--- /dev/null
+/*
+ * Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
+ *
+ * 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.
+ *
+ * Based on driver from 2011:
+ * Juergen Beisert, Pengutronix <kernel@pengutronix.de>
+ *
+ * This is the driver for the imx25 TCQ (Touchscreen Conversion Queue)
+ * connected to the imx25 ADC.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/imx25-tsadc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+static const char mx25_tcq_name[] = "mx25-tcq";
+
+enum mx25_tcq_mode {
+ MX25_TS_4WIRE,
+};
+
+struct mx25_tcq_priv {
+ struct regmap *regs;
+ struct regmap *core_regs;
+ struct input_dev *idev;
+ enum mx25_tcq_mode mode;
+ unsigned int pen_threshold;
+ unsigned int sample_count;
+ unsigned int expected_samples;
+ unsigned int pen_debounce;
+ unsigned int settling_time;
+ struct clk *clk;
+ int irq;
+ struct device *dev;
+};
+
+static struct regmap_config mx25_tcq_regconfig = {
+ .fast_io = true,
+ .max_register = 0x5c,
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+static const struct of_device_id mx25_tcq_ids[] = {
+ { .compatible = "fsl,imx25-tcq", },
+ { /* Sentinel */ }
+};
+
+#define TSC_4WIRE_PRE_INDEX 0
+#define TSC_4WIRE_X_INDEX 1
+#define TSC_4WIRE_Y_INDEX 2
+#define TSC_4WIRE_POST_INDEX 3
+#define TSC_4WIRE_LEAVE 4
+
+#define MX25_TSC_DEF_THRESHOLD 80
+#define TSC_MAX_SAMPLES 16
+
+#define MX25_TSC_REPEAT_WAIT 14
+
+enum mx25_adc_configurations {
+ MX25_CFG_PRECHARGE = 0,
+ MX25_CFG_TOUCH_DETECT,
+ MX25_CFG_X_MEASUREMENT,
+ MX25_CFG_Y_MEASUREMENT,
+};
+
+#define MX25_PRECHARGE_VALUE (\
+ MX25_ADCQ_CFG_YPLL_OFF | \
+ MX25_ADCQ_CFG_XNUR_OFF | \
+ MX25_ADCQ_CFG_XPUL_HIGH | \
+ MX25_ADCQ_CFG_REFP_INT | \
+ MX25_ADCQ_CFG_IN_XP | \
+ MX25_ADCQ_CFG_REFN_NGND2 | \
+ MX25_ADCQ_CFG_IGS)
+
+#define MX25_TOUCH_DETECT_VALUE (\
+ MX25_ADCQ_CFG_YNLR | \
+ MX25_ADCQ_CFG_YPLL_OFF | \
+ MX25_ADCQ_CFG_XNUR_OFF | \
+ MX25_ADCQ_CFG_XPUL_OFF | \
+ MX25_ADCQ_CFG_REFP_INT | \
+ MX25_ADCQ_CFG_IN_XP | \
+ MX25_ADCQ_CFG_REFN_NGND2 | \
+ MX25_ADCQ_CFG_PENIACK)
+
+static void imx25_setup_queue_cfgs(struct mx25_tcq_priv *priv,
+ unsigned int settling_cnt)
+{
+ u32 precharge_cfg =
+ MX25_PRECHARGE_VALUE |
+ MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt);
+ u32 touch_detect_cfg =
+ MX25_TOUCH_DETECT_VALUE |
+ MX25_ADCQ_CFG_NOS(1) |
+ MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt);
+
+ regmap_write(priv->core_regs, MX25_TSC_TICR, precharge_cfg);
+
+ /* PRECHARGE */
+ regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_PRECHARGE),
+ precharge_cfg);
+
+ /* TOUCH_DETECT */
+ regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_TOUCH_DETECT),
+ touch_detect_cfg);
+
+ /* X Measurement */
+ regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_X_MEASUREMENT),
+ MX25_ADCQ_CFG_YPLL_OFF |
+ MX25_ADCQ_CFG_XNUR_LOW |
