--- /dev/null
+/*
+ * Freescale i.MX28 LRADC driver
+ *
+ * Copyright (c) 2012 DENX Software Engineering, GmbH.
+ * Marek Vasut <marex@denx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/stmp_device.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+
+#include <mach/mxs.h>
+#include <mach/common.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define DRIVER_NAME "mxs-lradc"
+
+#define LRADC_MAX_DELAY_CHANS 4
+#define LRADC_MAX_MAPPED_CHANS 8
+#define LRADC_MAX_TOTAL_CHANS 16
+
+#define LRADC_DELAY_TIMER_HZ 2000
+
+/*
+ * Make this runtime configurable if necessary. Currently, if the buffered mode
+ * is enabled, the LRADC takes LRADC_DELAY_TIMER_LOOP samples of data before
+ * triggering IRQ. The sampling happens every (LRADC_DELAY_TIMER_PER / 2000)
+ * seconds. The result is that the samples arrive every 500mS.
+ */
+#define LRADC_DELAY_TIMER_PER 200
+#define LRADC_DELAY_TIMER_LOOP 5
+
+static const char * const mxs_lradc_irq_name[] = {
+ "mxs-lradc-touchscreen",
+ "mxs-lradc-thresh0",
+ "mxs-lradc-thresh1",
+ "mxs-lradc-channel0",
+ "mxs-lradc-channel1",
+ "mxs-lradc-channel2",
+ "mxs-lradc-channel3",
+ "mxs-lradc-channel4",
+ "mxs-lradc-channel5",
+ "mxs-lradc-channel6",
+ "mxs-lradc-channel7",
+ "mxs-lradc-button0",
+ "mxs-lradc-button1",
+};
+
+struct mxs_lradc_chan {
+ uint8_t slot;
+ uint8_t flags;
+};
+
+struct mxs_lradc {
+ struct device *dev;
+ void __iomem *base;
+ int irq[13];
+
+ uint32_t *buffer;
+ struct iio_trigger *trig;
+
+ struct mutex lock;
+
+ uint8_t enable;
+
+ struct completion completion;
+};
+
+#define LRADC_CTRL0 0x00
+#define LRADC_CTRL0_TOUCH_DETECT_ENABLE (1 << 23)
+#define LRADC_CTRL0_TOUCH_SCREEN_TYPE (1 << 22)
+
+#define LRADC_CTRL1 0x10
+#define LRADC_CTRL1_LRADC_IRQ(n) (1 << (n))
+#define LRADC_CTRL1_LRADC_IRQ_MASK 0x1fff
+#define LRADC_CTRL1_LRADC_IRQ_EN(n) (1 << ((n) + 16))
+#define LRADC_CTRL1_LRADC_IRQ_EN_MASK (0x1fff << 16)
+
+#define LRADC_CTRL2 0x20
+#define LRADC_CTRL2_TEMPSENSE_PWD (1 << 15)
+
+#define LRADC_CH(n) (0x50 + (0x10 * (n)))
+#define LRADC_CH_ACCUMULATE (1 << 29)
+#define LRADC_CH_NUM_SAMPLES_MASK (0x1f << 24)
+#define LRADC_CH_NUM_SAMPLES_OFFSET 24
+#define LRADC_CH_VALUE_MASK 0x3ffff
+#define LRADC_CH_VALUE_OFFSET 0
+
+#define LRADC_DELAY(n) (0xd0 + (0x10 * (n)))
+#define LRADC_DELAY_TRIGGER_LRADCS_MASK (0xff << 24)
+#define LRADC_DELAY_TRIGGER_LRADCS_OFFSET 24
+#define LRADC_DELAY_KICK (1 << 20)
+#define LRADC_DELAY_TRIGGER_DELAYS_MASK (0xf << 16)
+#define LRADC_DELAY_TRIGGER_DELAYS_OFFSET 16
+#define LRADC_DELAY_LOOP_COUNT_MASK (0x1f << 11)
+#define LRADC_DELAY_LOOP_COUNT_OFFSET 11
+#define LRADC_DELAY_DELAY_MASK 0x7ff
+#define LRADC_DELAY_DELAY_OFFSET 0
+
+#define LRADC_CTRL4 0x140
+#define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
+#define LRADC_CTRL4_LRADCSELECT_OFFSET(n) ((n) * 4)
+
+/*
+ * Raw I/O operations
+ */
+static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
+ const struct iio_chan_spec *chan,
+ int *val, int *val2, long m)
+{
+ struct mxs_lradc *lradc = iio_priv(iio_dev);
+ int ret;
+
+ if (m != IIO_CHAN_INFO_RAW)
+ return -EINVAL;
+
+ /* Check for invalid channel */
+ if (chan->channel > LRADC_MAX_TOTAL_CHANS)
+ return -EINVAL;
+
+ /*
+ * See if there is no buffered operation in progess. If there is, simply
+ * bail out. This can be improved to support both buffered and raw IO at
+ * the same time, yet the code becomes horribly complicated. Therefore I
+ * applied KISS principle here.
