[PATCH] aiodev: port Linux imx7d-adc driver
Ahmad Fatoum
a.fatoum at pengutronix.de
Thu Oct 20 08:28:53 PDT 2022
The i.MX7 has two ADCs of 16 channels each. Port the Linux v6.0 driver
of the peripheral to make them usable in barebox. This can be useful
for board type/revision detection that employs voltage dividers.
Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
drivers/aiodev/Kconfig | 8 +
drivers/aiodev/Makefile | 1 +
drivers/aiodev/imx7d_adc.c | 466 +++++++++++++++++++++++++++++++++++++
3 files changed, 475 insertions(+)
create mode 100644 drivers/aiodev/imx7d_adc.c
diff --git a/drivers/aiodev/Kconfig b/drivers/aiodev/Kconfig
index 6bd697702ecf..5c8706ffef4a 100644
--- a/drivers/aiodev/Kconfig
+++ b/drivers/aiodev/Kconfig
@@ -65,4 +65,12 @@ config ROCKCHIP_SARADC
help
Support for Successive Approximation Register (SAR) ADC in Rockchip
SoCs.
+
+config IMX7D_ADC
+ tristate "Freescale IMX7D ADC driver"
+ depends on ARCH_IMX7 || COMPILE_TEST
+ depends on OFDEVICE
+ help
+ Say yes here to build support for IMX7D ADC.
+
endif
diff --git a/drivers/aiodev/Makefile b/drivers/aiodev/Makefile
index 06a63b0d2d78..9cb11605ed09 100644
--- a/drivers/aiodev/Makefile
+++ b/drivers/aiodev/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_QORIQ_THERMAL) += qoriq_thermal.o
obj-$(CONFIG_AM335X_ADC) += am335x_adc.o
obj-$(CONFIG_STM32_ADC) += stm32-adc.o stm32-adc-core.o
obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
diff --git a/drivers/aiodev/imx7d_adc.c b/drivers/aiodev/imx7d_adc.c
new file mode 100644
index 000000000000..9820aaff1ac4
--- /dev/null
+++ b/drivers/aiodev/imx7d_adc.c
@@ -0,0 +1,466 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Freescale i.MX7D ADC driver
+ *
+ * Copyright (C) 2015 Freescale Semiconductor, Inc.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <io.h>
+#include <linux/printk.h>
+#include <driver.h>
+#include <init.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <regulator.h>
+#include <linux/barebox-wrapper.h>
+
+#include <linux/iopoll.h>
+#include <aiodev.h>
+
+/* ADC register */
+#define IMX7D_REG_ADC_CH_A_CFG1 0x00
+#define IMX7D_REG_ADC_CH_A_CFG2 0x10
+#define IMX7D_REG_ADC_CH_B_CFG1 0x20
+#define IMX7D_REG_ADC_CH_B_CFG2 0x30
+#define IMX7D_REG_ADC_CH_C_CFG1 0x40
+#define IMX7D_REG_ADC_CH_C_CFG2 0x50
+#define IMX7D_REG_ADC_CH_D_CFG1 0x60
+#define IMX7D_REG_ADC_CH_D_CFG2 0x70
+#define IMX7D_REG_ADC_CH_SW_CFG 0x80
+#define IMX7D_REG_ADC_TIMER_UNIT 0x90
+#define IMX7D_REG_ADC_DMA_FIFO 0xa0
+#define IMX7D_REG_ADC_FIFO_STATUS 0xb0
+#define IMX7D_REG_ADC_INT_SIG_EN 0xc0
+#define IMX7D_REG_ADC_INT_EN 0xd0
+#define IMX7D_REG_ADC_INT_STATUS 0xe0
+#define IMX7D_REG_ADC_CHA_B_CNV_RSLT 0xf0
+#define IMX7D_REG_ADC_CHC_D_CNV_RSLT 0x100
+#define IMX7D_REG_ADC_CH_SW_CNV_RSLT 0x110
+#define IMX7D_REG_ADC_DMA_FIFO_DAT 0x120
+#define IMX7D_REG_ADC_ADC_CFG 0x130
+
+#define IMX7D_REG_ADC_CHANNEL_CFG2_BASE 0x10
+#define IMX7D_EACH_CHANNEL_REG_OFFSET 0x20
+
+#define IMX7D_REG_ADC_CH_CFG1_CHANNEL_EN (0x1 << 31)
+#define IMX7D_REG_ADC_CH_CFG1_CHANNEL_SINGLE BIT(30)
+#define IMX7D_REG_ADC_CH_CFG1_CHANNEL_AVG_EN BIT(29)
+#define IMX7D_REG_ADC_CH_CFG1_CHANNEL_SEL(x) ((x) << 24)
+
