spi_software: Implementation of software spi

Signed-off-by: Matt Janus <FragginRight@variabl.es>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example-extras.cfg

@@ -680,6 +680,13 @@
 #   The pin corresponding to the AD5206 chip select line. This pin
 #   will be set to low at the start of SPI messages and raised to high
 #   after the message completes. This parameter must be provided.
+#spi_bus:
+#spi_speed:
+#spi_software_sclk_pin:
+#spi_software_mosi_pin:
+#spi_software_miso_pin:
+#   These optional parameters allow one to customize the SPI settings
+#   used to communicate with the chip.
 #channel_1:
 #channel_2:
 #channel_3:
@@ -787,6 +794,13 @@
 #   The pin corresponding to the TMC2130 chip select line. This pin
 #   will be set to low at the start of SPI messages and raised to high
 #   after the message completes. This parameter must be provided.
+#spi_bus:
+#spi_speed:
+#spi_software_sclk_pin:
+#spi_software_mosi_pin:
+#spi_software_miso_pin:
+#   These optional parameters allow one to customize the SPI settings
+#   used to communicate with the chip.
 #microsteps:
 #   The number of microsteps to configure the driver to use. Valid
 #   values are 1, 2, 4, 8, 16, 32, 64, 128, 256. This parameter must
@@ -908,6 +922,11 @@
 #spi_speed: 2000000
 #   SPI bus frequency used to communicate with the TMC2660 stepper
 #   driver. The default is 2000000.
+#spi_software_sclk_pin:
+#spi_software_mosi_pin:
+#spi_software_miso_pin:
+#   These optional parameters allow one to customize the SPI settings
+#   used to communicate with the chip.
 #microsteps:
 #   The number of microsteps to configure the driver to use. Valid
 #   values are 1, 2, 4, 8, 16, 32, 64, 128, 256. This parameter must
@@ -1043,8 +1062,15 @@
 #   provided when using an uc1701 display.
 #cs_pin:
 #dc_pin:
+#spi_bus:
+#spi_speed:
+#spi_software_sclk_pin:
+#spi_software_mosi_pin:
+#spi_software_miso_pin:
 #   The pins connected to an ssd1306 type lcd when in "4-wire" spi
-#   mode. The default is to use i2c mode for ssd1306 displays.
+#   mode. The parameters that start with "spi_" are optional and they
+#   control the spi settings used to communicate with the chip. The
+#   default is to use i2c mode for ssd1306 displays.
 #menu_root:
 #   Entry point for menu, root menu container name. If this parameter
 #   is not provided then default menu root is used. When provided
@@ -1140,6 +1166,12 @@
 #spi_speed: 4000000
 #   The SPI speed (in hz) to use when communicating with the chip.
 #   The default is 4000000.
+#spi_bus:
+#spi_software_sclk_pin:
+#spi_software_mosi_pin:
+#spi_software_miso_pin:
+#   These optional parameters allow one to customize the SPI settings
+#   used to communicate with the chip.
 #sensor_pin:
 #   The chip select line for the sensor chip. This parameter must be
 #   provided.

