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|
/*
* Freescale MXS LRADC touchscreen driver
*
* Copyright (c) 2012 DENX Software Engineering, GmbH.
* Copyright (c) 2017 Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
*
* Authors:
* Marek Vasut <marex@denx.de>
* Ksenija Stanojevic <ksenija.stanojevic@gmail.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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/mfd/core.h>
#include <linux/mfd/mxs-lradc.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
static const char * const mxs_lradc_ts_irq_names[] = {
"mxs-lradc-touchscreen",
"mxs-lradc-channel6",
"mxs-lradc-channel7",
};
/*
* Touchscreen handling
*/
enum mxs_lradc_ts_plate {
LRADC_TOUCH = 0,
LRADC_SAMPLE_X,
LRADC_SAMPLE_Y,
LRADC_SAMPLE_PRESSURE,
LRADC_SAMPLE_VALID,
};
struct mxs_lradc_ts {
struct mxs_lradc *lradc;
struct device *dev;
void __iomem *base;
/*
* When the touchscreen is enabled, we give it two private virtual
* channels: #6 and #7. This means that only 6 virtual channels (instead
* of 8) will be available for buffered capture.
*/
#define TOUCHSCREEN_VCHANNEL1 7
#define TOUCHSCREEN_VCHANNEL2 6
struct input_dev *ts_input;
enum mxs_lradc_ts_plate cur_plate; /* state machine */
bool ts_valid;
unsigned int ts_x_pos;
unsigned int ts_y_pos;
unsigned int ts_pressure;
/* handle touchscreen's physical behaviour */
/* samples per coordinate */
unsigned int over_sample_cnt;
/* time clocks between samples */
unsigned int over_sample_delay;
/* time in clocks to wait after the plates where switched */
unsigned int settling_delay;
spinlock_t lock;
};
struct state_info {
u32 mask;
u32 bit;
u32 x_plate;
u32 y_plate;
u32 pressure;
};
static struct state_info info[] = {
{LRADC_CTRL0_MX23_PLATE_MASK, LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE,
LRADC_CTRL0_MX23_XP | LRADC_CTRL0_MX23_XM,
LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_YM,
LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_XM},
{LRADC_CTRL0_MX28_PLATE_MASK, LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE,
LRADC_CTRL0_MX28_XPPSW | LRADC_CTRL0_MX28_XNNSW,
LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_YNNSW,
LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW}
};
static bool mxs_lradc_check_touch_event(struct mxs_lradc_ts *ts)
{
return !!(readl(ts->base + LRADC_STATUS) &
LRADC_STATUS_TOUCH_DETECT_RAW);
}
static void mxs_lradc_map_ts_channel(struct mxs_lradc_ts *ts, unsigned int vch,
unsigned int ch)
{
writel(LRADC_CTRL4_LRADCSELECT_MASK(vch),
ts->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
writel(LRADC_CTRL4_LRADCSELECT(vch, ch),
ts->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
}
static void mxs_lradc_setup_ts_channel(struct mxs_lradc_ts *ts, unsigned int ch)
{
/*
* prepare for oversampling conversion
*
* from the datasheet:
* "The ACCUMULATE bit in the appropriate channel register
* HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
* otherwise, the IRQs will not fire."
*/
writel(LRADC_CH_ACCUMULATE |
LRADC_CH_NUM_SAMPLES(ts->over_sample_cnt - 1),
ts->base + LRADC_CH(ch));
/* from the datasheet:
* "Software must clear this register in preparation for a
* multi-cycle accumulation.
*/
writel(LRADC_CH_VALUE_MASK,
ts->base + LRADC_CH(ch) + STMP_OFFSET_REG_CLR);
/*
* prepare the delay/loop unit according to the oversampling count
*
* from the datasheet:
* "The DELAY fields in HW_LRADC_DELAY0, HW_LRADC_DELAY1,
* HW_LRADC_DELAY2, and HW_LRADC_DELAY3 must be non-zero; otherwise,
* the LRADC will not trigger the delay group."
