[PATCH] aiodev: port Linux imx7d-adc driver
Ahmad Fatoum
a.fatoum at pengutronix.de
Mon Oct 24 02:56:12 PDT 2022
The i.MX7 has two ADCs of 4 logical 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>
---
v1 -> v2:
- squash fixup for functional devinfo/driver removal
- remove unused macro definitions (Sascha)
- define IMX7D_REG_ADC_CFG1/2(ch) instead of opencoded arithmetic
(Sascha)
- reduce (logical) channel count to 4 from 16 (Sascha)
- use xzalloc for channels instead of xmalloc (Sascha)
- rename original ISR function for readability (Sascha)
- u32 i -> unsigned i (Sascha)
---
drivers/aiodev/Kconfig | 8 +
drivers/aiodev/Makefile | 1 +
drivers/aiodev/imx7d_adc.c | 431 +++++++++++++++++++++++++++++++++++++
3 files changed, 440 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..21cb06368695
--- /dev/null
+++ b/drivers/aiodev/imx7d_adc.c
@@ -0,0 +1,431 @@
+// 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_TIMER_UNIT 0x90
+#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_ADC_CFG 0x130
+
+#define IMX7D_REG_ADC_CFG1(ch) ((ch) * 0x20)
+#define IMX7D_REG_ADC_CFG2(ch) ((ch) * 0x20 + 0x10)
+
+#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_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_analogue_clk;
+ unsigned 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 + IMX7D_REG_ADC_CFG1(i));
+ tmp_cfg1 &= ~IMX7D_REG_ADC_CH_CFG1_CHANNEL_EN;
+ writel(tmp_cfg1, info->regs + IMX7D_REG_ADC_CFG1(i));
+ }
+
+ adc_analogue_clk = imx7d_adc_analogue_clk[adc_feature->clk_pre_div];
+ sample_rate |= adc_analogue_clk.reg_config;
+ info->pre_div_num = adc_analogue_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);
+
+ 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_REG_ADC_CFG2(channel));
+
+ 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_REG_ADC_CFG2(channel));
+ writel(cfg1, info->regs + IMX7D_REG_ADC_CFG1(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_read_data(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_read_data(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->parent->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 = info;
+ aiodev = &info->aiodev;
+
+ aiodev->num_channels = 4;
+ aiodev->hwdev = dev;
+ aiodev->read = imx7d_adc_read_raw;
+ aiodev->channels = xzalloc(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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