--- /dev/null
+/*
+ * Copyright (c) 2014-2015 Imagination Technologies Ltd.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+/* Registers */
+#define CC10001_ADC_CONFIG 0x00
+#define CC10001_ADC_START_CONV BIT(4)
+#define CC10001_ADC_MODE_SINGLE_CONV BIT(5)
+
+#define CC10001_ADC_DDATA_OUT 0x04
+#define CC10001_ADC_EOC 0x08
+#define CC10001_ADC_EOC_SET BIT(0)
+
+#define CC10001_ADC_CHSEL_SAMPLED 0x0c
+#define CC10001_ADC_POWER_UP 0x10
+#define CC10001_ADC_POWER_UP_SET BIT(0)
+#define CC10001_ADC_DEBUG 0x14
+#define CC10001_ADC_DATA_COUNT 0x20
+
+#define CC10001_ADC_DATA_MASK GENMASK(9, 0)
+#define CC10001_ADC_NUM_CHANNELS 8
+#define CC10001_ADC_CH_MASK GENMASK(2, 0)
+
+#define CC10001_INVALID_SAMPLED 0xffff
+#define CC10001_MAX_POLL_COUNT 20
+
+/*
+ * As per device specification, wait six clock cycles after power-up to
+ * activate START. Since adding two more clock cycles delay does not
+ * impact the performance too much, we are adding two additional cycles delay
+ * intentionally here.
+ */
+#define CC10001_WAIT_CYCLES 8
+
+struct cc10001_adc_device {
+ void __iomem *reg_base;
+ struct clk *adc_clk;
+ struct regulator *reg;
+ u16 *buf;
+
+ struct mutex lock;
+ unsigned long channel_map;
+ unsigned int start_delay_ns;
+ unsigned int eoc_delay_ns;
+};
+
+static inline void cc10001_adc_write_reg(struct cc10001_adc_device *adc_dev,
+ u32 reg, u32 val)
+{
+ writel(val, adc_dev->reg_base + reg);
+}
+
+static inline u32 cc10001_adc_read_reg(struct cc10001_adc_device *adc_dev,
+ u32 reg)
+{
+ return readl(adc_dev->reg_base + reg);
+}
+
+static void cc10001_adc_start(struct cc10001_adc_device *adc_dev,
+ unsigned int channel)
+{
+ u32 val;
+
+ /* Channel selection and mode of operation */
+ val = (channel & CC10001_ADC_CH_MASK) | CC10001_ADC_MODE_SINGLE_CONV;
+ cc10001_adc_write_reg(adc_dev, CC10001_ADC_CONFIG, val);
+
+ val = cc10001_adc_read_reg(adc_dev, CC10001_ADC_CONFIG);
+ val = val | CC10001_ADC_START_CONV;
+ cc10001_adc_write_reg(adc_dev, CC10001_ADC_CONFIG, val);
+}
+
+static u16 cc10001_adc_poll_done(struct iio_dev *indio_dev,
+ unsigned int channel,
+ unsigned int delay)
+{
+ struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
+ unsigned int poll_count = 0;
+
+ while (!(cc10001_adc_read_reg(adc_dev, CC10001_ADC_EOC) &
+ CC10001_ADC_EOC_SET)) {
+
+ ndelay(delay);
+ if (poll_count++ == CC10001_MAX_POLL_COUNT)
+ return CC10001_INVALID_SAMPLED;
+ }
+
+ poll_count = 0;
+ while ((cc10001_adc_read_reg(adc_dev, CC10001_ADC_CHSEL_SAMPLED) &
+ CC10001_ADC_CH_MASK) != channel) {
+
+ ndelay(delay);
+ if (poll_count++ == CC10001_MAX_POLL_COUNT)
+ return CC10001_INVALID_SAMPLED;
+ }
+
+ /* Read the 10 bit output register */
+ return cc10001_adc_read_reg(adc_dev, CC10001_ADC_DDATA_OUT) &
+ CC10001_ADC_DATA_MASK;
+}
+
+static irqreturn_t cc10001_adc_trigger_h(int irq, void *p)
+{
+ struct cc10001_adc_device *adc_dev;
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev;
+ unsigned int delay_ns;
+ unsigned int channel;
+ bool sample_invalid;
+ u16 *data;
+ int i;
+
+ indio_dev = pf->indio_dev;
+ adc_dev = iio_priv(indio_dev);
+ data = adc_dev->buf;
+
+ mutex_lock(&adc_dev->lock);
+
+ cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP,
+ CC10001_ADC_POWER_UP_SET);
+
+ /* Wait for 8 (6+2) clock cycles before activating START */
+ ndelay(adc_dev->start_delay_ns);
+
+ /* Calculate delay step for eoc and sampled data */
+ delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT;
+
+ i = 0;
+ sample_invalid = false;
+ for_each_set_bit(channel, indio_dev->active_scan_mask,
+ indio_dev->masklength) {
+
+ cc10001_adc_start(adc_dev, channel);
+
+ data[i] = cc10001_adc_poll_done(indio_dev, channel, delay_ns);
+ if (data[i] == CC10001_INVALID_SAMPLED) {
+ dev_warn(&indio_dev->dev,
+ "invalid sample on channel %d\n", channel);
+ sample_invalid = true;
+ goto done;
+ }
+ i++;
+ }
+
+done:
+ cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP, 0);
+
+ mutex_unlock(&adc_dev->lock);
+
+ if (!sample_invalid)
+ iio_push_to_buffers_with_timestamp(indio_dev, data,
+ iio_get_time_ns());
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan)
+{
+ struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
+ unsigned int delay_ns;
+ u16 val;
+
+ cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP,
+ CC10001_ADC_POWER_UP_SET);
+
+ /* Wait for 8 (6+2) clock cycles before activating START */
+ ndelay(adc_dev->start_delay_ns);
+
+ /* Calculate delay step for eoc and sampled data */
+ delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT;
+
+ cc10001_adc_start(adc_dev, chan->channel);
+
+ val = cc10001_adc_poll_done(indio_dev, chan->channel, delay_ns);
+
+ cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP, 0);
+
+ return val;
+}
+
+static int cc10001_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (iio_buffer_enabled(indio_dev))
+ return -EBUSY;
+ mutex_lock(&adc_dev->lock);
+ *val = cc10001_adc_read_raw_voltage(indio_dev, chan);
+ mutex_unlock(&adc_dev->lock);
+
+ if (*val == CC10001_INVALID_SAMPLED)
+ return -EIO;
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ ret = regulator_get_voltage(adc_dev->reg);
+ if (ret)
+ return ret;
+
+ *val = ret / 1000;
+ *val2 = chan->scan_type.realbits;
+ return IIO_VAL_FRACTIONAL_LOG2;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int cc10001_update_scan_mode(struct iio_dev *indio_dev,
+ const unsigned long *scan_mask)
+{
+ struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
+
+ kfree(adc_dev->buf);
+ adc_dev->buf = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
+ if (!adc_dev->buf)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static const struct iio_info cc10001_adc_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = &cc10001_adc_read_raw,
+ .update_scan_mode = &cc10001_update_scan_mode,
+};
+
+static int cc10001_adc_channel_init(struct iio_dev *indio_dev)
+{
+ struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
+ struct iio_chan_spec *chan_array, *timestamp;
+ unsigned int bit, idx = 0;
+
+ indio_dev->num_channels = bitmap_weight(&adc_dev->channel_map,
+ CC10001_ADC_NUM_CHANNELS);
+
+ chan_array = devm_kcalloc(&indio_dev->dev, indio_dev->num_channels + 1,
+ sizeof(struct iio_chan_spec),
+ GFP_KERNEL);
+ if (!chan_array)
+ return -ENOMEM;
+
+ for_each_set_bit(bit, &adc_dev->channel_map, CC10001_ADC_NUM_CHANNELS) {
+ struct iio_chan_spec *chan = &chan_array[idx];
+
+ chan->type = IIO_VOLTAGE;
+ chan->indexed = 1;
+ chan->channel = bit;
+ chan->scan_index = idx;
+ chan->scan_type.sign = 'u';
+ chan->scan_type.realbits = 10;
+ chan->scan_type.storagebits = 16;
+ chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
+ chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+ idx++;
+ }
+
+ timestamp = &chan_array[idx];
