Merge pull request #13631 from benpicco/cpu/sam0_common/spi-deinit

drivers/periph/spi: add periph_spi_reconfigure feature & implementation for sam0

cpu/sam0_common/Kconfig

@@ -15,6 +15,7 @@ config CPU_COMMON_SAM0
     select HAS_PERIPH_GPIO
     select HAS_PERIPH_GPIO_IRQ
     select HAS_PERIPH_I2C_RECONFIGURE
+    select HAS_PERIPH_SPI_RECONFIGURE
     select HAS_PERIPH_TIMER_PERIODIC
     select HAS_PERIPH_UART_MODECFG
     select HAS_PERIPH_UART_NONBLOCKING

cpu/sam0_common/Makefile.features

@@ -5,6 +5,7 @@ FEATURES_PROVIDED += periph_flashpage_raw
 FEATURES_PROVIDED += periph_flashpage_rwee
 FEATURES_PROVIDED += periph_gpio periph_gpio_irq
 FEATURES_PROVIDED += periph_i2c_reconfigure
+FEATURES_PROVIDED += periph_spi_reconfigure
 FEATURES_PROVIDED += periph_timer_periodic # implements timer_set_periodic()
 FEATURES_PROVIDED += periph_uart_modecfg
 FEATURES_PROVIDED += periph_uart_nonblocking

cpu/sam0_common/include/periph_cpu_common.h

@@ -263,6 +263,16 @@ typedef enum {
     SPI_CLK_10MHZ  = 10000000U  /**< drive the SPI bus with 10MHz */
 } spi_clk_t;
 /** @} */
+
+/**
+ * @brief   SPI pin getters
+ * @{
+ */
+#define spi_pin_mosi(dev) spi_config[dev].mosi_pin
+#define spi_pin_miso(dev) spi_config[dev].miso_pin
+#define spi_pin_clk(dev)  spi_config[dev].clk_pin
+/** @} */
+
 #endif /* ndef DOXYGEN */
 
 /**

cpu/sam0_common/periph/spi.c

@@ -134,6 +134,16 @@ void spi_init_pins(spi_t bus)
     gpio_init_mux(spi_config[bus].miso_pin, spi_config[bus].miso_mux);
     gpio_init_mux(spi_config[bus].mosi_pin, spi_config[bus].mosi_mux);
     /* clk_pin will be muxed during acquire / release */
+
+    mutex_unlock(&locks[bus]);
+}
+
+void spi_deinit_pins(spi_t bus)
+{
+    mutex_lock(&locks[bus]);
+
+    gpio_disable_mux(spi_config[bus].miso_pin);
+    gpio_disable_mux(spi_config[bus].mosi_pin);
 }
 
 int spi_acquire(spi_t bus, spi_cs_t cs, spi_mode_t mode, spi_clk_t clk)

drivers/Makefile.dep

@@ -683,6 +683,7 @@ endif
 ifneq (,$(filter sdcard_spi,$(USEMODULE)))
   FEATURES_REQUIRED += periph_gpio
   FEATURES_REQUIRED += periph_spi
+  FEATURES_OPTIONAL += periph_spi_reconfigure
   DEFAULT_MODULE += auto_init_storage
   USEMODULE += checksum
   USEMODULE += xtimer

drivers/include/periph/spi.h

@@ -203,7 +203,6 @@ void spi_init(spi_t bus);
 /**
  * @brief   Initialize the used SPI bus pins, i.e. MISO, MOSI, and CLK
  *
- *
  * After calling spi_init, the pins must be initialized (i.e. spi_init is
  * calling this function internally). In normal cases, this function will not be
  * used. But there are some devices (e.g. CC110x), that use SPI bus lines also
@@ -211,6 +210,9 @@ void spi_init(spi_t bus);
  * more of the used pins. So they can take control over certain pins and return
  * control back to the SPI driver using this function.
  *
+ * This function must be called after @ref spi_deinit_pins to return the pins to
+ * SPI operation.
+ *
  * The pins used are configured in the board's periph_conf.h.
  *
  * @param[in] bus       SPI device the pins are configure for
@@ -238,6 +240,71 @@ void spi_init_pins(spi_t bus);
  */
 int spi_init_cs(spi_t bus, spi_cs_t cs);
 
