From 66935e66ced53e85f4b86da928bbcf6fcbda3b35 Mon Sep 17 00:00:00 2001
From: bartool <bartoolina@gmail.com>
Date: Sun, 26 Mar 2023 01:53:19 +0100
Subject: [PATCH] driver: mcp41x

---
 firmware/func_gen_stm32f303re_nucleo/Makefile |  4 +
 firmware/shared_libs/drivers/mcp41x/mcp41x.c  | 74 +++++++++++++++++++
 firmware/shared_libs/drivers/mcp41x/mcp41x.h  | 50 +++++++++++++
 3 files changed, 128 insertions(+)
 create mode 100644 firmware/shared_libs/drivers/mcp41x/mcp41x.c
 create mode 100644 firmware/shared_libs/drivers/mcp41x/mcp41x.h

diff --git a/firmware/func_gen_stm32f303re_nucleo/Makefile b/firmware/func_gen_stm32f303re_nucleo/Makefile
index 8db43f6..9ac5855 100644
--- a/firmware/func_gen_stm32f303re_nucleo/Makefile
+++ b/firmware/func_gen_stm32f303re_nucleo/Makefile
@@ -71,6 +71,8 @@ Core/Src/i2c.c
 C_SOURCES += ../shared_libs/drivers/ad9833/ad9833.c
 # ltc2631
 C_SOURCES += ../shared_libs/drivers/ltc2631/ltc2631.c
+# mcp41x
+C_SOURCES += ../shared_libs/drivers/mcp41x/mcp41x.c
 
 # ASM sources
 ASM_SOURCES =  \
@@ -137,6 +139,8 @@ C_INCLUDES =  \
 C_INCLUDES += -I../shared_libs/drivers/ad9833
 # ltc2631 includes
 C_INCLUDES += -I../shared_libs/drivers/ltc2631
+# mcp41x includes
+C_INCLUDES += -I../shared_libs/drivers/mcp41x
 