+#define IMX7D_REG_ADC_CH_CFG2_AVG_NUM_4 (0x0 << 12)
+#define IMX7D_REG_ADC_CH_CFG2_AVG_NUM_8 (0x1 << 12)
+#define IMX7D_REG_ADC_CH_CFG2_AVG_NUM_16 (0x2 << 12)
+#define IMX7D_REG_ADC_CH_CFG2_AVG_NUM_32 (0x3 << 12)
+
+#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_4 (0x0 << 29)
+#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_8 (0x1 << 29)
+#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_16 (0x2 << 29)
+#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_32 (0x3 << 29)
+#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_64 (0x4 << 29)
+#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_128 (0x5 << 29)
+
+#define IMX7D_REG_ADC_ADC_CFG_ADC_CLK_DOWN BIT(31)
+#define IMX7D_REG_ADC_ADC_CFG_ADC_POWER_DOWN BIT(1)
+#define IMX7D_REG_ADC_ADC_CFG_ADC_EN BIT(0)
+
+#define IMX7D_REG_ADC_INT_CHA_COV_INT_EN BIT(8)
+#define IMX7D_REG_ADC_INT_CHB_COV_INT_EN BIT(9)
+#define IMX7D_REG_ADC_INT_CHC_COV_INT_EN BIT(10)
+#define IMX7D_REG_ADC_INT_CHD_COV_INT_EN BIT(11)
+#define IMX7D_REG_ADC_INT_CHANNEL_INT_EN \
+ (IMX7D_REG_ADC_INT_CHA_COV_INT_EN | \
+ IMX7D_REG_ADC_INT_CHB_COV_INT_EN | \
+ IMX7D_REG_ADC_INT_CHC_COV_INT_EN | \
+ IMX7D_REG_ADC_INT_CHD_COV_INT_EN)
+#define IMX7D_REG_ADC_INT_STATUS_CHANNEL_INT_STATUS 0xf00
+#define IMX7D_REG_ADC_INT_STATUS_CHANNEL_CONV_TIME_OUT 0xf0000
+
+#define IMX7D_ADC_TIMEOUT_NSEC (100 * NSEC_PER_MSEC)
+#define IMX7D_ADC_INPUT_CLK 24000000
+
+enum imx7d_adc_clk_pre_div {
+ IMX7D_ADC_ANALOG_CLK_PRE_DIV_4,
+ IMX7D_ADC_ANALOG_CLK_PRE_DIV_8,
+ IMX7D_ADC_ANALOG_CLK_PRE_DIV_16,
+ IMX7D_ADC_ANALOG_CLK_PRE_DIV_32,
+ IMX7D_ADC_ANALOG_CLK_PRE_DIV_64,
+ IMX7D_ADC_ANALOG_CLK_PRE_DIV_128,
+};
+
+enum imx7d_adc_average_num {
+ IMX7D_ADC_AVERAGE_NUM_4,
+ IMX7D_ADC_AVERAGE_NUM_8,
+ IMX7D_ADC_AVERAGE_NUM_16,
+ IMX7D_ADC_AVERAGE_NUM_32,
+};
+
+struct imx7d_adc_feature {
+ enum imx7d_adc_clk_pre_div clk_pre_div;
+ enum imx7d_adc_average_num avg_num;
+
+ u32 core_time_unit; /* impact the sample rate */
+};
+
+struct imx7d_adc {
+ struct device_d *dev;
+ void __iomem *regs;
+ struct clk *clk;
+ struct aiodevice aiodev;
+ void (*aiodev_info)(struct device_d *);
+
+ u32 vref_uv;
+ u32 pre_div_num;
+
+ struct regulator *vref;
+ struct imx7d_adc_feature adc_feature;
+
+ struct aiochannel aiochan[16];
+};
+
+struct imx7d_adc_analogue_core_clk {
+ u32 pre_div;
+ u32 reg_config;
+};
+
+#define IMX7D_ADC_ANALOGUE_CLK_CONFIG(_pre_div, _reg_conf) { \
+ .pre_div = (_pre_div), \
+ .reg_config = (_reg_conf), \
+}
+
+static const struct imx7d_adc_analogue_core_clk imx7d_adc_analogue_clk[] = {
+ IMX7D_ADC_ANALOGUE_CLK_CONFIG(4, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_4),
+ IMX7D_ADC_ANALOGUE_CLK_CONFIG(8, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_8),
+ IMX7D_ADC_ANALOGUE_CLK_CONFIG(16, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_16),
+ IMX7D_ADC_ANALOGUE_CLK_CONFIG(32, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_32),
+ IMX7D_ADC_ANALOGUE_CLK_CONFIG(64, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_64),
+ IMX7D_ADC_ANALOGUE_CLK_CONFIG(128, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_128),
+};
+
+static const u32 imx7d_adc_average_num[] = {
+ IMX7D_REG_ADC_CH_CFG2_AVG_NUM_4,
