442 lines
10 KiB
C
442 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* drivers/input/touchscreen/tsc2007.c
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*
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* Copyright (c) 2008 MtekVision Co., Ltd.
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* Kwangwoo Lee <kwlee@mtekvision.com>
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*
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* Using code from:
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* - ads7846.c
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* Copyright (c) 2005 David Brownell
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* Copyright (c) 2006 Nokia Corporation
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* - corgi_ts.c
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* Copyright (C) 2004-2005 Richard Purdie
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* - omap_ts.[hc], ads7846.h, ts_osk.c
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* Copyright (C) 2002 MontaVista Software
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* Copyright (C) 2004 Texas Instruments
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* Copyright (C) 2005 Dirk Behme
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/gpio/consumer.h>
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#include <linux/input.h>
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#include <linux/interrupt.h>
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#include <linux/i2c.h>
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#include <linux/mod_devicetable.h>
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#include <linux/property.h>
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#include <linux/platform_data/tsc2007.h>
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#include "tsc2007.h"
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int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
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{
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s32 data;
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u16 val;
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data = i2c_smbus_read_word_data(tsc->client, cmd);
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if (data < 0) {
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dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
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return data;
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}
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/* The protocol and raw data format from i2c interface:
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* S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
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* Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
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*/
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val = swab16(data) >> 4;
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dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
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return val;
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}
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static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
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{
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/* y- still on; turn on only y+ (and ADC) */
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tc->y = tsc2007_xfer(tsc, READ_Y);
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/* turn y- off, x+ on, then leave in lowpower */
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tc->x = tsc2007_xfer(tsc, READ_X);
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/* turn y+ off, x- on; we'll use formula #1 */
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tc->z1 = tsc2007_xfer(tsc, READ_Z1);
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tc->z2 = tsc2007_xfer(tsc, READ_Z2);
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/* Prepare for next touch reading - power down ADC, enable PENIRQ */
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tsc2007_xfer(tsc, PWRDOWN);
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}
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u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc)
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{
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u32 rt = 0;
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/* range filtering */
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if (tc->x == MAX_12BIT)
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tc->x = 0;
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if (likely(tc->x && tc->z1)) {
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/* compute touch resistance using equation #1 */
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rt = tc->z2 - tc->z1;
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rt *= tc->x;
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rt *= tsc->x_plate_ohms;
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rt /= tc->z1;
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rt = (rt + 2047) >> 12;
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}
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return rt;
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}
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bool tsc2007_is_pen_down(struct tsc2007 *ts)
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{
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/*
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* NOTE: We can't rely on the pressure to determine the pen down
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* state, even though this controller has a pressure sensor.
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* The pressure value can fluctuate for quite a while after
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* lifting the pen and in some cases may not even settle at the
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* expected value.
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*
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* The only safe way to check for the pen up condition is in the
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* work function by reading the pen signal state (it's a GPIO
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* and IRQ). Unfortunately such callback is not always available,
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* in that case we assume that the pen is down and expect caller
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* to fall back on the pressure reading.
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*/
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if (!ts->get_pendown_state)
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return true;
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return ts->get_pendown_state(&ts->client->dev);
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}
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static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
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{
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struct tsc2007 *ts = handle;
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struct input_dev *input = ts->input;
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struct ts_event tc;
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u32 rt;
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while (!ts->stopped && tsc2007_is_pen_down(ts)) {
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/* pen is down, continue with the measurement */
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mutex_lock(&ts->mlock);
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tsc2007_read_values(ts, &tc);
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mutex_unlock(&ts->mlock);
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rt = tsc2007_calculate_resistance(ts, &tc);
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if (!rt && !ts->get_pendown_state) {
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/*
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* If pressure reported is 0 and we don't have
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* callback to check pendown state, we have to
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* assume that pen was lifted up.