+ */
+ ret = mutex_trylock(&lradc->lock);
+ if (!ret)
+ return -EBUSY;
+
+ INIT_COMPLETION(lradc->completion);
+
+ /*
+ * No buffered operation in progress, map the channel and trigger it.
+ * Virtual channel 0 is always used here as the others are always not
+ * used if doing raw sampling.
+ */
+ writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
+ lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+ writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
+
+ writel(chan->channel, lradc->base + LRADC_CTRL4);
+ writel(0, lradc->base + LRADC_CH(0));
+
+ /* Enable the IRQ and start sampling the channel. */
+ writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
+ lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
+ writel(1 << 0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
+
+ /* Wait for completion on the channel, 1 second max. */
+ ret = wait_for_completion_killable_timeout(&lradc->completion, HZ);
+ if (!ret)
+ ret = -ETIMEDOUT;
+ if (ret < 0)
+ goto err;
+
+ /* Read the data. */
+ *val = readl(lradc->base + LRADC_CH(0)) & LRADC_CH_VALUE_MASK;
+ ret = IIO_VAL_INT;
+
+err:
+ writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
+ lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+
+ mutex_unlock(&lradc->lock);
+
+ return ret;
+}
+
+static const struct iio_info mxs_lradc_iio_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = mxs_lradc_read_raw,
+};
+
+/*
+ * IRQ Handling
+ */
+static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
+{
+ struct iio_dev *iio = data;
+ struct mxs_lradc *lradc = iio_priv(iio);
+ unsigned long reg = readl(lradc->base + LRADC_CTRL1);
+
+ if (!(reg & LRADC_CTRL1_LRADC_IRQ_MASK))
+ return IRQ_NONE;
+
+ /*
+ * Touchscreen IRQ handling code shall probably have priority
+ * and therefore shall be placed here.
+ */
+
+ if (iio_buffer_enabled(iio))
+ iio_trigger_poll(iio->trig, iio_get_time_ns());
+ else if (reg & LRADC_CTRL1_LRADC_IRQ(0))
+ complete(&lradc->completion);
+
+ writel(reg & LRADC_CTRL1_LRADC_IRQ_MASK,
+ lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * Trigger handling
+ */
+static irqreturn_t mxs_lradc_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *iio = pf->indio_dev;
+ struct mxs_lradc *lradc = iio_priv(iio);
+ struct iio_buffer *buffer = iio->buffer;
+ const uint32_t chan_value = LRADC_CH_ACCUMULATE |
+ ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
+ int i, j = 0;
+
+ for_each_set_bit(i, iio->active_scan_mask, iio->masklength) {
+ lradc->buffer[j] = readl(lradc->base + LRADC_CH(j));
+ writel(chan_value, lradc->base + LRADC_CH(j));
+ lradc->buffer[j] &= LRADC_CH_VALUE_MASK;
+ lradc->buffer[j] /= LRADC_DELAY_TIMER_LOOP;
+ j++;
+ }
+
+ if (iio->scan_timestamp) {
+ s64 *timestamp = (s64 *)((u8 *)lradc->buffer +
+ ALIGN(j, sizeof(s64)));
+ *timestamp = pf->timestamp;
+ }
+
+ iio_push_to_buffer(buffer, (u8 *)lradc->buffer, pf->timestamp);
+
+ iio_trigger_notify_done(iio->trig);
+
+ return IRQ_HANDLED;
+}
+
+static int mxs_lradc_configure_trigger(struct iio_trigger *trig, bool state)
+{
+ struct iio_dev *iio = trig->private_data;
+ struct mxs_lradc *lradc = iio_priv(iio);
+ const uint32_t st = state ? STMP_OFFSET_REG_SET : STMP_OFFSET_REG_CLR;
+
+ writel(LRADC_DELAY_KICK, lradc->base + LRADC_DELAY(0) + st);
+
+ return 0;
+}
+
+static const struct iio_trigger_ops mxs_lradc_trigger_ops = {
+ .owner = THIS_MODULE,
+ .set_trigger_state = &mxs_lradc_configure_trigger,
+};
+
+static int mxs_lradc_trigger_init(struct iio_dev *iio)
+{
+ int ret;
+ struct iio_trigger *trig;
+
+ trig = iio_trigger_alloc("%s-dev%i", iio->name, iio->id);
+ if (trig == NULL)
+ return -ENOMEM;
+
+ trig->dev.parent = iio->dev.parent;
+ trig->private_data = iio;
+ trig->ops = &mxs_lradc_trigger_ops;
+
+ ret = iio_trigger_register(trig);
+ if (ret) {
+ iio_trigger_free(trig);
+ return ret;
+ }
+
+ iio->trig = trig;
+
+ return 0;
+}
+
+static void mxs_lradc_trigger_remove(struct iio_dev *iio)
+{
+ iio_trigger_unregister(iio->trig);
+ iio_trigger_free(iio->trig);
+}
+
+static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
+{
+ struct mxs_lradc *lradc = iio_priv(iio);
+ struct iio_buffer *buffer = iio->buffer;
+ int ret = 0, chan, ofs = 0, enable = 0;
+ uint32_t ctrl4 = 0;
+ uint32_t ctrl1_irq = 0;
+ const uint32_t chan_value = LRADC_CH_ACCUMULATE |
+ ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
+ const int len = bitmap_weight(buffer->scan_mask, LRADC_MAX_TOTAL_CHANS);
+
+ if (!len)
+ return -EINVAL;
+
+ /*
+ * Lock the driver so raw access can not be done during buffered
+ * operation. This simplifies the code a lot.
