From 22487d95e9b9b0ada171c72df5f5fbb3f3985724 Mon Sep 17 00:00:00 2001
From: Kevin O'Connor <kevin@koconnor.net>
Date: Fri, 4 May 2018 12:27:52 -0400
Subject: 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>
---
 src/avr/gpio.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
 src/avr/gpio.h |  8 +++--
 2 files changed, 91 insertions(+), 13 deletions(-)

(limited to 'src/avr')

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
-- 
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