klippy/extras/bus.py

@@ -12,22 +12,33 @@ import mcu
 
 # Helper code for working with devices connected to an MCU via an SPI bus
 class MCU_SPI:
-    def __init__(self, mcu, bus, pin, mode, speed, shutdown_seq):
+    def __init__(self, mcu, bus, pin, mode, speed, shutdown_seq, sw_pins=None):
         self.mcu = mcu
         shutdown_msg = "".join(["%02x" % (x,) for x in shutdown_seq])
         self.oid = self.mcu.create_oid()
-        if pin is None:
+        if pin is not None:
-            self.config_msg = (
-                "config_spi_without_cs oid=%d bus=%d mode=%d rate=%d"
-                " shutdown_msg=%s" % (
-                    self.oid, bus, mode, speed, shutdown_msg))
-        else:
             # Set all CS pins high before first config_spi
             self.mcu.add_config_cmd("set_digital_out pin=%s value=1" % (pin,))
-            self.config_msg = (
+        if sw_pins is not None:
+            software_spi_oid = self.mcu.create_oid()
+            self.config_msgs = [
+                "config_software_spi oid=%d sclk_pin=%s mosi_pin=%s miso_pin=%s"
+                " mode=%d rate=%d" % (
+                    software_spi_oid, sw_pins[0], sw_pins[1], sw_pins[2],
+                    mode, speed),
+                "config_spi_from_software oid=%d sw_oid=%d pin=%s"
+                " shutdown_msg=%s" % (
+                    self.oid, software_spi_oid, pin, shutdown_msg)]
+        elif pin is None:
+            self.config_msgs = [
+                "config_spi_without_cs oid=%d bus=%d mode=%d rate=%d"
+                " shutdown_msg=%s" % (
+                    self.oid, bus, mode, speed, shutdown_msg)]
+        else:
+            self.config_msgs = [
                 "config_spi oid=%d bus=%d pin=%s mode=%d rate=%d"
                 " shutdown_msg=%s" % (
-                    self.oid, bus, pin, mode, speed, shutdown_msg))
+                    self.oid, bus, pin, mode, speed, shutdown_msg)]
         self.cmd_queue = self.mcu.alloc_command_queue()
         self.mcu.register_config_callback(self.build_config)
         self.spi_send_cmd = self.spi_transfer_cmd = None
@@ -38,7 +49,8 @@ class MCU_SPI:
     def get_command_queue(self):
         return self.cmd_queue
     def build_config(self):
-        self.mcu.add_config_cmd(self.config_msg)
+        for msg in self.config_msgs:
+            self.mcu.add_config_cmd(msg)
         self.spi_send_cmd = self.mcu.lookup_command(
             "spi_send oid=%c data=%*s", cq=self.cmd_queue)
         self.spi_transfer_cmd = self.mcu.lookup_command(
@@ -68,11 +80,24 @@ def MCU_SPI_from_config(config, mode, pin_option="cs_pin",
         ppins.reset_pin_sharing(cs_pin_params)
         pin = None
     # Load bus parameters
-    speed = config.getint('spi_speed', default_speed, minval=100000)
-    bus = config.getint('spi_bus', 0, minval=0)
-    # Create MCU_SPI object
     mcu = cs_pin_params['chip']
-    return MCU_SPI(mcu, bus, pin, mode, speed, shutdown_seq)
+    speed = config.getint('spi_speed', default_speed, minval=100000)
+    if config.get('spi_software_sclk_pin', None) is not None:
+        sw_pin_names = ['spi_software_%s_pin' % (name,)
+                        for name in ['sclk', 'mosi', 'miso']]
+        sw_pin_params = [ppins.lookup_pin(config.get(name), share_type=name)
+                         for name in sw_pin_names]
+        for pin_params in sw_pin_params:
+            if pin_params['chip'] != mcu:
+                raise ppins.error("%s: spi pins must be on same mcu" % (
+                    config.get_name(),))
+        sw_pins = tuple([pin_params['pin'] for pin_params in sw_pin_params])
+        bus = None
+    else:
+        bus = config.getint('spi_bus', 0, minval=0)
+        sw_pins = None
+    # Create MCU_SPI object
+    return MCU_SPI(mcu, bus, pin, mode, speed, shutdown_seq, sw_pins)
 
 
 ######################################################################

src/Makefile

@@ -7,4 +7,4 @@ src-$(CONFIG_HAVE_GPIO_SPI) += spicmds.c thermocouple.c
 src-$(CONFIG_HAVE_GPIO_I2C) += i2ccmds.c
 src-$(CONFIG_HAVE_GPIO_HARD_PWM) += pwmcmds.c
 src-$(CONFIG_HAVE_GPIO_BITBANGING) += lcd_st7920.c lcd_hd44780.c buttons.c \
-    tmcuart.c
+    tmcuart.c spi_software.c

src/spi_software.c

@@ -0,0 +1,81 @@
+// Software SPI emulation
+//
+// Copyright (C) 2019  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "board/irq.h" // gpio_out_setup
+#include "board/gpio.h" // gpio_out_setup
+#include "basecmd.h" // oid_alloc
+#include "command.h" // DECL_COMMAND
+#include "sched.h" // sched_shutdown
+
+struct spi_software {
+    struct gpio_out sclk, mosi;
+    struct gpio_in miso;
+    uint8_t mode;
+};
+
+void
+command_config_software_spi(uint32_t *args)
+{
+    uint8_t oid = args[0], sclk_pin = args[1], mosi_pin = args[2];
+    uint8_t miso_pin = args[3], mode = args[4];
+    if (mode > 3)
+        shutdown("Invalid spi mode");
+
+    struct spi_software *spi = oid_alloc(oid, command_config_software_spi
+                                         , sizeof(*spi));
+
+    spi->sclk = gpio_out_setup(sclk_pin, 0);
+    spi->mosi = gpio_out_setup(mosi_pin, 0);
+    spi->miso = gpio_in_setup(miso_pin, 1);
+}
+DECL_COMMAND(command_config_software_spi,
+             "config_software_spi oid=%c sclk_pin=%u mosi_pin=%u miso_pin=%u"
+             " mode=%u rate=%u");
+
+struct spi_software *
+spi_software_oid_lookup(uint8_t oid)
+{
+    return oid_lookup(oid, command_config_software_spi);
+}
+
+void
+spi_software_prepare(struct spi_software *ss)
+{
+    gpio_out_write(ss->sclk, ss->mode < 2 ? 0 : 1);
+}
+
+void
+spi_software_transfer(struct spi_software *ss, uint8_t receive_data
+                      , uint8_t len, uint8_t *data)
+{
+    while (len--) {
+        uint8_t outbuf = *data;
+        uint8_t inbuf = 0;
+        for (uint_fast8_t i = 0; i < 8; i++) {
+            if (ss->mode & 0x01) {
+                // MODE 1 & 3
+                gpio_out_toggle(ss->sclk);
+                gpio_out_write(ss->mosi, outbuf & 0x80);
+                outbuf <<= 1;
+                gpio_out_toggle(ss->sclk);
+                inbuf <<= 1;
+                inbuf |= gpio_in_read(ss->miso);
+            } else {
+                // MODE 0 & 2
+                gpio_out_write(ss->mosi, outbuf & 0x80);
+                outbuf <<= 1;
+                gpio_out_toggle(ss->sclk);
+                inbuf <<= 1;
+                inbuf |= gpio_in_read(ss->miso);
+                gpio_out_toggle(ss->sclk);
+            }
+        }
+
+        if (receive_data)
+            *data = inbuf;
+        data++;
+    }
+}