+ */
+ ret = mutex_trylock(&lradc->lock);
+ if (!ret)
+ return -EBUSY;
+
+ lradc->buffer = kmalloc(len * sizeof(*lradc->buffer), GFP_KERNEL);
+ if (!lradc->buffer) {
+ ret = -ENOMEM;
+ goto err_mem;
+ }
+
+ ret = iio_sw_buffer_preenable(iio);
+ if (ret < 0)
+ goto err_buf;
+
+ writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
+ lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+ writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
+
+ for_each_set_bit(chan, buffer->scan_mask, LRADC_MAX_TOTAL_CHANS) {
+ ctrl4 |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
+ ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
+ writel(chan_value, lradc->base + LRADC_CH(ofs));
+ enable |= 1 << ofs;
+ ofs++;
+ };
+
+ writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
+ lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
+
+ writel(ctrl4, lradc->base + LRADC_CTRL4);
+ writel(ctrl1_irq, lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
+
+ writel(enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
+ lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_SET);
+
+ return 0;
+
+err_buf:
+ kfree(lradc->buffer);
+err_mem:
+ mutex_unlock(&lradc->lock);
+ return ret;
+}
+
+static int mxs_lradc_buffer_postdisable(struct iio_dev *iio)
+{
+ struct mxs_lradc *lradc = iio_priv(iio);
+
+ writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
+ lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
+
+ writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
+ writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
+ lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+
+ kfree(lradc->buffer);
+ mutex_unlock(&lradc->lock);
+
+ return 0;
+}
+
+static bool mxs_lradc_validate_scan_mask(struct iio_dev *iio,
+ const unsigned long *mask)
+{
+ const int mw = bitmap_weight(mask, iio->masklength);
+
+ return mw <= LRADC_MAX_MAPPED_CHANS;
+}
+
+static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
+ .preenable = &mxs_lradc_buffer_preenable,
+ .postenable = &iio_triggered_buffer_postenable,
+ .predisable = &iio_triggered_buffer_predisable,
+ .postdisable = &mxs_lradc_buffer_postdisable,
+ .validate_scan_mask = &mxs_lradc_validate_scan_mask,
+};
+
+/*
+ * Driver initialization
+ */
+
+#define MXS_ADC_CHAN(idx, chan_type) { \
+ .type = (chan_type), \
+ .indexed = 1, \
+ .scan_index = (idx), \
+ .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT, \
+ .channel = (idx), \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = 18, \
+ .storagebits = 32, \
+ }, \
+}
+
+static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
+ MXS_ADC_CHAN(0, IIO_VOLTAGE),
+ MXS_ADC_CHAN(1, IIO_VOLTAGE),
+ MXS_ADC_CHAN(2, IIO_VOLTAGE),
+ MXS_ADC_CHAN(3, IIO_VOLTAGE),
+ MXS_ADC_CHAN(4, IIO_VOLTAGE),
+ MXS_ADC_CHAN(5, IIO_VOLTAGE),
+ MXS_ADC_CHAN(6, IIO_VOLTAGE),
+ MXS_ADC_CHAN(7, IIO_VOLTAGE), /* VBATT */
+ MXS_ADC_CHAN(8, IIO_TEMP), /* Temp sense 0 */
+ MXS_ADC_CHAN(9, IIO_TEMP), /* Temp sense 1 */
+ MXS_ADC_CHAN(10, IIO_VOLTAGE), /* VDDIO */
+ MXS_ADC_CHAN(11, IIO_VOLTAGE), /* VTH */
+ MXS_ADC_CHAN(12, IIO_VOLTAGE), /* VDDA */
+ MXS_ADC_CHAN(13, IIO_VOLTAGE), /* VDDD */
+ MXS_ADC_CHAN(14, IIO_VOLTAGE), /* VBG */
+ MXS_ADC_CHAN(15, IIO_VOLTAGE), /* VDD5V */
+};
+
+static void mxs_lradc_hw_init(struct mxs_lradc *lradc)
+{
+ int i;
+ const uint32_t cfg =
+ (LRADC_DELAY_TIMER_PER << LRADC_DELAY_DELAY_OFFSET);
