--- /dev/null
+/* ADC driver for sunxi platforms' (A10, A13 and A31) GPADC
+ *
+ * Copyright (c) 2016 Quentin Schulz <quentin.schulz@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation.
+ *
+ * The Allwinner SoCs all have an ADC that can also act as a touchscreen
+ * controller and a thermal sensor.
+ * The thermal sensor works only when the ADC acts as a touchscreen controller
+ * and is configured to throw an interrupt every fixed periods of time (let say
+ * every X seconds).
+ * One would be tempted to disable the IP on the hardware side rather than
+ * disabling interrupts to save some power but that resets the internal clock of
+ * the IP, resulting in having to wait X seconds every time we want to read the
+ * value of the thermal sensor.
+ * This is also the reason of using autosuspend in pm_runtime. If there was no
+ * autosuspend, the thermal sensor would need X seconds after every
+ * pm_runtime_get_sync to get a value from the ADC. The autosuspend allows the
+ * thermal sensor to be requested again in a certain time span before it gets
+ * shutdown for not being used.
+ */
+
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/thermal.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/iio/machine.h>
+#include <linux/mfd/sun4i-gpadc.h>
+
+static unsigned int sun4i_gpadc_chan_select(unsigned int chan)
+{
+ return SUN4I_GPADC_CTRL1_ADC_CHAN_SELECT(chan);
+}
+
+static unsigned int sun6i_gpadc_chan_select(unsigned int chan)
+{
+ return SUN6I_GPADC_CTRL1_ADC_CHAN_SELECT(chan);
+}
+
+struct gpadc_data {
+ int temp_offset;
+ int temp_scale;
+ unsigned int tp_mode_en;
+ unsigned int tp_adc_select;
+ unsigned int (*adc_chan_select)(unsigned int chan);
+ unsigned int adc_chan_mask;
+};
+
+static const struct gpadc_data sun4i_gpadc_data = {
+ .temp_offset = -1932,
+ .temp_scale = 133,
+ .tp_mode_en = SUN4I_GPADC_CTRL1_TP_MODE_EN,
+ .tp_adc_select = SUN4I_GPADC_CTRL1_TP_ADC_SELECT,
+ .adc_chan_select = &sun4i_gpadc_chan_select,
+ .adc_chan_mask = SUN4I_GPADC_CTRL1_ADC_CHAN_MASK,
+};
+
+static const struct gpadc_data sun5i_gpadc_data = {
+ .temp_offset = -1447,
+ .temp_scale = 100,
+ .tp_mode_en = SUN4I_GPADC_CTRL1_TP_MODE_EN,
+ .tp_adc_select = SUN4I_GPADC_CTRL1_TP_ADC_SELECT,
+ .adc_chan_select = &sun4i_gpadc_chan_select,
+ .adc_chan_mask = SUN4I_GPADC_CTRL1_ADC_CHAN_MASK,
+};
+
+static const struct gpadc_data sun6i_gpadc_data = {
+ .temp_offset = -1623,
+ .temp_scale = 167,
+ .tp_mode_en = SUN6I_GPADC_CTRL1_TP_MODE_EN,
+ .tp_adc_select = SUN6I_GPADC_CTRL1_TP_ADC_SELECT,
+ .adc_chan_select = &sun6i_gpadc_chan_select,
+ .adc_chan_mask = SUN6I_GPADC_CTRL1_ADC_CHAN_MASK,
+};
+
+struct sun4i_gpadc_iio {
+ struct iio_dev *indio_dev;
+ struct completion completion;
+ int temp_data;
+ u32 adc_data;
+ struct regmap *regmap;
+ unsigned int fifo_data_irq;
+ atomic_t ignore_fifo_data_irq;
+ unsigned int temp_data_irq;
+ atomic_t ignore_temp_data_irq;
+ const struct gpadc_data *data;