*/
writel(LRADC_DELAY_TRIGGER(1 << ch) | LRADC_DELAY_TRIGGER_DELAYS(0) |
LRADC_DELAY_LOOP(ts->over_sample_cnt - 1) |
LRADC_DELAY_DELAY(ts->over_sample_delay - 1),
ts->base + LRADC_DELAY(3));
writel(LRADC_CTRL1_LRADC_IRQ(ch),
ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
/*
* after changing the touchscreen plates setting
* the signals need some initial time to settle. Start the
* SoC's delay unit and start the conversion later
* and automatically.
*/
writel(LRADC_DELAY_TRIGGER(0) | LRADC_DELAY_TRIGGER_DELAYS(BIT(3)) |
LRADC_DELAY_KICK | LRADC_DELAY_DELAY(ts->settling_delay),
ts->base + LRADC_DELAY(2));
}
/*
* Pressure detection is special:
* We want to do both required measurements for the pressure detection in
* one turn. Use the hardware features to chain both conversions and let the
* hardware report one interrupt if both conversions are done
*/
static void mxs_lradc_setup_ts_pressure(struct mxs_lradc_ts *ts,
unsigned int ch1, unsigned int ch2)
{
u32 reg;
/*
* prepare for oversampling conversion
*
* from the datasheet:
* "The ACCUMULATE bit in the appropriate channel register
* HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
* otherwise, the IRQs will not fire."
*/
reg = LRADC_CH_ACCUMULATE |
LRADC_CH_NUM_SAMPLES(ts->over_sample_cnt - 1);
writel(reg, ts->base + LRADC_CH(ch1));
writel(reg, ts->base + LRADC_CH(ch2));
/* from the datasheet:
* "Software must clear this register in preparation for a
* multi-cycle accumulation.
*/
writel(LRADC_CH_VALUE_MASK,
ts->base + LRADC_CH(ch1) + STMP_OFFSET_REG_CLR);
writel(LRADC_CH_VALUE_MASK,
ts->base + LRADC_CH(ch2) + STMP_OFFSET_REG_CLR);
/* prepare the delay/loop unit according to the oversampling count */
writel(LRADC_DELAY_TRIGGER(1 << ch1) | LRADC_DELAY_TRIGGER(1 << ch2) |
LRADC_DELAY_TRIGGER_DELAYS(0) |
LRADC_DELAY_LOOP(ts->over_sample_cnt - 1) |
LRADC_DELAY_DELAY(ts->over_sample_delay - 1),
ts->base + LRADC_DELAY(3));
writel(LRADC_CTRL1_LRADC_IRQ(ch2),
ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
/*
* after changing the touchscreen plates setting
* the signals need some initial time to settle. Start the
* SoC's delay unit and start the conversion later
* and automatically.
*/
writel(LRADC_DELAY_TRIGGER(0) | LRADC_DELAY_TRIGGER_DELAYS(BIT(3)) |
LRADC_DELAY_KICK | LRADC_DELAY_DELAY(ts->settling_delay),
ts->base + LRADC_DELAY(2));
}
static unsigned int mxs_lradc_ts_read_raw_channel(struct mxs_lradc_ts *ts,
unsigned int channel)
{
u32 reg;
unsigned int num_samples, val;
reg = readl(ts->base + LRADC_CH(channel));
if (reg & LRADC_CH_ACCUMULATE)
num_samples = ts->over_sample_cnt;
else
num_samples = 1;
val = (reg & LRADC_CH_VALUE_MASK) >> LRADC_CH_VALUE_OFFSET;
return val / num_samples;
}
static unsigned int mxs_lradc_read_ts_pressure(struct mxs_lradc_ts *ts,
unsigned int ch1, unsigned int ch2)
{
u32 reg, mask;
unsigned int
|