+ timestamp->type = IIO_TIMESTAMP;
+ timestamp->channel = -1;
+ timestamp->scan_index = idx;
+ timestamp->scan_type.sign = 's';
+ timestamp->scan_type.realbits = 64;
+ timestamp->scan_type.storagebits = 64;
+
+ indio_dev->channels = chan_array;
+
+ return 0;
+}
+
+static int cc10001_adc_probe(struct platform_device *pdev)
+{
+ struct device_node *node = pdev->dev.of_node;
+ struct cc10001_adc_device *adc_dev;
+ unsigned long adc_clk_rate;
+ struct resource *res;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
+ if (indio_dev == NULL)
+ return -ENOMEM;
+
+ adc_dev = iio_priv(indio_dev);
+
+ adc_dev->channel_map = GENMASK(CC10001_ADC_NUM_CHANNELS - 1, 0);
+ if (!of_property_read_u32(node, "adc-reserved-channels", &ret))
+ adc_dev->channel_map &= ~ret;
+
+ adc_dev->reg = devm_regulator_get(&pdev->dev, "vref");
+ if (IS_ERR(adc_dev->reg))
+ return PTR_ERR(adc_dev->reg);
+
+ ret = regulator_enable(adc_dev->reg);
+ if (ret)
+ return ret;
+
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->info = &cc10001_adc_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ adc_dev->reg_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(adc_dev->reg_base)) {
+ ret = PTR_ERR(adc_dev->reg_base);
+ goto err_disable_reg;
+ }
+
+ adc_dev->adc_clk = devm_clk_get(&pdev->dev, "adc");
+ if (IS_ERR(adc_dev->adc_clk)) {
+ dev_err(&pdev->dev, "failed to get the clock\n");
+ ret = PTR_ERR(adc_dev->adc_clk);
+ goto err_disable_reg;
+ }
+
+ ret = clk_prepare_enable(adc_dev->adc_clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable the clock\n");
+ goto err_disable_reg;
+ }
+
+ adc_clk_rate = clk_get_rate(adc_dev->adc_clk);
+ if (!adc_clk_rate) {
+ ret = -EINVAL;
+ dev_err(&pdev->dev, "null clock rate!\n");
+ goto err_disable_clk;
+ }
+
+ adc_dev->eoc_delay_ns = NSEC_PER_SEC / adc_clk_rate;
+ adc_dev->start_delay_ns = adc_dev->eoc_delay_ns * CC10001_WAIT_CYCLES;
+
+ /* Setup the ADC channels available on the device */
+ ret = cc10001_adc_channel_init(indio_dev);
+ if (ret < 0)
+ goto err_disable_clk;
+
+ mutex_init(&adc_dev->lock);
+
+ ret = iio_triggered_buffer_setup(indio_dev, NULL,
+ &cc10001_adc_trigger_h, NULL);
+ if (ret < 0)
+ goto err_disable_clk;
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0)
+ goto err_cleanup_buffer;
+
+ platform_set_drvdata(pdev, indio_dev);
+
+ return 0;
+
+err_cleanup_buffer:
+ iio_triggered_buffer_cleanup(indio_dev);
+err_disable_clk:
+ clk_disable_unprepare(adc_dev->adc_clk);
+err_disable_reg:
+ regulator_disable(adc_dev->reg);
+ return ret;
+}
+
+static int cc10001_adc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ iio_triggered_buffer_cleanup(indio_dev);
+ clk_disable_unprepare(adc_dev->adc_clk);
+ regulator_disable(adc_dev->reg);
+
+ return 0;
+}
+
+static const struct of_device_id cc10001_adc_dt_ids[] = {
+ { .compatible = "cosmic,10001-adc", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, cc10001_adc_dt_ids);
+
+static struct platform_driver cc10001_adc_driver = {
+ .driver = {
+ .name = "cc10001-adc",
+ .of_match_table = cc10001_adc_dt_ids,
+ },
+ .probe = cc10001_adc_probe,
+ .remove = cc10001_adc_remove,
+};
+module_platform_driver(cc10001_adc_driver);
+
+MODULE_AUTHOR("Phani Movva <Phani.Movva@imgtec.com>");
+MODULE_DESCRIPTION("Cosmic Circuits ADC driver");
+MODULE_LICENSE("GPL v2");
projects / GitHub / exynos8895 / android_kernel_samsung_universal8895.git / commitdiff