Re: [PATCH 3/3] input: touchscreen: mxs-lradc: Add support for touchscreen

From: Jonathan Cameron
Date: Sun May 29 2016 - 12:49:40 EST

On 28/05/16 18:45, Ksenija StanojeviÄ wrote:
> On Sun, May 1, 2016 at 6:47 PM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
>> On 29/04/16 12:49, Ksenija Stanojevic wrote:
>>> Add mxs-lradc touchscreen driver.
>>>
>>> Signed-off-by: Ksenija Stanojevic <ksenija.stanojevic@xxxxxxxxx>
>> The only real thing this raises for me is why we are grabbing IRQs that I
>> don't think this driver even cares about...
>>
>> Jonathan
>>> ---
>>> drivers/input/touchscreen/Kconfig | 14 +-
>>> drivers/input/touchscreen/Makefile | 1 +
>>> drivers/input/touchscreen/mxs-lradc-ts.c | 729 +++++++++++++++++++++++++++++++
>>> 3 files changed, 742 insertions(+), 2 deletions(-)
>>> create mode 100644 drivers/input/touchscreen/mxs-lradc-ts.c
>>>
>>> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
>>> index 8ecdc38..d614d248 100644
>>> --- a/drivers/input/touchscreen/Kconfig
>>> +++ b/drivers/input/touchscreen/Kconfig
>>> @@ -566,7 +566,7 @@ config TOUCHSCREEN_HP600
>>> depends on SH_HP6XX && SH_ADC
>>> help
>>> Say Y here if you have a HP Jornada 620/660/680/690 and want to
>>> - support the built-in touchscreen.
>>> + support the built-in touchscreen.
>>>
>>> To compile this driver as a module, choose M here: the
>>> module will be called hp680_ts_input.
>>> @@ -685,7 +685,7 @@ config TOUCHSCREEN_UCB1400
>>> This enables support for the Philips UCB1400 touchscreen interface.
>>> The UCB1400 is an AC97 audio codec. The touchscreen interface
>>> will be initialized only after the ALSA subsystem has been
>>> - brought up and the UCB1400 detected. You therefore have to
>>> + brought up and the UCB1400 detected. You therefore have to
>>> configure ALSA support as well (either built-in or modular,
>>> independently of whether this driver is itself built-in or
>>> modular) for this driver to work.
>>> @@ -842,6 +842,16 @@ config TOUCHSCREEN_MX25
>>> To compile this driver as a module, choose M here: the
>>> module will be called fsl-imx25-tcq.
>>>
>>> +config TOUCHSCREEN_MXS_LRADC
>>> + tristate "Freescale i.MX23/i.MX28 LRADC touchscreen"
>>> + depends on MFD_MXS_LRADC
>>> + help
>>> + Say Y here if you have a touchscreen connected to the low-resolution
>>> + analog-to-digital converter (LRADC) on an i.MX23 or i.MX28 processor.
>>> +
>>> + To compile this driver as a module, choose M here: the module will be
>>> + called mxs-lradc-ts.
>>> +
>>> config TOUCHSCREEN_MC13783
>>> tristate "Freescale MC13783 touchscreen input driver"
>>> depends on MFD_MC13XXX
>>> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
>>> index f42975e..513a6ff 100644
>>> --- a/drivers/input/touchscreen/Makefile
>>> +++ b/drivers/input/touchscreen/Makefile
>>> @@ -54,6 +54,7 @@ obj-$(CONFIG_TOUCHSCREEN_MIGOR) += migor_ts.o
>>> obj-$(CONFIG_TOUCHSCREEN_MMS114) += mms114.o
>>> obj-$(CONFIG_TOUCHSCREEN_MTOUCH) += mtouch.o
>>> obj-$(CONFIG_TOUCHSCREEN_MK712) += mk712.o
>>> +obj-$(CONFIG_TOUCHSCREEN_MXS_LRADC) += mxs-lradc-ts.o
>>> obj-$(CONFIG_TOUCHSCREEN_HP600) += hp680_ts_input.o
>>> obj-$(CONFIG_TOUCHSCREEN_HP7XX) += jornada720_ts.o
>>> obj-$(CONFIG_TOUCHSCREEN_IPAQ_MICRO) += ipaq-micro-ts.o
>>> diff --git a/drivers/input/touchscreen/mxs-lradc-ts.c b/drivers/input/touchscreen/mxs-lradc-ts.c
>>> new file mode 100644
>>> index 0000000..27abb8e
>>> --- /dev/null
>>> +++ b/drivers/input/touchscreen/mxs-lradc-ts.c
>>> @@ -0,0 +1,729 @@
>>> +/*
>>> + * Freescale MXS LRADC driver
>>> + *
>>> + * Copyright (c) 2012 DENX Software Engineering, GmbH.
