iio: at91: introduce touch screen support in iio adc driver (c8b11de0) · Commits · 戴 / test

Documentation/devicetree/bindings/arm/atmel-adc.txt

+7 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,13 @@ Optional properties:
		resolution will be used.
		- atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
		- atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
		- atmel,adc-ts-wires: Number of touch screen wires. Should be 4 or 5. If this
		value is set, then adc driver will enable touch screen
		support.
		NOTE: when adc touch screen enabled, the adc hardware trigger will be
		disabled. Since touch screen will occupied the trigger register.
		- atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It
		make touch detect more precision.

		Optional trigger Nodes:
		- Required properties:

arch/arm/mach-at91/include/mach/at91_adc.h

+34 −0

Original line number	Diff line number	Diff line
		@@ -60,14 +60,48 @@
		#define AT91_ADC_IER 0x24 /* Interrupt Enable Register */
		#define AT91_ADC_IDR 0x28 /* Interrupt Disable Register */
		#define AT91_ADC_IMR 0x2C /* Interrupt Mask Register */
		#define AT91_ADC_IER_PEN (1 << 29)
		#define AT91_ADC_IER_NOPEN (1 << 30)
		#define AT91_ADC_IER_XRDY (1 << 20)
		#define AT91_ADC_IER_YRDY (1 << 21)
		#define AT91_ADC_IER_PRDY (1 << 22)
		#define AT91_ADC_ISR_PENS (1 << 31)

		#define AT91_ADC_CHR(n) (0x30 + ((n) * 4)) /* Channel Data Register N */
		#define AT91_ADC_DATA (0x3ff)

		#define AT91_ADC_CDR0_9X5 (0x50) /* Channel Data Register 0 for 9X5 */

		#define AT91_ADC_ACR 0x94 /* Analog Control Register */
		#define AT91_ADC_ACR_PENDETSENS (0x3 << 0) /* pull-up resistor */

		#define AT91_ADC_TSMR 0xB0
		#define AT91_ADC_TSMR_TSMODE (3 << 0) /* Touch Screen Mode */
		#define AT91_ADC_TSMR_TSMODE_NONE (0 << 0)
		#define AT91_ADC_TSMR_TSMODE_4WIRE_NO_PRESS (1 << 0)
		#define AT91_ADC_TSMR_TSMODE_4WIRE_PRESS (2 << 0)
		#define AT91_ADC_TSMR_TSMODE_5WIRE (3 << 0)
		#define AT91_ADC_TSMR_TSAV (3 << 4) /* Averages samples */
		#define AT91_ADC_TSMR_TSAV_(x) ((x) << 4)
		#define AT91_ADC_TSMR_SCTIM (0x0f << 16) /* Switch closure time */
		#define AT91_ADC_TSMR_PENDBC (0x0f << 28) /* Pen Debounce time */
		#define AT91_ADC_TSMR_PENDBC_(x) ((x) << 28)
		#define AT91_ADC_TSMR_NOTSDMA (1 << 22) /* No Touchscreen DMA */
		#define AT91_ADC_TSMR_PENDET_DIS (0 << 24) /* Pen contact detection disable */
		#define AT91_ADC_TSMR_PENDET_ENA (1 << 24) /* Pen contact detection enable */

		#define AT91_ADC_TSXPOSR 0xB4
		#define AT91_ADC_TSYPOSR 0xB8
		#define AT91_ADC_TSPRESSR 0xBC

		#define AT91_ADC_TRGR_9260 AT91_ADC_MR
		#define AT91_ADC_TRGR_9G45 0x08
		#define AT91_ADC_TRGR_9X5 0xC0

		/* Trigger Register bit field */
		#define AT91_ADC_TRGR_TRGPER (0xffff << 16)
		#define AT91_ADC_TRGR_TRGPER_(x) ((x) << 16)
		#define AT91_ADC_TRGR_TRGMOD (0x7 << 0)
		#define AT91_ADC_TRGR_MOD_PERIOD_TRIG (5 << 0)