+ MX25_ADCQ_CFG_XPUL_HIGH |
+ MX25_ADCQ_CFG_REFP_XP |
+ MX25_ADCQ_CFG_IN_YP |
+ MX25_ADCQ_CFG_REFN_XN |
+ MX25_ADCQ_CFG_NOS(priv->sample_count) |
+ MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt));
+
+ /* Y Measurement */
+ regmap_write(priv->regs, MX25_ADCQ_CFG(MX25_CFG_Y_MEASUREMENT),
+ MX25_ADCQ_CFG_YNLR |
+ MX25_ADCQ_CFG_YPLL_HIGH |
+ MX25_ADCQ_CFG_XNUR_OFF |
+ MX25_ADCQ_CFG_XPUL_OFF |
+ MX25_ADCQ_CFG_REFP_YP |
+ MX25_ADCQ_CFG_IN_XP |
+ MX25_ADCQ_CFG_REFN_YN |
+ MX25_ADCQ_CFG_NOS(priv->sample_count) |
+ MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt));
+
+ /* Enable the touch detection right now */
+ regmap_write(priv->core_regs, MX25_TSC_TICR, touch_detect_cfg |
+ MX25_ADCQ_CFG_IGS);
+}
+
+static int imx25_setup_queue_4wire(struct mx25_tcq_priv *priv,
+ unsigned settling_cnt, int *items)
+{
+ imx25_setup_queue_cfgs(priv, settling_cnt);
+
+ /* Setup the conversion queue */
+ regmap_write(priv->regs, MX25_ADCQ_ITEM_7_0,
+ MX25_ADCQ_ITEM(0, MX25_CFG_PRECHARGE) |
+ MX25_ADCQ_ITEM(1, MX25_CFG_TOUCH_DETECT) |
+ MX25_ADCQ_ITEM(2, MX25_CFG_X_MEASUREMENT) |
+ MX25_ADCQ_ITEM(3, MX25_CFG_Y_MEASUREMENT) |
+ MX25_ADCQ_ITEM(4, MX25_CFG_PRECHARGE) |
+ MX25_ADCQ_ITEM(5, MX25_CFG_TOUCH_DETECT));
+
+ /*
+ * We measure X/Y with 'sample_count' number of samples and execute a
+ * touch detection twice, with 1 sample each
+ */
+ priv->expected_samples = priv->sample_count * 2 + 2;
+ *items = 6;
+
+ return 0;
+}
+
+static void mx25_tcq_disable_touch_irq(struct mx25_tcq_priv *priv)
+{
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_PDMSK,
+ MX25_ADCQ_CR_PDMSK);
+}
+
+static void mx25_tcq_enable_touch_irq(struct mx25_tcq_priv *priv)
+{
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_PDMSK, 0);
+}
+
+static void mx25_tcq_disable_fifo_irq(struct mx25_tcq_priv *priv)
+{
+ regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_FDRY_IRQ,
+ MX25_ADCQ_MR_FDRY_IRQ);
+}
+
+static void mx25_tcq_enable_fifo_irq(struct mx25_tcq_priv *priv)
+{
+ regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_FDRY_IRQ, 0);
+}
+
+static void mx25_tcq_force_queue_start(struct mx25_tcq_priv *priv)
+{
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+ MX25_ADCQ_CR_FQS,
+ MX25_ADCQ_CR_FQS);
+}
+
+static void mx25_tcq_force_queue_stop(struct mx25_tcq_priv *priv)
+{
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+ MX25_ADCQ_CR_FQS, 0);
+}
+
+static void mx25_tcq_fifo_reset(struct mx25_tcq_priv *priv)
+{
+ u32 tcqcr;
+
+ regmap_read(priv->regs, MX25_ADCQ_CR, &tcqcr);
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FRST,
+ MX25_ADCQ_CR_FRST);
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FRST, 0);
+ regmap_write(priv->regs, MX25_ADCQ_CR, tcqcr);
+}
+
+static void mx25_tcq_re_enable_touch_detection(struct mx25_tcq_priv *priv)
+{
+ /* stop the queue from looping */
+ mx25_tcq_force_queue_stop(priv);
