399 lines
10 KiB
C
399 lines
10 KiB
C
/*
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* TI Touch Screen driver
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*
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* Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation version 2.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/input.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/clk.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/input/ti_am335x_tsc.h>
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#include <linux/delay.h>
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#include <linux/mfd/ti_am335x_tscadc.h>
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#define ADCFSM_STEPID 0x10
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#define SEQ_SETTLE 275
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#define MAX_12BIT ((1 << 12) - 1)
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struct titsc {
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struct input_dev *input;
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struct ti_tscadc_dev *mfd_tscadc;
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unsigned int irq;
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unsigned int wires;
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unsigned int x_plate_resistance;
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bool pen_down;
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int steps_to_configure;
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};
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static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
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{
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return readl(ts->mfd_tscadc->tscadc_base + reg);
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}
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static void titsc_writel(struct titsc *tsc, unsigned int reg,
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unsigned int val)
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{
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writel(val, tsc->mfd_tscadc->tscadc_base + reg);
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}
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static void titsc_step_config(struct titsc *ts_dev)
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{
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unsigned int config;
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int i, total_steps;
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/* Configure the Step registers */
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total_steps = 2 * ts_dev->steps_to_configure;
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config = STEPCONFIG_MODE_HWSYNC |
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STEPCONFIG_AVG_16 | STEPCONFIG_XPP;
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switch (ts_dev->wires) {
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case 4:
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config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN;
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break;
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case 5:
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config |= STEPCONFIG_YNN |
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STEPCONFIG_INP_AN4 | STEPCONFIG_XNN |
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STEPCONFIG_YPP;
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break;
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case 8:
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config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN;
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break;
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}
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for (i = 1; i <= ts_dev->steps_to_configure; i++) {
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titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
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titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
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}
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config = 0;
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config = STEPCONFIG_MODE_HWSYNC |
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STEPCONFIG_AVG_16 | STEPCONFIG_YNN |
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STEPCONFIG_INM_ADCREFM | STEPCONFIG_FIFO1;
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switch (ts_dev->wires) {
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case 4:
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config |= STEPCONFIG_YPP;
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break;
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case 5:
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config |= STEPCONFIG_XPP | STEPCONFIG_INP_AN4 |
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STEPCONFIG_XNP | STEPCONFIG_YPN;
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break;
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case 8:
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config |= STEPCONFIG_YPP;
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break;
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}
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for (i = (ts_dev->steps_to_configure + 1); i <= total_steps; i++) {
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titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
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titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
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}
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config = 0;
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/* Charge step configuration */
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config = STEPCONFIG_XPP | STEPCONFIG_YNN |
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STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
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STEPCHARGE_INM_AN1 | STEPCHARGE_INP_AN1;
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titsc_writel(ts_dev, REG_CHARGECONFIG, config);
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titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);
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config = 0;
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/* Configure to calculate pressure */
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config = STEPCONFIG_MODE_HWSYNC |
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STEPCONFIG_AVG_16 | STEPCONFIG_YPP |
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STEPCONFIG_XNN | STEPCONFIG_INM_ADCREFM;
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titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 1), config);
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titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 1),
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STEPCONFIG_OPENDLY);
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config |= STEPCONFIG_INP_AN3 | STEPCONFIG_FIFO1;
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titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 2), config);
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titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 2),
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STEPCONFIG_OPENDLY);
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titsc_writel(ts_dev, REG_SE, STPENB_STEPENB_TC);
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}
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static void titsc_read_coordinates(struct titsc *ts_dev,
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unsigned int *x, unsigned int *y)
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{
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unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT);
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unsigned int prev_val_x = ~0, prev_val_y = ~0;
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unsigned int prev_diff_x = ~0, prev_diff_y = ~0;
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unsigned int read, diff;
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unsigned int i, channel;
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/*
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* Delta filter is used to remove large variations in sampled
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* values from ADC. The filter tries to predict where the next
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* coordinate could be. This is done by taking a previous
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* coordinate and subtracting it form current one. Further the
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* algorithm compares the difference with that of a present value,
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* if true the value is reported to the sub system.
