lpc176x: Add support for additional i2c buses

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/lpc176x/gpio.h

@@ -39,6 +39,7 @@ void spi_transfer(struct spi_config config, uint8_t receive_data
                   , uint8_t len, uint8_t *data);
 
 struct i2c_config {
+    void *i2c;
     uint8_t addr;
 };
 

src/lpc176x/i2c.c

@@ -10,51 +10,67 @@
 #include "internal.h" // gpio_peripheral
 #include "sched.h" // sched_shutdown
 
+struct i2c_info {
+    LPC_I2C_TypeDef *i2c;
+    uint8_t scl_pin, sda_pin, function, pclk;
+};
+
 DECL_ENUMERATION("i2c_bus", "i2c1", 0);
+DECL_ENUMERATION("i2c_bus", "i2c1a", 1);
+DECL_ENUMERATION("i2c_bus", "i2c0", 2);
+DECL_ENUMERATION("i2c_bus", "i2c2", 3);
 DECL_CONSTANT_STR("BUS_PINS_i2c1", "P0.1,P0.0");
+DECL_CONSTANT_STR("BUS_PINS_i2c1a", "P0.20,P0.19");
+DECL_CONSTANT_STR("BUS_PINS_i2c0", "P0.28,P0.27");
+DECL_CONSTANT_STR("BUS_PINS_i2c2", "P0.11,P0.10");
+
+static const struct i2c_info i2c_bus[] = {
+    { LPC_I2C1, GPIO(0, 1), GPIO(0, 0), 3, PCLK_I2C1 },
+    { LPC_I2C1, GPIO(0, 20), GPIO(0, 19), 3, PCLK_I2C1 },
+    { LPC_I2C0, GPIO(0, 28), GPIO(0, 27), 1, PCLK_I2C0 },
+    { LPC_I2C2, GPIO(0, 11), GPIO(0, 10), 2, PCLK_I2C2 },
+};
 
 // i2c connection status flags
 enum {
     IF_START = 1<<5, IF_STOP = 1<<4, IF_IRQ = 1<<3, IF_ACK = 1<<2, IF_ENA = 1<<6
 };
 
-static void
-i2c_init(void)
-{
-    static int have_run_init;
-    if (have_run_init)
-        return;
-    have_run_init = 1;
-
-    // Init i2c bus 1 pins
-    gpio_peripheral(GPIO(0, 1), 3, 0);
-    gpio_peripheral(GPIO(0, 0), 3, 0);
-
-    // Set 100Khz frequency
-    enable_pclock(PCLK_I2C1);
-    uint32_t pclk = SystemCoreClock, pulse = pclk / (100000 * 2);
-    LPC_I2C1->I2SCLL = pulse;
-    LPC_I2C1->I2SCLH = pulse;
-
-    // Enable interface
-    LPC_I2C1->I2CONCLR = IF_START | IF_IRQ | IF_ACK | IF_ENA;
-    LPC_I2C1->I2CONSET = IF_ENA;
-}
-
 struct i2c_config
 i2c_setup(uint32_t bus, uint32_t rate, uint8_t addr)
 {
-    if (bus)
+    if (bus >= ARRAY_SIZE(i2c_bus))
-        shutdown("Unsupported i2c bus");
+        shutdown("Invalid i2c bus");
-    i2c_init();
+
-    return (struct i2c_config){ .addr=addr<<1 };
+    const struct i2c_info *info = &i2c_bus[bus];
+    LPC_I2C_TypeDef *i2c = info->i2c;
+    static uint8_t have_run_init;
+    if (!(have_run_init & (1 << bus))) {
+        have_run_init |= 1 << bus;
+
+        // Init pins
+        gpio_peripheral(info->scl_pin, info->function, 0);
+        gpio_peripheral(info->sda_pin, info->function, 0);
+
+        // Set 100Khz frequency
+        enable_pclock(info->pclk);
+        uint32_t pclk = SystemCoreClock, pulse = pclk / (100000 * 2);
+        i2c->I2SCLL = pulse;
+        i2c->I2SCLH = pulse;
+
+        // Enable interface
+        i2c->I2CONCLR = IF_START | IF_IRQ | IF_ACK | IF_ENA;
+        i2c->I2CONSET = IF_ENA;
+    }
+
+    return (struct i2c_config){ .i2c=i2c, .addr=addr<<1 };
 }
 