+
+ /* for a clean touch detection, preload the X plane */
+ regmap_write(priv->core_regs, MX25_TSC_TICR, MX25_PRECHARGE_VALUE);
+
+ /* waste some time now to pre-load the X plate to high voltage */
+ mx25_tcq_fifo_reset(priv);
+
+ /* re-enable the detection right now */
+ regmap_write(priv->core_regs, MX25_TSC_TICR,
+ MX25_TOUCH_DETECT_VALUE | MX25_ADCQ_CFG_IGS);
+
+ regmap_update_bits(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_PD,
+ MX25_ADCQ_SR_PD);
+
+ /* enable the pen down event to be a source for the interrupt */
+ regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_PD_IRQ, 0);
+
+ /* lets fire the next IRQ if someone touches the touchscreen */
+ mx25_tcq_enable_touch_irq(priv);
+}
+
+static void mx25_tcq_create_event_for_4wire(struct mx25_tcq_priv *priv,
+ u32 *sample_buf,
+ unsigned int samples)
+{
+ unsigned int x_pos = 0;
+ unsigned int y_pos = 0;
+ unsigned int touch_pre = 0;
+ unsigned int touch_post = 0;
+ unsigned int i;
+
+ for (i = 0; i < samples; i++) {
+ unsigned int index = MX25_ADCQ_FIFO_ID(sample_buf[i]);
+ unsigned int val = MX25_ADCQ_FIFO_DATA(sample_buf[i]);
+
+ switch (index) {
+ case 1:
+ touch_pre = val;
+ break;
+ case 2:
+ x_pos = val;
+ break;
+ case 3:
+ y_pos = val;
+ break;
+ case 5:
+ touch_post = val;
+ break;
+ default:
+ dev_dbg(priv->dev, "Dropped samples because of invalid index %d\n",
+ index);
+ return;
+ }
+ }
+
+ if (samples != 0) {
+ /*
+ * only if both touch measures are below a threshold,
+ * the position is valid
+ */
+ if (touch_pre < priv->pen_threshold &&
+ touch_post < priv->pen_threshold) {
+ /* valid samples, generate a report */
+ x_pos /= priv->sample_count;
+ y_pos /= priv->sample_count;
+ input_report_abs(priv->idev, ABS_X, x_pos);
+ input_report_abs(priv->idev, ABS_Y, y_pos);
+ input_report_key(priv->idev, BTN_TOUCH, 1);
+ input_sync(priv->idev);
+
+ /* get next sample */
+ mx25_tcq_enable_fifo_irq(priv);
+ } else if (touch_pre >= priv->pen_threshold &&
+ touch_post >= priv->pen_threshold) {
+ /*
+ * if both samples are invalid,
+ * generate a release report
+ */
+ input_report_key(priv->idev, BTN_TOUCH, 0);
+ input_sync(priv->idev);
+ mx25_tcq_re_enable_touch_detection(priv);
+ } else {
+ /*
+ * if only one of both touch measurements are
+ * below the threshold, still some bouncing
+ * happens. Take additional samples in this
+ * case to be sure
+ */
+ mx25_tcq_enable_fifo_irq(priv);
+ }
+ }
+}
+
+static irqreturn_t mx25_tcq_irq_thread(int irq, void *dev_id)
+{
+ struct mx25_tcq_priv *priv = dev_id;
+ u32 sample_buf[TSC_MAX_SAMPLES];
+ unsigned int samples;
+ u32 stats;
+ unsigned int i;
+
+ /*
+ * Check how many samples are available. We always have to read exactly
+ * sample_count samples from the fifo, or a multiple of sample_count.
+ * Otherwise we mixup samples into different touch events.