+ /* prevents concurrent reads of temperature and ADC */
+ struct mutex mutex;
+};
+
+#define SUN4I_GPADC_ADC_CHANNEL(_channel, _name) { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = _channel, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .datasheet_name = _name, \
+}
+
+static struct iio_map sun4i_gpadc_hwmon_maps[] = {
+ {
+ .adc_channel_label = "temp_adc",
+ .consumer_dev_name = "iio_hwmon.0",
+ },
+ { /* sentinel */ },
+};
+
+static const struct iio_chan_spec sun4i_gpadc_channels[] = {
+ SUN4I_GPADC_ADC_CHANNEL(0, "adc_chan0"),
+ SUN4I_GPADC_ADC_CHANNEL(1, "adc_chan1"),
+ SUN4I_GPADC_ADC_CHANNEL(2, "adc_chan2"),
+ SUN4I_GPADC_ADC_CHANNEL(3, "adc_chan3"),
+ {
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_OFFSET),
+ .datasheet_name = "temp_adc",
+ },
+};
+
+static const struct iio_chan_spec sun4i_gpadc_channels_no_temp[] = {
+ SUN4I_GPADC_ADC_CHANNEL(0, "adc_chan0"),
+ SUN4I_GPADC_ADC_CHANNEL(1, "adc_chan1"),
+ SUN4I_GPADC_ADC_CHANNEL(2, "adc_chan2"),
+ SUN4I_GPADC_ADC_CHANNEL(3, "adc_chan3"),
+};
+
+static int sun4i_prepare_for_irq(struct iio_dev *indio_dev, int channel,
+ unsigned int irq)
+{
+ struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
+ int ret;
+ u32 reg;
+
+ pm_runtime_get_sync(indio_dev->dev.parent);
+
+ reinit_completion(&info->completion);
+
+ ret = regmap_write(info->regmap, SUN4I_GPADC_INT_FIFOC,
+ SUN4I_GPADC_INT_FIFOC_TP_FIFO_TRIG_LEVEL(1) |
+ SUN4I_GPADC_INT_FIFOC_TP_FIFO_FLUSH);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(info->regmap, SUN4I_GPADC_CTRL1, ®);
+ if (ret)
+ return ret;
+
+ if (irq == info->fifo_data_irq) {
+ ret = regmap_write(info->regmap, SUN4I_GPADC_CTRL1,
+ info->data->tp_mode_en |
+ info->data->tp_adc_select |
+ info->data->adc_chan_select(channel));
+ /*
+ * When the IP changes channel, it needs a bit of time to get
+ * correct values.
+ */
+ if ((reg & info->data->adc_chan_mask) !=
+ info->data->adc_chan_select(channel))
+ mdelay(10);
+
+ } else {
+ /*
+ * The temperature sensor returns valid data only when the ADC
+ * operates in touchscreen mode.
+ */
+ ret = regmap_write(info->regmap, SUN4I_GPADC_CTRL1,
+ info->data->tp_mode_en);
+ }
+
+ if (ret)
+ return ret;
+
+ /*
+ * When the IP changes mode between ADC or touchscreen, it
+ * needs a bit of time to get correct values.
+ */
+ if ((reg & info->data->tp_adc_select) != info->data->tp_adc_select)
+ mdelay(100);
+
+ return 0;
+}
+
+static int sun4i_gpadc_read(struct iio_dev *indio_dev, int channel, int *val,
+ unsigned int irq)
+{
+ struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
+ int ret;
+
+ mutex_lock(&info->mutex);
+
+ ret = sun4i_prepare_for_irq(indio_dev, channel, irq);
+ if (ret)
+ goto err;
+
+ enable_irq(irq);
+
+ /*
+ * The temperature sensor throws an interruption periodically (currently
+ * set at periods of ~0.6s in sun4i_gpadc_runtime_resume). A 1s delay
+ * makes sure an interruption occurs in normal conditions. If it doesn't
+ * occur, then there is a timeout.