+ IMX7D_REG_ADC_CH_CFG2_AVG_NUM_8,
+ IMX7D_REG_ADC_CH_CFG2_AVG_NUM_16,
+ IMX7D_REG_ADC_CH_CFG2_AVG_NUM_32,
+};
+
+static void imx7d_adc_feature_config(struct imx7d_adc *info)
+{
+ info->adc_feature.clk_pre_div = IMX7D_ADC_ANALOG_CLK_PRE_DIV_4;
+ info->adc_feature.avg_num = IMX7D_ADC_AVERAGE_NUM_32;
+ info->adc_feature.core_time_unit = 1;
+}
+
+static void imx7d_adc_sample_rate_set(struct imx7d_adc *info)
+{
+ struct imx7d_adc_feature *adc_feature = &info->adc_feature;
+ struct imx7d_adc_analogue_core_clk adc_analogure_clk;
+ u32 i;
+ u32 tmp_cfg1;
+ u32 sample_rate = 0;
+
+ /*
+ * Before sample set, disable channel A,B,C,D. Here we
+ * clear the bit 31 of register REG_ADC_CH_A\B\C\D_CFG1.
+ */
+ for (i = 0; i < 4; i++) {
+ tmp_cfg1 =
+ readl(info->regs + i * IMX7D_EACH_CHANNEL_REG_OFFSET);
+ tmp_cfg1 &= ~IMX7D_REG_ADC_CH_CFG1_CHANNEL_EN;
+ writel(tmp_cfg1,
+ info->regs + i * IMX7D_EACH_CHANNEL_REG_OFFSET);
+ }
+
+ adc_analogure_clk = imx7d_adc_analogue_clk[adc_feature->clk_pre_div];
+ sample_rate |= adc_analogure_clk.reg_config;
+ info->pre_div_num = adc_analogure_clk.pre_div;
+
+ sample_rate |= adc_feature->core_time_unit;
+ writel(sample_rate, info->regs + IMX7D_REG_ADC_TIMER_UNIT);
+}
+
+static void imx7d_adc_hw_init(struct imx7d_adc *info)
+{
+ u32 cfg;
+
+ /* power up and enable adc analogue core */
+ cfg = readl(info->regs + IMX7D_REG_ADC_ADC_CFG);
+ cfg &= ~(IMX7D_REG_ADC_ADC_CFG_ADC_CLK_DOWN |
+ IMX7D_REG_ADC_ADC_CFG_ADC_POWER_DOWN);
+ cfg |= IMX7D_REG_ADC_ADC_CFG_ADC_EN;
+ writel(cfg, info->regs + IMX7D_REG_ADC_ADC_CFG);
+
+#if 0
+ /* enable channel A,B,C,D interrupt */
+ writel(IMX7D_REG_ADC_INT_CHANNEL_INT_EN,
+ info->regs + IMX7D_REG_ADC_INT_SIG_EN);
+ writel(IMX7D_REG_ADC_INT_CHANNEL_INT_EN,
+ info->regs + IMX7D_REG_ADC_INT_EN);
+#endif
+
+ imx7d_adc_sample_rate_set(info);
+}
+
+static void imx7d_adc_channel_set(struct imx7d_adc *info, u32 channel)
+{
+ u32 cfg1 = 0;
+ u32 cfg2;
+
+ /* the channel choose single conversion, and enable average mode */
+ cfg1 |= (IMX7D_REG_ADC_CH_CFG1_CHANNEL_EN |
+ IMX7D_REG_ADC_CH_CFG1_CHANNEL_SINGLE |
+ IMX7D_REG_ADC_CH_CFG1_CHANNEL_AVG_EN);
+
+ /*
+ * physical channel 0 chose logical channel A
+ * physical channel 1 chose logical channel B
+ * physical channel 2 chose logical channel C
+ * physical channel 3 chose logical channel D
+ */
+ cfg1 |= IMX7D_REG_ADC_CH_CFG1_CHANNEL_SEL(channel);
+
+ /*
+ * read register REG_ADC_CH_A\B\C\D_CFG2, according to the
+ * channel chosen
+ */
+ cfg2 = readl(info->regs + IMX7D_EACH_CHANNEL_REG_OFFSET * channel +
+ IMX7D_REG_ADC_CHANNEL_CFG2_BASE);
+
+ cfg2 |= imx7d_adc_average_num[info->adc_feature.avg_num];
+
+ /*
+ * write the register REG_ADC_CH_A\B\C\D_CFG2, according to
+ * the channel chosen
+ */
+ writel(cfg2, info->regs + IMX7D_EACH_CHANNEL_REG_OFFSET * channel +
+ IMX7D_REG_ADC_CHANNEL_CFG2_BASE);
+ writel(cfg1, info->regs + IMX7D_EACH_CHANNEL_REG_OFFSET * channel);
+}
+
+static u16 imx7d_adc_read_data(struct imx7d_adc *info, u32 channel)
+{
+ u32 value;
+
+ /*
+ * channel A and B conversion result share one register,
+ * bit[27~16] is the channel B conversion result,
+ * bit[11~0] is the channel A conversion result.