+ */
+ regmap_read(priv->regs, MX25_ADCQ_SR, &stats);
+ samples = MX25_ADCQ_SR_FDN(stats);
+ samples -= samples % priv->sample_count;
+
+ if (!samples)
+ return IRQ_HANDLED;
+
+ for (i = 0; i != samples; ++i)
+ regmap_read(priv->regs, MX25_ADCQ_FIFO, &sample_buf[i]);
+
+ mx25_tcq_create_event_for_4wire(priv, sample_buf, samples);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t mx25_tcq_irq(int irq, void *dev_id)
+{
+ struct mx25_tcq_priv *priv = dev_id;
+ u32 stat;
+ int ret = IRQ_HANDLED;
+
+ regmap_read(priv->regs, MX25_ADCQ_SR, &stat);
+
+ if (stat & (MX25_ADCQ_SR_FRR | MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR))
+ mx25_tcq_re_enable_touch_detection(priv);
+
+ if (stat & MX25_ADCQ_SR_PD) {
+ mx25_tcq_disable_touch_irq(priv);
+ mx25_tcq_force_queue_start(priv);
+ mx25_tcq_enable_fifo_irq(priv);
+ }
+
+ if (stat & MX25_ADCQ_SR_FDRY) {
+ mx25_tcq_disable_fifo_irq(priv);
+ ret = IRQ_WAKE_THREAD;
+ }
+
+ regmap_update_bits(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_FRR |
+ MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR |
+ MX25_ADCQ_SR_PD,
+ MX25_ADCQ_SR_FRR | MX25_ADCQ_SR_FUR |
+ MX25_ADCQ_SR_FOR | MX25_ADCQ_SR_PD);
+
+ return ret;
+}
+
+/* configure the state machine for a 4-wire touchscreen */
+static int mx25_tcq_init(struct mx25_tcq_priv *priv)
+{
+ u32 tgcr;
+ unsigned int ipg_div;
+ unsigned int adc_period;
+ unsigned int debounce_cnt;
+ unsigned int settling_cnt;
+ int itemct;
+ int error;
+
+ regmap_read(priv->core_regs, MX25_TSC_TGCR, &tgcr);
+ ipg_div = max_t(unsigned int, 4, MX25_TGCR_GET_ADCCLK(tgcr));
+ adc_period = USEC_PER_SEC * ipg_div * 2 + 2;
+ adc_period /= clk_get_rate(priv->clk) / 1000 + 1;
+ debounce_cnt = DIV_ROUND_UP(priv->pen_debounce, adc_period * 8) - 1;
+ settling_cnt = DIV_ROUND_UP(priv->settling_time, adc_period * 8) - 1;
+
+ /* Reset */
+ regmap_write(priv->regs, MX25_ADCQ_CR,
+ MX25_ADCQ_CR_QRST | MX25_ADCQ_CR_FRST);
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+ MX25_ADCQ_CR_QRST | MX25_ADCQ_CR_FRST, 0);
+
+ /* up to 128 * 8 ADC clocks are possible */
+ if (debounce_cnt > 127)
+ debounce_cnt = 127;
+
+ /* up to 255 * 8 ADC clocks are possible */
+ if (settling_cnt > 255)
+ settling_cnt = 255;
+
+ error = imx25_setup_queue_4wire(priv, settling_cnt, &itemct);
+ if (error)
+ return error;
+
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+ MX25_ADCQ_CR_LITEMID_MASK | MX25_ADCQ_CR_WMRK_MASK,
+ MX25_ADCQ_CR_LITEMID(itemct - 1) |
+ MX25_ADCQ_CR_WMRK(priv->expected_samples - 1));
+
+ /* setup debounce count */
+ regmap_update_bits(priv->core_regs, MX25_TSC_TGCR,
+ MX25_TGCR_PDBTIME_MASK,
+ MX25_TGCR_PDBTIME(debounce_cnt));
+
+ /* enable debounce */
+ regmap_update_bits(priv->core_regs, MX25_TSC_TGCR, MX25_TGCR_PDBEN,
+ MX25_TGCR_PDBEN);
+ regmap_update_bits(priv->core_regs, MX25_TSC_TGCR, MX25_TGCR_PDEN,
+ MX25_TGCR_PDEN);
+
+ /* enable the engine on demand */
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_QSM_MASK,
+ MX25_ADCQ_CR_QSM_FQS);
+
+ /* Enable repeat and repeat wait */
+ regmap_update_bits(priv->regs, MX25_ADCQ_CR,
+ MX25_ADCQ_CR_RPT | MX25_ADCQ_CR_RWAIT_MASK,
+ MX25_ADCQ_CR_RPT |
+ MX25_ADCQ_CR_RWAIT(MX25_TSC_REPEAT_WAIT));
+
+ return 0;
+}
+
+static int mx25_tcq_parse_dt(struct platform_device *pdev,
+ struct mx25_tcq_priv *priv)
+{
+ struct device_node *np = pdev->dev.of_node;
+ u32 wires;
+ int error;
+
+ /* Setup defaults */
+ priv->pen_threshold = 500;
+ priv->sample_count = 3;
+ priv->pen_debounce = 1000000;
+ priv->settling_time = 250000;
+
