spicmds: Rework SPI message transmission

Improve the SPI message transmit system.  Add support for bus speed
and bus mode.  Add support for sending SPI messages on shutdown.

Signed-off-by: Petri Honkala <cruwaller@gmail.com>
Signed-off-by: Douglas Hammond <wizhippo@gmail.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

5 files changed, 203 insertions, 28 deletions

diff --git a/src/avr/gpio.c b/src/avr/gpio.c
index d4b784f5..0ae7e52f 100644
--- a/src/avr/gpio.c
+++ b/src/avr/gpio.c
@@ -352,29 +352,103 @@ gpio_adc_cancel_sample(struct gpio_adc g)
  ****************************************************************/
 
 #if CONFIG_MACH_atmega168 || CONFIG_MACH_atmega328
-static const uint8_t SS = GPIO('B', 2), SCK = GPIO('B', 5), MOSI = GPIO('B', 3);
+static const uint8_t SS = GPIO('B', 2), SCK = GPIO('B', 5);
+static const uint8_t MOSI = GPIO('B', 3), MISO = GPIO('B', 4);
 #elif CONFIG_MACH_atmega644p || CONFIG_MACH_atmega1284p
-static const uint8_t SS = GPIO('B', 4), SCK = GPIO('B', 7), MOSI = GPIO('B', 5);
+static const uint8_t SS = GPIO('B', 4), SCK = GPIO('B', 7);
+static const uint8_t MOSI = GPIO('B', 5), MISO = GPIO('B', 6);
 #elif CONFIG_MACH_at90usb1286 || CONFIG_MACH_at90usb646 || CONFIG_MACH_atmega1280 || CONFIG_MACH_atmega2560
-static const uint8_t SS = GPIO('B', 0), SCK = GPIO('B', 1), MOSI = GPIO('B', 2);
+static const uint8_t SS = GPIO('B', 0), SCK = GPIO('B', 1);
+static const uint8_t MOSI = GPIO('B', 2), MISO = GPIO('B', 3);
 #endif
 
-void
-spi_config(void)
+static void
+spi_init(void)
 {
     gpio_out_setup(SS, 1);
     gpio_out_setup(SCK, 0);
     gpio_out_setup(MOSI, 0);
+    gpio_in_setup(MISO, 0);
+
     SPCR = (1<<MSTR) | (1<<SPE);
+    SPSR = 0;
+}
+
+struct spi_config
+spi_setup(uint32_t bus, uint8_t mode, uint32_t rate)
+{
+    if (bus || mode > 3)
+        shutdown("Invalid spi_setup parameters");
+
+    // Make sure the SPI interface is enabled
+    spi_init();
+
+    // Setup rate
+    struct spi_config config = {0, 0};
+    if (rate >= (CONFIG_CLOCK_FREQ / 2)) {
+        config.spsr = (1<<SPI2X);
+    } else if (rate >= (CONFIG_CLOCK_FREQ / 4)) {
+        config.spcr = 0;
+    } else if (rate >= (CONFIG_CLOCK_FREQ / 8)) {
+        config.spcr = 1;
+        config.spsr = (1<<SPI2X);
+    } else if (rate >= (CONFIG_CLOCK_FREQ / 16)) {
+        config.spcr = 1;
+    } else if (rate >= (CONFIG_CLOCK_FREQ / 32)) {
+        config.spcr = 2;
+        config.spsr = (1<<SPI2X);
+    } else if (rate >= (CONFIG_CLOCK_FREQ / 64)) {
+        config.spcr = 2;
+    } else {
+        config.spcr = 3;
+    }
+
+    // Setup mode
+    config.spcr |= (1<<SPE) | (1<<MSTR);
+    switch(mode) {
+        case 0: {
+            // MODE 0 - CPOL=0, CPHA=0
+            break;
+        }
+        case 1: {
+            // MODE 1 - CPOL=0, CPHA=1
+            config.spcr |= (1<<CPHA);
+            break;
+        }
+        case 2: {
+            // MODE 2 - CPOL=1, CPHA=0
+            config.spcr |= (1<<CPOL);
+            break;
+        }
+        case 3: {
+            // MODE 3 - CPOL=1, CPHA=1
+            config.spcr |= (1<<CPOL) | (1<<CPHA);
+            break;
+        }
+    }
+
+    return config;
 }
 