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*/
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for (i = 0; i < fifocount - 1; i++) {
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read = titsc_readl(ts_dev, REG_FIFO0);
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channel = read & 0xf0000;
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channel = channel >> 0x10;
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if ((channel >= 0) && (channel < ts_dev->steps_to_configure)) {
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read &= 0xfff;
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diff = abs(read - prev_val_x);
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if (diff < prev_diff_x) {
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prev_diff_x = diff;
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*x = read;
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}
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prev_val_x = read;
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}
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read = titsc_readl(ts_dev, REG_FIFO1);
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channel = read & 0xf0000;
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channel = channel >> 0x10;
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if ((channel >= ts_dev->steps_to_configure) &&
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(channel < (2 * ts_dev->steps_to_configure - 1))) {
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read &= 0xfff;
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diff = abs(read - prev_val_y);
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if (diff < prev_diff_y) {
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prev_diff_y = diff;
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*y = read;
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}
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prev_val_y = read;
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}
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}
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}
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static irqreturn_t titsc_irq(int irq, void *dev)
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{
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struct titsc *ts_dev = dev;
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struct input_dev *input_dev = ts_dev->input;
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unsigned int status, irqclr = 0;
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unsigned int x = 0, y = 0;
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unsigned int z1, z2, z;
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unsigned int fsm;
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unsigned int fifo1count, fifo0count;
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int i;
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status = titsc_readl(ts_dev, REG_IRQSTATUS);
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if (status & IRQENB_FIFO0THRES) {
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titsc_read_coordinates(ts_dev, &x, &y);
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z1 = titsc_readl(ts_dev, REG_FIFO0) & 0xfff;
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z2 = titsc_readl(ts_dev, REG_FIFO1) & 0xfff;
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fifo1count = titsc_readl(ts_dev, REG_FIFO1CNT);
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for (i = 0; i < fifo1count; i++)
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titsc_readl(ts_dev, REG_FIFO1);
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fifo0count = titsc_readl(ts_dev, REG_FIFO0CNT);
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for (i = 0; i < fifo0count; i++)
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titsc_readl(ts_dev, REG_FIFO0);
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if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
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/*
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* Calculate pressure using formula
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* Resistance(touch) = x plate resistance *
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* x postion/4096 * ((z2 / z1) - 1)
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*/
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z = z2 - z1;
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z *= x;
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z *= ts_dev->x_plate_resistance;
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z /= z1;
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z = (z + 2047) >> 12;
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if (z <= MAX_12BIT) {
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input_report_abs(input_dev, ABS_X, x);
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input_report_abs(input_dev, ABS_Y, y);
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input_report_abs(input_dev, ABS_PRESSURE, z);
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input_report_key(input_dev, BTN_TOUCH, 1);
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input_sync(input_dev);
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}
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}
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irqclr |= IRQENB_FIFO0THRES;
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}
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/*
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* Time for sequencer to settle, to read
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* correct state of the sequencer.
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*/
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udelay(SEQ_SETTLE);
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status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
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if (status & IRQENB_PENUP) {
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/* Pen up event */
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fsm = titsc_readl(ts_dev, REG_ADCFSM);
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if (fsm == ADCFSM_STEPID) {
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ts_dev->pen_down = false;
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input_report_key(input_dev, BTN_TOUCH, 0);
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input_report_abs(input_dev, ABS_PRESSURE, 0);
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input_sync(input_dev);
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} else {
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ts_dev->pen_down = true;
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}
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irqclr |= IRQENB_PENUP;
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}
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titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
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titsc_writel(ts_dev, REG_SE, STPENB_STEPENB_TC);
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return IRQ_HANDLED;
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}
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/*
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* The functions for inserting/removing driver as a module.
