141 lines
3.9 KiB
C
141 lines
3.9 KiB
C
/* $NetBSD: ddc.c,v 1.9 2019/12/23 18:12:50 thorpej Exp $ */
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/*-
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* Copyright (c) 2006 Itronix Inc.
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* All rights reserved.
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*
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* Written by Garrett D'Amore for Itronix Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of Itronix Inc. may not be used to endorse
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* or promote products derived from this software without specific
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* prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL ITRONIX INC. BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: ddc.c,v 1.9 2019/12/23 18:12:50 thorpej Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/device.h>
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#include <sys/kernel.h>
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#include <sys/bus.h>
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#include <dev/i2c/i2cvar.h>
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#include <dev/i2c/ddcreg.h>
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#include <dev/i2c/ddcvar.h>
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/*
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* VESA Display Data Channel I2C client, used to access EDID
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* information.
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*
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* Note that this only supports DDC version 2, which uses normal I2C.
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* The older DDCv1 standard used sync signaling to provide the I2C
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* clock, and is typically not used on reasonably recent monitors.
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*/
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struct ddc_softc {
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i2c_tag_t sc_tag;
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int sc_address;
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};
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static int ddc_match(device_t, cfdata_t, void *);
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static void ddc_attach(device_t, device_t, void *);
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CFATTACH_DECL_NEW(ddc, sizeof (struct ddc_softc),
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ddc_match, ddc_attach, NULL, NULL);
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static int
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ddc_match(device_t parent, cfdata_t cf, void *aux)
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{
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struct i2c_attach_args *ia = aux;
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if (ia->ia_addr == DDC_ADDR)
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return I2C_MATCH_ADDRESS_ONLY;
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return 0;
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}
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static void
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ddc_attach(device_t parent, device_t self, void *aux)
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{
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struct ddc_softc *sc = device_private(self);
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struct i2c_attach_args *ia = aux;
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sc->sc_tag = ia->ia_tag;
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sc->sc_address = ia->ia_addr;
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aprint_naive(": DDC\n");
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aprint_normal(": DDC\n");
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}
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/* XXX: add cdev ops? */
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int
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ddc_read_edid(i2c_tag_t tag, uint8_t *dest, size_t len)
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{
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return ddc_read_edid_block(tag, dest, len, DDC_EDID_START);
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}
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int
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ddc_read_edid_block(i2c_tag_t tag, uint8_t *dest, size_t len, uint8_t block)
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{
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uint8_t edid[256];
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uint8_t wbuf[2];
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int error;
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if ((error = iic_acquire_bus(tag, 0)) != 0)
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return error;
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wbuf[0] = block >> 1; /* start address */
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if ((error = iic_exec(tag, I2C_OP_READ_WITH_STOP, DDC_ADDR, wbuf, 1,
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edid, sizeof(edid), 0)) != 0) {
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iic_release_bus(tag, 0);
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return error;
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}
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iic_release_bus(tag, 0);
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if (block & 1) {
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memcpy(dest, &edid[128], uimin(len, 128));
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} else {
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memcpy(dest, &edid[0], uimin(len, 128));
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}
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return 0;
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}
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int
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ddc_dev_read_edid(device_t dev, uint8_t *dest, size_t len)
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{
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return ddc_dev_read_edid_block(dev, dest, len, DDC_EDID_START);
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}
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int
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ddc_dev_read_edid_block(device_t dev, uint8_t *dest, size_t len, uint8_t block)
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{
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if (!device_is_a(dev, "ddc"))
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return EINVAL;
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const struct ddc_softc *sc = device_private(dev);
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return ddc_read_edid_block(sc->sc_tag, dest, len, block);
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}
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