diff options
Diffstat (limited to 'drivers/staging/iio/adc/mxs-lradc.c')
| -rw-r--r-- | drivers/staging/iio/adc/mxs-lradc.c | 1037 |
1 files changed, 1037 insertions, 0 deletions
diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c new file mode 100644 index 00000000..972a0723 --- /dev/null +++ b/drivers/staging/iio/adc/mxs-lradc.c @@ -0,0 +1,1037 @@ +/* + * 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/err.h> +#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 <linux/delay.h> +#include <linux/input.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 + +/* + * Once the pen touches the touchscreen, the touchscreen switches from + * IRQ-driven mode to polling mode to prevent interrupt storm. The polling + * is realized by worker thread, which is called every 20 or so milliseconds. + * This gives the touchscreen enough fluence and does not strain the system + * too much. + */ +#define LRADC_TS_SAMPLE_DELAY_MS 5 + +/* + * The LRADC reads the following amount of samples from each touchscreen + * channel and the driver then computes avarage of these. + */ +#define LRADC_TS_SAMPLE_AMOUNT 4 + +enum mxs_lradc_id { + IMX23_LRADC, + IMX28_LRADC, +}; + +static const char * const mx23_lradc_irq_names[] = { + "mxs-lradc-touchscreen", + "mxs-lradc-channel0", + "mxs-lradc-channel1", + "mxs-lradc-channel2", + "mxs-lradc-channel3", + "mxs-lradc-channel4", + "mxs-lradc-channel5", + "mxs-lradc-channel6", + "mxs-lradc-channel7", +}; + +static const char * const mx28_lradc_irq_names[] = { + "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_of_config { + const int irq_count; + const char * const *irq_name; +}; + +static const struct mxs_lradc_of_config mxs_lradc_of_config[] = { + [IMX23_LRADC] = { + .irq_count = ARRAY_SIZE(mx23_lradc_irq_names), + .irq_name = mx23_lradc_irq_names, + }, + [IMX28_LRADC] = { + .irq_count = ARRAY_SIZE(mx28_lradc_irq_names), + .irq_name = mx28_lradc_irq_names, + }, +}; + +enum mxs_lradc_ts { + MXS_LRADC_TOUCHSCREEN_NONE = 0, + MXS_LRADC_TOUCHSCREEN_4WIRE, + MXS_LRADC_TOUCHSCREEN_5WIRE, +}; + +struct mxs_lradc { + struct device *dev; + void __iomem *base; + int irq[13]; + + uint32_t *buffer; + struct iio_trigger *trig; + + struct mutex lock; + + struct completion completion; + + /* + * Touchscreen LRADC channels receives a private slot in the CTRL4 + * register, the slot #7. Therefore only 7 slots instead of 8 in the + * CTRL4 register can be mapped to LRADC channels when using the + * touchscreen. + * + * Furthermore, certain LRADC channels are shared between touchscreen + * and/or touch-buttons and generic LRADC block. Therefore when using + * either of these, these channels are not available for the regular + * sampling. The shared channels are as follows: + * + * CH0 -- Touch button #0 + * CH1 -- Touch button #1 + * CH2 -- Touch screen XPUL + * CH3 -- Touch screen YPLL + * CH4 -- Touch screen XNUL + * CH5 -- Touch screen YNLR + * CH6 -- Touch screen WIPER (5-wire only) + * + * The bitfields below represents which parts of the LRADC block are + * switched into special mode of operation. These channels can not + * be sampled as regular LRADC channels. The driver will refuse any + * attempt to sample these channels. + */ +#define CHAN_MASK_TOUCHBUTTON (0x3 << 0) +#define CHAN_MASK_TOUCHSCREEN_4WIRE (0xf << 2) +#define CHAN_MASK_TOUCHSCREEN_5WIRE (0x1f << 2) + enum mxs_lradc_ts use_touchscreen; + bool stop_touchscreen; + bool use_touchbutton; + + struct input_dev *ts_input; + struct work_struct ts_work; +}; + +#define LRADC_CTRL0 0x00 +#define LRADC_CTRL0_TOUCH_DETECT_ENABLE (1 << 23) +#define LRADC_CTRL0_TOUCH_SCREEN_TYPE (1 << 22) +#define LRADC_CTRL0_YNNSW /* YM */ (1 << 21) +#define LRADC_CTRL0_YPNSW /* YP */ (1 << 20) +#define LRADC_CTRL0_YPPSW /* YP */ (1 << 19) +#define LRADC_CTRL0_XNNSW /* XM */ (1 << 18) +#define LRADC_CTRL0_XNPSW /* XM */ (1 << 17) +#define LRADC_CTRL0_XPPSW /* XP */ (1 << 16) +#define LRADC_CTRL0_PLATE_MASK (0x3f << 16) + +#define LRADC_CTRL1 0x10 +#define LRADC_CTRL1_TOUCH_DETECT_IRQ_EN (1 << 24) +#define LRADC_CTRL1_LRADC_IRQ_EN(n) (1 << ((n) + 16)) +#define LRADC_CTRL1_LRADC_IRQ_EN_MASK (0x1fff << 16) +#define LRADC_CTRL1_LRADC_IRQ_EN_OFFSET 16 +#define LRADC_CTRL1_TOUCH_DETECT_IRQ (1 << 8) +#define LRADC_CTRL1_LRADC_IRQ(n) (1 << (n)) +#define LRADC_CTRL1_LRADC_IRQ_MASK 0x1fff +#define LRADC_CTRL1_LRADC_IRQ_OFFSET 0 + +#define LRADC_CTRL2 0x20 +#define LRADC_CTRL2_TEMPSENSE_PWD (1 << 15) + +#define LRADC_STATUS 0x40 +#define LRADC_STATUS_TOUCH_DETECT_RAW (1 << 0) + +#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); + + /* Clean the slot's previous content, then set new one. */ + writel(LRADC_CTRL4_LRADCSELECT_MASK(0), + lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR); + writel(chan->channel, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET); + + 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, +}; + +/* + * Touchscreen handling + */ +enum lradc_ts_plate { + LRADC_SAMPLE_X, + LRADC_SAMPLE_Y, + LRADC_SAMPLE_PRESSURE, +}; + +static int mxs_lradc_ts_touched(struct mxs_lradc *lradc) +{ + uint32_t reg; + + /* Enable touch detection. */ + writel(LRADC_CTRL0_PLATE_MASK, + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR); + writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE, + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET); + + msleep(LRADC_TS_SAMPLE_DELAY_MS); + + reg = readl(lradc->base + LRADC_STATUS); + + return reg & LRADC_STATUS_TOUCH_DETECT_RAW; +} + +static int32_t mxs_lradc_ts_sample(struct mxs_lradc *lradc, + enum lradc_ts_plate plate, int change) +{ + unsigned long delay, jiff; + uint32_t reg, ctrl0 = 0, chan = 0; + /* The touchscreen always uses CTRL4 slot #7. */ + const uint8_t slot = 7; + uint32_t val; + + /* + * There are three correct configurations of the controller sampling + * the touchscreen, each of these configuration provides different + * information from the touchscreen. + * + * The following table describes the sampling configurations: + * +-------------+-------+-------+-------+ + * | Wire \ Axis | X | Y | Z | + * +---------------------+-------+-------+ + * | X+ (CH2) | HI | TS | TS | + * +-------------+-------+-------+-------+ + * | X- (CH4) | LO | SH | HI | + * +-------------+-------+-------+-------+ + * | Y+ (CH3) | SH | HI | HI | + * +-------------+-------+-------+-------+ + * | Y- (CH5) | TS | LO | SH | + * +-------------+-------+-------+-------+ + * + * HI ... strong '1' ; LO ... strong '0' + * SH ... sample here ; TS ... tri-state + * + * There are a few other ways of obtaining the Z coordinate + * (aka. pressure), but the one in the table seems to be the + * most reliable one. + */ + switch (plate) { + case LRADC_SAMPLE_X: + ctrl0 = LRADC_CTRL0_XPPSW | LRADC_CTRL0_XNNSW; + chan = 3; + break; + case LRADC_SAMPLE_Y: + ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_YNNSW; + chan = 4; + break; + case LRADC_SAMPLE_PRESSURE: + ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_XNNSW; + chan = 5; + break; + } + + if (change) { + writel(LRADC_CTRL0_PLATE_MASK, + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR); + writel(ctrl0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET); + + writel(LRADC_CTRL4_LRADCSELECT_MASK(slot), + lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR); + writel(chan << LRADC_CTRL4_LRADCSELECT_OFFSET(slot), + lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET); + } + + writel(0xffffffff, lradc->base + LRADC_CH(slot) + STMP_OFFSET_REG_CLR); + writel(1 << slot, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET); + + delay = jiffies + msecs_to_jiffies(LRADC_TS_SAMPLE_DELAY_MS); + do { + jiff = jiffies; + reg = readl_relaxed(lradc->base + LRADC_CTRL1); + if (reg & LRADC_CTRL1_LRADC_IRQ(slot)) + break; + } while (time_before(jiff, delay)); + + writel(LRADC_CTRL1_LRADC_IRQ(slot), + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR); + + if (time_after_eq(jiff, delay)) + return -ETIMEDOUT; + + val = readl(lradc->base + LRADC_CH(slot)); + val &= LRADC_CH_VALUE_MASK; + + return val; +} + +static int32_t mxs_lradc_ts_sample_filter(struct mxs_lradc *lradc, + enum lradc_ts_plate plate) +{ + int32_t val, tot = 0; + int i; + + val = mxs_lradc_ts_sample(lradc, plate, 1); + + /* Delay a bit so the touchscreen is stable. */ + mdelay(2); + + for (i = 0; i < LRADC_TS_SAMPLE_AMOUNT; i++) { + val = mxs_lradc_ts_sample(lradc, plate, 0); + tot += val; + } + + return tot / LRADC_TS_SAMPLE_AMOUNT; +} + +static void mxs_lradc_ts_work(struct work_struct *ts_work) +{ + struct mxs_lradc *lradc = container_of(ts_work, + struct mxs_lradc, ts_work); + int val_x, val_y, val_p; + bool valid = false; + + while (mxs_lradc_ts_touched(lradc)) { + /* Disable touch detector so we can sample the touchscreen. */ + writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE, + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR); + + if (likely(valid)) { + input_report_abs(lradc->ts_input, ABS_X, val_x); + input_report_abs(lradc->ts_input, ABS_Y, val_y); + input_report_abs(lradc->ts_input, ABS_PRESSURE, val_p); + input_report_key(lradc->ts_input, BTN_TOUCH, 1); + input_sync(lradc->ts_input); + } + + valid = false; + + val_x = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_X); + if (val_x < 0) + continue; + val_y = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_Y); + if (val_y < 0) + continue; + val_p = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_PRESSURE); + if (val_p < 0) + continue; + + valid = true; + } + + input_report_abs(lradc->ts_input, ABS_PRESSURE, 0); + input_report_key(lradc->ts_input, BTN_TOUCH, 0); + input_sync(lradc->ts_input); + + /* Do not restart the TS IRQ if the driver is shutting down. */ + if (lradc->stop_touchscreen) + return; + + /* Restart the touchscreen interrupts. */ + writel(LRADC_CTRL1_TOUCH_DETECT_IRQ, + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR); + writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET); +} + +static int mxs_lradc_ts_open(struct input_dev *dev) +{ + struct mxs_lradc *lradc = input_get_drvdata(dev); + + /* The touchscreen is starting. */ + lradc->stop_touchscreen = false; + + /* Enable the touch-detect circuitry. */ + writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE, + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET); + + /* Enable the touch-detect IRQ. */ + writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET); + + return 0; +} + +static void mxs_lradc_ts_close(struct input_dev *dev) +{ + struct mxs_lradc *lradc = input_get_drvdata(dev); + + /* Indicate the touchscreen is stopping. */ + lradc->stop_touchscreen = true; + mb(); + + /* Wait until touchscreen thread finishes any possible remnants. */ + cancel_work_sync(&lradc->ts_work); + + /* Disable touchscreen touch-detect IRQ. */ + writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR); + + /* Power-down touchscreen touch-detect circuitry. */ + writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE, + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR); +} + +static int mxs_lradc_ts_register(struct mxs_lradc *lradc) +{ + struct input_dev *input; + struct device *dev = lradc->dev; + int ret; + + if (!lradc->use_touchscreen) + return 0; + + input = input_allocate_device(); + if (!input) { + dev_err(dev, "Failed to allocate TS device!