+ error = of_property_read_u32(np, "fsl,wires", &wires);
+ if (error) {
+ dev_err(&pdev->dev, "Failed to find fsl,wires properties\n");
+ return error;
+ }
+
+ if (wires == 4) {
+ priv->mode = MX25_TS_4WIRE;
+ } else {
+ dev_err(&pdev->dev, "%u-wire mode not supported\n", wires);
+ return -EINVAL;
+ }
+
+ /* These are optional, we don't care about the return values */
+ of_property_read_u32(np, "fsl,pen-threshold", &priv->pen_threshold);
+ of_property_read_u32(np, "fsl,settling-time-ns", &priv->settling_time);
+ of_property_read_u32(np, "fsl,pen-debounce-ns", &priv->pen_debounce);
+
+ return 0;
+}
+
+static int mx25_tcq_open(struct input_dev *idev)
+{
+ struct device *dev = &idev->dev;
+ struct mx25_tcq_priv *priv = dev_get_drvdata(dev);
+ int error;
+
+ error = clk_prepare_enable(priv->clk);
+ if (error) {
+ dev_err(dev, "Failed to enable ipg clock\n");
+ return error;
+ }
+
+ error = mx25_tcq_init(priv);
+ if (error) {
+ dev_err(dev, "Failed to init tcq\n");
+ clk_disable_unprepare(priv->clk);
+ return error;
+ }
+
+ mx25_tcq_re_enable_touch_detection(priv);
+
+ return 0;
+}
+
+static void mx25_tcq_close(struct input_dev *idev)
+{
+ struct mx25_tcq_priv *priv = input_get_drvdata(idev);
+
+ mx25_tcq_force_queue_stop(priv);
+ mx25_tcq_disable_touch_irq(priv);
+ mx25_tcq_disable_fifo_irq(priv);
+ clk_disable_unprepare(priv->clk);
+}
+
+static int mx25_tcq_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct input_dev *idev;
+ struct mx25_tcq_priv *priv;
+ struct mx25_tsadc *tsadc = dev_get_drvdata(pdev->dev.parent);
+ struct resource *res;
+ void __iomem *mem;
+ int error;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ priv->dev = dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ mem = devm_ioremap_resource(dev, res);
+ if (IS_ERR(mem))
+ return PTR_ERR(mem);
+
+ error = mx25_tcq_parse_dt(pdev, priv);
+ if (error)
+ return error;
+
+ priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_tcq_regconfig);
+ if (IS_ERR(priv->regs)) {
+ dev_err(dev, "Failed to initialize regmap\n");
+ return PTR_ERR(priv->regs);
+ }
+
+ priv->irq = platform_get_irq(pdev, 0);
+ if (priv->irq <= 0) {
+ dev_err(dev, "Failed to get IRQ\n");
+ return priv->irq;
+ }
+
+ idev = devm_input_allocate_device(dev);
+ if (!idev) {
+ dev_err(dev, "Failed to allocate input device\n");
+ return -ENOMEM;
+ }
+
+ idev->name = mx25_tcq_name;
+ input_set_capability(idev, EV_KEY, BTN_TOUCH);
+ input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
+ input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
+
+ idev->id.bustype = BUS_HOST;
+ idev->open = mx25_tcq_open;
+ idev->close = mx25_tcq_close;
+
+ priv->idev = idev;
+ input_set_drvdata(idev, priv);
+
+ priv->core_regs = tsadc->regs;
+ if (!priv->core_regs)
+ return -EINVAL;
+
+ priv->clk = tsadc->clk;
+ if (!priv->clk)
+ return -EINVAL;
+
+ platform_set_drvdata(pdev, priv);
+
+ error = devm_request_threaded_irq(dev, priv->irq, mx25_tcq_irq,
+ mx25_tcq_irq_thread, 0, pdev->name,
+ priv);
+ if (error) {
+ dev_err(dev, "Failed requesting IRQ\n");
+ return error;
+ }
+
+ error = input_register_device(idev);
+ if (error) {
+ dev_err(dev, "Failed to register input device\n");
+ return error;
+ }
+
+ return 0;
+}
+
+static struct platform_driver mx25_tcq_driver = {
+ .driver = {
+ .name = "mx25-tcq",
+ .of_match_table = mx25_tcq_ids,
+ },
+ .probe = mx25_tcq_probe,
+};
+module_platform_driver(mx25_tcq_driver);
+
+MODULE_DESCRIPTION("TS input driver for Freescale mx25");
+MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-rpi.git / commitdiff