>>> + * Marek Vasut <marex@xxxxxxx>
>>> + *
>>> + * 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/module.h>
>>> +#include <linux/mfd/mxs-lradc.h>
>>> +#include <linux/platform_device.h>
>>> +
>>> +/*
>>> + * 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;
>>> + /*
>>> + * 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 ts_x_pos;
>>> + unsigned ts_y_pos;
>>> + unsigned ts_pressure;
>>> +
>>> + /* handle touchscreen's physical behaviour */
>>> + /* samples per coordinate */
>>> + unsigned over_sample_cnt;
>>> + /* time clocks between samples */
>>> + unsigned over_sample_delay;
>>> + /* time in clocks to wait after the plates where switched */
>>> + unsigned settling_delay;
>>> +};
>>> +
>>> +static u32 mxs_lradc_plate_mask(struct mxs_lradc *lradc)
>>> +{
>>> + if (lradc->soc == IMX23_LRADC)
>>> + return LRADC_CTRL0_MX23_PLATE_MASK;
>>> + return LRADC_CTRL0_MX28_PLATE_MASK;
>>> +}
>>> +
>>> +static u32 mxs_lradc_touch_detect_bit(struct mxs_lradc *lradc)
>>> +{
>>> + if (lradc->soc == IMX23_LRADC)
>>> + return LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE;
>>> + return LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE;
>>> +}
>>> +
>>> +static u32 mxs_lradc_drive_x_plate(struct mxs_lradc *lradc)
>>> +{
>>> + if (lradc->soc == IMX23_LRADC)
>>> + return LRADC_CTRL0_MX23_XP | LRADC_CTRL0_MX23_XM;
>>> + return LRADC_CTRL0_MX28_XPPSW | LRADC_CTRL0_MX28_XNNSW;
>>> +}
>>> +
>>> +static u32 mxs_lradc_drive_y_plate(struct mxs_lradc *lradc)
>>> +{
>>> + if (lradc->soc == IMX23_LRADC)
>>> + return LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_YM;
>>> + return LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_YNNSW;
>>> +}
>>> +
>>> +static u32 mxs_lradc_drive_pressure(struct mxs_lradc *lradc)
>>> +{
>>> + if (lradc->soc == IMX23_LRADC)
>>> + return LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_XM;
>>> + return LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW;
>>> +}
>>> +
>>> +static bool mxs_lradc_check_touch_event(struct mxs_lradc *lradc)
>>> +{
>>> + return !!(readl(lradc->base + LRADC_STATUS) &
>>> + LRADC_STATUS_TOUCH_DETECT_RAW);
>>> +}
>>> +
>>> +static void mxs_lradc_map_ts_channel(struct mxs_lradc *lradc, unsigned vch,
>>> + unsigned ch)
>>> +{
>>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL4_LRADCSELECT_MASK(vch),
>>> + LRADC_CTRL4);
>>> + mxs_lradc_reg_set(lradc, LRADC_CTRL4_LRADCSELECT(vch, ch), LRADC_CTRL4);
>>> +}
>>> +
>>> +static void mxs_lradc_setup_ts_channel(struct mxs_lradc_ts *ts, unsigned ch)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + /*
>>> + * 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."
