diff options
Diffstat (limited to 'drivers/iio/adc/sun4i-gpadc-iio.c')
| -rw-r--r-- | drivers/iio/adc/sun4i-gpadc-iio.c | 613 |
1 files changed, 613 insertions, 0 deletions
diff --git a/drivers/iio/adc/sun4i-gpadc-iio.c b/drivers/iio/adc/sun4i-gpadc-iio.c new file mode 100644 index 000000000000..a8e134fa190d --- /dev/null +++ b/drivers/iio/adc/sun4i-gpadc-iio.c @@ -0,0 +1,613 @@ +/* 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"); |