+ * channel C and D is the same.
+ */
+ if (channel < 2)
+ value = readl(info->regs + IMX7D_REG_ADC_CHA_B_CNV_RSLT);
+ else
+ value = readl(info->regs + IMX7D_REG_ADC_CHC_D_CNV_RSLT);
+ if (channel & 0x1) /* channel B or D */
+ value = (value >> 16) & 0xFFF;
+ else /* channel A or C */
+ value &= 0xFFF;
+
+ return value;
+}
+
+static int imx7d_adc_isr(struct imx7d_adc *info, u32 channel)
+{
+ int ret = -EAGAIN;
+ int status;
+
+ status = readl(info->regs + IMX7D_REG_ADC_INT_STATUS);
+ if (status & IMX7D_REG_ADC_INT_STATUS_CHANNEL_INT_STATUS) {
+ ret = imx7d_adc_read_data(info, channel);
+
+ /*
+ * The register IMX7D_REG_ADC_INT_STATUS can't clear
+ * itself after read operation, need software to write
+ * 0 to the related bit. Here we clear the channel A/B/C/D
+ * conversion finished flag.
+ */
+ status &= ~IMX7D_REG_ADC_INT_STATUS_CHANNEL_INT_STATUS;
+ writel(status, info->regs + IMX7D_REG_ADC_INT_STATUS);
+ }
+
+ /*
+ * If the channel A/B/C/D conversion timeout, report it and clear these
+ * timeout flags.
+ */
+ if (status & IMX7D_REG_ADC_INT_STATUS_CHANNEL_CONV_TIME_OUT) {
+ dev_err(info->dev,
+ "ADC got conversion time out interrupt: 0x%08x\n",
+ status);
+ status &= ~IMX7D_REG_ADC_INT_STATUS_CHANNEL_CONV_TIME_OUT;
+ writel(status, info->regs + IMX7D_REG_ADC_INT_STATUS);
+ ret = -ETIMEDOUT;
+ }
+
+ return ret;
+}
+
+
+static int imx7d_adc_read_raw(struct aiochannel *chan, int *data)
+{
+ struct imx7d_adc *info = container_of(chan->aiodev, struct imx7d_adc, aiodev);
+ u64 raw64, start;
+ u32 channel;
+ int ret;
+
+ channel = chan->index & 0x03;
+ imx7d_adc_channel_set(info, channel);
+
+ start = get_time_ns();
+ do {
+ if (is_timeout(start, IMX7D_ADC_TIMEOUT_NSEC)) {
+ ret = -ETIMEDOUT;
+ break;
+ }
+
+ ret = imx7d_adc_isr(info, channel);
+ } while (ret == -EAGAIN);
+
+ if (ret < 0)
+ return ret;
+
+ raw64 = ret;
+ raw64 *= info->vref_uv;
+ raw64 = div_u64(raw64, 1000);
+ *data = div_u64(raw64, (1 << 12));
+
+ return 0;
+}
+
+static const struct of_device_id imx7d_adc_match[] = {
+ { .compatible = "fsl,imx7d-adc", },
+ { /* sentinel */ }
+};
+
+static void imx7d_adc_power_down(struct imx7d_adc *info)
+{
+ u32 adc_cfg;
+
+ adc_cfg = readl(info->regs + IMX7D_REG_ADC_ADC_CFG);
+ adc_cfg |= IMX7D_REG_ADC_ADC_CFG_ADC_CLK_DOWN |
+ IMX7D_REG_ADC_ADC_CFG_ADC_POWER_DOWN;
+ adc_cfg &= ~IMX7D_REG_ADC_ADC_CFG_ADC_EN;
+ writel(adc_cfg, info->regs + IMX7D_REG_ADC_ADC_CFG);
+}
+
+static int imx7d_adc_enable(struct imx7d_adc *info)
+{
+ struct device_d *dev = info->dev;
+ int ret;
+
+ ret = regulator_enable(info->vref);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Can't enable adc reference top voltage\n");
+
+ ret = clk_enable(info->clk);
+ if (ret) {