>>> + */
>>> + mxs_lradc_reg_wrt(lradc, LRADC_CH_ACCUMULATE |
>>> + LRADC_CH_NUM_SAMPLES(ts->over_sample_cnt - 1),
>>> + LRADC_CH(ch));
>>> +
>>> + /* from the datasheet:
>>> + * "Software must clear this register in preparation for a
>>> + * multi-cycle accumulation.
>>> + */
>>> + mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch));
>>> +
>>> + /*
>>> + * 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."
>>> + */
>>> + mxs_lradc_reg_wrt(lradc, 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),
>>> + LRADC_DELAY(3));
>>> +
>>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(ch), LRADC_CTRL1);
>>> +
>>> + /*
>>> + * 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.
>>> + */
>>> + mxs_lradc_reg_wrt(
>>> + lradc,
>>> + LRADC_DELAY_TRIGGER(0) | /* don't trigger ADC */
>>> + LRADC_DELAY_TRIGGER_DELAYS(BIT(3)) | /* trigger DELAY unit#3 */
>>> + LRADC_DELAY_KICK |
>>> + LRADC_DELAY_DELAY(ts->settling_delay),
>>> + 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 ch1,
>>> + unsigned ch2)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> + 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);
>>> + mxs_lradc_reg_wrt(lradc, reg, LRADC_CH(ch1));
>>> + mxs_lradc_reg_wrt(lradc, reg, LRADC_CH(ch2));
>>> +
>>> + /* from the datasheet:
>>> + * "Software must clear this register in preparation for a
>>> + * multi-cycle accumulation.
>>> + */
>>> + mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch1));
>>> + mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch2));
>>> +
>>> + /* prepare the delay/loop unit according to the oversampling count */
>>> + mxs_lradc_reg_wrt(
>>> + lradc,
>>> + LRADC_DELAY_TRIGGER(1 << ch1) |
>>> + LRADC_DELAY_TRIGGER(1 << ch2) | /* start both channels */
>>> + LRADC_DELAY_TRIGGER_DELAYS(0) |
>>> + LRADC_DELAY_LOOP(ts->over_sample_cnt - 1) |
>>> + LRADC_DELAY_DELAY(ts->over_sample_delay - 1),
>>> + LRADC_DELAY(3));
>>> +
>>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(ch2), LRADC_CTRL1);
>>> +
>>> + /*
>>> + * 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.
>>> + */
>>> + mxs_lradc_reg_wrt(
>>> + lradc,
>>> + LRADC_DELAY_TRIGGER(0) | /* don't trigger ADC */
>>> + LRADC_DELAY_TRIGGER_DELAYS(BIT(3)) | /* trigger DELAY unit#3 */
>>> + LRADC_DELAY_KICK |
>>> + LRADC_DELAY_DELAY(ts->settling_delay), LRADC_DELAY(2));
>>> +}
>>> +
>>> +static unsigned mxs_lradc_ts_read_raw_channel(struct mxs_lradc_ts *ts,
>>> + unsigned channel)
>>> +{
>>> + u32 reg;
>>> + unsigned num_samples, val;
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + reg = readl(lradc->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 mxs_lradc_read_ts_pressure(struct mxs_lradc_ts *ts,
>>> + unsigned ch1, unsigned ch2)
>>> +{
>>> + u32 reg, mask;
>>> + unsigned pressure, m1, m2;
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + mask = LRADC_CTRL1_LRADC_IRQ(ch1) | LRADC_CTRL1_LRADC_IRQ(ch2);
>>> + reg = readl(lradc->base + LRADC_CTRL1) & mask;
>>> +
>>> + while (reg != mask) {
>>> + reg = readl(lradc->base + LRADC_CTRL1) & mask;
>>> + dev_dbg(ts->dev, "One channel is still busy: %X\n", reg);
>>> + }
>>> +
>>> + m1 = mxs_lradc_ts_read_raw_channel(ts, ch1);
>>> + m2 = mxs_lradc_ts_read_raw_channel(ts, ch2);
>>> +
>>> + if (m2 == 0) {
>>> + dev_warn(ts->dev, "Cannot calculate pressure\n");
>>> + return 1 << (LRADC_RESOLUTION - 1);
