[Core] PWM Backlight for RP2040 (#17706)

docs/platformdev_rp2040.md

@@ -6,6 +6,7 @@ The following table shows the current driver status for peripherals on RP2040 MC
 | ---------------------------------------------------------------- | ---------------------------------------------- |
 | [ADC driver](adc_driver.md)                                      | Support planned (no ETA)                       |
 | [Audio](audio_driver.md)                                         | Support planned (no ETA)                       |
+| [Backlight](feature_backlight.md)                                | :heavy_check_mark:                             |
 | [I2C driver](i2c_driver.md)                                      | :heavy_check_mark:                             |
 | [SPI driver](spi_driver.md)                                      | :heavy_check_mark:                             |
 | [WS2812 driver](ws2812_driver.md)                                | :heavy_check_mark: using `PIO` driver          |

keyboards/handwired/onekey/blackpill_f401/config.h

@@ -20,6 +20,7 @@
 
 #define BACKLIGHT_PWM_DRIVER  PWMD5
 #define BACKLIGHT_PWM_CHANNEL 1
+#define BACKLIGHT_PAL_MODE 2
 
 #define ADC_PIN A0
 

keyboards/handwired/onekey/blackpill_f411/config.h

@@ -20,6 +20,7 @@
 
 #define BACKLIGHT_PWM_DRIVER  PWMD5
 #define BACKLIGHT_PWM_CHANNEL 1
+#define BACKLIGHT_PAL_MODE 2
 
 #define ADC_PIN A0
 

keyboards/handwired/onekey/blackpill_f411_tinyuf2/config.h

@@ -20,6 +20,7 @@
 
 #define BACKLIGHT_PWM_DRIVER  PWMD5
 #define BACKLIGHT_PWM_CHANNEL 1
+#define BACKLIGHT_PAL_MODE 2
 
 #define ADC_PIN A0
 

keyboards/handwired/onekey/rp2040/config.h

@@ -13,3 +13,6 @@
 #define RP2040_BOOTLOADER_DOUBLE_TAP_RESET
 #define RP2040_BOOTLOADER_DOUBLE_TAP_RESET_LED GP25
 #define RP2040_BOOTLOADER_DOUBLE_TAP_RESET_TIMEOUT 500U
+
+#define BACKLIGHT_PWM_DRIVER PWMD4
+#define BACKLIGHT_PWM_CHANNEL RP2040_PWM_CHANNEL_B

keyboards/handwired/onekey/rp2040/halconf.h

@@ -0,0 +1,9 @@
+// Copyright 2022 Stefan Kerkmann
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#define HAL_USE_I2C TRUE
+#define HAL_USE_PWM TRUE
+
+#include_next <halconf.h>

keyboards/handwired/onekey/rp2040/info.json

@@ -6,7 +6,10 @@
         "cols": ["GP4"],
         "rows": ["GP5"]
     },
+    "backlight": {
+        "pin": "GP25"
+    },
     "rgblight": {
-        "pin": "A1"
+        "pin": "GP25"
     }
 }

keyboards/handwired/onekey/rp2040/mcuconf.h

@@ -0,0 +1,9 @@
+// Copyright 2022 Stefan Kerkmann
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include_next "mcuconf.h"
+
+#undef RP_PWM_USE_PWM4
+#define RP_PWM_USE_PWM4 TRUE

platforms/chibios/boards/GENERIC_PROMICRO_RP2040/configs/mcuconf.h

@@ -78,6 +78,19 @@
 #define RP_SPI_SPI1_DMA_PRIORITY            1
 #define RP_SPI_DMA_ERROR_HOOK(spip)
 
+/*
+ * PWM driver system settings.
+ */
+#define RP_PWM_USE_PWM0                     FALSE
+#define RP_PWM_USE_PWM1                     FALSE
+#define RP_PWM_USE_PWM2                     FALSE
+#define RP_PWM_USE_PWM3                     FALSE
+#define RP_PWM_USE_PWM4                     FALSE
+#define RP_PWM_USE_PWM5                     FALSE
+#define RP_PWM_USE_PWM6                     FALSE
+#define RP_PWM_USE_PWM7                     FALSE
+#define RP_PWM_IRQ_WRAP_NUMBER_PRIORITY     3
+
 /*
  * I2C driver system settings.
  */

platforms/chibios/boards/GENERIC_RP_RP2040/configs/mcuconf.h

@@ -78,6 +78,19 @@
 #define RP_SPI_SPI1_DMA_PRIORITY            1
 #define RP_SPI_DMA_ERROR_HOOK(spip)
 
