path: root/drivers/iio/adc/at91_adc.c

/*
 * Driver for the ADC present in the Atmel AT91 evaluation boards.
 *
 * Copyright 2011 Free Electrons
 *
 * Licensed under the GPLv2 or later.
 */

#include <linux/bitmap.h>
#include <linux/bitops.h>
#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>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/wait.h>

#include <linux/platform_data/at91_adc.h>

#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#include <mach/at91_adc.h>

#define AT91_ADC_CHAN(st, ch) \
	(st->registers->channel_base + (ch * 4))
#define at91_adc_readl(st, reg) \
	(readl_relaxed(st->reg_base + reg))
#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);

	u8	num_channels;
	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;
	unsigned long		channels_mask;
	struct clk		*clk;
	bool			done;
	int			irq;
	u16			last_value;
	struct mutex		lock;
	u8			num_channels;
	void __iomem		*reg_base;
	struct at91_adc_reg_desc *registers;
	u8			startup_time;
	u8			sample_hold_time;
	bool			sleep_mode;
	struct iio_trigger	**trig;
	struct at91_adc_trigger	*trigger_list;
	u32			trigger_number;
	bool			use_external;
	u32			vref_mv;
	u32			res;		/* resolution used for convertions */
	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)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *idev = pf->indio_dev;
	struct at91_adc_state *st = iio_priv(idev);
	int i, j = 0;

	for (i = 0; i < idev->masklength; i++) {
		if (!test_bit(i, idev->active_scan_mask))
			continue;
		st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i));
		j++;
	}

	iio_push_to_buffers_with_timestamp(idev, st->buffer, pf->timestamp);

	iio_trigger_notify_done(idev->trig);

	/* Needed to ACK the DRDY interruption */
	at91_adc_readl(st, AT91_ADC_LCDR);

	enable_irq(st->irq);

	return IRQ_HANDLED;
}

/* Handler for classic adc channel eoc trigger */
void handle_adc_eoc_trigger