cregit-Linux how code gets into the kernel

Release 4.7 drivers/input/keyboard/lpc32xx-keys.c

/*
 * NXP LPC32xx SoC Key Scan Interface
 *
 * Authors:
 *    Kevin Wells <kevin.wells@nxp.com>
 *    Roland Stigge <stigge@antcom.de>
 *
 * Copyright (C) 2010 NXP Semiconductors
 * Copyright (C) 2012 Roland Stigge
 *
 * 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.
 *
 *
 * This controller supports square key matrices from 1x1 up to 8x8
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/input/matrix_keypad.h>


#define DRV_NAME				"lpc32xx_keys"

/*
 * Key scanner register offsets
 */

#define LPC32XX_KS_DEB(x)			((x) + 0x00)

#define LPC32XX_KS_STATE_COND(x)		((x) + 0x04)

#define LPC32XX_KS_IRQ(x)			((x) + 0x08)

#define LPC32XX_KS_SCAN_CTL(x)			((x) + 0x0C)

#define LPC32XX_KS_FAST_TST(x)			((x) + 0x10)

#define LPC32XX_KS_MATRIX_DIM(x)		((x) + 0x14) 
/* 1..8 */

#define LPC32XX_KS_DATA(x, y)			((x) + 0x40 + ((y) << 2))


#define LPC32XX_KSCAN_DEB_NUM_DEB_PASS(n)	((n) & 0xFF)


#define LPC32XX_KSCAN_SCOND_IN_IDLE		0x0

#define LPC32XX_KSCAN_SCOND_IN_SCANONCE		0x1

#define LPC32XX_KSCAN_SCOND_IN_IRQGEN		0x2

#define LPC32XX_KSCAN_SCOND_IN_SCAN_MATRIX	0x3


#define LPC32XX_KSCAN_IRQ_PENDING_CLR		0x1


#define LPC32XX_KSCAN_SCTRL_SCAN_DELAY(n)	((n) & 0xFF)


#define LPC32XX_KSCAN_FTST_FORCESCANONCE	0x1

#define LPC32XX_KSCAN_FTST_USE32K_CLK		0x2


#define LPC32XX_KSCAN_MSEL_SELECT(n)		((n) & 0xF)


struct lpc32xx_kscan_drv {
	
struct input_dev *input;
	
struct clk *clk;
	
void __iomem *kscan_base;
	
unsigned int irq;

	
u32 matrix_sz;		/* Size of matrix in XxY, ie. 3 = 3x3 */
	
u32 deb_clks;		/* Debounce clocks (based on 32KHz clock) */
	
u32 scan_delay;		/* Scan delay (based on 32KHz clock) */

	
unsigned short *keymap;	/* Pointer to key map for the scan matrix */
	
unsigned int row_shift;

	
u8 lastkeystates[8];
};


static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col) { struct input_dev *input = kscandat->input; unsigned row, changed, scancode, keycode; u8 key; key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col)); changed = key ^ kscandat->lastkeystates[col]; kscandat->lastkeystates[col] = key; for (row = 0; changed; row++, changed >>= 1) { if (changed & 1) { /* Key state changed, signal an event */ scancode = MATRIX_SCAN_CODE(row, col, kscandat->row_shift); keycode = kscandat->keymap[scancode]; input_event(input, EV_MSC, MSC_SCAN, scancode); input_report_key(input, keycode, key & (1 << row)); } } }

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static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id) { struct lpc32xx_kscan_drv *kscandat = dev_id; int i; for (i = 0; i < kscandat->matrix_sz; i++) lpc32xx_mod_states(kscandat, i); writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base)); input_sync(kscandat->input); return IRQ_HANDLED; }

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static int lpc32xx_kscan_open(struct input_dev *dev) { struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev); int error; error = clk_prepare_enable(kscandat->clk); if (error) return error; writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base)); return 0; }

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static void lpc32xx_kscan_close(struct input_dev *dev) { struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev); writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base)); clk_disable_unprepare(kscandat->clk); }

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static int lpc32xx_parse_dt(struct device *dev, struct lpc32xx_kscan_drv *kscandat) { struct device_node *np = dev->of_node; u32 rows = 0, columns = 0; int err; err = matrix_keypad_parse_of_params(dev, &rows, &columns); if (err) return err; if (rows != columns) { dev_err(dev, "rows and columns must be equal!\n"); return -EINVAL; } kscandat->matrix_sz = rows; kscandat->row_shift = get_count_order(columns); of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks); of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay); if (!kscandat->deb_clks || !kscandat->scan_delay) { dev_err(dev, "debounce or scan delay not specified\n"); return -EINVAL; } return 0; }

