diff options
Diffstat (limited to 'drivers/input/touchscreen/tsc2007_core.c')
| -rw-r--r-- | drivers/input/touchscreen/tsc2007_core.c | 441 |
1 files changed, 441 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/tsc2007_core.c b/drivers/input/touchscreen/tsc2007_core.c new file mode 100644 index 000000000..3e871d182 --- /dev/null +++ b/drivers/input/touchscreen/tsc2007_core.c @@ -0,0 +1,441 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/input/touchscreen/tsc2007.c + * + * Copyright (c) 2008 MtekVision Co., Ltd. + * Kwangwoo Lee <kwlee@mtekvision.com> + * + * Using code from: + * - ads7846.c + * Copyright (c) 2005 David Brownell + * Copyright (c) 2006 Nokia Corporation + * - corgi_ts.c + * Copyright (C) 2004-2005 Richard Purdie + * - omap_ts.[hc], ads7846.h, ts_osk.c + * Copyright (C) 2002 MontaVista Software + * Copyright (C) 2004 Texas Instruments + * Copyright (C) 2005 Dirk Behme + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/gpio/consumer.h> +#include <linux/input.h> +#include <linux/interrupt.h> +#include <linux/i2c.h> +#include <linux/mod_devicetable.h> +#include <linux/property.h> +#include <linux/platform_data/tsc2007.h> +#include "tsc2007.h" + +int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd) +{ + s32 data; + u16 val; + + data = i2c_smbus_read_word_data(tsc->client, cmd); + if (data < 0) { + dev_err(&tsc->client->dev, "i2c io error: %d\n", data); + return data; + } + + /* The protocol and raw data format from i2c interface: + * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P + * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit]. + */ + val = swab16(data) >> 4; + + dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val); + + return val; +} + +static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc) +{ + /* y- still on; turn on only y+ (and ADC) */ + tc->y = tsc2007_xfer(tsc, READ_Y); + + /* turn y- off, x+ on, then leave in lowpower */ + tc->x = tsc2007_xfer(tsc, READ_X); + + /* turn y+ off, x- on; we'll use formula #1 */ + tc->z1 = tsc2007_xfer(tsc, READ_Z1); + tc->z2 = tsc2007_xfer(tsc, READ_Z2); + + /* Prepare for next touch reading - power down ADC, enable PENIRQ */ + tsc2007_xfer(tsc, PWRDOWN); +} + +u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc) +{ + u32 rt = 0; + + /* range filtering */ + if (tc->x == MAX_12BIT) + tc->x = 0; + + if (likely(tc->x && tc->z1)) { + /* compute touch resistance using equation #1 */ + rt = tc->z2 - tc->z1; + rt *= tc->x; + rt *= tsc->x_plate_ohms; + rt /= tc->z1; + rt = (rt + 2047) >> 12; + } + + return rt; +} + +bool tsc2007_is_pen_down(struct tsc2007 *ts) +{ + /* + * NOTE: We can't rely on the pressure to determine the pen down + * state, even though this controller has a pressure sensor. + * The pressure value can fluctuate for quite a while after + * lifting the pen and in some cases may not even settle at the + * expected value. + * + * The only safe way to check for the pen up condition is in the + * work function by reading the pen signal state (it's a GPIO + * and IRQ). Unfortunately such callback is not always available, + * in that case we assume that the pen is down and expect caller + * to fall back on the pressure reading. + */ + + if (!ts->get_pendown_state) + return true; + + return ts->get_pendown_state(&ts->client->dev); +} + +static irqreturn_t tsc2007_soft_irq(int irq, void *handle) +{ + struct tsc2007 *ts = handle; + struct input_dev *input = ts->input; + struct ts_event tc; + u32 rt; + + while (!ts->stopped && tsc2007_is_pen_down(ts)) { + + /* pen is down, continue with the measurement */ + + mutex_lock(&ts->mlock); + tsc2007_read_values(ts, &tc); + mutex_unlock(&ts->mlock); + + rt = tsc2007_calculate_resistance(ts, &tc); + + if (!rt && !ts->get_pendown_state) { + /* + * If pressure reported is 0 and we don't have + * callback to check pendown state, we have to + * assume that pen was lifted up. + */ + break; + } + + if (rt <= ts->max_rt) { + dev_dbg(&ts->client->dev, + "DOWN point(%4d,%4d), resistance (%4u)\n", + tc.x, tc.y, rt); + + rt = ts->max_rt - rt; + + input_report_key(input, BTN_TOUCH, 1); + input_report_abs(input, ABS_X, tc.x); + input_report_abs(input, ABS_Y, tc.y); + input_report_abs(input, ABS_PRESSURE, rt); + + input_sync(input); + + } else { + /* + * Sample found inconsistent by debouncing or pressure is + * beyond the maximum. Don't report it to user space, + * repeat at least once more the measurement. + */ + dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt); + } + + wait_event_timeout(ts->wait, ts->stopped, ts->poll_period); + } + + dev_dbg(&ts->client->dev, "UP\n"); + + input_report_key(input, BTN_TOUCH, 0); + input_report_abs(input, ABS_PRESSURE, 0); + input_sync(input); + + if (ts->clear_penirq) + ts->clear_penirq(); + + return IRQ_HANDLED; +} + +static irqreturn_t tsc2007_hard_irq(int irq, void *handle) +{ + struct tsc2007 *ts = handle; + + if (tsc2007_is_pen_down(ts)) + return IRQ_WAKE_THREAD; + + if (ts->clear_penirq) + ts->clear_penirq(); + + return IRQ_HANDLED; +} + +static void tsc2007_stop(struct tsc2007 *ts) +{ + ts->stopped = true; + mb(); + wake_up(&ts->wait); + + disable_irq(ts->irq); +} + +static int tsc2007_open(struct input_dev *input_dev) +{ + struct tsc2007 *ts = input_get_drvdata(input_dev); + int err; + + ts->stopped = false; + mb(); + + enable_irq(ts->irq); + + /* Prepare for touch readings - power down ADC and enable PENIRQ */ + err = tsc2007_xfer(ts, PWRDOWN); + if (err < 0) { + tsc2007_stop(ts); + return err; + } + + return 0; +} + +static void tsc2007_close(struct input_dev *input_dev) +{ + struct tsc2007 *ts = input_get_drvdata(input_dev); + + tsc2007_stop(ts); +} + +static int tsc2007_get_pendown_state_gpio(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct tsc2007 *ts = i2c_get_clientdata(client); + + return gpiod_get_value(ts->gpiod); +} + +static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts) +{ + u32 val32; + u64 val64; + + if (!device_property_read_u32(dev, "ti,max-rt", &val32)) + ts->max_rt = val32; + else + ts->max_rt = MAX_12BIT; + + if (!device_property_read_u32(dev, "ti,fuzzx", &val32)) + ts->fuzzx = val32; + + if (!device_property_read_u32(dev, "ti,fuzzy", &val32)) + ts->fuzzy = val32; + + if (!device_property_read_u32(dev, "ti,fuzzz", &val32)) + ts->fuzzz = val32; + + if (!device_property_read_u64(dev, "ti,poll-period", &val64)) + ts->poll_period = msecs_to_jiffies(val64); + else + ts->poll_period = msecs_to_jiffies(1); + + if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) { + ts->x_plate_ohms = val32; + } else { + dev_err(dev, "Missing ti,x-plate-ohms device property\n"); + return -EINVAL; + } + + ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN); + if (IS_ERR(ts->gpiod)) + return PTR_ERR(ts->gpiod); + + if (ts->gpiod) + ts->get_pendown_state = tsc2007_get_pendown_state_gpio; + else + dev_warn(dev, "Pen down GPIO is not specified in properties\n"); + + return 0; +} + +static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts, + const struct tsc2007_platform_data *pdata, + const struct i2c_device_id *id) +{ + ts->model = pdata->model; + ts->x_plate_ohms = pdata->x_plate_ohms; + ts->max_rt = pdata->max_rt ? : MAX_12BIT; + ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1); + ts->get_pendown_state = pdata->get_pendown_state; + ts->clear_penirq = pdata->clear_penirq; + ts->fuzzx = pdata->fuzzx; + ts->fuzzy = pdata->fuzzy; + ts->fuzzz = pdata->fuzzz; + + if (pdata->x_plate_ohms == 0) { + dev_err(dev, "x_plate_ohms is not set up in platform data\n"); + return -EINVAL; + } + + return 0; +} + +static void tsc2007_call_exit_platform_hw(void *data) +{ + struct device *dev = data; + const struct tsc2007_platform_data *pdata = dev_get_platdata(dev); + + pdata->exit_platform_hw(); +} + +static int tsc2007_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + const struct tsc2007_platform_data *pdata = + dev_get_platdata(&client->dev); + struct tsc2007 *ts; + struct input_dev *input_dev; + int err; + + if (!i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_READ_WORD_DATA)) + return -EIO; + + ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL); + if (!ts) + return -ENOMEM; + + if (pdata) + err = tsc2007_probe_pdev(&client->dev, ts, pdata, id); + else + err = tsc2007_probe_properties(&client->dev, ts); + if (err) + return err; + + input_dev = devm_input_allocate_device(&client->dev); + if (!input_dev) + return -ENOMEM; + + i2c_set_clientdata(client, ts); + + ts->client = client; + ts->irq = client->irq; + ts->input = input_dev; + + init_waitqueue_head(&ts->wait); + mutex_init(&ts->mlock); + + snprintf(ts->phys, sizeof(ts->phys), + "%s/input0", dev_name(&client->dev)); + + input_dev->name = "TSC2007 Touchscreen"; + input_dev->phys = ts->phys; + input_dev->id.bustype = BUS_I2C; + + input_dev->open = tsc2007_open; + input_dev->close = tsc2007_close; + + input_set_drvdata(input_dev, ts); + + input_set_capability(input_dev, EV_KEY, BTN_TOUCH); + + input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0); + input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0); + input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, + ts->fuzzz, 0); + + if (pdata) { + if (pdata->exit_platform_hw) { + err = devm_add_action(&client->dev, + tsc2007_call_exit_platform_hw, + &client->dev); + if (err) { + dev_err(&client->dev, + "Failed to register exit_platform_hw action, %d\n", + err); + return err; + } + } + + if (pdata->init_platform_hw) + pdata->init_platform_hw(); + } + + err = devm_request_threaded_irq(&client->dev, ts->irq, + tsc2007_hard_irq, tsc2007_soft_irq, + IRQF_ONESHOT, + client->dev.driver->name, ts); + if (err) { + dev_err(&client->dev, "Failed to request irq %d: %d\n", + ts->irq, err); + return err; + } + + tsc2007_stop(ts); + + /* power down the chip (TSC2007_SETUP does not ACK on I2C) */ + err = tsc2007_xfer(ts, PWRDOWN); + if (err < 0) { + dev_err(&client->dev, + "Failed to setup chip: %d\n", err); + return err; /* chip does not respond */ + } + + err = input_register_device(input_dev); + if (err) { + dev_err(&client->dev, + "Failed to register input device: %d\n", err); + return err; + } + + err = tsc2007_iio_configure(ts); + if (err) { + dev_err(&client->dev, + "Failed to register with IIO: %d\n", err); + return err; + } + + return 0; +} + +static const struct i2c_device_id tsc2007_idtable[] = { + { "tsc2007", 0 }, + { } +}; + +MODULE_DEVICE_TABLE(i2c, tsc2007_idtable); + +static const struct of_device_id tsc2007_of_match[] = { + { .compatible = "ti,tsc2007" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, tsc2007_of_match); + +static struct i2c_driver tsc2007_driver = { + .driver = { + .name = "tsc2007", + .of_match_table = tsc2007_of_match, + }, + .id_table = tsc2007_idtable, + .probe = tsc2007_probe, +}; + +module_i2c_driver(tsc2007_driver); + +MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>"); +MODULE_DESCRIPTION("TSC2007 TouchScreen Driver"); +MODULE_LICENSE("GPL"); |