 static void
-i2c_wait(uint32_t bit, uint32_t timeout)
+i2c_wait(LPC_I2C_TypeDef *i2c, uint32_t bit, uint32_t timeout)
 {
     for (;;) {
-        uint32_t flags = LPC_I2C1->I2CONSET;
+        uint32_t flags = i2c->I2CONSET;
         if (flags & bit)
             break;
         if (!timer_is_before(timer_read_time(), timeout))
@@ -63,44 +79,45 @@ i2c_wait(uint32_t bit, uint32_t timeout)
 }
 
 static void
-i2c_start(uint32_t timeout)
+i2c_start(LPC_I2C_TypeDef *i2c, uint32_t timeout)
 {
-    LPC_I2C1->I2CONCLR = IF_ACK | IF_IRQ | IF_START;
+    i2c->I2CONCLR = IF_ACK | IF_IRQ | IF_START;
-    LPC_I2C1->I2CONSET = IF_ACK | IF_START;
+    i2c->I2CONSET = IF_ACK | IF_START;
-    i2c_wait(IF_IRQ, timeout);
+    i2c_wait(i2c, IF_IRQ, timeout);
-    uint32_t status = LPC_I2C1->I2STAT;
+    uint32_t status = i2c->I2STAT;
     if (status != 0x10 && status != 0x08)
         shutdown("Failed to send i2c start");
-    LPC_I2C1->I2CONCLR = IF_START;
+    i2c->I2CONCLR = IF_START;
 }
 
 static uint32_t
-i2c_send_byte(uint8_t b, uint32_t timeout)
+i2c_send_byte(LPC_I2C_TypeDef *i2c, uint8_t b, uint32_t timeout)
 {
-    LPC_I2C1->I2DAT = b;
+    i2c->I2DAT = b;
-    LPC_I2C1->I2CONCLR = IF_IRQ;
+    i2c->I2CONCLR = IF_IRQ;
-    i2c_wait(IF_IRQ, timeout);
+    i2c_wait(i2c, IF_IRQ, timeout);
-    return LPC_I2C1->I2STAT;
+    return i2c->I2STAT;
 }
 
 static void
-i2c_stop(uint32_t timeout)
+i2c_stop(LPC_I2C_TypeDef *i2c, uint32_t timeout)
 {
-    LPC_I2C1->I2CONSET = IF_STOP;
+    i2c->I2CONSET = IF_STOP;
-    LPC_I2C1->I2CONCLR = IF_IRQ;
+    i2c->I2CONCLR = IF_IRQ;
-    i2c_wait(IF_STOP, timeout);
+    i2c_wait(i2c, IF_STOP, timeout);
 }
 
 void
 i2c_write(struct i2c_config config, uint8_t write_len, uint8_t *write)
 {
+    LPC_I2C_TypeDef *i2c = config.i2c;
     uint32_t timeout = timer_read_time() + timer_from_us(5000);
 
-    i2c_start(timeout);
+    i2c_start(i2c, timeout);
-    i2c_send_byte(config.addr, timeout);
+    i2c_send_byte(i2c, config.addr, timeout);
     while (write_len--)
-        i2c_send_byte(*write++, timeout);
+        i2c_send_byte(i2c, *write++, timeout);
-    i2c_stop(timeout);
+    i2c_stop(i2c, timeout);
 }
 
 void

src/lpc176x/internal.h

@@ -10,10 +10,12 @@
 
 #define PCLK_TIMER0 1
 #define PCLK_UART0 3
+#define PCLK_I2C0 7
 #define PCLK_SSP1 10
 #define PCLK_ADC 12
 #define PCLK_I2C1 19
 #define PCLK_SSP0 21
+#define PCLK_I2C2 26
 #define PCLK_USB 31
 int is_enabled_pclock(uint32_t pclk);
 void enable_pclock(uint32_t pclk);