>>> + }
>>> +
>>> + /* simply scale the value from 0 ... max ADC resolution */
>>> + pressure = m1;
>>> + pressure *= (1 << LRADC_RESOLUTION);
>>> + pressure /= m2;
>>> +
>>> + dev_dbg(ts->dev, "Pressure = %u\n", pressure);
>>> + return pressure;
>>> +}
>>> +
>>> +#define TS_CH_XP 2
>>> +#define TS_CH_YP 3
>>> +#define TS_CH_XM 4
>>> +#define TS_CH_YM 5
>>> +
>>> +/*
>>> + * YP(open)--+-------------+
>>> + * | |--+
>>> + * | | |
>>> + * YM(-)--+-------------+ |
>>> + * +--------------+
>>> + * | |
>>> + * XP(weak+) XM(open)
>>> + *
>>> + * "weak+" means 200k Ohm VDDIO
>>> + * (-) means GND
>>> + */
>>> +static void mxs_lradc_setup_touch_detection(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + /*
>>> + * In order to detect a touch event the 'touch detect enable' bit
>>> + * enables:
>>> + * - a weak pullup to the X+ connector
>>> + * - a strong ground at the Y- connector
>>> + */
>>> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
>>> + mxs_lradc_reg_set(lradc, mxs_lradc_touch_detect_bit(lradc),
>>> + LRADC_CTRL0);
>>> +}
>>> +
>>> +/*
>>> + * YP(meas)--+-------------+
>>> + * | |--+
>>> + * | | |
>>> + * YM(open)--+-------------+ |
>>> + * +--------------+
>>> + * | |
>>> + * XP(+) XM(-)
>>> + *
>>> + * (+) means here 1.85 V
>>> + * (-) means here GND
>>> + */
>>> +static void mxs_lradc_prepare_x_pos(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
>>> + mxs_lradc_reg_set(lradc, mxs_lradc_drive_x_plate(lradc), LRADC_CTRL0);
>>> +
>>> + ts->cur_plate = LRADC_SAMPLE_X;
>>> + mxs_lradc_map_ts_channel(lradc, TOUCHSCREEN_VCHANNEL1, TS_CH_YP);
>>> + mxs_lradc_setup_ts_channel(ts, TOUCHSCREEN_VCHANNEL1);
>>> +}
>>> +
>>> +/*
>>> + * YP(+)--+-------------+
>>> + * | |--+
>>> + * | | |
>>> + * YM(-)--+-------------+ |
>>> + * +--------------+
>>> + * | |
>>> + * XP(open) XM(meas)
>>> + *
>>> + * (+) means here 1.85 V
>>> + * (-) means here GND
>>> + */
>>> +static void mxs_lradc_prepare_y_pos(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
>>> + mxs_lradc_reg_set(lradc, mxs_lradc_drive_y_plate(lradc), LRADC_CTRL0);
>>> +
>>> + ts->cur_plate = LRADC_SAMPLE_Y;
>>> + mxs_lradc_map_ts_channel(lradc, TOUCHSCREEN_VCHANNEL1, TS_CH_XM);
>>> + mxs_lradc_setup_ts_channel(ts, TOUCHSCREEN_VCHANNEL1);
>>> +}
>>> +
>>> +/*
>>> + * YP(+)--+-------------+
>>> + * | |--+
>>> + * | | |
>>> + * YM(meas)--+-------------+ |
>>> + * +--------------+
>>> + * | |
>>> + * XP(meas) XM(-)
>>> + *
>>> + * (+) means here 1.85 V
>>> + * (-) means here GND
>>> + */
>>> +static void mxs_lradc_prepare_pressure(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
>>> + mxs_lradc_reg_set(lradc, mxs_lradc_drive_pressure(lradc), LRADC_CTRL0);
>>> +
>>> + ts->cur_plate = LRADC_SAMPLE_PRESSURE;
>>> + mxs_lradc_map_ts_channel(lradc, TOUCHSCREEN_VCHANNEL1, TS_CH_YM);
>>> + mxs_lradc_map_ts_channel(lradc, TOUCHSCREEN_VCHANNEL2, TS_CH_XP);
>>> + mxs_lradc_setup_ts_pressure(ts, TOUCHSCREEN_VCHANNEL2,
>>> + TOUCHSCREEN_VCHANNEL1);
>>> +}
>>> +
>>> +static void mxs_lradc_enable_touch_detection(struct mxs_lradc_ts *ts)
>>> +{
>>> + mxs_lradc_setup_touch_detection(ts);
>>> +
>>> + ts->cur_plate = LRADC_TOUCH;
>>> + mxs_lradc_reg_clear(ts->lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ |
>>> + LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
