Hi all,
I'm working on a touchscreen driver for T.I.'s TSC2008 controller. It's an SPI hybrid of the ADS784x and TSC2007 families. Patch is attached, use "patch -p0 < tsc2008.patch" to update your branch. (I'll switch to -p1 for the final release, after runtime testing is finished.)
I'm hoping that someone out there has an interest in reviewing the code. It currently passes both checkpatch.pl standards and compiles (as built-in and module).
Thanks in advance!
Chris
-----------------
Index: include/linux/spi/tsc2008.h
===================================================================
--- include/linux/spi/tsc2008.h (revision 0)
+++ include/linux/spi/tsc2008.h (revision 21)
@@ -0,0 +1,22 @@
+#ifndef __LINUX_SPI_TSC2008_H
+#define __LINUX_SPI_TSC2008_H
+
+/* linux/spi/tsc2008.h */
+
+#define TSC2008_ADC_8BITS (0x01)
+#define TSC2008_ADC_12BITS (0x02)
+
+struct tsc2008_platform_data {
+ u16 model; /* 2008. */
+ u16 x_plate_ohms;
+ u16 adc_bits; /* TSC2008_ADC_12BITS (default)
+ or TSC2008_ADC_8BITS */
+ u16 irq; /* GPIO to be used for IRQ */
+
+ u8 pull_up; /* 50 (default) or 90 ohms */
+ u8 mav; /* 0 (enable) or 1 (bypass) */
+
+ int (*get_pendown_state)(void);
+};
+
+#endif
Index: drivers/input/touchscreen/Kconfig
===================================================================
--- drivers/input/touchscreen/Kconfig (revision 11)
+++ drivers/input/touchscreen/Kconfig (revision 21)
@@ -408,4 +408,17 @@
To compile this driver as a module, choose M here: the
module will be called tsc2007.
+config TOUCHSCREEN_TSC2008
+ tristate "TSC2008 based touchscreens"
+ depends on SPI_MASTER
+ help
+ Say Y here if you have a touchscreen interface using the
+ TSC2008 controller, and your board-specific setup code
+ includes that in its table of SPI devices.
+
+ If unsure, say N.
+
+ To compile this driver as a module, choose M here: the
+ module will be called tsc2008.
+
endif
Index: drivers/input/touchscreen/tsc2008.c
===================================================================
--- drivers/input/touchscreen/tsc2008.c (revision 0)
+++ drivers/input/touchscreen/tsc2008.c (revision 21)
@@ -0,0 +1,557 @@
+/*
+ * drivers/input/touchscreen/tsc2008.c
+ *
+ * Copyright (c) 2009 Cyber Switching, Inc.
+ * Chris Verges <chrisv@xxxxxxxxxxxxxxxxxx>
+ *
+ * Using code from:
+ * - tsc2008_core.c, tsc2008.h, tsc2008_platform.c
+ * Copyright (c) 2008 MindTree Limited
+ * - tsc2007.c
+ * Copyright (c) 2008 MtekVision Co., Ltd.
+ * - 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
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/hrtimer.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/tsc2008.h>
+
+#define DRV_VERSION "0.1"
+
+#define TS_POLL_DELAY (10 * 1000) /* ns delay before the first sample */
+#define TS_POLL_PERIOD (5 * 1000) /* ns delay between samples */
+
+#define TSC2008_MEASURE_Y (0x1 << 4)
+#define TSC2008_SETUP (0x2 << 4)
+#define TSC2008_MEASURE_Z1 (0x3 << 4)
+#define TSC2008_MEASURE_Z2 (0x4 << 4)
+#define TSC2008_MEASURE_X (0x5 << 4)
+#define TSC2008_MEASURE_AUX (0x6 << 4)
+#define TSC2008_MEASURE_TEMP2 (0x7 << 4)
+#define TSC2008_START (0x8 << 4)
+
+#define TSC2008_12BIT (0x0 << 3)
+#define TSC2008_8BIT (0x1 << 3)
+
+#define TSC2008_REF_DIFF (0x0 << 2)
+#define TSC2008_REF_SINGLE (0x1 << 2)
+
+#define TSC2008_POWER_OFF_IRQ_EN (0x0 << 0)
+#define TSC2008_ADC_ON_IRQ_DIS0 (0x1 << 0)
+#define TSC2008_ADC_OFF_IRQ_EN (0x2 << 0)
+#define TSC2008_ADC_ON_IRQ_DIS1 (0x3 << 0)
