@@ -1123,6 +1123,16 @@ config SUN4I_GPADC
To compile this driver as a module, choose M here: the module will be
called sun4i-gpadc-iio.
+config SUN20I_GPADC
+ tristate "Support for the Allwinner SoCs GPADC"
+ depends on ARCH_SUNXI || COMPILE_TEST
+ help
+ Say yes here to build support for Allwinner (D1, T113, T507 and R329)
+ SoCs GPADC. This ADC provides up to 16 channels.
+
+ To compile this driver as a module, choose M here: the module will be
+ called sun20i-gpadc-iio.
+
config TI_ADC081C
tristate "Texas Instruments ADC081C/ADC101C/ADC121C family"
depends on I2C
@@ -95,6 +95,7 @@ obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
obj-$(CONFIG_SUN4I_GPADC) += sun4i-gpadc-iio.o
+obj-$(CONFIG_SUN20I_GPADC) += sun20i-gpadc-iio.o
obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
obj-$(CONFIG_STM32_ADC) += stm32-adc.o
obj-$(CONFIG_STM32_DFSDM_CORE) += stm32-dfsdm-core.o
new file mode 100644
@@ -0,0 +1,281 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * GPADC driver for sunxi platforms (D1, T113-S3 and R329)
+ * Copyright (c) 2023 Maksim Kiselev <bigunclemax@gmail.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/reset.h>
+
+#include <linux/iio/iio.h>
+
+#define SUN20I_GPADC_DRIVER_NAME "sun20i-gpadc"
+
+/* Register map definition */
+#define SUN20I_GPADC_SR 0x00
+#define SUN20I_GPADC_CTRL 0x04
+#define SUN20I_GPADC_CS_EN 0x08
+#define SUN20I_GPADC_FIFO_INTC 0x0c
+#define SUN20I_GPADC_FIFO_INTS 0x10
+#define SUN20I_GPADC_FIFO_DATA 0X14
+#define SUN20I_GPADC_CB_DATA 0X18
+#define SUN20I_GPADC_DATAL_INTC 0x20
+#define SUN20I_GPADC_DATAH_INTC 0x24
+#define SUN20I_GPADC_DATA_INTC 0x28
+#define SUN20I_GPADC_DATAL_INTS 0x30
+#define SUN20I_GPADC_DATAH_INTS 0x34
+#define SUN20I_GPADC_DATA_INTS 0x38
+#define SUN20I_GPADC_CH_CMP_DATA(x) (0x40 + (x) * 4)
+#define SUN20I_GPADC_CH_DATA(x) (0x80 + (x) * 4)
+
+#define SUN20I_GPADC_CTRL_ADC_AUTOCALI_EN_MASK BIT(23)
+#define SUN20I_GPADC_CTRL_WORK_MODE_MASK GENMASK(19, 18)
+#define SUN20I_GPADC_CTRL_ADC_EN_MASK BIT(16)
+#define SUN20I_GPADC_CS_EN_ADC_CH(x) BIT(x)
+#define SUN20I_GPADC_DATA_INTC_CH_DATA_IRQ_EN(x) BIT(x)
+
+#define SUN20I_GPADC_WORK_MODE_SINGLE 0
+
+#define SUN20I_GPADC_MAX_CHANNELS 16
+
+struct sun20i_gpadc_iio {
+ void __iomem *regs;
+ struct completion completion;
+ int last_channel;
+ /*
+ * Lock to protect the device state during a potential concurrent
+ * read access from userspace. Reading a raw value requires a sequence
+ * of register writes, then a wait for a completion callback,
+ * and finally a register read, during which userspace could issue
+ * another read request. This lock protects a read access from
+ * ocurring before another one has finished.
+ */
+ struct mutex lock;
+};
+
+static int sun20i_gpadc_adc_read(struct sun20i_gpadc_iio *info,
+ struct iio_chan_spec const *chan, int *val)
+{
+ u32 ctrl;
+ int ret = IIO_VAL_INT;
+
+ mutex_lock(&info->lock);
+
+ reinit_completion(&info->completion);
+
+ if (info->last_channel != chan->channel) {
+ info->last_channel = chan->channel;
+
+ /* enable the analog input channel */
+ writel(SUN20I_GPADC_CS_EN_ADC_CH(chan->channel),
+ info->regs + SUN20I_GPADC_CS_EN);
+
+ /* enable the data irq for input channel */
+ writel(SUN20I_GPADC_DATA_INTC_CH_DATA_IRQ_EN(chan->channel),
+ info->regs + SUN20I_GPADC_DATA_INTC);
+ }
+
+ /* enable the ADC function */
+ ctrl = readl(info->regs + SUN20I_GPADC_CTRL);
+ ctrl |= FIELD_PREP(SUN20I_GPADC_CTRL_ADC_EN_MASK, 1);
+ writel(ctrl, info->regs + SUN20I_GPADC_CTRL);
+
+ /*
+ * According to the datasheet maximum acquire time(TACQ) can be
+ * (65535+1)/24Mhz and conversion time(CONV_TIME) is always constant
+ * and equal to 14/24Mhz, so (TACQ+CONV_TIME) <= 2.73125ms.
+ * A 10ms delay should be enough to make sure an interrupt occurs in
+ * normal conditions. If it doesn't occur, then there is a timeout.