		#endif

drivers/iio/adc/at91_adc.c

+364 −24

Original line number	Diff line number	Diff line
		@@ -11,6 +11,7 @@
		#include <linux/clk.h>
		#include <linux/err.h>
		#include <linux/io.h>
		#include <linux/input.h>
		#include <linux/interrupt.h>
		#include <linux/jiffies.h>
		#include <linux/kernel.h>
		@@ -39,7 +40,23 @@
		#define at91_adc_writel(st, reg, val) \
		(writel_relaxed(val, st->reg_base + reg))

		#define DRIVER_NAME "at91_adc"
		#define MAX_POS_BITS 12

		#define TOUCH_SAMPLE_PERIOD_US 2000 /* 2ms */
		#define TOUCH_PEN_DETECT_DEBOUNCE_US 200

		struct at91_adc_caps {
		bool has_ts; /* Support touch screen */
		bool has_tsmr; /* only at91sam9x5, sama5d3 have TSMR reg */
		/*
		* Numbers of sampling data will be averaged. Can be 0~3.
		* Hardware can average (2 ^ ts_filter_average) sample data.
		*/
		u8 ts_filter_average;
		/* Pen Detection input pull-up resistor, can be 0~3 */
		u8 ts_pen_detect_sensitivity;

		/* startup time calculate function */
		u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);

		@@ -47,6 +64,12 @@ struct at91_adc_caps {
		struct at91_adc_reg_desc registers;
		};

		enum atmel_adc_ts_type {
		ATMEL_ADC_TOUCHSCREEN_NONE = 0,
		ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
		ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
		};

		struct at91_adc_state {
		struct clk *adc_clk;
		u16 *buffer;
		@@ -71,6 +94,26 @@ struct at91_adc_state {
		bool low_res; /* the resolution corresponds to the lowest one */
		wait_queue_head_t wq_data_avail;
		struct at91_adc_caps *caps;

		/*
		* Following ADC channels are shared by touchscreen:
		*
		* CH0 -- Touch screen XP/UL
		* CH1 -- Touch screen XM/UR
		* CH2 -- Touch screen YP/LL
		* CH3 -- Touch screen YM/Sense
		* CH4 -- Touch screen LR(5-wire only)
		*
		* The bitfields below represents the reserved channel in the
		* touchscreen mode.
		*/
		#define CHAN_MASK_TOUCHSCREEN_4WIRE (0xf << 0)
		#define CHAN_MASK_TOUCHSCREEN_5WIRE (0x1f << 0)
		enum atmel_adc_ts_type touchscreen_type;
		struct input_dev *ts_input;

		u16 ts_sample_period_val;
		u32 ts_pressure_threshold;
		};

		static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
		@@ -99,14 +142,10 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
		return IRQ_HANDLED;
		}

		static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
		/* Handler for classic adc channel eoc trigger */
		void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
		{
		struct iio_dev *idev = private;
		struct at91_adc_state *st = iio_priv(idev);
		u32 status = at91_adc_readl(st, st->registers->status_register);

		if (!(status & st->registers->drdy_mask))
		return IRQ_HANDLED;

		if (iio_buffer_enabled(idev)) {
		disable_irq_nosync(irq);
		@@ -116,6 +155,115 @@ static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
		st->done = true;
		wake_up_interruptible(&st->wq_data_avail);
		}
		}

		static int at91_ts_sample(struct at91_adc_state *st)
		{
		unsigned int xscale, yscale, reg, z1, z2;
		unsigned int x, y, pres, xpos, ypos;
		unsigned int rxp = 1;
		unsigned int factor = 1000;
		struct iio_dev *idev = iio_priv_to_dev(st);

		unsigned int xyz_mask_bits = st->res;
		unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;