src/spi_software.h

@@ -0,0 +1,11 @@
+#ifndef __SPI_SOFTWARE_H
+#define __SPI_SOFTWARE_H
+
+#include <stdint.h> // uint8_t
+
+struct spi_software *spi_software_oid_lookup(uint8_t oid);
+void spi_software_prepare(struct spi_software *ss);
+void spi_software_transfer(struct spi_software *ss, uint8_t receive_data
+                           , uint8_t len, uint8_t *data);
+
+#endif // spi_software.h

src/spicmds.c

@@ -5,14 +5,19 @@
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
 #include <string.h> // memcpy
+#include "autoconf.h" // CONFIG_HAVE_GPIO_BITBANGING
 #include "board/gpio.h" // gpio_out_write
 #include "basecmd.h" // oid_alloc
 #include "command.h" // DECL_COMMAND
 #include "sched.h" // DECL_SHUTDOWN
+#include "spi_software.h" // spi_software_setup
 #include "spicmds.h" // spidev_transfer
 
 struct spidev_s {
-    struct spi_config spi_config;
+    union {
+        struct spi_config spi_config;
+        struct spi_software *spi_software;
+    };
     struct gpio_out pin;
     uint8_t flags;
     uint8_t shutdown_msg_len;
@@ -20,7 +25,7 @@ struct spidev_s {
 };
 
 enum {
-    SF_HAVE_PIN = 1,
+    SF_HAVE_PIN = 1, SF_SOFTWARE = 2,
 };
 
 void
@@ -58,6 +63,26 @@ DECL_COMMAND(command_config_spi_without_cs,
              "config_spi_without_cs oid=%c bus=%u mode=%u rate=%u"
              " shutdown_msg=%*s");
 
+void
+command_config_spi_from_software(uint32_t *args)
+{
+    uint8_t shutdown_msg_len = args[3];
+    struct spi_software *sspi = spi_software_oid_lookup(args[1]);
+    struct spidev_s *spi = oid_alloc(args[0], command_config_spi
+                                     , sizeof(*spi) + shutdown_msg_len);
+    spi->pin = gpio_out_setup(args[2], 1);
+    spi->flags = SF_HAVE_PIN | SF_SOFTWARE;
+    spi->spi_software = sspi;
+    spi->shutdown_msg_len = shutdown_msg_len;
+    uint8_t *shutdown_msg = (void*)(size_t)args[4];
+    memcpy(spi->shutdown_msg, shutdown_msg, shutdown_msg_len);
+}
+#if CONFIG_HAVE_GPIO_BITBANGING
+DECL_COMMAND(command_config_spi_from_software,
+             "config_spi_from_software oid=%c sw_oid=%u pin=%u"
+             " shutdown_msg=%*s");
+#endif
+
 struct spidev_s *
 spidev_oid_lookup(uint8_t oid)
 {
@@ -68,12 +93,18 @@ void
 spidev_transfer(struct spidev_s *spi, uint8_t receive_data
                 , uint8_t data_len, uint8_t *data)
 {
-    spi_prepare(spi->spi_config);
+    if (CONFIG_HAVE_GPIO_BITBANGING && spi->flags & SF_SOFTWARE)
+        spi_software_prepare(spi->spi_software);
+    else
+        spi_prepare(spi->spi_config);
 
     if (spi->flags & SF_HAVE_PIN)
         gpio_out_write(spi->pin, 0);
 
-    spi_transfer(spi->spi_config, receive_data, data_len, data);
+    if (CONFIG_HAVE_GPIO_BITBANGING && spi->flags & SF_SOFTWARE)
+        spi_software_transfer(spi->spi_software, receive_data, data_len, data);
+    else
+        spi_transfer(spi->spi_config, receive_data, data_len, data);
 
     if (spi->flags & SF_HAVE_PIN)
         gpio_out_write(spi->pin, 1);