\n"); + return -ENOMEM; + } + + input->name = DRIVER_NAME; + input->id.bustype = BUS_HOST; + input->dev.parent = dev; + input->open = mxs_lradc_ts_open; + input->close = mxs_lradc_ts_close; + + __set_bit(EV_ABS, input->evbit); + __set_bit(EV_KEY, input->evbit); + __set_bit(BTN_TOUCH, input->keybit); + input_set_abs_params(input, ABS_X, 0, LRADC_CH_VALUE_MASK, 0, 0); + input_set_abs_params(input, ABS_Y, 0, LRADC_CH_VALUE_MASK, 0, 0); + input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_CH_VALUE_MASK, 0, 0); + + lradc->ts_input = input; + input_set_drvdata(input, lradc); + ret = input_register_device(input); + if (ret) + input_free_device(lradc->ts_input); + + return ret; +} + +static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc) +{ + if (!lradc->use_touchscreen) + return; + + cancel_work_sync(&lradc->ts_work); + + input_unregister_device(lradc->ts_input); +} + +/* + * 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); + const uint32_t ts_irq_mask = + LRADC_CTRL1_TOUCH_DETECT_IRQ_EN | + LRADC_CTRL1_TOUCH_DETECT_IRQ; + + if (!(reg & LRADC_CTRL1_LRADC_IRQ_MASK)) + return IRQ_NONE; + + /* + * Touchscreen IRQ handling code has priority and therefore + * is placed here. In case touchscreen IRQ arrives, disable + * it ASAP + */ + if (reg & LRADC_CTRL1_TOUCH_DETECT_IRQ) { + writel(ts_irq_mask, + lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR); + if (!lradc->stop_touchscreen) + schedule_work(&lradc->ts_work); + } + + 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); + const uint32_t chan_value = LRADC_CH_ACCUMULATE | + ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET); + unsigned 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_buffers(iio, (u8 *)lradc->buffer); + + 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 = iio_trigger_get_drvdata(trig); + 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; + struct mxs_lradc *lradc = iio_priv(iio); + + trig = iio_trigger_alloc("%s-dev%i", iio->name, iio->id); + if (trig == NULL) + return -ENOMEM; + + trig->dev.parent = lradc->dev; + iio_trigger_set_drvdata(trig, iio); + trig->ops = &mxs_lradc_trigger_ops; + + ret = iio_trigger_register(trig); + if (ret) { + iio_trigger_free(trig); + return ret; + } + + lradc->trig = trig; + + return 0; +} + +static void mxs_lradc_trigger_remove(struct iio_dev *iio) +{ + struct mxs_lradc *lradc = iio_priv(iio); + + iio_trigger_unregister(lradc->trig); + iio_trigger_free(lradc->trig); +} + +static int mxs_lradc_buffer_preenable(struct iio_dev *iio) +{ + struct mxs_lradc *lradc = iio_priv(iio); + int ret = 0, chan, ofs = 0; + unsigned long enable = 0; + uint32_t ctrl4_set = 0; + uint32_t ctrl4_clr = 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(iio->active_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, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) { + ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs); + ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs); + ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs); + writel(chan_value, lradc->base + LRADC_CH(ofs)); + bitmap_set(&enable, ofs, 1); + ofs++; + } + + writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK, + lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR); + + writel(ctrl4_clr, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR); + writel(ctrl4_set, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET); + + 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) +{ + struct mxs_lradc *lradc = iio_priv(iio); + const int len = iio->masklength; + const int map_chans = bitmap_weight(mask, len); + int rsvd_chans = 0; + unsigned long rsvd_mask = 0; + + if (lradc->use_touchbutton) + rsvd_mask |= CHAN_MASK_TOUCHBUTTON; + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_4WIRE) + rsvd_mask |= CHAN_MASK_TOUCHSCREEN_4WIRE; + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE) + rsvd_mask |= CHAN_MASK_TOUCHSCREEN_5WIRE; + + if (lradc->use_touchbutton) + rsvd_chans++; + if (lradc->use_touchscreen) + rsvd_chans++; + + /* Test for attempts to map channels with special mode of operation. */ + if (bitmap_intersects(mask, &rsvd_mask, len)) + return false; + + /* Test for attempts to map more channels then available slots. */ + if (map_chans + rsvd_chans > LRADC_MAX_MAPPED_CHANS) + return false; + + return true; +} + +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_separate = BIT(IIO_CHAN_INFO_RAW), \ + .