+
+#define TSC2008_RESET (0x1)
+
+#define TSC2008_PENIRQ_50_OHM (0x0 << 3)
+#define TSC2008_PENIRQ_90_OHM (0x1 << 3)
+
+#define TSC2008_MAV_ENABLE (0x0 << 2)
+#define TSC2008_MAV_BYPASS (0x1 << 2)
+
+#define TSC2008_SOFTWARE_RESET \
+ (TSC2008_START | TSC2008_SETUP | TSC2008_RESET)
+
+static struct spi_driver tsc2008_driver;
+
+struct ts_event {
+ u16 x;
+ u16 y;
+ u16 z1, z2;
+};
+
+struct tsc2008 {
+ struct input_dev *input;
+ char phys[32];
+
+ struct spi_device *spi;
+
+ u16 model;
+ u16 x_plate_ohms;
+ u8 adc_bits;
+ int irq;
+
+ spinlock_t lock;
+ unsigned pendown;
+ struct ts_event tc;
+
+ struct timer_list timer;
+ struct spi_message msg[6];
+ struct spi_transfer xfer[12];
+
+ u8 read_x;
+ u8 read_y;
+ u8 read_z1;
+ u8 read_z2;
+
+ u16 x_pos;
+ u16 y_pos;
+ u16 z1_val;
+ u16 z2_val;
+
+ u8 msg_idx;
+
+ int (*get_pendown_state)(void);
+};
+
+static void tsc2008_report(void *data)
+{
+ struct tsc2008 *ts = (struct tsc2008 *)data;
+ struct input_dev *input = ts->input;
+ u16 tmp;
+ u16 pressure;
+
+ /* The X and Y coordinates read from the TSC2008 need to be swapped
+ * to work with the X window system.
+ */
+ switch (ts->adc_bits) {
+ case TSC2008_ADC_12BITS:
+ /* TSC2008 transfers in big endian format (MSB to LSB) as a
+ * 12-bit number. Need to convert endianness and truncate.
+ */
+ tmp = ts->x_pos;
+ ts->x_pos = ((be16_to_cpu(ts->y_pos) << 1) >> 4) & 0x0FFF;
+ ts->y_pos = ((be16_to_cpu(tmp) << 1) >> 4) & 0x0FFF;
+ ts->z1_val = ((be16_to_cpu(ts->z1_val) << 1) >> 4) & 0x0FFF;
+ ts->z2_val = ((be16_to_cpu(ts->z2_val) << 1) >> 4) & 0x0FFF;
+ break;
+ case TSC2008_ADC_8BITS:
+ tmp = ts->x_pos;
+ ts->x_pos = (ts->y_pos << 1) & 0x00FF;
+ ts->y_pos = (tmp << 1) & 0x00FF;
+ ts->z1_val = (ts->z1_val << 1) & 0x00FF;
+ ts->z2_val = (ts->z2_val << 1) & 0x00FF;
+ break;
+ }
+
+ /* Calculate the pressure according to Equation #1 on page 12
+ * of the TSC2008 datasheet.
+ */
+ pressure = ts->z2_val / ts->z1_val;
+ pressure -= 1;
+ pressure *= ts->y_pos;
+ pressure *= ts->x_plate_ohms;
+ pressure /= 4096;
+
+ /* Report the values to the input subsystem */
+ input_report_abs(input, ABS_X, ts->x_pos);
+ input_report_abs(input, ABS_Y, ts->y_pos);
+ input_report_abs(input, ABS_PRESSURE, pressure);
+ input_report_abs(input, BTN_TOUCH, 1);
+
+ /* Reset the SPI message queue */
+ ts->msg_idx = 0;
+
+ /* Check for prolonged touches (i.e. drags and drawings) */
+ if (ts->get_pendown_state())
+ mod_timer(&ts->timer, jiffies + 2);
+ else {
+ input_report_abs(input, ABS_PRESSURE, 0);
+ input_report_abs(input, BTN_TOUCH, 0);
+ input_sync(input);
+ enable_irq(ts->irq);
+ }
+}
+
+static void tsc2008_spi_again_submit(void *data)
+{
+ struct tsc2008 *ts = data;
+ struct spi_message *m;
+ struct spi_transfer *t;
+
+ spin_lock(&ts->lock);
+
+ m = &ts->msg[ts->msg_idx];
+ t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
+ ts->msg_idx++;
+
+ m = &ts->msg[ts->msg_idx];
+ spi_async(ts->spi, m);
+
+ spin_unlock(&ts->lock);
+}
+
+static void tsc2008_timer(unsigned long arg)
+{
+ struct tsc2008 *ts = (struct tsc2008 *)arg;
+ int stat;
+
+ spin_lock_irq(&ts->lock);
+
+ if (unlikely(!ts->get_pendown_state() && ts->pendown)) {
+ struct input_dev *input = ts->input;
+
+ dev_dbg(&ts->spi->dev, "pen is up\n");
+
+ input_report_key(input, BTN_TOUCH, 0);
+ input_report_abs(input, ABS_PRESSURE, 0);
+ input_sync(input);
+
+ ts->pendown = 0;
+ enable_irq(ts->irq);