 void
-spi_transfer(char *data, uint8_t len)
+spi_transfer(struct spi_config config, uint8_t receive_data
+             , uint8_t len, uint8_t *data)
 {
-    while (len--) {
-        SPDR = *data;
-        while (!(SPSR & (1<<SPIF)))
-            ;
-        *data++ = SPDR;
+    SPCR = config.spcr;
+    SPSR = config.spsr;
+
+    if (receive_data) {
+        while (len--) {
+            SPDR = *data;
+            while (!(SPSR & (1<<SPIF)))
+                ;
+            *data++ = SPDR;
+        }
+    } else {
+        while (len--) {
+            SPDR = *data++;
+            while (!(SPSR & (1<<SPIF)))
+                ;
+        }
     }
 }
diff --git a/src/avr/gpio.h b/src/avr/gpio.h
index 4eb37204..6e12efe0 100644
--- a/src/avr/gpio.h
+++ b/src/avr/gpio.h
@@ -34,7 +34,11 @@ uint32_t gpio_adc_sample(struct gpio_adc g);
 uint16_t gpio_adc_read(struct gpio_adc g);
 void gpio_adc_cancel_sample(struct gpio_adc g);
 
-void spi_config(void);
-void spi_transfer(char *data, uint8_t len);
+struct spi_config {
+    uint8_t spcr, spsr;
+};
+struct spi_config spi_setup(uint32_t bus, uint8_t mode, uint32_t rate);
+void spi_transfer(struct spi_config config, uint8_t receive_data
+                  , uint8_t len, uint8_t *data);
 
 #endif // gpio.h
diff --git a/src/generic/gpio.h b/src/generic/gpio.h
index 1b649cab..fcb785d4 100644
--- a/src/generic/gpio.h
+++ b/src/generic/gpio.h
@@ -30,7 +30,11 @@ uint32_t gpio_adc_sample(struct gpio_adc g);
 uint16_t gpio_adc_read(struct gpio_adc g);
 void gpio_adc_cancel_sample(struct gpio_adc g);
 
-void spi_config(void);
-void spi_transfer(char *data, uint8_t len);
+struct spi_config {
+    uint32_t cfg;
+};
+struct spi_config spi_setup(uint32_t bus, uint8_t mode, uint32_t rate);
+void spi_transfer(struct spi_config config, uint8_t receive_data
+                  , uint8_t len, uint8_t *data);
 
 #endif // gpio.h
diff --git a/src/simulator/gpio.c b/src/simulator/gpio.c
index 569f4b78..08359679 100644
--- a/src/simulator/gpio.c
+++ b/src/simulator/gpio.c
@@ -36,7 +36,13 @@ uint16_t gpio_adc_read(struct gpio_adc g) {
 void gpio_adc_cancel_sample(struct gpio_adc g) {
 }
 
