leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity
eecbf54fdd
linux/drivers/input/touchscreen/ti_am335x_tsc.c
Vignesh R 83edfdf30b Input: ti_am335x_tsc - replace delta filtering with median filtering 
Previously, delta filtering was applied TSC co-ordinate readouts before
reporting a single value to user space. This patch replaces delta filtering
with median filtering. Median filtering sorts co-ordinate readouts, drops
min and max values, and reports the average of remaining values. This
method is more sensible than delta filtering. Median filtering is applied
only if number of readouts is greater than 3 else just average of
co-ordinate readouts is reported.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2015-02-03 11:50:39 -08:00

555 lines
14 KiB
C
Raw Blame History

/*
* TI Touch Screen driver
*
* Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/sort.h>
#include <linux/mfd/ti_am335x_tscadc.h>
#define ADCFSM_STEPID 0x10
#define SEQ_SETTLE 275
#define MAX_12BIT ((1 << 12) - 1)
static const int config_pins[] = {
STEPCONFIG_XPP,
STEPCONFIG_XNN,
STEPCONFIG_YPP,
STEPCONFIG_YNN,
};
struct titsc {
struct input_dev *input;
struct ti_tscadc_dev *mfd_tscadc;
unsigned int irq;
unsigned int wires;
unsigned int x_plate_resistance;
bool pen_down;
int coordinate_readouts;
u32 config_inp[4];
u32 bit_xp, bit_xn, bit_yp, bit_yn;
u32 inp_xp, inp_xn, inp_yp, inp_yn;
u32 step_mask;
u32 charge_delay;
};
static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
{
return readl(ts->mfd_tscadc->tscadc_base + reg);
}
static void titsc_writel(struct titsc *tsc, unsigned int reg,
unsigned int val)
{
writel(val, tsc->mfd_tscadc->tscadc_base + reg);
}
static int titsc_config_wires(struct titsc *ts_dev)
{
u32 analog_line[4];
u32 wire_order[4];
int i, bit_cfg;
for (i = 0; i < 4; i++) {
/*
* Get the order in which TSC wires are attached
* w.r.t. each of the analog input lines on the EVM.
*/
analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4;
wire_order[i] = ts_dev->config_inp[i] & 0x0F;
if (WARN_ON(analog_line[i] > 7))
return -EINVAL;
if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins)))
return -EINVAL;
}
for (i = 0; i < 4; i++) {
int an_line;
int wi_order;
an_line = analog_line[i];
wi_order = wire_order[i];
bit_cfg = config_pins[wi_order];
if (bit_cfg == 0)
return -EINVAL;
switch (wi_order) {
case 0:
ts_dev->bit_xp = bit_cfg;
ts_dev->inp_xp = an_line;
break;
case 1:
ts_dev->bit_xn = bit_cfg;
ts_dev->inp_xn = an_line;
break;
case 2:
ts_dev->bit_yp = bit_cfg;
ts_dev->inp_yp = an_line;
break;
case 3:
ts_dev->bit_yn = bit_cfg;
ts_dev->inp_yn = an_line;
break;
}
}
return 0;
}
static void titsc_step_config(struct titsc *ts_dev)
{
unsigned int config;
int i;
int end_step, first_step, tsc_steps;
u32 stepenable;
config = STEPCONFIG_MODE_HWSYNC |
STEPCONFIG_AVG_16 | ts_dev->bit_xp;
switch (ts_dev->wires) {
case 4:
config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
break;
case 5:
config |= ts_dev->bit_yn |
STEPCONFIG_INP_AN4 | ts_dev->bit_xn |
ts_dev->bit_yp;
break;
case 8:
config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
break;
}
tsc_steps = ts_dev->coordinate_readouts * 2 + 2;
first_step = TOTAL_STEPS - tsc_steps;
/* Steps 16 to 16-coordinate_readouts is for X */
end_step = first_step + tsc_steps;
for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) {
titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
}
config = 0;
config = STEPCONFIG_MODE_HWSYNC |
STEPCONFIG_AVG_16 | ts_dev->bit_yn |
STEPCONFIG_INM_ADCREFM;
switch (ts_dev->wires) {
case 4:
config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
break;
case 5:
config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
ts_dev->bit_xn | ts_dev->bit_yp;
break;
case 8:
config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
break;
}
/* 1 ... coordinate_readouts is for Y */
end_step = first_step + ts_dev->coordinate_readouts;
for (i = first_step; i < end_step; i++) {
titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
}
/* Make CHARGECONFIG same as IDLECONFIG */
config = titsc_readl(ts_dev, REG_IDLECONFIG);
titsc_writel(ts_dev, REG_CHARGECONFIG, config);
titsc_writel(ts_dev, REG_CHARGEDELAY, ts_dev->charge_delay);
/* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
config = STEPCONFIG_MODE_HWSYNC |
STEPCONFIG_AVG_16 | ts_dev->bit_yp |
ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
STEPCONFIG_INP(ts_dev->inp_xp);
titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
titsc_writel(ts_dev, REG_STEPDELAY(end_step),
STEPCONFIG_OPENDLY);
end_step++;
config |= STEPCONFIG_INP(ts_dev->inp_yn);
titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
titsc_writel(ts_dev, REG_STEPDELAY(end_step),
STEPCONFIG_OPENDLY);
/* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
stepenable = 1;
for (i = 0; i < tsc_steps; i++)
stepenable |= 1 << (first_step + i + 1);
ts_dev->step_mask = stepenable;
am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
}
static int titsc_cmp_coord(const void *a, const void *b)
{
return *(int *)a - *(int *)b;
}
static void titsc_read_coordinates(struct titsc *ts_dev,
u32 *x, u32 *y, u32 *z1, u32 *z2)
{
unsigned int yvals[7], xvals[7];
unsigned int i, xsum = 0, ysum = 0;
unsigned int creads = ts_dev->coordinate_readouts;
for (i = 0; i < creads; i++) {
yvals[i] = titsc_readl(ts_dev, REG_FIFO0);
yvals[i] &= 0xfff;
}
*z1 = titsc_readl(ts_dev, REG_FIFO0);
*z1 &= 0xfff;
*z2 = titsc_readl(ts_dev, REG_FIFO0);
*z2 &= 0xfff;
for (i = 0; i < creads; i++) {
xvals[i] = titsc_readl(ts_dev, REG_FIFO0);
xvals[i] &= 0xfff;
}
/*
* If co-ordinates readouts is less than 4 then
* report the average. In case of 4 or more
* readouts, sort the co-ordinate samples, drop
* min and max values and report the average of
* remaining values.
*/
if (creads <= 3) {
for (i = 0; i < creads; i++) {
ysum += yvals[i];
xsum += xvals[i];
}
ysum /= creads;
xsum /= creads;
} else {
sort(yvals, creads, sizeof(unsigned int),
titsc_cmp_coord, NULL);
sort(xvals, creads, sizeof(unsigned int),
titsc_cmp_coord, NULL);
for (i = 1; i < creads - 1; i++) {
ysum += yvals[i];
xsum += xvals[i];
}
ysum /= creads - 2;
xsum /= creads - 2;
}
*y = ysum;
*x = xsum;
}
static irqreturn_t titsc_irq(int irq, void *dev)
{
struct titsc *ts_dev = dev;
struct input_dev *input_dev = ts_dev->input;
unsigned int fsm, status, irqclr = 0;
unsigned int x = 0, y = 0;
unsigned int z1, z2, z;
status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
if (status & IRQENB_HW_PEN) {
ts_dev->pen_down = true;
titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00);
titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
irqclr |= IRQENB_HW_PEN;
}
if (status & IRQENB_PENUP) {
fsm = titsc_readl(ts_dev, REG_ADCFSM);
if (fsm == ADCFSM_STEPID) {
ts_dev->pen_down = false;
input_report_key(input_dev, BTN_TOUCH, 0);
input_report_abs(input_dev, ABS_PRESSURE, 0);
input_sync(input_dev);
} else {
ts_dev->pen_down = true;
}
irqclr |= IRQENB_PENUP;
}
if (status & IRQENB_EOS)
irqclr |= IRQENB_EOS;
/*
* ADC and touchscreen share the IRQ line.
* FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
*/
if (status & IRQENB_FIFO0THRES) {
titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
/*
* Calculate pressure using formula
* Resistance(touch) = x plate resistance *
* x postion/4096 * ((z2 / z1) - 1)
*/
z = z1 - z2;
z *= x;
z *= ts_dev->x_plate_resistance;
z /= z2;
z = (z + 2047) >> 12;
if (z <= MAX_12BIT) {
input_report_abs(input_dev, ABS_X, x);
input_report_abs(input_dev, ABS_Y, y);
input_report_abs(input_dev, ABS_PRESSURE, z);
input_report_key(input_dev, BTN_TOUCH, 1);
input_sync(input_dev);
}
}
irqclr |= IRQENB_FIFO0THRES;
}
if (irqclr) {
titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
if (status & IRQENB_EOS)
am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
ts_dev->step_mask);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static int titsc_parse_dt(struct platform_device *pdev,
struct titsc *ts_dev)
{
struct device_node *node = pdev->dev.of_node;
int err;
if (!node)
return -EINVAL;
err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
if (err < 0)
return err;
switch (ts_dev->wires) {
case 4:
case 5:
case 8:
break;
default:
return -EINVAL;
}
err = of_property_read_u32(node, "ti,x-plate-resistance",
&ts_dev->x_plate_resistance);
if (err < 0)
return err;
/*
* Try with the new binding first. If it fails, try again with
* bogus, miss-spelled version.