>>> + mxs_lradc_reg_set(ts->lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
>>> + LRADC_CTRL1);
>>> +}
>>> +
>>> +static void mxs_lradc_start_touch_event(struct mxs_lradc_ts *ts)
>>> +{
>>> + mxs_lradc_reg_clear(ts->lradc,
>>> + LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
>>> + LRADC_CTRL1);
>>> + mxs_lradc_reg_set(ts->lradc,
>>> + LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1),
>>> + LRADC_CTRL1);
>>> + /*
>>> + * start with the Y-pos, because it uses nearly the same plate
>>> + * settings like the touch detection
>>> + */
>>> + mxs_lradc_prepare_y_pos(ts);
>>> +}
>>> +
>>> +static void mxs_lradc_report_ts_event(struct mxs_lradc_ts *ts)
>>> +{
>>> + input_report_abs(ts->ts_input, ABS_X, ts->ts_x_pos);
>>> + input_report_abs(ts->ts_input, ABS_Y, ts->ts_y_pos);
>>> + input_report_abs(ts->ts_input, ABS_PRESSURE, ts->ts_pressure);
>>> + input_report_key(ts->ts_input, BTN_TOUCH, 1);
>>> + input_sync(ts->ts_input);
>>> +}
>>> +
>>> +static void mxs_lradc_complete_touch_event(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + mxs_lradc_setup_touch_detection(ts);
>>> + ts->cur_plate = LRADC_SAMPLE_VALID;
>>> + /*
>>> + * start a dummy conversion to burn time to settle the signals
>>> + * note: we are not interested in the conversion's value
>>> + */
>>> + mxs_lradc_reg_wrt(lradc, 0, LRADC_CH(TOUCHSCREEN_VCHANNEL1));
>>> + mxs_lradc_reg_clear(lradc,
>>> + LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
>>> + LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2),
>>> + LRADC_CTRL1);
>>> + mxs_lradc_reg_wrt(
>>> + lradc,
>>> + LRADC_DELAY_TRIGGER(1 << TOUCHSCREEN_VCHANNEL1) |
>>> + LRADC_DELAY_KICK | LRADC_DELAY_DELAY(10), /* waste 5 ms */
>>> + LRADC_DELAY(2));
>>> +}
>>> +
>>> +/*
>>> + * in order to avoid false measurements, report only samples where
>>> + * the surface is still touched after the position measurement
>>> + */
>>> +static void mxs_lradc_finish_touch_event(struct mxs_lradc_ts *ts, bool valid)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + /* if it is still touched, report the sample */
>>> + if (valid && mxs_lradc_check_touch_event(lradc)) {
>>> + ts->ts_valid = true;
>>> + mxs_lradc_report_ts_event(ts);
>>> + }
>>> +
>>> + /* if it is even still touched, continue with the next measurement */
>>> + if (mxs_lradc_check_touch_event(lradc)) {
>>> + mxs_lradc_prepare_y_pos(ts);
>>> + return;
>>> + }
>>> +
>>> + if (ts->ts_valid) {
>>> + /* signal the release */
>>> + ts->ts_valid = false;
>>> + input_report_key(ts->ts_input, BTN_TOUCH, 0);
>>> + input_sync(ts->ts_input);
>>> + }
>>> +
>>> + /* if it is released, wait for the next touch via IRQ */
>>> + ts->cur_plate = LRADC_TOUCH;
>>> + mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(2));
>>> + mxs_lradc_reg_wrt(lradc, 0, LRADC_DELAY(3));
>>> + mxs_lradc_reg_clear(lradc,
>>> + LRADC_CTRL1_TOUCH_DETECT_IRQ |
>>> + LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1) |
>>> + LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1),
>>> + LRADC_CTRL1);
>>> + mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
>>> +}
>>> +
>>> +/* touchscreen's state machine */
>>> +static void mxs_lradc_handle_touch(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + switch (ts->cur_plate) {
>>> + case LRADC_TOUCH:
>>> + if (mxs_lradc_check_touch_event(lradc))
>>> + mxs_lradc_start_touch_event(ts);