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*/
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break;
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}
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if (rt <= ts->max_rt) {
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dev_dbg(&ts->client->dev,
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"DOWN point(%4d,%4d), resistance (%4u)\n",
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tc.x, tc.y, rt);
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rt = ts->max_rt - rt;
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input_report_key(input, BTN_TOUCH, 1);
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input_report_abs(input, ABS_X, tc.x);
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input_report_abs(input, ABS_Y, tc.y);
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input_report_abs(input, ABS_PRESSURE, rt);
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input_sync(input);
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} else {
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/*
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* Sample found inconsistent by debouncing or pressure is
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* beyond the maximum. Don't report it to user space,
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* repeat at least once more the measurement.
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*/
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dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
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}
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wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
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}
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dev_dbg(&ts->client->dev, "UP\n");
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input_report_key(input, BTN_TOUCH, 0);
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input_report_abs(input, ABS_PRESSURE, 0);
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input_sync(input);
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if (ts->clear_penirq)
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ts->clear_penirq();
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return IRQ_HANDLED;
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}
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static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
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{
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struct tsc2007 *ts = handle;
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if (tsc2007_is_pen_down(ts))
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return IRQ_WAKE_THREAD;
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if (ts->clear_penirq)
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ts->clear_penirq();
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return IRQ_HANDLED;
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}
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static void tsc2007_stop(struct tsc2007 *ts)
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{
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ts->stopped = true;
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mb();
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wake_up(&ts->wait);
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disable_irq(ts->irq);
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}
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static int tsc2007_open(struct input_dev *input_dev)
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{
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struct tsc2007 *ts = input_get_drvdata(input_dev);
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int err;
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ts->stopped = false;
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mb();
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enable_irq(ts->irq);
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/* Prepare for touch readings - power down ADC and enable PENIRQ */
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err = tsc2007_xfer(ts, PWRDOWN);
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if (err < 0) {
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tsc2007_stop(ts);
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return err;
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}
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return 0;
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}
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static void tsc2007_close(struct input_dev *input_dev)
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{
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struct tsc2007 *ts = input_get_drvdata(input_dev);
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tsc2007_stop(ts);
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}
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static int tsc2007_get_pendown_state_gpio(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct tsc2007 *ts = i2c_get_clientdata(client);
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return gpiod_get_value(ts->gpiod);
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}
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static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts)
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{
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u32 val32;
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u64 val64;
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if (!device_property_read_u32(dev, "ti,max-rt", &val32))
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ts->max_rt = val32;
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else
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ts->max_rt = MAX_12BIT;
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if (!device_property_read_u32(dev, "ti,fuzzx", &val32))
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ts->fuzzx = val32;
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if (!device_property_read_u32(dev, "ti,fuzzy", &val32))
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ts->fuzzy = val32;
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if (!device_property_read_u32(dev, "ti,fuzzz", &val32))
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ts->fuzzz = val32;
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if (!device_property_read_u64(dev, "ti,poll-period", &val64))
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ts->poll_period = msecs_to_jiffies(val64);
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else
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ts->poll_period = msecs_to_jiffies(1);
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if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) {
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ts->x_plate_ohms = val32;
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} else {
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dev_err(dev, "Missing ti,x-plate-ohms device property\n");
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return -EINVAL;
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}
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ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
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if (IS_ERR(ts->gpiod))
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return PTR_ERR(ts->gpiod);
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if (ts->gpiod)
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ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
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else
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dev_warn(dev, "Pen down GPIO is not specified in properties\n");
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return 0;
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}
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static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts,
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const struct tsc2007_platform_data *pdata,
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const struct i2c_device_id *id)
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{
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ts->model = pdata->model;
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ts->x_plate_ohms = pdata->x_plate_ohms;
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ts->max_rt = pdata->max_rt ? : MAX_12BIT;
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ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1);
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ts->get_pendown_state = pdata->get_pendown_state;
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ts->clear_penirq = pdata->clear_penirq;
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ts->fuzzx = pdata->fuzzx;
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ts->fuzzy = pdata->fuzzy;
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ts->fuzzz = pdata->fuzzz;