+/*
+ * PWM driver system settings.
+ */
+#define RP_PWM_USE_PWM0                     FALSE
+#define RP_PWM_USE_PWM1                     FALSE
+#define RP_PWM_USE_PWM2                     FALSE
+#define RP_PWM_USE_PWM3                     FALSE
+#define RP_PWM_USE_PWM4                     FALSE
+#define RP_PWM_USE_PWM5                     FALSE
+#define RP_PWM_USE_PWM6                     FALSE
+#define RP_PWM_USE_PWM7                     FALSE
+#define RP_PWM_IRQ_WRAP_NUMBER_PRIORITY     3
+
 /*
  * I2C driver system settings.
  */

platforms/chibios/boards/QMK_PM2040/configs/mcuconf.h

@@ -78,6 +78,19 @@
 #define RP_SPI_SPI1_DMA_PRIORITY            1
 #define RP_SPI_DMA_ERROR_HOOK(spip)
 
+/*
+ * PWM driver system settings.
+ */
+#define RP_PWM_USE_PWM0                     FALSE
+#define RP_PWM_USE_PWM1                     FALSE
+#define RP_PWM_USE_PWM2                     FALSE
+#define RP_PWM_USE_PWM3                     FALSE
+#define RP_PWM_USE_PWM4                     FALSE
+#define RP_PWM_USE_PWM5                     FALSE
+#define RP_PWM_USE_PWM6                     FALSE
+#define RP_PWM_USE_PWM7                     FALSE
+#define RP_PWM_IRQ_WRAP_NUMBER_PRIORITY     3
+
 /*
  * I2C driver system settings.
  */

platforms/chibios/chibios_config.h

@@ -28,6 +28,10 @@
 #    define USE_GPIOV1
 #    define PAL_OUTPUT_TYPE_OPENDRAIN _Static_assert(0, "RP2040 has no Open Drain GPIO configuration, setting this is not possible");
 
+#    define BACKLIGHT_PAL_MODE (PAL_MODE_ALTERNATE_PWM | PAL_RP_PAD_DRIVE12 | PAL_RP_GPIO_OE)
+#    define BACKLIGHT_PWM_COUNTER_FREQUENCY 1000000
+#    define BACKLIGHT_PWM_PERIOD BACKLIGHT_PWM_COUNTER_FREQUENCY / 2048
+
 #    define usb_lld_endpoint_fields
 
 #    define I2C1_SCL_PAL_MODE (PAL_MODE_ALTERNATE_I2C | PAL_RP_PAD_SLEWFAST | PAL_RP_PAD_PUE | PAL_RP_PAD_DRIVE4)

platforms/chibios/vendors/RP/_pin_defs.h

@@ -35,3 +35,8 @@
 #define GP28 28U
 #define GP29 29U
 #define GP30 30U
+
+/* Aliases for GPIO PWM channels - every pin has at least one PWM channel
+ * assigned */
+#define RP2040_PWM_CHANNEL_A 1U
+#define RP2040_PWM_CHANNEL_B 2U

quantum/backlight/backlight_chibios.c

@@ -40,16 +40,22 @@
 #    endif
 #endif
 
-static PWMConfig pwmCFG = {0xFFFF, /* PWM clock frequency  */
-                           256,    /* PWM period (in ticks) 1S (1/10kHz=0.1mS 0.1ms*10000 ticks=1S) */
-                           NULL,   /* Breathing Callback */
-                           {       /* Default all channels to disabled - Channels will be configured durring init */
-                            {PWM_OUTPUT_DISABLED, NULL},
-                            {PWM_OUTPUT_DISABLED, NULL},
-                            {PWM_OUTPUT_DISABLED, NULL},
-                            {PWM_OUTPUT_DISABLED, NULL}},
-                           0, /* HW dependent part.*/
-                           0};
+#ifndef BACKLIGHT_PWM_COUNTER_FREQUENCY
+#    define BACKLIGHT_PWM_COUNTER_FREQUENCY 0xFFFF
+#endif
+
+#ifndef BACKLIGHT_PWM_PERIOD
+#    define BACKLIGHT_PWM_PERIOD 256
+#endif
+
+static PWMConfig pwmCFG = {
+    .frequency = BACKLIGHT_PWM_COUNTER_FREQUENCY, /* PWM clock frequency  */
+    .period    = BACKLIGHT_PWM_PERIOD,            /* PWM period in counter ticks. e.g. clock frequency is 10KHz, period is 256 ticks then t_period is 25.6ms */
+};
+
+#ifdef BACKLIGHT_BREATHING
+static virtual_timer_t breathing_vt;
+#endif
 