+ regulator_disable(info->vref);
+ return dev_err_probe(dev, ret, "Could not enable clock.\n");
+ }
+
+ imx7d_adc_hw_init(info);
+
+ ret = regulator_get_voltage(info->vref);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "can't get vref-supply value\n");
+
+ info->vref_uv = ret;
+ return 0;
+}
+
+static u32 imx7d_adc_get_sample_rate(struct imx7d_adc *info)
+{
+ u32 analogue_core_clk;
+ u32 core_time_unit = info->adc_feature.core_time_unit;
+ u32 tmp;
+
+ analogue_core_clk = IMX7D_ADC_INPUT_CLK / info->pre_div_num;
+ tmp = (core_time_unit + 1) * 6;
+
+ return analogue_core_clk / tmp;
+}
+
+static void imx7d_adc_devinfo(struct device_d *dev)
+{
+ struct imx7d_adc *info = dev->priv;
+
+ if (info->aiodev_info)
+ info->aiodev_info(dev);
+
+ printf("Sample Rate: %u\n", imx7d_adc_get_sample_rate(info));
+}
+
+static int imx7d_adc_probe(struct device_d *dev)
+{
+ struct aiodevice *aiodev;
+ struct imx7d_adc *info;
+ int ret, i;
+
+ info = xzalloc(sizeof(*info));
+
+ info->dev = dev;
+
+ info->clk = clk_get(dev, "adc");
+ if (IS_ERR(info->clk))
+ return dev_err_probe(dev, PTR_ERR(info->clk), "Failed getting clock\n");
+
+ info->vref = regulator_get(dev, "vref");
+ if (IS_ERR(info->vref))
+ return dev_err_probe(dev, PTR_ERR(info->vref),
+ "Failed getting reference voltage\n");
+
+ info->regs = dev_request_mem_region(dev, 0);
+ if (IS_ERR(info->regs))
+ return dev_err_probe(dev, PTR_ERR(info->regs),
+ "Failed to get memory region\n");
+
+ dev->priv = aiodev = &info->aiodev;
+
+ aiodev->num_channels = 16;
+ aiodev->hwdev = dev;
+ aiodev->read = imx7d_adc_read_raw;
+ aiodev->channels = xmalloc(aiodev->num_channels * sizeof(aiodev->channels[0]));;
+
+ for (i = 0; i < aiodev->num_channels; i++) {
+ aiodev->channels[i] = &info->aiochan[i];
+ info->aiochan[i].unit = "mV";
+ }
+
+ imx7d_adc_feature_config(info);
+
+ ret = imx7d_adc_enable(info);
+ if (ret)
+ return ret;
+
+ ret = aiodevice_register(aiodev);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to register aiodev\n");
+
+ info->aiodev_info = aiodev->dev.info;
+ aiodev->dev.info = imx7d_adc_devinfo;
+
+ return 0;
+}
+
+static void imx7d_adc_disable(struct device_d *dev)
+{
+ struct imx7d_adc *info = dev->priv;
+
+ imx7d_adc_power_down(info);
+
+ clk_disable(info->clk);
+ regulator_disable(info->vref);
+}
+
+static struct driver_d imx7d_adc_driver = {
+ .probe = imx7d_adc_probe,
+ .name = "imx7d_adc",
+ .of_compatible = imx7d_adc_match,
+ .remove = imx7d_adc_disable,
+};
+device_platform_driver(imx7d_adc_driver);
+
+MODULE_AUTHOR("Haibo Chen <haibo.chen at freescale.com>");
+MODULE_DESCRIPTION("Freescale IMX7D ADC driver");
+MODULE_LICENSE("GPL v2");
--
2.30.2
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