>>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ,
>>> + LRADC_CTRL1);
>>> + return;
>>> +
>>> + case LRADC_SAMPLE_Y:
>>> + ts->ts_y_pos =
>>> + mxs_lradc_ts_read_raw_channel(ts, TOUCHSCREEN_VCHANNEL1);
>>> + mxs_lradc_prepare_x_pos(ts);
>>> + return;
>>> +
>>> + case LRADC_SAMPLE_X:
>>> + ts->ts_x_pos =
>>> + mxs_lradc_ts_read_raw_channel(ts, TOUCHSCREEN_VCHANNEL1);
>>> + mxs_lradc_prepare_pressure(ts);
>>> + return;
>>> +
>>> + case LRADC_SAMPLE_PRESSURE:
>>> + ts->ts_pressure =
>>> + mxs_lradc_read_ts_pressure(ts,
>>> + TOUCHSCREEN_VCHANNEL2,
>>> + TOUCHSCREEN_VCHANNEL1);
>>> + mxs_lradc_complete_touch_event(ts);
>>> + return;
>>> +
>>> + case LRADC_SAMPLE_VALID:
>>> + mxs_lradc_finish_touch_event(ts, 1);
>>> + break;
>>> + }
>>> +}
>>> +
>>> +/*
>>> + * IRQ Handling
>>> + */
>>> +static irqreturn_t mxs_lradc_ts_handle_irq(int irq, void *data)
>>> +{
>>> + struct mxs_lradc_ts *ts = data;
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> + unsigned long reg = readl(lradc->base + LRADC_CTRL1);
>>> + u32 clr_irq = mxs_lradc_irq_mask(lradc);
>>> + const u32 ts_irq_mask =
>>> + LRADC_CTRL1_TOUCH_DETECT_IRQ |
>>> + LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
>>> + LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2);
>>> +
>>> + if (!(reg & mxs_lradc_irq_mask(lradc)))
>>> + return IRQ_NONE;
>>> +
>>> + if (lradc->use_touchscreen && (reg & ts_irq_mask)) {
>>> + mxs_lradc_handle_touch(ts);
>>> +
>>> + /* Make sure we don't clear the next conversion's interrupt. */
>>> + clr_irq &= ~(LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
>>> + LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2));
>>> + mxs_lradc_reg_clear(lradc, reg & clr_irq, LRADC_CTRL1);
>>> + }
>>> +
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>> +static int mxs_lradc_ts_open(struct input_dev *dev)
>>> +{
>>> + struct mxs_lradc_ts *ts = input_get_drvdata(dev);
>>> +
>>> + /* Enable the touch-detect circuitry. */
>>> + mxs_lradc_enable_touch_detection(ts);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static void mxs_lradc_disable_ts(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + /* stop all interrupts from firing */
>>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
>>> + LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1) |
>>> + LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL2), LRADC_CTRL1);
>>> +
>>> + /* Power-down touchscreen touch-detect circuitry. */
>>> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
>>> +}
>>> +
>>> +static void mxs_lradc_ts_close(struct input_dev *dev)
>>> +{
>>> + struct mxs_lradc_ts *ts = input_get_drvdata(dev);
>>> +
>>> + mxs_lradc_disable_ts(ts);
>>> +}
>>> +
>>> +static void mxs_lradc_ts_hw_init(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + /* Configure the touchscreen type */
>>> + if (lradc->soc == IMX28_LRADC) {
>>> + mxs_lradc_reg_clear(lradc, LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE,
>>> + LRADC_CTRL0);
>>> +
>>> + if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
>>> + mxs_lradc_reg_set(lradc,
>>> + LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE,
>>> + LRADC_CTRL0);
>>> + }
>>> +}
>>> +
>>> +static void mxs_lradc_ts_hw_stop(struct mxs_lradc_ts *ts)
>>> +{
>>> + int i;
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + mxs_lradc_reg_clear(lradc,