 # compile gcc flags
 ASFLAGS = $(MCU) $(AS_DEFS) $(AS_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections
diff --git a/firmware/shared_libs/drivers/mcp41x/mcp41x.c b/firmware/shared_libs/drivers/mcp41x/mcp41x.c
new file mode 100644
index 0000000..83b616d
--- /dev/null
+++ b/firmware/shared_libs/drivers/mcp41x/mcp41x.c
@@ -0,0 +1,74 @@
+#include "main.h"
+#include "mcp41x.h"
+
+static uint32_t pot_value[MCP41X_RES_MAX] = {10000, 50000, 100000};
+
+static void mcp41x_transmit(mcp41x_handle_t *hpot, uint8_t *data)
+{
+    HAL_GPIO_WritePin(hpot->cs_port, hpot->cs_pin, GPIO_PIN_RESET);
+    HAL_SPI_Transmit(hpot->hspi, data, 2, 1);
+    HAL_GPIO_WritePin(hpot->cs_port, hpot->cs_pin, GPIO_PIN_SET);
+}
+
+void mcp41x_init(mcp41x_handle_t *hpot, SPI_HandleTypeDef *hspi, GPIO_TypeDef *cs_port, uint16_t cs_pin, mcp41x_res_t res)
+{
+    hpot->hspi = hspi;
+    hpot->cs_port = cs_port;
+    hpot->cs_pin = cs_pin;
+    hpot->max_res = res;
+    hpot->dir = MCP41X_ATOB;
+}
+
+void mcp41x_setValue(mcp41x_handle_t *hpot, uint8_t value)
+{
+    if (hpot->dir == MCP41X_BTOA)
+    {
+        value = 255 - value;
+    }
+
+    hpot->value = value;
+    uint8_t data[2] = {MCP41X_WRITE0, value};
+    mcp41x_transmit(hpot, data);
+}
+
+void mcp41x_setVolume(mcp41x_handle_t *hpot, uint8_t volume)
+{
+    if (volume > 100)
+    {
+        volume = 100;
+    }
+    uint32_t value = volume * 255U / 100U;
+    mcp41x_setValue(hpot, value);
+}
+
+uint8_t mcp41x_getVolume(mcp41x_handle_t *hpot)
+{
+    return hpot->value * 100U / 255U;
+}
+
+void mcp41x_setResistance(mcp41x_handle_t *hpot, uint32_t resistance)
+{
+    if (resistance > pot_value[hpot->max_res])
+    {
+        resistance = pot_value[hpot->max_res];
+    }
+
+    uint32_t value = resistance * 255U / pot_value[hpot->max_res];
+    mcp41x_setValue(hpot, value);
+}
+
+uint32_t mcp41x_getResistance(mcp41x_handle_t *hpot)
+{
+    return hpot->value * pot_value[hpot->max_res] / 255;
+}
+
+void mcp41x_setWiperDir(mcp41x_handle_t *hpot, mcp41x_dir_t dir)
+{
+    hpot->dir = dir;
+}
+
+void mcp41x_sleep(mcp41x_handle_t *hpot)
+{
+    uint8_t data[2] = {MCP41X_SLEEP, 0};
+    mcp41x_transmit(hpot, data);
+}
\ No newline at end of file
diff --git a/firmware/shared_libs/drivers/mcp41x/mcp41x.h b/firmware/shared_libs/drivers/mcp41x/mcp41x.h
new file mode 100644
index 0000000..7a53452
--- /dev/null
+++ b/firmware/shared_libs/drivers/mcp41x/mcp41x.h
@@ -0,0 +1,50 @@
+#pragma once
+
+#define MCP41X_C1 5
+#define MCP41X_C0 4
+#define MCP41X_P1 1
+#define MCP41X_P0 0
+
+#define MCP41X_SHUTDOWN_BIT (1 << MCP41X_C1)
+#define MCP41X_WRITE_BIT (1 << MCP41X_C0)
+#define MCP41X_POT0_BIT (1 << MCP41X_P0)
+#define MCP41X_POT1_BIT (1 << MCP41X_P1)
+
+#define MCP41X_SLEEP (MCP41X_SHUTDOWN_BIT | MCP41X_POT0_BIT | MCP41X_POT0_BIT)
+#define MCP41X_WRITE0 (MCP41X_WRITE_BIT | MCP41X_POT0_BIT)
+#define MCP41X_WRITE1 (MCP41X_WRITE_BIT | MCP41X_POT1_BIT)
+
+typedef enum
+{
+    MCP41X_ATOB,
+    MCP41X_BTOA
+} mcp41x_dir_t;
+
+typedef enum
+{
+    MCP41X_10K,
+    MCP41X_50K,
+    MCP41X_100K,
+    MCP41X_RES_MAX
+} mcp41x_res_t;
+
+typedef struct
+{
+    mcp41x_res_t max_res;
+    mcp41x_dir_t dir;
+
+    uint8_t value;
+
+    SPI_HandleTypeDef *hspi;
+    GPIO_TypeDef *cs_port;
+    uint16_t cs_pin;
+} mcp41x_handle_t;
+
+void mcp41x_init(mcp41x_handle_t *hpot, SPI_HandleTypeDef *hspi, GPIO_TypeDef *cs_port, uint16_t cs_pin, mcp41x_res_t res);
+void mcp41x_setValue(mcp41x_handle_t *hpot, uint8_t value);
+void mcp41x_setVolume(mcp41x_handle_t *hpot, uint8_t volume);
+uint8_t mcp41x_getVolume(mcp41x_handle_t *hpot);
+void mcp41x_setResistance(mcp41x_handle_t *hpot, uint32_t resistance);
+uint32_t mcp41x_getResistance(mcp41x_handle_t *hpot);
+void mcp41x_setWiperDir(mcp41x_handle_t *hpot, mcp41x_dir_t dir);
+void mcp41x_sleep(mcp41x_handle_t *hpot);
\ No newline at end of file