+ */
+ if (!wait_for_completion_timeout(&info->completion,
+ msecs_to_jiffies(1000))) {
+ ret = -ETIMEDOUT;
+ goto err;
+ }
+
+ if (irq == info->fifo_data_irq)
+ *val = info->adc_data;
+ else
+ *val = info->temp_data;
+
+ ret = 0;
+ pm_runtime_mark_last_busy(indio_dev->dev.parent);
+
+err:
+ pm_runtime_put_autosuspend(indio_dev->dev.parent);
+ mutex_unlock(&info->mutex);
+
+ return ret;
+}
+
+static int sun4i_gpadc_adc_read(struct iio_dev *indio_dev, int channel,
+ int *val)
+{
+ struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
+
+ return sun4i_gpadc_read(indio_dev, channel, val, info->fifo_data_irq);
+}
+
+static int sun4i_gpadc_temp_read(struct iio_dev *indio_dev, int *val)
+{
+ struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
+
+ return sun4i_gpadc_read(indio_dev, 0, val, info->temp_data_irq);
+}
+
+static int sun4i_gpadc_temp_offset(struct iio_dev *indio_dev, int *val)
+{
+ struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
+
+ *val = info->data->temp_offset;
+
+ return 0;
+}
+
+static int sun4i_gpadc_temp_scale(struct iio_dev *indio_dev, int *val)
+{
+ struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
+
+ *val = info->data->temp_scale;
+
+ return 0;
+}
+
+static int sun4i_gpadc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_OFFSET:
+ ret = sun4i_gpadc_temp_offset(indio_dev, val);
+ if (ret)
+ return ret;
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_RAW:
+ if (chan->type == IIO_VOLTAGE)
+ ret = sun4i_gpadc_adc_read(indio_dev, chan->channel,
+ val);
+ else
+ ret = sun4i_gpadc_temp_read(indio_dev, val);
+
+ if (ret)
+ return ret;
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ if (chan->type == IIO_VOLTAGE) {
+ /* 3000mV / 4096 * raw */
+ *val = 0;
+ *val2 = 732421875;
+ return IIO_VAL_INT_PLUS_NANO;
+ }
+
+ ret = sun4i_gpadc_temp_scale(indio_dev, val);
+ if (ret)
+ return ret;
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info sun4i_gpadc_iio_info = {
+ .read_raw = sun4i_gpadc_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static irqreturn_t sun4i_gpadc_temp_data_irq_handler(int irq, void *dev_id)
+{
+ struct sun4i_gpadc_iio *info = dev_id;
+
+ if (atomic_read(&info->ignore_temp_data_irq))
+ goto out;
+
+ if (!regmap_read(info->regmap, SUN4I_GPADC_TEMP_DATA, &info->temp_data))
+ complete(&info->completion);
+
+out:
+ disable_irq_nosync(info->temp_data_irq);
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t sun4i_gpadc_fifo_data_irq_handler(int irq, void *dev_id)
+{
+ struct sun4i_gpadc_iio *info = dev_id;
+
+ if (atomic_read(&info->ignore_fifo_data_irq))
+ goto out;
+
+ if (!regmap_read(info->regmap, SUN4I_GPADC_DATA, &info->adc_data))
+ complete(&info->completion);
+
+out:
+ disable_irq_nosync(info->fifo_data_irq);
+ return IRQ_HANDLED;
+}
+
+static int sun4i_gpadc_runtime_suspend(struct device *dev)
+{
+ struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
+
+ /* Disable the ADC on IP */
+ regmap_write(info->regmap, SUN4I_GPADC_CTRL1, 0);
+ /* Disable temperature sensor on IP */
+ regmap_write(info->regmap, SUN4I_GPADC_TPR, 0);
+
+ return 0;
+}
+
+static int sun4i_gpadc_runtime_resume(struct device *dev)
+{
+ struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
+
+ /* clkin = 6MHz */
+ regmap_write(info->regmap, SUN4I_GPADC_CTRL0,
+ SUN4I_GPADC_CTRL0_ADC_CLK_DIVIDER(2) |
+ SUN4I_GPADC_CTRL0_FS_DIV(7) |
+ SUN4I_GPADC_CTRL0_T_ACQ(63));
+ regmap_write(info->regmap, SUN4I_GPADC_CTRL1, info->data->tp_mode_en);
+ regmap_write(info->regmap, SUN4I_GPADC_CTRL3,
+ SUN4I_GPADC_CTRL3_FILTER_EN |
+ SUN4I_GPADC_CTRL3_FILTER_TYPE(1));
+ /* period = SUN4I_GPADC_TPR_TEMP_PERIOD * 256 * 16 / clkin; ~0.6s */
+ regmap_write(info->regmap, SUN4I_GPADC_TPR,