+ */
+ if (!wait_for_completion_timeout(&info->completion, msecs_to_jiffies(10))) {
+ ret = -ETIMEDOUT;
+ goto err_unlock;
+ }
+
+ /* read the ADC data */
+ *val = readl(info->regs + SUN20I_GPADC_CH_DATA(chan->channel));
+
+err_unlock:
+ mutex_unlock(&info->lock);
+
+ return ret;
+}
+
+static int sun20i_gpadc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct sun20i_gpadc_iio *info = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ return sun20i_gpadc_adc_read(info, chan, val);
+ case IIO_CHAN_INFO_SCALE:
+ /* value in mv = 1800mV / 4096 raw */
+ *val = 1800;
+ *val2 = 12;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static irqreturn_t sun20i_gpadc_irq_handler(int irq, void *data)
+{
+ struct sun20i_gpadc_iio *info = data;
+
+ /* clear data interrupt status register */
+ writel(GENMASK(31, 0), info->regs + SUN20I_GPADC_DATA_INTS);
+
+ complete(&info->completion);
+
+ return IRQ_HANDLED;
+}
+
+static const struct iio_info sun20i_gpadc_iio_info = {
+ .read_raw = sun20i_gpadc_read_raw,
+};
+
+static void sun20i_gpadc_reset_assert(void *data)
+{
+ struct reset_control *rst = data;
+
+ reset_control_assert(rst);
+}
+
+static int sun20i_gpadc_alloc_channels(struct iio_dev *indio_dev,
+ struct device *dev)
+{
+ unsigned int channel;
+ int num_channels, i, ret;
+ struct iio_chan_spec *channels;
+ struct fwnode_handle *node;
+
+ num_channels = device_get_child_node_count(dev);
+ if (num_channels == 0)
+ return dev_err_probe(dev, -ENODEV, "no channel children\n");
+
+ if (num_channels > SUN20I_GPADC_MAX_CHANNELS)
+ return dev_err_probe(dev, -EINVAL, "num of channel children out of range\n");
+
+ channels = devm_kcalloc(dev, num_channels, sizeof(*channels),
+ GFP_KERNEL);
+ if (!channels)
+ return -ENOMEM;
+
+ i = 0;
+ device_for_each_child_node(dev, node) {
+ ret = fwnode_property_read_u32(node, "reg", &channel);
+ if (ret) {
+ fwnode_handle_put(node);
+ return dev_err_probe(dev, ret, "invalid channel number\n");
+ }
+
+ channels[i].type = IIO_VOLTAGE;
+ channels[i].indexed = 1;
+ channels[i].channel = channel;
+ channels[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+ channels[i].info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
+
+ i++;
+ }
+
+ indio_dev->channels = channels;
+ indio_dev->num_channels = num_channels;
+
+ return 0;
+}
+
+static int sun20i_gpadc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct iio_dev *indio_dev;
+ struct sun20i_gpadc_iio *info;
+ struct reset_control *rst;
+ struct clk *clk;
+ int irq;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*info));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ info = iio_priv(indio_dev);
+ info->last_channel = -1;
+
+ mutex_init(&info->lock);
+ init_completion(&info->completion);
+
+ ret = sun20i_gpadc_alloc_channels(indio_dev, dev);
+ if (ret)
+ return ret;
+
+ indio_dev->info = &sun20i_gpadc_iio_info;
+ indio_dev->name = SUN20I_GPADC_DRIVER_NAME;
+
+ info->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(info->regs))
+ return PTR_ERR(info->regs);
+
+ clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(clk))
+ return dev_err_probe(dev, PTR_ERR(clk), "failed to enable bus clock\n");
+
+ rst = devm_reset_control_get_exclusive(dev, NULL);
+ if (IS_ERR(rst))
+ return dev_err_probe(dev, PTR_ERR(rst), "failed to get reset control\n");
+
+ ret = reset_control_deassert(rst);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to deassert reset\n");
+
+ ret = devm_add_action_or_reset(dev, sun20i_gpadc_reset_assert, rst);
+ if (ret)
+ return ret;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ ret = devm_request_irq(dev, irq, sun20i_gpadc_irq_handler, 0,
+ dev_name(dev), info);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed requesting irq %d\n", irq);
+
+ writel(FIELD_PREP(SUN20I_GPADC_CTRL_ADC_AUTOCALI_EN_MASK, 1) |
+ FIELD_PREP(SUN20I_GPADC_CTRL_WORK_MODE_MASK, SUN20I_GPADC_WORK_MODE_SINGLE),
+ info->regs + SUN20I_GPADC_CTRL);
+
+ ret = devm_iio_device_register(dev, indio_dev);
+ if (ret)
+ return dev_err_probe(dev, ret, "could not register the device\n");
+
+ return 0;
+}
+
+static const struct of_device_id sun20i_gpadc_of_id[] = {
+ { .compatible = "allwinner,sun20i-d1-gpadc" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sun20i_gpadc_of_id);
+
+static struct platform_driver sun20i_gpadc_driver = {
+ .driver = {
+ .name = SUN20I_GPADC_DRIVER_NAME,
+ .of_match_table = sun20i_gpadc_of_id,
+ },
+ .probe = sun20i_gpadc_probe,
+};
+module_platform_driver(sun20i_gpadc_driver);
+
+MODULE_DESCRIPTION("ADC driver for sunxi platforms");
+MODULE_AUTHOR("Maksim Kiselev <bigunclemax@gmail.com>");
+MODULE_LICENSE("GPL");