+ } else {
+ /* pen is still down, continue with the measurement */
+ dev_dbg(&ts->spi->dev, "pen is still down\n");
+
+ ts->msg_idx = 0;
+ stat = spi_async(ts->spi, &ts->msg[0]);
+ if (stat)
+ dev_err(&ts->spi->dev, "spi_async----> %d\n", stat);
+ }
+
+ spin_unlock_irq(&ts->lock);
+}
+
+static irqreturn_t tsc2008_handle_penirq(int irq, void *handle)
+{
+ struct tsc2008 *ts = handle;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ts->lock, flags);
+
+ if (likely(ts->get_pendown_state())) {
+ disable_irq(ts->irq);
+ mod_timer(&ts->timer, jiffies + 3);
+ }
+
+ spin_unlock_irqrestore(&ts->lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static void tsc2008_spi_setup(struct tsc2008 *ts)
+{
+ struct spi_message *m;
+ struct spi_transfer *t;
+ u16 rx_len;
+ u16 tx_delay;
+
+ switch (ts->adc_bits) {
+ case TSC2008_ADC_8BITS:
+ tx_delay = 50;
+ rx_len = 1;
+ break;
+ case TSC2008_ADC_12BITS:
+ default:
+ tx_delay = 100;
+ rx_len = 2;
+ break;
+ }
+
+ /* Setup the SPI message for reading X */
+ {
+ m = &ts->msg[0];
+ t = &ts->xfer[0];
+
+ /* Transmit the command */
+ spi_message_init(m);
+ memset(t, 0, sizeof(*t));
+ t->tx_buf = &ts->read_x;
+ t->len = 1;
+ t->delay_usecs = tx_delay;
+ spi_message_add_tail(t, m);
+
+ /* Receive the results */
+ t++;
+ memset(t, 0, sizeof(*t));
+ t->rx_buf = &ts->x_pos;
+ t->len = rx_len;
+ spi_message_add_tail(t, m);
+
+ m->complete = tsc2008_spi_again_submit;
+ m->context = ts;
+ }
+
+ /* Setup the SPI message for reading Y */
+ {
+ m++;
+ t++;
+
+ /* Transmit the command */
+ spi_message_init(m);
+ memset(t, 0, sizeof(*t));
+ t->tx_buf = &ts->read_y;
+ t->len = 1;
+ t->delay_usecs = tx_delay;
+ spi_message_add_tail(t, m);
+
+ /* Receive the results */
+ t++;
+ memset(t, 0, sizeof(*t));
+ t->rx_buf = &ts->y_pos;
+ t->len = rx_len;
+ spi_message_add_tail(t, m);
+
+ m->complete = tsc2008_spi_again_submit;
+ m->context = ts;
+ }
+
+ /* Setup the SPI message for reading Z1 */
+ {
+ m++;
+ t++;
+
+ /* Transmit the command */
+ spi_message_init(m);
+ memset(t, 0, sizeof(*t));
+ t->tx_buf = &ts->read_z1;
+ t->len = 1;
+ t->delay_usecs = tx_delay;
+ spi_message_add_tail(t, m);
+
+ /* Receive the results */
+ t++;
+ memset(t, 0, sizeof(*t));
+ t->rx_buf = &ts->z1_val;
+ t->len = rx_len;
+ spi_message_add_tail(t, m);
+
+ m->complete = tsc2008_spi_again_submit;
+ m->context = ts;
+ }
+
+ /* Setup the SPI message for reading Z2 */
+ {
+ m++;
+ t++;
+
+ /* Transmit the command */
+ spi_message_init(m);
+ memset(t, 0, sizeof(*t));
+ t->tx_buf = &ts->read_z2;
+ t->len = 1;
+ t->delay_usecs = tx_delay;
+ spi_message_add_tail(t, m);
+
+ /* Receive the results */
+ t++;
+ memset(t, 0, sizeof(*t));
+ t->rx_buf = &ts->z2_val;
+ t->len = rx_len;
+ spi_message_add_tail(t, m);
+
+ m->complete = tsc2008_report;
+ m->context = ts;
+ }
+}
+
+static int __devinit tsc2008_probe(struct spi_device *spi)
+{
+ struct tsc2008 *ts;
+ struct tsc2008_platform_data *pdata;
+ struct input_dev *input;
+ int err;
+ u8 tx_buf;
+
+ pdata = spi->dev.platform_data;
+ if (!pdata) {
+ dev_err(&spi->dev, "no platform data?!\n");
+ return -ENODEV;
+ }
+
+ /* don't exceed the max specified sample rate */
+ if (spi->max_speed_hz > 25000000) {
+ dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
+ (spi->max_speed_hz / 1000));
+ return -EINVAL;
+ }
+
+ /* While the TSC2008 may like 12-bit words, most SPI controller
+ * drivers may not. Stick with something portable.
