74 lines
1.6 KiB
C
74 lines
1.6 KiB
C
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/*
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* (C) Copyright 2020 Rockchip Electronics Co., Ltd
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <adc.h>
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#include <fdtdec.h>
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DECLARE_GLOBAL_DATA_PTR;
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int key_read(int code)
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{
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const void *fdt_blob = gd->fdt_blob;
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int adc_node, offset;
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int cd, channel, adc;
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int ret, vref, mv;
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int min, max;
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int margin = 30;
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uint val;
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u32 chn[2];
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adc_node = fdt_node_offset_by_compatible(fdt_blob, 0, "adc-keys");
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if (adc_node < 0) {
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debug("No 'adc-keys' node, ret=%d\n", adc_node);
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return 0;
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}
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ret = fdtdec_get_int_array(fdt_blob, adc_node, "io-channels",
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chn, ARRAY_SIZE(chn));
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if (ret) {
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debug("Can't read 'io-channels', ret=%d\n", ret);
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return 0;
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}
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vref = fdtdec_get_int(fdt_blob, adc_node,
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"keyup-threshold-microvolt", -1);
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if (vref < 0) {
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debug("Can't read 'keyup-threshold-microvolt'\n");
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return 0;
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}
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channel = chn[1];
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for (offset = fdt_first_subnode(fdt_blob, adc_node);
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offset >= 0;
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offset = fdt_next_subnode(fdt_blob, offset)) {
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cd = fdtdec_get_int(fdt_blob, offset, "linux,code", -1);
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if (cd == code) {
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mv = fdtdec_get_int(fdt_blob, offset,
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"press-threshold-microvolt", -1);
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if (mv < 0) {
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debug("Can't read 'press-threshold-microvolt'\n");
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return 0;
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}
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adc = mv / (vref / 1024); /* 10-bit adc */
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max = adc + margin;
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min = adc > margin ? adc - margin : 0;
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ret = adc_channel_single_shot("saradc", channel, &val);
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if (ret) {
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debug("Failed to read adc%d, ret=%d\n",
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channel, ret);
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return 0;
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}
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return (val >= min && val <= max);
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}
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}
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return 0;
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}
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