-void spi_config(void) {
+struct spi_config
+spi_setup(uint32_t bus, uint8_t mode, uint32_t rate)
+{
+    return (struct spi_config){ };
 }
-void spi_transfer(char *data, uint8_t len) {
+void
+spi_transfer(struct spi_config config, uint8_t receive_data
+             , uint8_t len, uint8_t *data)
+{
 }
diff --git a/src/spicmds.c b/src/spicmds.c
index bb37be2b..f87972a0 100644
--- a/src/spicmds.c
+++ b/src/spicmds.c
@@ -1,22 +1,109 @@
 // Commands for sending messages on an SPI bus
 //
-// Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+// Copyright (C) 2016-2018  Kevin O'Connor <kevin@koconnor.net>
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
+#include <string.h> // memcpy
 #include "board/gpio.h" // gpio_out_write
+#include "basecmd.h" // oid_alloc
 #include "command.h" // DECL_COMMAND
+#include "sched.h" // DECL_SHUTDOWN
+
+struct spidev_s {
+    struct spi_config spi_config;
+    struct gpio_out pin;
+    uint8_t flags;
+    uint8_t shutdown_msg_len;
+    uint8_t shutdown_msg[];
+};
+
+enum {
+    SF_HAVE_PIN = 1,
+};
+
+void
+command_config_spi(uint32_t *args)
+{
+    uint8_t shutdown_msg_len = args[5];
+    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;
+    spi->spi_config = spi_setup(args[1], args[3], args[4]);
+    spi->shutdown_msg_len = shutdown_msg_len;
+    uint8_t *shutdown_msg = (void*)(size_t)args[6];
+    memcpy(spi->shutdown_msg, shutdown_msg, shutdown_msg_len);
+}
+DECL_COMMAND(command_config_spi,
+             "config_spi oid=%c bus=%u pin=%u mode=%u rate=%u shutdown_msg=%*s");
+
+void
+command_config_spi_without_cs(uint32_t *args)
+{
+    uint8_t shutdown_msg_len = args[4];
+    struct spidev_s *spi = oid_alloc(args[0], command_config_spi
+                                     , sizeof(*spi) + shutdown_msg_len);
+    spi->spi_config = spi_setup(args[1], args[2], args[3]);
+    spi->shutdown_msg_len = shutdown_msg_len;
+    uint8_t *shutdown_msg = (void*)(size_t)args[5];
+    memcpy(spi->shutdown_msg, shutdown_msg, shutdown_msg_len);
+}
+DECL_COMMAND(command_config_spi_without_cs,
+             "config_spi_without_cs oid=%c bus=%u mode=%u rate=%u"
+             " shutdown_msg=%*s");
+
+static void
+spidev_transfer(struct spidev_s *spi, uint8_t receive_data
+                , uint8_t data_len, uint8_t *data)
+{
+    if (spi->flags & SF_HAVE_PIN) {
+        gpio_out_write(spi->pin, 0);
+        spi_transfer(spi->spi_config, receive_data, data_len, data);
+        gpio_out_write(spi->pin, 1);
+    } else {
+        spi_transfer(spi->spi_config, receive_data, data_len, data);
+    }
+}
+
+void
+command_spi_transfer(uint32_t *args)
+{
+    uint8_t oid = args[0];
+    struct spidev_s *spi = oid_lookup(oid, command_config_spi);
+    uint8_t data_len = args[1];
+    uint8_t *data = (void*)(size_t)args[2];
+    spidev_transfer(spi, 1, data_len, data);
+    sendf("spi_transfer_response oid=%c response=%*s", oid, data_len, data);
+}
+DECL_COMMAND(command_spi_transfer, "spi_transfer oid=%c data=%*s");
 
 void
-command_send_spi_message(uint32_t *args)
+command_spi_send(uint32_t *args)
 {
-    // For now, this only implements enough to program an ad5206 digipot
-    uint8_t len = args[1];
-    char *msg = (void*)(size_t)args[2];
-    spi_config();
-    struct gpio_out pin = gpio_out_setup(args[0], 0);
-    spi_transfer(msg, len);
-    gpio_out_write(pin, 1);
-    sendf("spi_response response=%*s", len, msg);
+    uint8_t oid = args[0];
+    struct spidev_s *spi = oid_lookup(oid, command_config_spi);
+    uint8_t data_len = args[1];
+    uint8_t *data = (void*)(size_t)args[2];
+    spidev_transfer(spi, 0, data_len, data);
+}
+DECL_COMMAND(command_spi_send, "spi_send oid=%c data=%*s");
+
+void
+spidev_shutdown(void)
+{
+    // Cancel any transmissions that may be in progress
+    uint8_t oid;
+    struct spidev_s *spi;
+    foreach_oid(oid, spi, command_config_spi) {
+        if (spi->flags & SF_HAVE_PIN)
+            gpio_out_write(spi->pin, 1);
+    }
+
+    // Send shutdown messages
+    foreach_oid(oid, spi, command_config_spi) {
+        if (spi->shutdown_msg_len)
+            spidev_transfer(spi, 0, spi->shutdown_msg_len, spi->shutdown_msg);
+    }
 }
-DECL_COMMAND(command_send_spi_message, "send_spi_message pin=%u msg=%*s");
+DECL_SHUTDOWN(spidev_shutdown);