+ SUN4I_GPADC_TPR_TEMP_ENABLE |
+ SUN4I_GPADC_TPR_TEMP_PERIOD(800));
+
+ return 0;
+}
+
+static int sun4i_gpadc_get_temp(void *data, int *temp)
+{
+ struct sun4i_gpadc_iio *info = (struct sun4i_gpadc_iio *)data;
+ int val, scale, offset;
+
+ if (sun4i_gpadc_temp_read(info->indio_dev, &val))
+ return -ETIMEDOUT;
+
+ sun4i_gpadc_temp_scale(info->indio_dev, &scale);
+ sun4i_gpadc_temp_offset(info->indio_dev, &offset);
+
+ *temp = (val + offset) * scale;
+
+ return 0;
+}
+
+static const struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
+ .get_temp = &sun4i_gpadc_get_temp,
+};
+
+static const struct dev_pm_ops sun4i_gpadc_pm_ops = {
+ .runtime_suspend = &sun4i_gpadc_runtime_suspend,
+ .runtime_resume = &sun4i_gpadc_runtime_resume,
+};
+
+static int sun4i_irq_init(struct platform_device *pdev, const char *name,
+ irq_handler_t handler, const char *devname,
+ unsigned int *irq, atomic_t *atomic)
+{
+ int ret;
+ struct sun4i_gpadc_dev *mfd_dev = dev_get_drvdata(pdev->dev.parent);
+ struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(&pdev->dev));
+
+ /*
+ * Once the interrupt is activated, the IP continuously performs
+ * conversions thus throws interrupts. The interrupt is activated right
+ * after being requested but we want to control when these interrupts
+ * occur thus we disable it right after being requested. However, an
+ * interrupt might occur between these two instructions and we have to
+ * make sure that does not happen, by using atomic flags. We set the
+ * flag before requesting the interrupt and unset it right after
+ * disabling the interrupt. When an interrupt occurs between these two
+ * instructions, reading the atomic flag will tell us to ignore the
+ * interrupt.
+ */
+ atomic_set(atomic, 1);
+
+ ret = platform_get_irq_byname(pdev, name);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "no %s interrupt registered\n", name);
+ return ret;
+ }
+
+ ret = regmap_irq_get_virq(mfd_dev->regmap_irqc, ret);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to get virq for irq %s\n", name);
+ return ret;
+ }
+
+ *irq = ret;
+ ret = devm_request_any_context_irq(&pdev->dev, *irq, handler, 0,
+ devname, info);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "could not request %s interrupt: %d\n",
+ name, ret);
+ return ret;
+ }
+
+ disable_irq(*irq);
+ atomic_set(atomic, 0);
+
+ return 0;
+}
+
+static int sun4i_gpadc_probe(struct platform_device *pdev)
+{
+ struct sun4i_gpadc_iio *info;
+ struct iio_dev *indio_dev;
+ int ret;
+ struct sun4i_gpadc_dev *sun4i_gpadc_dev;
+
+ sun4i_gpadc_dev = dev_get_drvdata(pdev->dev.parent);
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ info = iio_priv(indio_dev);
+ platform_set_drvdata(pdev, indio_dev);
+
+ mutex_init(&info->mutex);
+ info->regmap = sun4i_gpadc_dev->regmap;
+ info->indio_dev = indio_dev;
+ init_completion(&info->completion);
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->dev.of_node = pdev->dev.of_node;
+ indio_dev->info = &sun4i_gpadc_iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->num_channels = ARRAY_SIZE(sun4i_gpadc_channels);
+ indio_dev->channels = sun4i_gpadc_channels;
+
+ info->data = (struct gpadc_data *)platform_get_device_id(pdev)->driver_data;
+
+ /*
+ * Since the controller needs to be in touchscreen mode for its thermal
+ * sensor to operate properly, and that switching between the two modes
+ * needs a delay, always registering in the thermal framework will
+ * significantly slow down the conversion rate of the ADCs.
+ *
+ * Therefore, instead of depending on THERMAL_OF in Kconfig, we only
+ * register the sensor if that option is enabled, eventually leaving
+ * that choice to the user.