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*/
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static int titsc_probe(struct platform_device *pdev)
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{
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struct titsc *ts_dev;
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struct input_dev *input_dev;
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struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
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struct mfd_tscadc_board *pdata;
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int err;
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pdata = tscadc_dev->dev->platform_data;
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if (!pdata) {
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dev_err(&pdev->dev, "Could not find platform data\n");
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return -EINVAL;
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}
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/* Allocate memory for device */
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ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
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input_dev = input_allocate_device();
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if (!ts_dev || !input_dev) {
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dev_err(&pdev->dev, "failed to allocate memory.\n");
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err = -ENOMEM;
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goto err_free_mem;
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}
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tscadc_dev->tsc = ts_dev;
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ts_dev->mfd_tscadc = tscadc_dev;
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ts_dev->input = input_dev;
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ts_dev->irq = tscadc_dev->irq;
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ts_dev->wires = pdata->tsc_init->wires;
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ts_dev->x_plate_resistance = pdata->tsc_init->x_plate_resistance;
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ts_dev->steps_to_configure = pdata->tsc_init->steps_to_configure;
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err = request_irq(ts_dev->irq, titsc_irq,
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0, pdev->dev.driver->name, ts_dev);
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if (err) {
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dev_err(&pdev->dev, "failed to allocate irq.\n");
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goto err_free_mem;
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}
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titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
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titsc_step_config(ts_dev);
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titsc_writel(ts_dev, REG_FIFO0THR, ts_dev->steps_to_configure);
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input_dev->name = "ti-tsc";
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input_dev->dev.parent = &pdev->dev;
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input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
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input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
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input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
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input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
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input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
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/* register to the input system */
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err = input_register_device(input_dev);
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if (err)
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goto err_free_irq;
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platform_set_drvdata(pdev, ts_dev);
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return 0;
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err_free_irq:
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free_irq(ts_dev->irq, ts_dev);
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err_free_mem:
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input_free_device(input_dev);
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kfree(ts_dev);
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return err;
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}
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static int titsc_remove(struct platform_device *pdev)
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{
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struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
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struct titsc *ts_dev = tscadc_dev->tsc;
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free_irq(ts_dev->irq, ts_dev);
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input_unregister_device(ts_dev->input);
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platform_set_drvdata(pdev, NULL);
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kfree(ts_dev);
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return 0;
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}
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#ifdef CONFIG_PM
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static int titsc_suspend(struct device *dev)
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{
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struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
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struct titsc *ts_dev = tscadc_dev->tsc;
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unsigned int idle;
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if (device_may_wakeup(tscadc_dev->dev)) {
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idle = titsc_readl(ts_dev, REG_IRQENABLE);
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titsc_writel(ts_dev, REG_IRQENABLE,
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(idle | IRQENB_HW_PEN));
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titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
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}
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return 0;
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}
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static int titsc_resume(struct device *dev)
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{
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struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
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struct titsc *ts_dev = tscadc_dev->tsc;
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if (device_may_wakeup(tscadc_dev->dev)) {
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titsc_writel(ts_dev, REG_IRQWAKEUP,
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0x00);
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titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
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}
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titsc_step_config(ts_dev);
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titsc_writel(ts_dev, REG_FIFO0THR,
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ts_dev->steps_to_configure);
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return 0;
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}
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static const struct dev_pm_ops titsc_pm_ops = {
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.suspend = titsc_suspend,
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.resume = titsc_resume,
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};
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#define TITSC_PM_OPS (&titsc_pm_ops)
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#else
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#define TITSC_PM_OPS NULL
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#endif
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static struct platform_driver ti_tsc_driver = {
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.probe = titsc_probe,
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.remove = titsc_remove,
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.driver = {
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.name = "tsc",
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.owner = THIS_MODULE,
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.pm = TITSC_PM_OPS,
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},
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};
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module_platform_driver(ti_tsc_driver);
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MODULE_DESCRIPTION("TI touchscreen controller driver");
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MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
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MODULE_LICENSE("GPL");
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