 // See http://jared.geek.nz/2013/feb/linear-led-pwm
 static uint16_t cie_lightness(uint16_t v) {
@@ -60,10 +66,11 @@ static uint16_t cie_lightness(uint16_t v) {
         // to get a useful result with integer division, we shift left in the expression above
         // and revert what we've done again after squaring.
         y = y * y * y >> 8;
-        if (y > 0xFFFFUL) // prevent overflow
+        if (y > 0xFFFFUL) { // prevent overflow
             return 0xFFFFU;
-        else
+        } else {
             return (uint16_t)y;
+        }
     }
 }
 
@@ -85,6 +92,7 @@ void backlight_init_ports(void) {
     backlight_set(get_backlight_level());
 
 #ifdef BACKLIGHT_BREATHING
+    chVTObjectInit(&breathing_vt);
     if (is_backlight_breathing()) {
         breathing_enable();
     }
@@ -92,7 +100,9 @@ void backlight_init_ports(void) {
 }
 
 void backlight_set(uint8_t level) {
-    if (level > BACKLIGHT_LEVELS) level = BACKLIGHT_LEVELS;
+    if (level > BACKLIGHT_LEVELS) {
+        level = BACKLIGHT_LEVELS;
+    }
 
     if (level == 0) {
         // Turn backlight off
@@ -115,20 +125,19 @@ void backlight_task(void) {}
  */
 static const uint8_t breathing_table[BREATHING_STEPS] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 17, 20, 24, 28, 32, 36, 41, 46, 51, 57, 63, 70, 76, 83, 91, 98, 106, 113, 121, 129, 138, 146, 154, 162, 170, 178, 185, 193, 200, 207, 213, 220, 225, 231, 235, 240, 244, 247, 250, 252, 253, 254, 255, 254, 253, 252, 250, 247, 244, 240, 235, 231, 225, 220, 213, 207, 200, 193, 185, 178, 170, 162, 154, 146, 138, 129, 121, 113, 106, 98, 91, 83, 76, 70, 63, 57, 51, 46, 41, 36, 32, 28, 24, 20, 17, 15, 12, 10, 8, 6, 5, 4, 3, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 
-void breathing_callback(PWMDriver *pwmp);
+static void breathing_callback(virtual_timer_t *vtp, void *p);
 
 bool is_breathing(void) {
-    return pwmCFG.callback != NULL;
+    return chVTIsArmed(&breathing_vt);
 }
 
 void breathing_enable(void) {
-    pwmCFG.callback = breathing_callback;
-    pwmEnablePeriodicNotification(&BACKLIGHT_PWM_DRIVER);
+    /* Update frequency is 256Hz -> 3906us intervals */
+    chVTSetContinuous(&breathing_vt, TIME_US2I(3906), breathing_callback, NULL);
 }
 
 void breathing_disable(void) {
-    pwmCFG.callback = NULL;
-    pwmDisablePeriodicNotification(&BACKLIGHT_PWM_DRIVER);
+    chVTReset(&breathing_vt);
 
     // Restore backlight level
     backlight_set(get_backlight_level());
@@ -139,7 +148,7 @@ static inline uint16_t scale_backlight(uint16_t v) {
     return v / BACKLIGHT_LEVELS * get_backlight_level();
 }
 
-void breathing_callback(PWMDriver *pwmp) {
+static void breathing_callback(virtual_timer_t *vtp, void *p) {
     uint8_t  breathing_period = get_breathing_period();
     uint16_t interval         = (uint16_t)breathing_period * 256 / BREATHING_STEPS;
 
@@ -150,7 +159,7 @@ void breathing_callback(PWMDriver *pwmp) {
     uint32_t duty                     = cie_lightness(rescale_limit_val(scale_backlight(breathing_table[index] * 256)));
 
     chSysLockFromISR();
-    pwmEnableChannelI(pwmp, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
+    pwmEnableChannelI(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
     chSysUnlockFromISR();
 }