// SPDX-License-Identifier: GPL-2.0
//
// Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <[email protected]>
// Based on driver from 2011:
// Juergen Beisert, Pengutronix <[email protected]>
//
// 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 const 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 */ }
};
MODULE_DEVICE_TABLE(of, mx25_tcq_ids);
#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(dev->parent);
void __iomem *mem;
int error;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = dev;
mem = devm_platform_ioremap_resource(pdev, 0);
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)
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 <[email protected]>");
MODULE_LICENSE("GPL v2");
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