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Release 4.11 drivers/input/keyboard/sun4i-lradc-keys.c

/*
 * Allwinner sun4i low res adc attached tablet keys driver
 *
 * Copyright (C) 2014 Hans de Goede <hdegoede@redhat.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.
 */

/*
 * Allwinnner sunxi SoCs have a lradc which is specifically designed to have
 * various (tablet) keys (ie home, back, search, etc). attached to it using
 * a resistor network. This driver is for the keys on such boards.
 *
 * There are 2 channels, currently this driver only supports channel 0 since
 * there are no boards known to use channel 1.
 */

#include <linux/err.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>


#define LRADC_CTRL		0x00

#define LRADC_INTC		0x04

#define LRADC_INTS		0x08

#define LRADC_DATA0		0x0c

#define LRADC_DATA1		0x10

/* LRADC_CTRL bits */

#define FIRST_CONVERT_DLY(x)	((x) << 24) 
/* 8 bits */

#define CHAN_SELECT(x)		((x) << 22) 
/* 2 bits */

#define CONTINUE_TIME_SEL(x)	((x) << 16) 
/* 4 bits */

#define KEY_MODE_SEL(x)		((x) << 12) 
/* 2 bits */

#define LEVELA_B_CNT(x)		((x) << 8)  
/* 4 bits */

#define HOLD_EN(x)		((x) << 6)

#define LEVELB_VOL(x)		((x) << 4)  
/* 2 bits */

#define SAMPLE_RATE(x)		((x) << 2)  
/* 2 bits */

#define ENABLE(x)		((x) << 0)

/* LRADC_INTC and LRADC_INTS bits */

#define CHAN1_KEYUP_IRQ		BIT(12)

#define CHAN1_ALRDY_HOLD_IRQ	BIT(11)

#define CHAN1_HOLD_IRQ		BIT(10)

#define	CHAN1_KEYDOWN_IRQ	BIT(9)

#define CHAN1_DATA_IRQ		BIT(8)

#define CHAN0_KEYUP_IRQ		BIT(4)

#define CHAN0_ALRDY_HOLD_IRQ	BIT(3)

#define CHAN0_HOLD_IRQ		BIT(2)

#define	CHAN0_KEYDOWN_IRQ	BIT(1)

#define CHAN0_DATA_IRQ		BIT(0)


struct sun4i_lradc_keymap {
	
u32 voltage;
	
u32 keycode;
};


struct sun4i_lradc_data {
	
struct device *dev;
	
struct input_dev *input;
	
void __iomem *base;
	
struct regulator *vref_supply;
	
struct sun4i_lradc_keymap *chan0_map;
	
u32 chan0_map_count;
	
u32 chan0_keycode;
	
u32 vref;
};


static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id) { struct sun4i_lradc_data *lradc = dev_id; u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff; ints = readl(lradc->base + LRADC_INTS); /* * lradc supports only one keypress at a time, release does not give * any info as to which key was released, so we cache the keycode. */ if (ints & CHAN0_KEYUP_IRQ) { input_report_key(lradc->input, lradc->chan0_keycode, 0); lradc->chan0_keycode = 0; } if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) { val = readl(lradc->base + LRADC_DATA0) & 0x3f; voltage = val * lradc->vref / 63; for (i = 0; i < lradc->chan0_map_count; i++) { diff = abs(lradc->chan0_map[i].voltage - voltage); if (diff < closest) { closest = diff; keycode = lradc->chan0_map[i].keycode; } } lradc->chan0_keycode = keycode; input_report_key(lradc->input, lradc->chan0_keycode, 1); } input_sync(lradc->input); writel(ints, lradc->base + LRADC_INTS); return IRQ_HANDLED; }