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) +{ + /* The ADC always uses DELAY CHANNEL 0. */ + const uint32_t adc_cfg = + (1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + 0)) | + (LRADC_DELAY_TIMER_PER << LRADC_DELAY_DELAY_OFFSET); + + stmp_reset_block(lradc->base); + + /* Configure DELAY CHANNEL 0 for generic ADC sampling. */ + writel(adc_cfg, lradc->base + LRADC_DELAY(0)); + + /* Disable remaining DELAY CHANNELs */ + writel(0, lradc->base + LRADC_DELAY(1)); + writel(0, lradc->base + LRADC_DELAY(2)); + writel(0, lradc->base + LRADC_DELAY(3)); + + /* Configure the touchscreen type */ + writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE, + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR); + + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE) { + writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE, + lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET); + } + + /* 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 const struct of_device_id mxs_lradc_dt_ids[] = { + { .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, }, + { .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids); + +static int mxs_lradc_probe(struct platform_device *pdev) +{ + const struct of_device_id *of_id = + of_match_device(mxs_lradc_dt_ids, &pdev->dev); + const struct mxs_lradc_of_config *of_cfg = + &mxs_lradc_of_config[(enum mxs_lradc_id)of_id->data]; + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node; + struct mxs_lradc *lradc; + struct iio_dev *iio; + struct resource *iores; + uint32_t ts_wires = 0; + 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_ioremap_resource(dev, iores); + if (IS_ERR(lradc->base)) { + ret = PTR_ERR(lradc->base); + goto err_addr; + } + + INIT_WORK(&lradc->ts_work, mxs_lradc_ts_work); + + /* Check if touchscreen is enabled in DT. */ + ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires", + &ts_wires); + if (ret) + dev_info(dev, "Touchscreen not enabled.\n"); + else if (ts_wires == 4) + lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE; + else if (ts_wires == 5) + lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE; + else + dev_warn(dev, "Unsupported number of touchscreen wires (%d)\n", + ts_wires); + + /* Grab all IRQ sources */ + for (i = 0; i < of_cfg->irq_count; 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, + of_cfg->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; + + /* Configure the hardware. */ + mxs_lradc_hw_init(lradc); + + /* Register the touchscreen input device. */ + ret = mxs_lradc_ts_register(lradc); + if (ret) + goto err_dev; + + /* Register IIO device. */ + ret = iio_device_register(iio); + if (ret) { + dev_err(dev, "Failed to register IIO device\n"); + goto err_ts; + } + + return 0; + +err_ts: + mxs_lradc_ts_unregister(lradc); +err_dev: + mxs_lradc_trigger_remove(iio); +err_trig: + iio_triggered_buffer_cleanup(iio); +err_addr: + iio_device_free(iio); + return ret; +} + +static int mxs_lradc_remove(struct platform_device *pdev) +{ + struct iio_dev *iio = platform_get_drvdata(pdev); + struct mxs_lradc *lradc = iio_priv(iio); + + mxs_lradc_ts_unregister(lradc); + + 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 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 = 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"); |