err("Requested channel is not active!\n");
+ return -EINVAL;
+ }
+
+ ret = readl_poll_timeout(adc->regs + IMX93_ADC_ISR, isr,
+ (isr & IMX93_ADC_ISR_EOC_MASK), IMX93_ADC_TIMEOUT);
+
+ /* clear interrupts */
+ writel(isr, adc->regs + IMX93_ADC_ISR);
+
+ if (ret == -ETIMEDOUT) {
+ pr_warn("ADC conversion timeout!\n");
+ return ret;
+ }
+
+ pcda = readl(adc->regs + IMX93_ADC_PCDR0 + channel * 4);
+
+ *data = FIELD_GET(IMX93_ADC_PCDR_CDATA_MASK, pcda);
+
+ return 0;
+}
+
+static int imx93_adc_start_channel(struct udevice *dev, int channel)
+{
+ struct imx93_adc_priv *adc = dev_get_priv(dev);
+ u32 imr, mcr;
+
+ /* config channel mask register */
+ writel(1 << channel, adc->regs + IMX93_ADC_NCMR0);
+
+ /* config interrupt mask */
+ imr = FIELD_PREP(IMX93_ADC_IMR_EOC_MASK, 1);
+ writel(imr, adc->regs + IMX93_ADC_IMR);
+ writel(1 << 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);
+
+ adc->active_channel = channel;
+
+ return 0;
+}
+
+static int imx93_adc_stop(struct udevice *dev)
+{
+ struct imx93_adc_priv *adc = dev_get_priv(dev);
+
+ imx93_adc_power_down(adc);
+
+ adc->active_channel = -1;
+
+ return 0;
+}
+
+static int imx93_adc_probe(struct udevice *dev)
+{
+ struct imx93_adc_priv *adc = dev_get_priv(dev);
+ unsigned int ret;
+
+ ret = imx93_adc_calibration(adc);
+ if (ret < 0)
+ return ret;
+
+ imx93_adc_config_ad_clk(adc);
+
+ adc->active_channel = -1;
+
+ return 0;
+}
+
+static int imx93_adc_of_to_plat(struct udevice *dev)
+{
+ struct adc_uclass_plat *uc_pdata = dev_get_uclass_plat(dev);
+ struct imx93_adc_priv *adc = dev_get_priv(dev);
+ unsigned int ret;
+
+ adc->regs = dev_read_addr_ptr(dev);
+ if (adc->regs == (struct imx93_adc *)FDT_ADDR_T_NONE) {
+ pr_err("Dev: %s - can't get address!", dev->name);
+ return -ENODATA;
+ }
+
+ ret = clk_get_by_name(dev, "ipg", &adc->ipg_clk);
+ if (ret < 0) {
+ pr_err("Can't get ADC ipg clk: %d\n", ret);
+ return ret;
+ }
+ ret = clk_enable(&adc->ipg_clk);
+ if(ret) {
+ pr_err("Can't enable ADC ipg clk: %d\n", ret);
+ return ret;
+ }
+
+ uc_pdata->data_mask = IMX93_ADC_DAT_MASK;
+ uc_pdata->data_format = ADC_DATA_FORMAT_BIN;
+ uc_pdata->data_timeout_us = IMX93_ADC_TIMEOUT;
+
+ /* Mask available channel bits: [0:3] */
+ uc_pdata->channel_mask = (2 << IMX93_ADC_MAX_CHANNEL) - 1;
+
+ return 0;
+}
+
+static const struct adc_ops imx93_adc_ops = {
+ .start_channel = imx93_adc_start_channel,
+ .channel_data = imx93_adc_channel_data,
+ .stop = imx93_adc_stop,
+};
+
+static const struct udevice_id imx93_adc_ids[] = {
+ { .compatible = "nxp,imx93-adc" },
+ { }
+};
+
+U_BOOT_DRIVER(imx93_adc) = {
+ .name = "imx93-adc",
+ .id = UCLASS_ADC,
+ .of_match = imx93_adc_ids,
+ .ops = &imx93_adc_ops,
+ .probe = imx93_adc_probe,
+ .of_to_plat = imx93_adc_of_to_plat,
+ .priv_auto = sizeof(struct imx93_adc_priv),
+};
--
2.25.1