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static int sun4i_lradc_open(struct input_dev *dev) { struct sun4i_lradc_data *lradc = input_get_drvdata(dev); int error; error = regulator_enable(lradc->vref_supply); if (error) return error; /* lradc Vref internally is divided by 2/3 */ lradc->vref = regulator_get_voltage(lradc->vref_supply) * 2 / 3; /* * Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to * stabilize on press, wait (1 + 1) * 4 ms for key release */ writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) | SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL); writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC); return 0; }

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static void sun4i_lradc_close(struct input_dev *dev) { struct sun4i_lradc_data *lradc = input_get_drvdata(dev); /* Disable lradc, leave other settings unchanged */ writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) | SAMPLE_RATE(2), lradc->base + LRADC_CTRL); writel(0, lradc->base + LRADC_INTC); regulator_disable(lradc->vref_supply); }

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static int sun4i_lradc_load_dt_keymap(struct device *dev, struct sun4i_lradc_data *lradc) { struct device_node *np, *pp; int i; int error; np = dev->of_node; if (!np) return -EINVAL; lradc->chan0_map_count = of_get_child_count(np); if (lradc->chan0_map_count == 0) { dev_err(dev, "keymap is missing in device tree\n"); return -EINVAL; } lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count, sizeof(struct sun4i_lradc_keymap), GFP_KERNEL); if (!lradc->chan0_map) return -ENOMEM; i = 0; for_each_child_of_node(np, pp) { struct sun4i_lradc_keymap *map = &lradc->chan0_map[i]; u32 channel; error = of_property_read_u32(pp, "channel", &channel); if (error || channel != 0) { dev_err(dev, "%s: Inval channel prop\n", pp->name); return -EINVAL; } error = of_property_read_u32(pp, "voltage", &map->voltage); if (error) { dev_err(dev, "%s: Inval voltage prop\n", pp->name); return -EINVAL; } error = of_property_read_u32(pp, "linux,code", &map->keycode); if (error) { dev_err(dev, "%s: Inval linux,code prop\n", pp->name); return -EINVAL; } i++; } return 0; }

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static int sun4i_lradc_probe(struct platform_device *pdev) { struct sun4i_lradc_data *lradc; struct device *dev = &pdev->dev; int i; int error; lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL); if (!lradc) return -ENOMEM; error = sun4i_lradc_load_dt_keymap(dev, lradc); if (error) return error; lradc->vref_supply = devm_regulator_get(dev, "vref"); if (IS_ERR(lradc->vref_supply)) return PTR_ERR(lradc->vref_supply); lradc->dev = dev; lradc->input = devm_input_allocate_device(dev); if (!lradc->input) return -ENOMEM; lradc->input->name = pdev->name; lradc->input->phys = "sun4i_lradc/input0"; lradc->input->open = sun4i_lradc_open; lradc->input->close = sun4i_lradc_close; lradc->input->id.bustype = BUS_HOST; lradc->input->id.vendor = 0x0001; lradc->input->id.product = 0x0001; lradc->input->id.version = 0x0100; __set_bit(EV_KEY, lradc->input->evbit); for (i = 0; i < lradc->chan0_map_count; i++) __set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit); input_set_drvdata(lradc->input, lradc); lradc->base = devm_ioremap_resource(dev, platform_get_resource(pdev, IORESOURCE_MEM, 0)); if (IS_ERR(lradc->base)) return PTR_ERR(lradc->base); error = devm_request_irq(dev, platform_get_irq(pdev, 0), sun4i_lradc_irq, 0, "sun4i-a10-lradc-keys", lradc); if (error) return error; error = input_register_device(lradc->input); if (error) return error; return 0; }

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static const struct of_device_id sun4i_lradc_of_match[] = { { .compatible = "allwinner,sun4i-a10-lradc-keys", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match); static struct platform_driver sun4i_lradc_driver = { .driver = { .name = "sun4i-a10-lradc-keys", .of_match_table = of_match_ptr(sun4i_lradc_of_match), }, .probe = sun4i_lradc_probe, }; module_platform_driver(sun4i_lradc_driver); MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver"); MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); MODULE_LICENSE("GPL");

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