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if (pdata->x_plate_ohms == 0) {
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dev_err(dev, "x_plate_ohms is not set up in platform data\n");
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return -EINVAL;
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}
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return 0;
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}
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static void tsc2007_call_exit_platform_hw(void *data)
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{
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struct device *dev = data;
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const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
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pdata->exit_platform_hw();
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}
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static int tsc2007_probe(struct i2c_client *client)
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{
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const struct i2c_device_id *id = i2c_client_get_device_id(client);
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const struct tsc2007_platform_data *pdata =
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dev_get_platdata(&client->dev);
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struct tsc2007 *ts;
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struct input_dev *input_dev;
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int err;
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if (!i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_READ_WORD_DATA))
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return -EIO;
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ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
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if (!ts)
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return -ENOMEM;
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if (pdata)
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err = tsc2007_probe_pdev(&client->dev, ts, pdata, id);
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else
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err = tsc2007_probe_properties(&client->dev, ts);
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if (err)
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return err;
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input_dev = devm_input_allocate_device(&client->dev);
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if (!input_dev)
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return -ENOMEM;
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i2c_set_clientdata(client, ts);
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ts->client = client;
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ts->irq = client->irq;
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ts->input = input_dev;
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init_waitqueue_head(&ts->wait);
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mutex_init(&ts->mlock);
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snprintf(ts->phys, sizeof(ts->phys),
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"%s/input0", dev_name(&client->dev));
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input_dev->name = "TSC2007 Touchscreen";
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input_dev->phys = ts->phys;
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input_dev->id.bustype = BUS_I2C;
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input_dev->open = tsc2007_open;
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input_dev->close = tsc2007_close;
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input_set_drvdata(input_dev, ts);
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input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
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input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
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input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
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input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
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ts->fuzzz, 0);
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if (pdata) {
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if (pdata->exit_platform_hw) {
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err = devm_add_action(&client->dev,
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tsc2007_call_exit_platform_hw,
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&client->dev);
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if (err) {
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dev_err(&client->dev,
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"Failed to register exit_platform_hw action, %d\n",
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err);
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return err;
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}
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}
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if (pdata->init_platform_hw)
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pdata->init_platform_hw();
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}
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err = devm_request_threaded_irq(&client->dev, ts->irq,
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tsc2007_hard_irq, tsc2007_soft_irq,
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IRQF_ONESHOT,
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client->dev.driver->name, ts);
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if (err) {
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dev_err(&client->dev, "Failed to request irq %d: %d\n",
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ts->irq, err);
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return err;
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}
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tsc2007_stop(ts);
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/* power down the chip (TSC2007_SETUP does not ACK on I2C) */
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err = tsc2007_xfer(ts, PWRDOWN);
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if (err < 0) {
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dev_err(&client->dev,
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"Failed to setup chip: %d\n", err);
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return err; /* chip does not respond */
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}
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err = input_register_device(input_dev);
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if (err) {
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dev_err(&client->dev,
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"Failed to register input device: %d\n", err);
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return err;
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}
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err = tsc2007_iio_configure(ts);
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if (err) {
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dev_err(&client->dev,
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"Failed to register with IIO: %d\n", err);
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return err;
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}
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return 0;
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}
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static const struct i2c_device_id tsc2007_idtable[] = {
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{ "tsc2007", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
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static const struct of_device_id tsc2007_of_match[] = {
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{ .compatible = "ti,tsc2007" },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, tsc2007_of_match);
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static struct i2c_driver tsc2007_driver = {
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.driver = {
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.name = "tsc2007",
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.of_match_table = tsc2007_of_match,
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},
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.id_table = tsc2007_idtable,
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.probe_new = tsc2007_probe,
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};
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module_i2c_driver(tsc2007_driver);
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MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
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MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
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MODULE_LICENSE("GPL");
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