+#if defined(MODULE_PERIPH_SPI_RECONFIGURE) || DOXYGEN
+
+/**
+ * @brief   Change the pins of the given SPI bus back to plain GPIO functionality
+ *
+ * The pin mux of the MISO, MOSI and CLK pins of the bus will be changed back to
+ * default (GPIO) mode and the SPI bus is powered off.
+ * This allows to use the SPI pins for another function and return to SPI
+ * functionality again by calling spi_init_pins()
+ *
+ * If you want the pin to be in a defined state, call gpio_init() on it.
+ *
+ * The bus MUST not be acquired before initializing it, as this is handled
+ * internally by the spi_deinit_pins() function!
+ *
+ * Calls to spi_acquire() will block until spi_init_pins() is called again.
+ *
+ * @note Until this is implemented on all platforms, this requires the
+ *       periph_spi_reconfigure feature to be used.
+ *
+ * @param[in] dev       the device to de-initialize
+ */
+void spi_deinit_pins(spi_t dev);
+
+#if DOXYGEN
+
+/**
+ * @brief   Get the MISO pin of the given SPI bus.
+ *
+ * @param[in] dev       The device to query
+ *
+ * @note Until this is implemented on all platforms, this requires the
+ *       periph_spi_reconfigure feature to be used.
+ *
+ * @return              The GPIO used for the SPI MISO line.
+ */
+gpio_t spi_pin_miso(spi_t dev);
+
+/**
+ * @brief   Get the MOSI pin of the given SPI bus.
+ *
+ * @param[in] dev       The device to query
+ *
+ * @note Until this is implemented on all platforms, this requires the
+ *       periph_spi_reconfigure feature to be used.
+ *
+ * @return              The GPIO used for the SPI MOSI line.
+ */
+gpio_t spi_pin_mosi(spi_t dev);
+
+/**
+ * @brief   Get the CLK pin of the given SPI bus.
+ *
+ * @param[in] dev       The device to query
+ *
+ * @note Until this is implemented on all platforms, this requires the
+ *       periph_spi_reconfigure feature to be used.
+ *
+ * @return              The GPIO used for the SPI CLK line.
+ */
+gpio_t spi_pin_clk(spi_t dev);
+
+#endif /* DOXYGEN */
+#endif /* MODULE_PERIPH_SPI_RECONFIGURE */
+
 #if defined(MODULE_PERIPH_SPI_GPIO_MODE) || DOXYGEN
 
 /**

drivers/sdcard_spi/sdcard_spi.c

@@ -84,6 +84,9 @@ static sd_init_fsm_state_t _init_sd_fsm_step(sdcard_spi_t *card, sd_init_fsm_sta
         case SD_INIT_START:
             DEBUG("SD_INIT_START\n");
 
+#ifdef MODULE_PERIPH_SPI_RECONFIGURE
+            spi_deinit_pins(card->params.spi_dev);
+#endif
             if ((gpio_init(card->params.mosi, GPIO_OUT) == 0) &&
                 (gpio_init(card->params.clk,  GPIO_OUT) == 0) &&
                 (gpio_init(card->params.cs,   GPIO_OUT) == 0) &&

kconfigs/Kconfig.features

@@ -205,6 +205,11 @@ config HAS_PERIPH_SPI
     help
         Indicates that an SPI peripheral is present.
 
+config HAS_PERIPH_SPI_RECONFIGURE
+    bool
+    help
+        Indicates that the SPI peripheral allows pin reconfiguration.
+
 config HAS_PERIPH_SPI_GPIO_MODE
     bool
     help

tests/periph_spi/Makefile

@@ -2,6 +2,7 @@ BOARD ?= samr21-xpro
 include ../Makefile.tests_common
 
 FEATURES_REQUIRED += periph_spi
+FEATURES_OPTIONAL += periph_spi_reconfigure
 
 USEMODULE += xtimer
 USEMODULE += shell

tests/periph_spi/main.c

@@ -541,10 +541,59 @@ int cmd_bench(int argc, char **argv)
     return 0;
 }
 
+#ifdef MODULE_PERIPH_SPI_RECONFIGURE
+int cmd_spi_gpio(int argc, char **argv)
+{
+    int dev = -1;
+
+    /* parse the given SPI device */
+    if (argc > 1) {
+        dev = atoi(argv[1]);
+    }
+
+    if (dev < 0 || dev >= (int)SPI_NUMOF) {
+        puts("error: invalid SPI device specified");
+        return 1;
+    }
+
+    gpio_t miso_pin = spi_pin_miso(dev);
+    gpio_t mosi_pin = spi_pin_mosi(dev);
+
+    printf("Command: spi_deinit_pins(%i)\n", dev);
+    spi_deinit_pins(dev);
+
+    gpio_init(miso_pin, GPIO_OUT);
+    gpio_init(mosi_pin, GPIO_OUT);
+
+    xtimer_sleep(1);
+
+    printf("Command: gpio_set()\n");
+    gpio_set(miso_pin);
+    gpio_set(mosi_pin);
+
+    xtimer_sleep(1);
+
+    printf("Command: gpio_clear()\n");
+    gpio_clear(miso_pin);
+    gpio_clear(mosi_pin);
+
+    xtimer_sleep(1);
+
+    printf("Command: spi_init_pins(%i)\n", dev);
+    spi_init_pins(dev);
+
+    printf("Success: spi_%i re-init\n", dev);
+    return 0;
+}
+#endif
+
 static const shell_command_t shell_commands[] = {
     { "init", "Setup a particular SPI configuration", cmd_init },
     { "send", "Transfer string to slave", cmd_transfer },
     { "bench", "Runs some benchmarks", cmd_bench },
+#ifdef MODULE_PERIPH_SPI_RECONFIGURE
+    { "spi_gpio", "Re-configures MISO & MOSI pins to GPIO mode and back.", cmd_spi_gpio },
+#endif
     { NULL, NULL, NULL }
 };