		/* calculate position */
		/* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
		reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
		xpos = reg & xyz_mask;
		x = (xpos << MAX_POS_BITS) - xpos;
		xscale = (reg >> 16) & xyz_mask;
		if (xscale == 0) {
		dev_err(&idev->dev, "Error: xscale == 0!\n");
		return -1;
		}
		x /= xscale;

		/* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
		reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
		ypos = reg & xyz_mask;
		y = (ypos << MAX_POS_BITS) - ypos;
		yscale = (reg >> 16) & xyz_mask;
		if (yscale == 0) {
		dev_err(&idev->dev, "Error: yscale == 0!\n");
		return -1;
		}
		y /= yscale;

		/* calculate the pressure */
		reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
		z1 = reg & xyz_mask;
		z2 = (reg >> 16) & xyz_mask;

		if (z1 != 0)
		pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
		/ factor;
		else
		pres = st->ts_pressure_threshold; /* no pen contacted */

		dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
		xpos, xscale, ypos, yscale, z1, z2, pres);

		if (pres < st->ts_pressure_threshold) {
		dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
		x, y, pres / factor);
		input_report_abs(st->ts_input, ABS_X, x);
		input_report_abs(st->ts_input, ABS_Y, y);
		input_report_abs(st->ts_input, ABS_PRESSURE, pres);
		input_report_key(st->ts_input, BTN_TOUCH, 1);
		input_sync(st->ts_input);
		} else {
		dev_dbg(&idev->dev, "pressure too low: not reporting\n");
		}

		return 0;
		}

		static irqreturn_t at91_adc_interrupt(int irq, void *private)
		{
		struct iio_dev *idev = private;
		struct at91_adc_state *st = iio_priv(idev);
		u32 status = at91_adc_readl(st, st->registers->status_register);
		const uint32_t ts_data_irq_mask =
		AT91_ADC_IER_XRDY \|
		AT91_ADC_IER_YRDY \|
		AT91_ADC_IER_PRDY;

		if (status & st->registers->drdy_mask)
		handle_adc_eoc_trigger(irq, idev);

		if (status & AT91_ADC_IER_PEN) {
		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN \|
		ts_data_irq_mask);
		/* Set up period trigger for sampling */
		at91_adc_writel(st, st->registers->trigger_register,
		AT91_ADC_TRGR_MOD_PERIOD_TRIG \|
		AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
		} else if (status & AT91_ADC_IER_NOPEN) {
		at91_adc_writel(st, st->registers->trigger_register, 0);
		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN \|
		ts_data_irq_mask);
		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);

		input_report_key(st->ts_input, BTN_TOUCH, 0);
		input_sync(st->ts_input);
		} else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
		/* Now all touchscreen data is ready */

		if (status & AT91_ADC_ISR_PENS) {
		/* validate data by pen contact */
		at91_ts_sample(st);
		} else {
		/* triggered by event that is no pen contact, just read
		* them to clean the interrupt and discard all.
		*/
		at91_adc_readl(st, AT91_ADC_TSXPOSR);
		at91_adc_readl(st, AT91_ADC_TSYPOSR);
		at91_adc_readl(st, AT91_ADC_TSPRESSR);
		}
		}

		return IRQ_HANDLED;
		}
		@@ -125,6 +273,16 @@ static int at91_adc_channel_init(struct iio_dev *idev)
		struct at91_adc_state *st = iio_priv(idev);
		struct iio_chan_spec chan_array, timestamp;
		int bit, idx = 0;
		unsigned long rsvd_mask = 0;

		/* If touchscreen is enable, then reserve the adc channels */
		if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
		rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
		else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
		rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;

		/* set up the channel mask to reserve touchscreen channels */
		st->channels_mask &= ~rsvd_mask;

		idev->num_channels = bitmap_weight(&st->channels_mask,
		st->num_channels) + 1;
		@@ -473,6 +631,39 @@ static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)

		static const struct of_device_id at91_adc_dt_ids[];

		static int at91_adc_probe_dt_ts(struct device_node *node,
		struct at91_adc_state st, struct device dev)
		{
		int ret;
		u32 prop;

		ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
		if (ret) {
		dev_info(dev, "ADC Touch screen is disabled.\n");
		return 0;
		}

		switch (prop) {
		case 4:
		case 5:
		st->touchscreen_type = prop;
		break;
		default:
		dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
		return -EINVAL;
		}

		prop = 0;
		of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
		st->ts_pressure_threshold = prop;
		if (st->ts_pressure_threshold) {
		return 0;
		} else {
		dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
		return -EINVAL;
		}
		}

		static int at91_adc_probe_dt(struct at91_adc_state *st,
		struct platform_device *pdev)
		{
		@@ -554,6 +745,12 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
		i++;
		}

		/* Check if touchscreen is supported. */
		if (st->caps->has_ts)
		return at91_adc_probe_dt_ts(node, st, &idev->dev);
		else
		dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");

		return 0;

		error_ret:
		@@ -585,6 +782,114 @@ static const struct iio_info at91_adc_info = {
		.read_raw = &at91_adc_read_raw,
		};

		/* Touchscreen related functions */
		static int atmel_ts_open(struct input_dev *dev)
		{
		struct at91_adc_state *st = input_get_drvdata(dev);

		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
		return 0;
		}

		static void atmel_ts_close(struct input_dev *dev)
		{
		struct at91_adc_state *st = input_get_drvdata(dev);

		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
		}

		static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
		{
		u32 reg = 0, pendbc;
		int i = 0;

		if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
		else
		reg = AT91_ADC_TSMR_TSMODE_5WIRE;

		/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
		* pen detect noise.
		* The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
		*/
		pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);

		while (pendbc >> ++i)
		; /* Empty! Find the shift offset */
		if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
		pendbc = i;
		else
		pendbc = i - 1;

		if (st->caps->has_tsmr) {
		reg \|= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
		& AT91_ADC_TSMR_TSAV;
		reg \|= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
		reg \|= AT91_ADC_TSMR_NOTSDMA;
		reg \|= AT91_ADC_TSMR_PENDET_ENA;
		reg \|= 0x03 << 8; /* TSFREQ, need bigger than TSAV */

		at91_adc_writel(st, AT91_ADC_TSMR, reg);
		} else {
		/* TODO: for 9g45 which has no TSMR */
		}

		/* Change adc internal resistor value for better pen detection,
		* default value is 100 kOhm.
		* 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
		* option only available on ES2 and higher
		*/
		at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
		& AT91_ADC_ACR_PENDETSENS);

		/* Sample Peroid Time = (TRGPER + 1) / ADCClock */
		st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
		adc_clk_khz / 1000) - 1, 1);

		return 0;
		}

		static int at91_ts_register(struct at91_adc_state *st,
		struct platform_device *pdev)
		{
		struct input_dev *input;
		struct iio_dev *idev = iio_priv_to_dev(st);
		int ret;

		input = input_allocate_device();
		if (!input) {
		dev_err(&idev->dev, "Failed to allocate TS device!\n");
		return -ENOMEM;
		}

		input->name = DRIVER_NAME;
		input->id.bustype = BUS_HOST;
		input->dev.parent = &pdev->dev;
		input->open = atmel_ts_open;
		input->close = atmel_ts_close;

		__set_bit(EV_ABS, input->evbit);
		__set_bit(EV_KEY, input->evbit);
		__set_bit(BTN_TOUCH, input->keybit);
		input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
		input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
		input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);

		st->ts_input = input;
		input_set_drvdata(input, st);

		ret = input_register_device(input);
		if (ret)
		input_free_device(st->ts_input);

		return ret;
		}

		static void at91_ts_unregister(struct at91_adc_state *st)
		{
		input_unregister_device(st->ts_input);
		}