+ */
+ spi->bits_per_word = 8;
+ spi->mode = SPI_MODE_0;
+ err = spi_setup(spi);
+ if (err < 0)
+ return err;
+
+ /* Allocate the memory required for this driver */
+ ts = kzalloc(sizeof(*ts), GFP_KERNEL);
+ input = input_allocate_device();
+ if (!ts || !input) {
+ err = -ENOMEM;
+ goto err_free_mem;
+ }
+
+ /* Initialize the TSC2008 driver data structure */
+ dev_set_drvdata(&spi->dev, ts);
+
+ init_timer(&ts->timer);
+ spin_lock_init(&ts->lock);
+
+ ts->spi = spi;
+ ts->input = input;
+ ts->timer.function = tsc2008_timer;
+ ts->timer.data = (unsigned long)ts;
+ ts->model = pdata->model ? : 2008;
+ ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
+ ts->adc_bits = pdata->adc_bits ? : TSC2008_ADC_12BITS;
+ ts->irq = pdata->irq;
+ ts->get_pendown_state = pdata->get_pendown_state;
+
+ snprintf(ts->phys, sizeof(ts->phys),
+ "%s/input0", dev_name(&spi->dev));
+
+ /* Initialize the input driver */
+ input->name = "TSC2008 TouchScreen";
+ input->phys = ts->phys;
+ input->dev.parent = &spi->dev;
+ input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+ input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+
+ /* Set the resolution mode that will be used -- 8 bits or 12 bits */
+ switch (ts->adc_bits) {
+ default:
+ /* If nothing valid is specified, assume 12 bits */
+ ts->adc_bits = TSC2008_ADC_12BITS;
+ case TSC2008_ADC_12BITS:
+ ts->read_x = TSC2008_START | TSC2008_MEASURE_X
+ | TSC2008_12BIT | TSC2008_REF_DIFF
+ | TSC2008_ADC_ON_IRQ_DIS0;
+ ts->read_y = TSC2008_START | TSC2008_MEASURE_Y
+ | TSC2008_12BIT | TSC2008_REF_DIFF
+ | TSC2008_ADC_ON_IRQ_DIS0;
+ ts->read_z1 = TSC2008_START | TSC2008_MEASURE_Z1
+ | TSC2008_12BIT | TSC2008_REF_DIFF
+ | TSC2008_ADC_ON_IRQ_DIS0;
+ ts->read_z2 = TSC2008_START | TSC2008_MEASURE_Z2
+ | TSC2008_12BIT | TSC2008_REF_DIFF
+ | TSC2008_ADC_ON_IRQ_DIS0;
+
+ input_set_abs_params(input, ABS_X, 0, 4096, 0, 0);
+ input_set_abs_params(input, ABS_Y, 0, 4096, 0, 0);
+ input_set_abs_params(input, ABS_PRESSURE, 0, 4096, 0, 0);
+ break;
+ case TSC2008_ADC_8BITS:
+ ts->read_x = TSC2008_START | TSC2008_MEASURE_X
+ | TSC2008_8BIT | TSC2008_REF_DIFF
+ | TSC2008_ADC_ON_IRQ_DIS0;
+ ts->read_y = TSC2008_START | TSC2008_MEASURE_Y
+ | TSC2008_8BIT | TSC2008_REF_DIFF
+ | TSC2008_ADC_ON_IRQ_DIS0;
+ ts->read_z1 = TSC2008_START | TSC2008_MEASURE_Z1
+ | TSC2008_8BIT | TSC2008_REF_DIFF
+ | TSC2008_ADC_ON_IRQ_DIS0;
+ ts->read_z2 = TSC2008_START | TSC2008_MEASURE_Z2
+ | TSC2008_8BIT | TSC2008_REF_DIFF
+ | TSC2008_ADC_ON_IRQ_DIS0;
+
+ input_set_abs_params(input, ABS_X, 0, 256, 0, 0);
+ input_set_abs_params(input, ABS_Y, 0, 256, 0, 0);
+ input_set_abs_params(input, ABS_PRESSURE, 0, 256, 0, 0);
+ break;
+ }
+
+ /* Register the IRQ */