>>> + lradc->buffer_vchans << LRADC_CTRL1_LRADC_IRQ_EN_OFFSET,
>>> + LRADC_CTRL1);
>>> +
>>> + for (i = 1; i < LRADC_MAX_DELAY_CHANS; i++)
>>> + mxs_lradc_reg_wrt(ts->lradc, 0, LRADC_DELAY(i));
>>> +}
>>> +
>>> +static int mxs_lradc_ts_register(struct mxs_lradc_ts *ts)
>>> +{
>>> + struct input_dev *input = ts->ts_input;
>>> + struct device *dev = ts->dev;
>>> + struct mxs_lradc *lradc = ts->lradc;
>>> +
>>> + if (!lradc->use_touchscreen)
>>> + return 0;
>>> +
>>> + input->name = DRIVER_NAME_TS;
>>> + input->id.bustype = BUS_HOST;
>>> + input->dev.parent = dev;
>>> + input->open = mxs_lradc_ts_open;
>>> + input->close = mxs_lradc_ts_close;
>>> +
>>> + __set_bit(EV_ABS, input->evbit);
>>> + __set_bit(EV_KEY, input->evbit);
>>> + __set_bit(BTN_TOUCH, input->keybit);
>>> + __set_bit(INPUT_PROP_DIRECT, input->propbit);
>>> + input_set_abs_params(input, ABS_X, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
>>> + input_set_abs_params(input, ABS_Y, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
>>> + input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_SINGLE_SAMPLE_MASK,
>>> + 0, 0);
>>> +
>>> + ts->ts_input = input;
>>> + input_set_drvdata(input, ts);
>>> +
>>> + return input_register_device(input);
>>> +}
>>> +
>>> +static int mxs_lradc_ts_probe(struct platform_device *pdev)
>>> +{
>>> + struct device *dev = &pdev->dev;
>>> + struct device_node *node = dev->parent->of_node;
>>> + struct mxs_lradc *lradc = dev_get_platdata(dev);
>>> + struct mxs_lradc_ts *ts;
>>> + struct input_dev *input;
>>> + int touch_ret, ret, i;
>>> + u32 ts_wires = 0, adapt;
>>> +
>>> + ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
>>> + input = devm_input_allocate_device(dev);
>>> + if (!ts || !input)
>>> + return -ENOMEM;
>>> +
>>> + ts->lradc = lradc;
>>> + ts->dev = dev;
>>> + ts->ts_input = input;
>>> + platform_set_drvdata(pdev, ts);
>>> + input_set_drvdata(input, ts);
>>> +
>>> + touch_ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
>>> + &ts_wires);
>>> +
>>> + if (of_property_read_u32(node, "fsl,ave-ctrl", &adapt)) {
>>> + ts->over_sample_cnt = 4;
>>> + } else {
>>> + if (adapt < 1 || adapt > 32) {
>>> + dev_err(ts->dev, "Invalid sample count (%u)\n",
>>> + adapt);
>>> + touch_ret = -EINVAL;
>>> + } else {
>>> + ts->over_sample_cnt = adapt;
>>> + }
>>> + }
>>> +
>>> + if (of_property_read_u32(node, "fsl,ave-delay", &adapt)) {
>>> + ts->over_sample_delay = 2;
>>> + } else {
>>> + if (adapt < 2 || adapt > LRADC_DELAY_DELAY_MASK + 1) {
>>> + dev_err(ts->dev, "Invalid sample delay (%u)\n",
>>> + adapt);
>>> + touch_ret = -EINVAL;
>>> + } else {
>>> + ts->over_sample_delay = adapt;
>>> + }
>>> + }
>>> +
>>> + if (of_property_read_u32(node, "fsl,settling", &adapt)) {
>>> + ts->settling_delay = 10;
>>> + } else {
>>> + if (adapt < 1 || adapt > LRADC_DELAY_DELAY_MASK) {
>>> + dev_err(ts->dev, "Invalid settling delay (%u)\n",
>>> + adapt);
>>> + touch_ret = -EINVAL;
>>> + } else {
>>> + ts->settling_delay = adapt;
>>> + }
>>> + }
>>> +
>>> + mxs_lradc_ts_hw_init(ts);
>>> + for (i = 0; i < lradc->irq_count; i++) {
>>> + ret = devm_request_irq(dev, lradc->irq[i],
>>> + mxs_lradc_ts_handle_irq,
>>> + IRQF_SHARED, lradc->irq_name[i], ts);
>> As with the adc driver, are we actually using all of these? I'd prefer we
>> only grab the ones that are actually relevant.