+
+ stmp_reset_block(lradc->base);
+
+ for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
+ writel(cfg | (1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + i)),
+ lradc->base + LRADC_DELAY(i));
+
+ /* Start internal temperature sensing. */
+ writel(0, lradc->base + LRADC_CTRL2);
+}
+
+static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
+{
+ int i;
+
+ writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
+ lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
+
+ for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
+ writel(0, lradc->base + LRADC_DELAY(i));
+}
+
+static int __devinit mxs_lradc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mxs_lradc *lradc;
+ struct iio_dev *iio;
+ struct resource *iores;
+ int ret = 0;
+ int i;
+
+ /* Allocate the IIO device. */
+ iio = iio_device_alloc(sizeof(*lradc));
+ if (!iio) {
+ dev_err(dev, "Failed to allocate IIO device\n");
+ return -ENOMEM;
+ }
+
+ lradc = iio_priv(iio);
+
+ /* Grab the memory area */
+ iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ lradc->dev = &pdev->dev;
+ lradc->base = devm_request_and_ioremap(dev, iores);
+ if (!lradc->base) {
+ ret = -EADDRNOTAVAIL;
+ goto err_addr;
+ }
+
+ /* Grab all IRQ sources */
+ for (i = 0; i < 13; i++) {
+ lradc->irq[i] = platform_get_irq(pdev, i);
+ if (lradc->irq[i] < 0) {
+ ret = -EINVAL;
+ goto err_addr;
+ }
+
+ ret = devm_request_irq(dev, lradc->irq[i],
+ mxs_lradc_handle_irq, 0,
+ mxs_lradc_irq_name[i], iio);
+ if (ret)
+ goto err_addr;
+ }
+
+ platform_set_drvdata(pdev, iio);
+
+ init_completion(&lradc->completion);
+ mutex_init(&lradc->lock);
+
+ iio->name = pdev->name;
+ iio->dev.parent = &pdev->dev;
+ iio->info = &mxs_lradc_iio_info;
+ iio->modes = INDIO_DIRECT_MODE;
+ iio->channels = mxs_lradc_chan_spec;
+ iio->num_channels = ARRAY_SIZE(mxs_lradc_chan_spec);
+
+ ret = iio_triggered_buffer_setup(iio, &iio_pollfunc_store_time,
+ &mxs_lradc_trigger_handler,
+ &mxs_lradc_buffer_ops);
+ if (ret)
+ goto err_addr;
+
+ ret = mxs_lradc_trigger_init(iio);
+ if (ret)
+ goto err_trig;
+
+ /* Register IIO device. */
+ ret = iio_device_register(iio);
+ if (ret) {
+ dev_err(dev, "Failed to register IIO device\n");
+ goto err_dev;
+ }
+
+ /* Configure the hardware. */
+ mxs_lradc_hw_init(lradc);
+
+ return 0;
+
+err_dev:
+ mxs_lradc_trigger_remove(iio);
+err_trig:
+ iio_triggered_buffer_cleanup(iio);
+err_addr:
+ iio_device_free(iio);
+ return ret;
+}
+
+static int __devexit mxs_lradc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *iio = platform_get_drvdata(pdev);
+ struct mxs_lradc *lradc = iio_priv(iio);
+
+ mxs_lradc_hw_stop(lradc);
+
+ iio_device_unregister(iio);
+ iio_triggered_buffer_cleanup(iio);
+ mxs_lradc_trigger_remove(iio);
+ iio_device_free(iio);
+
+ return 0;
+}
+
+static const struct of_device_id mxs_lradc_dt_ids[] = {
+ { .compatible = "fsl,imx28-lradc", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
+
+static struct platform_driver mxs_lradc_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = mxs_lradc_dt_ids,
+ },
+ .probe = mxs_lradc_probe,
+ .remove = __devexit_p(mxs_lradc_remove),
+};
+
+module_platform_driver(mxs_lradc_driver);
+
+MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
+MODULE_DESCRIPTION("Freescale i.MX28 LRADC driver");
+MODULE_LICENSE("GPL v2");
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / commitdiff