*/
err = of_property_read_u32(node, "ti,coordinate-readouts",
&ts_dev->coordinate_readouts);
if (err < 0) {
dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n");
err = of_property_read_u32(node, "ti,coordiante-readouts",
&ts_dev->coordinate_readouts);
}
if (err < 0)
return err;
if (ts_dev->coordinate_readouts <= 0) {
dev_warn(&pdev->dev,
"invalid co-ordinate readouts, resetting it to 5\n");
ts_dev->coordinate_readouts = 5;
}
err = of_property_read_u32(node, "ti,charge-delay",
&ts_dev->charge_delay);
/*
* If ti,charge-delay value is not specified, then use
* CHARGEDLY_OPENDLY as the default value.
*/
if (err < 0) {
ts_dev->charge_delay = CHARGEDLY_OPENDLY;
dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
}
return of_property_read_u32_array(node, "ti,wire-config",
ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
}
/*
* The functions for inserting/removing driver as a module.
*/
static int titsc_probe(struct platform_device *pdev)
{
struct titsc *ts_dev;
struct input_dev *input_dev;
struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
int err;
/* Allocate memory for device */
ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
input_dev = input_allocate_device();
if (!ts_dev || !input_dev) {
dev_err(&pdev->dev, "failed to allocate memory.\n");
err = -ENOMEM;
goto err_free_mem;
}
tscadc_dev->tsc = ts_dev;
ts_dev->mfd_tscadc = tscadc_dev;
ts_dev->input = input_dev;
ts_dev->irq = tscadc_dev->irq;
err = titsc_parse_dt(pdev, ts_dev);
if (err) {
dev_err(&pdev->dev, "Could not find valid DT data.\n");
goto err_free_mem;
}
err = request_irq(ts_dev->irq, titsc_irq,
IRQF_SHARED, pdev->dev.driver->name, ts_dev);
if (err) {
dev_err(&pdev->dev, "failed to allocate irq.\n");
goto err_free_mem;
}
titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS);
err = titsc_config_wires(ts_dev);
if (err) {
dev_err(&pdev->dev, "wrong i/p wire configuration\n");
goto err_free_irq;
}
titsc_step_config(ts_dev);
titsc_writel(ts_dev, REG_FIFO0THR,
ts_dev->coordinate_readouts * 2 + 2 - 1);
input_dev->name = "ti-tsc";
input_dev->dev.parent = &pdev->dev;
input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
/* register to the input system */
err = input_register_device(input_dev);
if (err)
goto err_free_irq;
platform_set_drvdata(pdev, ts_dev);
return 0;
err_free_irq:
free_irq(ts_dev->irq, ts_dev);
err_free_mem:
input_free_device(input_dev);
kfree(ts_dev);
return err;
}
static int titsc_remove(struct platform_device *pdev)
{
struct titsc *ts_dev = platform_get_drvdata(pdev);
u32 steps;
free_irq(ts_dev->irq, ts_dev);
/* total steps followed by the enable mask */
steps = 2 * ts_dev->coordinate_readouts + 2;
steps = (1 << steps) - 1;
am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
input_unregister_device(ts_dev->input);
kfree(ts_dev);
return 0;
}
#ifdef CONFIG_PM
static int titsc_suspend(struct device *dev)
{
struct titsc *ts_dev = dev_get_drvdata(dev);
struct ti_tscadc_dev *tscadc_dev;
unsigned int idle;
tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
if (device_may_wakeup(tscadc_dev->dev)) {
idle = titsc_readl(ts_dev, REG_IRQENABLE);
titsc_writel(ts_dev, REG_IRQENABLE,
(idle | IRQENB_HW_PEN));
titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
}
return 0;
}
static int titsc_resume(struct device *dev)
{
struct titsc *ts_dev = dev_get_drvdata(dev);
struct ti_tscadc_dev *tscadc_dev;
tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
if (device_may_wakeup(tscadc_dev->dev)) {
titsc_writel(ts_dev, REG_IRQWAKEUP,
0x00);
titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
}
titsc_step_config(ts_dev);
titsc_writel(ts_dev, REG_FIFO0THR,
ts_dev->coordinate_readouts * 2 + 2 - 1);
return 0;
}
static const struct dev_pm_ops titsc_pm_ops = {
.suspend = titsc_suspend,
.resume = titsc_resume,
};
#define TITSC_PM_OPS (&titsc_pm_ops)
#else
#define TITSC_PM_OPS NULL
#endif
static const struct of_device_id ti_tsc_dt_ids[] = {
{ .compatible = "ti,am3359-tsc", },
{ }
};
MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
static struct platform_driver ti_tsc_driver = {
.probe = titsc_probe,
.remove = titsc_remove,
.driver = {
.name = "TI-am335x-tsc",
.pm = TITSC_PM_OPS,
.of_match_table = ti_tsc_dt_ids,
},
};
module_platform_driver(ti_tsc_driver);
MODULE_DESCRIPTION("TI touchscreen controller driver");
MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
MODULE_LICENSE("GPL");
Reference in New Issue View Git Blame Copy Permalink