+ */
+
+ if (IS_ENABLED(CONFIG_THERMAL_OF)) {
+ /*
+ * This driver is a child of an MFD which has a node in the DT
+ * but not its children, because of DT backward compatibility
+ * for A10, A13 and A31 SoCs. Therefore, the resulting devices
+ * of this driver do not have an of_node variable.
+ * However, its parent (the MFD driver) has an of_node variable
+ * and since devm_thermal_zone_of_sensor_register uses its first
+ * argument to match the phandle defined in the node of the
+ * thermal driver with the of_node of the device passed as first
+ * argument and the third argument to call ops from
+ * thermal_zone_of_device_ops, the solution is to use the parent
+ * device as first argument to match the phandle with its
+ * of_node, and the device from this driver as third argument to
+ * return the temperature.
+ */
+ struct thermal_zone_device *tzd;
+ tzd = devm_thermal_zone_of_sensor_register(pdev->dev.parent, 0,
+ info,
+ &sun4i_ts_tz_ops);
+ if (IS_ERR(tzd)) {
+ dev_err(&pdev->dev,
+ "could not register thermal sensor: %ld\n",
+ PTR_ERR(tzd));
+ ret = PTR_ERR(tzd);
+ goto err;
+ }
+ } else {
+ indio_dev->num_channels =
+ ARRAY_SIZE(sun4i_gpadc_channels_no_temp);
+ indio_dev->channels = sun4i_gpadc_channels_no_temp;
+ }
+
+ pm_runtime_set_autosuspend_delay(&pdev->dev,
+ SUN4I_GPADC_AUTOSUSPEND_DELAY);
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
+ if (IS_ENABLED(CONFIG_THERMAL_OF)) {
+ ret = sun4i_irq_init(pdev, "TEMP_DATA_PENDING",
+ sun4i_gpadc_temp_data_irq_handler,
+ "temp_data", &info->temp_data_irq,
+ &info->ignore_temp_data_irq);
+ if (ret < 0)
+ goto err;
+ }
+
+ ret = sun4i_irq_init(pdev, "FIFO_DATA_PENDING",
+ sun4i_gpadc_fifo_data_irq_handler, "fifo_data",
+ &info->fifo_data_irq, &info->ignore_fifo_data_irq);
+ if (ret < 0)
+ goto err;
+
+ if (IS_ENABLED(CONFIG_THERMAL_OF)) {
+ ret = iio_map_array_register(indio_dev, sun4i_gpadc_hwmon_maps);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "failed to register iio map array\n");
+ goto err;
+ }
+ }
+
+ ret = devm_iio_device_register(&pdev->dev, indio_dev);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "could not register the device\n");
+ goto err_map;
+ }
+
+ return 0;
+
+err_map:
+ if (IS_ENABLED(CONFIG_THERMAL_OF))
+ iio_map_array_unregister(indio_dev);
+
+err:
+ pm_runtime_put(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
+
+ return ret;
+}
+
+static int sun4i_gpadc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+
+ pm_runtime_put(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
+ if (IS_ENABLED(CONFIG_THERMAL_OF))
+ iio_map_array_unregister(indio_dev);
+
+ return 0;
+}
+
+static const struct platform_device_id sun4i_gpadc_id[] = {
+ { "sun4i-a10-gpadc-iio", (kernel_ulong_t)&sun4i_gpadc_data },
+ { "sun5i-a13-gpadc-iio", (kernel_ulong_t)&sun5i_gpadc_data },
+ { "sun6i-a31-gpadc-iio", (kernel_ulong_t)&sun6i_gpadc_data },
+ { /* sentinel */ },
+};
+
+static struct platform_driver sun4i_gpadc_driver = {
+ .driver = {
+ .name = "sun4i-gpadc-iio",
+ .pm = &sun4i_gpadc_pm_ops,
+ },
+ .id_table = sun4i_gpadc_id,
+ .probe = sun4i_gpadc_probe,
+ .remove = sun4i_gpadc_remove,
+};
+
+module_platform_driver(sun4i_gpadc_driver);
+
+MODULE_DESCRIPTION("ADC driver for sunxi platforms");
+MODULE_AUTHOR("Quentin Schulz <quentin.schulz@free-electrons.com>");
+MODULE_LICENSE("GPL v2");
projects / karo-tx-linux.git / commitdiff