		static int at91_adc_probe(struct platform_device *pdev)
		{
		unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
		@@ -636,7 +941,7 @@ static int at91_adc_probe(struct platform_device *pdev)
		at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
		at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
		ret = request_irq(st->irq,
		at91_adc_eoc_trigger,
		at91_adc_interrupt,
		0,
		pdev->dev.driver->name,
		idev);
		@@ -681,6 +986,10 @@ static int at91_adc_probe(struct platform_device *pdev)
		mstrclk = clk_get_rate(st->clk);
		adc_clk = clk_get_rate(st->adc_clk);
		adc_clk_khz = adc_clk / 1000;

		dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
		mstrclk, adc_clk);

		prsc = (mstrclk / (2 * adc_clk)) - 1;

		if (!st->startup_time) {
		@@ -717,6 +1026,12 @@ static int at91_adc_probe(struct platform_device *pdev)
		init_waitqueue_head(&st->wq_data_avail);
		mutex_init(&st->lock);

		/*
		* Since touch screen will set trigger register as period trigger. So
		* when touch screen is enabled, then we have to disable hardware
		* trigger for classic adc.
		*/
		if (!st->touchscreen_type) {
		ret = at91_adc_buffer_init(idev);
		if (ret < 0) {
		dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
		@@ -726,21 +1041,37 @@ static int at91_adc_probe(struct platform_device *pdev)
		ret = at91_adc_trigger_init(idev);
		if (ret < 0) {
		dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
		goto error_unregister_buffer;
		at91_adc_buffer_remove(idev);
		goto error_disable_adc_clk;
		}
		} else {
		if (!st->caps->has_tsmr) {
		dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
		goto error_disable_adc_clk;
		}

		ret = at91_ts_register(st, pdev);
		if (ret)
		goto error_disable_adc_clk;

		at91_ts_hw_init(st, adc_clk_khz);
		}

		ret = iio_device_register(idev);
		if (ret < 0) {
		dev_err(&pdev->dev, "Couldn't register the device.\n");
		goto error_remove_triggers;
		goto error_iio_device_register;
		}

		return 0;

		error_remove_triggers:
		error_iio_device_register:
		if (!st->touchscreen_type) {
		at91_adc_trigger_remove(idev);
		error_unregister_buffer:
		at91_adc_buffer_remove(idev);
		} else {
		at91_ts_unregister(st);
		}
		error_disable_adc_clk:
		clk_disable_unprepare(st->adc_clk);
		error_disable_clk:
		@@ -756,8 +1087,12 @@ static int at91_adc_remove(struct platform_device *pdev)
		struct at91_adc_state *st = iio_priv(idev);

		iio_device_unregister(idev);
		if (!st->touchscreen_type) {
		at91_adc_trigger_remove(idev);
		at91_adc_buffer_remove(idev);
		} else {
		at91_ts_unregister(st);
		}
		clk_disable_unprepare(st->adc_clk);
		clk_disable_unprepare(st->clk);
		free_irq(st->irq, idev);
		@@ -780,6 +1115,7 @@ static struct at91_adc_caps at91sam9260_caps = {
		};

		static struct at91_adc_caps at91sam9g45_caps = {
		.has_ts = true,
		.calc_startup_ticks = calc_startup_ticks_9260, /* same as 9260 */
		.num_channels = 8,
		.registers = {
		@@ -793,6 +1129,10 @@ static struct at91_adc_caps at91sam9g45_caps = {
		};

		static struct at91_adc_caps at91sam9x5_caps = {
		.has_ts = true,
		.has_tsmr = true,
		.ts_filter_average = 3,
		.ts_pen_detect_sensitivity = 2,
		.calc_startup_ticks = calc_startup_ticks_9x5,
		.num_channels = 12,
		.registers = {
		@@ -819,7 +1159,7 @@ static struct platform_driver at91_adc_driver = {
		.probe = at91_adc_probe,
		.remove = at91_adc_remove,
		.driver = {
		.name = "at91_adc",
		.name = DRIVER_NAME,
		.of_match_table = of_match_ptr(at91_adc_dt_ids),
		},
		};

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