+ err = request_irq(ts->irq, tsc2008_handle_penirq, IRQF_TRIGGER_FALLING,
+ spi->dev.driver->name, ts);
+ if (err < 0) {
+ dev_err(&spi->dev, "irq %d busy?\n", spi->irq);
+ goto err_free_mem;
+ }
+
+ /* Register the input driver */
+ err = input_register_device(input);
+ if (err)
+ goto err_free_irq;
+
+ /* Reset the controller */
+ tx_buf = TSC2008_SOFTWARE_RESET;
+ err = spi_write(spi, &tx_buf, 1);
+ if (err < 0)
+ goto err_free_irq;
+ udelay(200);
+
+ /* Initialize the controller */
+ tx_buf = TSC2008_START | TSC2008_SETUP;
+ switch (pdata->pull_up) {
+ case 50:
+ tx_buf |= TSC2008_PENIRQ_50_OHM;
+ break;
+ case 90:
+ tx_buf |= TSC2008_PENIRQ_90_OHM;
+ break;
+ }
+ switch (pdata->mav) {
+ case 0:
+ tx_buf |= TSC2008_MAV_ENABLE;
+ break;
+ case 1:
+ tx_buf |= TSC2008_MAV_BYPASS;
+ break;
+ }
+ err = spi_write(spi, &tx_buf, 1);
+ if (err < 0)
+ goto err_free_irq;
+ udelay(200);
+
+ /* Create the SPI message queue */
+ tsc2008_spi_setup(ts);
+
+ dev_info(&spi->dev, "touchscreen registered with irq (%d)\n", spi->irq);
+
+ return 0;
+
+ err_free_irq:
+ free_irq(spi->irq, ts);
+ err_free_mem:
+ input_free_device(input);
+ kfree(ts);
+ return err;
+}
+
+static int __devexit tsc2008_remove(struct spi_device *spi)
+{
+ struct tsc2008 *ts = dev_get_drvdata(&spi->dev);
+
+ input_unregister_device(ts->input);
+ free_irq(ts->spi->irq, ts);
+ kfree(ts);
+
+ dev_dbg(&spi->dev, "unregistered touchscreen\n");
+ return 0;
+}
+
+static struct spi_driver tsc2008_driver = {
+ .driver = {
+ .name = "tsc2008",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = tsc2008_probe,
+ .remove = __devexit_p(tsc2008_remove),
+};
+
+static int __init tsc2008_init(void)
+{
+ return spi_register_driver(&tsc2008_driver);
+}
+
+static void __exit tsc2008_exit(void)
+{
+ spi_unregister_driver(&tsc2008_driver);
+}
+
+MODULE_AUTHOR("Chris Verges <chrisv@xxxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Texas Instruments TSC2008 TouchScreen driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(tsc2008_init);
+module_exit(tsc2008_exit);
Index: drivers/input/touchscreen/Makefile
===================================================================
--- drivers/input/touchscreen/Makefile (revision 11)
+++ drivers/input/touchscreen/Makefile (revision 21)
@@ -26,6 +26,7 @@
obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT) += touchright.o
obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN) += touchwin.o
obj-$(CONFIG_TOUCHSCREEN_TSC2007) += tsc2007.o
+obj-$(CONFIG_TOUCHSCREEN_TSC2008) += tsc2008.o
obj-$(CONFIG_TOUCHSCREEN_UCB1400) += ucb1400_ts.o
obj-$(CONFIG_TOUCHSCREEN_WACOM_W8001) += wacom_w8001.o
obj-$(CONFIG_TOUCHSCREEN_WM97XX) += wm97xx-ts.o
--
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