Re: [PATCH 3/3] input: touchscreen: mxs-lradc: Add support for touchscreen
From: Ksenija StanojeviÄ
Date: Sun May 29 2016 - 14:00:55 EST
On Sun, May 29, 2016 at 6:49 PM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> 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 ;)
Sorry for being unclear...
The point I was trying to make was that even though touchscreen and
adc don't share irq lines, irqs mxs-lradc-channel(2,3,4,5,6) are never
being used.
So touchscreen is only use 2 out of 3 irqs assigned to it:
mxs-lradc-touchscreen and mxs-lradc-channel7 . And adc
is only using 2 irq lines mxs-lradc-channel(0,1) during buffered
capture, even when all virtal channels are enabled.
I found that odd...
>> 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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>