>
> Only irq lines relevant for touchscreen are:
> mxs-lradc-touchscreen, mxs-lradc-channel6 and mxs-lradc-channel7
> But not all interrupts are beiing used even when I enabled all remaining
> channels (not used by touchscreen) for bufferd capture via
> echo 1 >/sys/bus/iio/devices/iio\:device0/scan_elements/in_voltagexx_en
>
> So I don't know if it's supposed to work like this...
> (It works the same on the original code)
Certainly should only grab the relevant ones to touch screen use in here..
Original code probably being overly enthusiastic and we never noticed ;)
>
> root@cfa100xx:~# cat /proc/interrupts
> CPU0
> 16: 13108 - 48 Edge MXS Timer Tick
> 17: 4240 - 82 Edge mxs-dma
> 25: 6 - 96 Edge 80010000.ssp
> 196: 0 - 68 Edge mxs-dma
> 210: 13 - 10 Edge mxs-lradc-touchscreen
> 211: 0 - 14 Edge mxs-lradc-thresh0
> 212: 0 - 15 Edge mxs-lradc-thresh1
> 213: 10 - 16 Edge mxs-lradc-channel0
> 214: 10 - 17 Edge mxs-lradc-channel1
> 215: 0 - 18 Edge mxs-lradc-channel2
> 216: 0 - 19 Edge mxs-lradc-channel3
> 217: 0 - 20 Edge mxs-lradc-channel4
> 218: 0 - 21 Edge mxs-lradc-channel5
> 219: 0 - 22 Edge mxs-lradc-channel6
> 220: 412 - 23 Edge mxs-lradc-channel7
> 221: 0 - 24 Edge mxs-lradc-button0
> 222: 0 - 25 Edge mxs-lradc-button1
> 223: 0 - 29 Edge RTC alarm
> 224: 0 - 111 Edge 80058000.i2c
> 228: 174 - 47 Edge uart-pl011
> 229: 439 - 93 Edge 80080000.usb
> 230: 0 - 92 Edge 80090000.usb
> 231: 3610 - 101 Edge 800f0000.ethernet
> 232: 10 80050000.lradc-dev0 Edge
> Err: 0
>
>>> + if (ret)
>>> + return ret;
>>> + }
>>> +
>>> + if (!touch_ret) {
>>> + ret = mxs_lradc_ts_register(ts);
>>> + if (!ret)
>>> + goto err_ts_register;
>>> + }
>>> +
>>> + return 0;
>>> +
>>> +err_ts_register:
>>> + mxs_lradc_ts_hw_stop(ts);
>>> + return ret;
>>> +}
>>> +
>>> +static int mxs_lradc_ts_remove(struct platform_device *pdev)
>>> +{
>>> + struct mxs_lradc_ts *ts = platform_get_drvdata(pdev);
>>> +
>>> + mxs_lradc_ts_hw_stop(ts);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static struct platform_driver mxs_lradc_ts_driver = {
>>> + .driver = {
>>> + .name = DRIVER_NAME_TS,
>>> + },
>>> + .probe = mxs_lradc_ts_probe,
>>> + .remove = mxs_lradc_ts_remove,
>>> +};
>>> +module_platform_driver(mxs_lradc_ts_driver);
>>> +
>>> +MODULE_LICENSE("GPL v2");
>>>
>>
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