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static int lpc32xx_kscan_probe(struct platform_device *pdev) { struct lpc32xx_kscan_drv *kscandat; struct input_dev *input; struct resource *res; size_t keymap_size; int error; int irq; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { dev_err(&pdev->dev, "failed to get platform I/O memory\n"); return -EINVAL; } irq = platform_get_irq(pdev, 0); if (irq < 0 || irq >= NR_IRQS) { dev_err(&pdev->dev, "failed to get platform irq\n"); return -EINVAL; } kscandat = devm_kzalloc(&pdev->dev, sizeof(*kscandat), GFP_KERNEL); if (!kscandat) return -ENOMEM; error = lpc32xx_parse_dt(&pdev->dev, kscandat); if (error) { dev_err(&pdev->dev, "failed to parse device tree\n"); return error; } keymap_size = sizeof(kscandat->keymap[0]) * (kscandat->matrix_sz << kscandat->row_shift); kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL); if (!kscandat->keymap) return -ENOMEM; kscandat->input = input = devm_input_allocate_device(&pdev->dev); if (!input) { dev_err(&pdev->dev, "failed to allocate input device\n"); return -ENOMEM; } /* Setup key input */ input->name = pdev->name; input->phys = "lpc32xx/input0"; input->id.vendor = 0x0001; input->id.product = 0x0001; input->id.version = 0x0100; input->open = lpc32xx_kscan_open; input->close = lpc32xx_kscan_close; input->dev.parent = &pdev->dev; input_set_capability(input, EV_MSC, MSC_SCAN); error = matrix_keypad_build_keymap(NULL, NULL, kscandat->matrix_sz, kscandat->matrix_sz, kscandat->keymap, kscandat->input); if (error) { dev_err(&pdev->dev, "failed to build keymap\n"); return error; } input_set_drvdata(kscandat->input, kscandat); kscandat->kscan_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(kscandat->kscan_base)) return PTR_ERR(kscandat->kscan_base); /* Get the key scanner clock */ kscandat->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(kscandat->clk)) { dev_err(&pdev->dev, "failed to get clock\n"); return PTR_ERR(kscandat->clk); } /* Configure the key scanner */ error = clk_prepare_enable(kscandat->clk); if (error) return error; writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base)); writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base)); writel(LPC32XX_KSCAN_FTST_USE32K_CLK, LPC32XX_KS_FAST_TST(kscandat->kscan_base)); writel(kscandat->matrix_sz, LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base)); writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base)); clk_disable_unprepare(kscandat->clk); error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0, pdev->name, kscandat); if (error) { dev_err(&pdev->dev, "failed to request irq\n"); return error; } error = input_register_device(kscandat->input); if (error) { dev_err(&pdev->dev, "failed to register input device\n"); return error; } platform_set_drvdata(pdev, kscandat); return 0; }

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#ifdef CONFIG_PM_SLEEP
static int lpc32xx_kscan_suspend(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev); struct input_dev *input = kscandat->input; mutex_lock(&input->mutex); if (input->users) { /* Clear IRQ and disable clock */ writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base)); clk_disable_unprepare(kscandat->clk); } mutex_unlock(&input->mutex); return 0; }

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static int lpc32xx_kscan_resume(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev); struct input_dev *input = kscandat->input; int retval = 0; mutex_lock(&input->mutex); if (input->users) { /* Enable clock and clear IRQ */ retval = clk_prepare_enable(kscandat->clk); if (retval == 0) writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base)); } mutex_unlock(&input->mutex); return retval; }

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#endif static SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend, lpc32xx_kscan_resume); static const struct of_device_id lpc32xx_kscan_match[] = { { .compatible = "nxp,lpc3220-key" }, {}, }; MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match); static struct platform_driver lpc32xx_kscan_driver = { .probe = lpc32xx_kscan_probe, .driver = { .name = DRV_NAME, .pm = &lpc32xx_kscan_pm_ops, .of_match_table = lpc32xx_kscan_match, } }; module_platform_driver(lpc32xx_kscan_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>"); MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>"); MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");

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