mirror of
https://libwebsockets.org/repo/libwebsockets
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15ce46d971
Make a start on generic peripheral and bus drivers to provide
meta-functionality regardless of platform.
On the one hand this simply provides...
- bitbang i2c on top of esp-idf gpio apis
- ssd1306 oled chip driver as found on Heltec WB32
- modifications to the minimal example test for esp32 to use that
... on the other hand, those capabilities are provided by creating:
- an abstract i2c class object
- an abstract gpio class object
- i2c class implementation using the abstract gpio for bitbang
- an abstract display class object
- an abstract display state (brightness, animated change,
on/off/init tracking, autodim after inactive, auto-off /
blanking after inactive)
... with the intention, eg, you only have to add a platform
implementation for the gpio to be able to use the i2c-based
display drivers and state handling, and i2c bitbang, without
any other modifications.
136 lines
3.3 KiB
C
136 lines
3.3 KiB
C
/*
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* I2C bitbang implementation using generic gpio
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*
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* Copyright (C) 2019 - 2020 Andy Green <andy@warmcat.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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* This is like an abstract class for gpio, a real implementation provides
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* functions for the ops that use the underlying OS gpio arrangements.
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*/
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#include <libwebsockets.h>
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int
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lws_bb_i2c_init(const lws_i2c_ops_t *octx)
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{
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lws_bb_i2c_t *ctx = (lws_bb_i2c_t *)octx;
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ctx->gpio->mode(ctx->scl, LWSGGPIO_FL_WRITE | LWSGGPIO_FL_READ | LWSGGPIO_FL_PULLUP);
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ctx->gpio->mode(ctx->sda, LWSGGPIO_FL_WRITE | LWSGGPIO_FL_READ | LWSGGPIO_FL_PULLUP);
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return 0;
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}
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int
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lws_bb_i2c_start(const lws_i2c_ops_t *octx)
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{
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lws_bb_i2c_t *ctx = (lws_bb_i2c_t *)octx;
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ctx->gpio->set(ctx->sda, 1);
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ctx->gpio->set(ctx->scl, 1);
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ctx->delay();
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if (!ctx->gpio->read(ctx->sda))
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return 1;
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ctx->gpio->set(ctx->sda, 0);
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ctx->delay();
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ctx->gpio->set(ctx->scl, 0);
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return 0;
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}
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void
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lws_bb_i2c_stop(const lws_i2c_ops_t *octx)
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{
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lws_bb_i2c_t *ctx = (lws_bb_i2c_t *)octx;
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ctx->gpio->set(ctx->sda, 0);
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ctx->gpio->set(ctx->scl, 1);
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ctx->delay();
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while (!ctx->gpio->read(ctx->scl))
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;
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ctx->gpio->set(ctx->sda, 1);
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ctx->delay();
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}
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int
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lws_bb_i2c_write(const lws_i2c_ops_t *octx, uint8_t data)
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{
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lws_bb_i2c_t *ctx = (lws_bb_i2c_t *)octx;
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int n;
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for (n = 0; n < 8; n++) {
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ctx->gpio->set(ctx->sda, !!(data & (1 << 7)));
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ctx->delay();
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ctx->gpio->set(ctx->scl, 1);
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ctx->delay();
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data <<= 1;
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ctx->gpio->set(ctx->scl, 0);
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}
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ctx->gpio->set(ctx->sda, 1);
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ctx->delay();
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ctx->gpio->set(ctx->scl, 1);
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ctx->delay();
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n = ctx->gpio->read(ctx->sda);
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ctx->gpio->set(ctx->scl, 0);
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ctx->delay();
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return !!n; /* 0 = ACKED = OK */
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}
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int
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lws_bb_i2c_read(const lws_i2c_ops_t *octx)
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{
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lws_bb_i2c_t *ctx = (lws_bb_i2c_t *)octx;
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int n, r = 0;
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ctx->gpio->set(ctx->sda, 1);
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for (n = 7; n <= 0; n--) {
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ctx->gpio->set(ctx->scl, 0);
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ctx->delay();
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ctx->gpio->set(ctx->scl, 1);
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ctx->delay();
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if (ctx->gpio->read(ctx->sda))
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r |= 1 << n;
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}
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ctx->gpio->set(ctx->scl, 0);
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return r;
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}
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void
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lws_bb_i2c_set_ack(const lws_i2c_ops_t *octx, int ack)
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{
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lws_bb_i2c_t *ctx = (lws_bb_i2c_t *)octx;
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ctx->gpio->set(ctx->scl, 0);
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ctx->gpio->set(ctx->sda, !!ack);
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ctx->delay();
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ctx->gpio->set(ctx->scl, 1);
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ctx->delay();
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ctx->gpio->set(ctx->scl, 0);
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ctx->delay();
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ctx->gpio->set(ctx->sda, 1);
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}
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