metro-snek: Start adding i2c support (not working yet)

Signed-off-by: Keith Packard <keithp@keithp.com>

metro-snek/Makefile

@@ -19,6 +19,7 @@ SNEK_SAMD21 = $(SNEK_ROOT)/samd21
 include $(SNEK_SAMD21)/snek-samd21.defs
 
 SNEK_LOCAL_SRC = \
+	ao-i2c.c \
 	$(SNEK_SAMD21_SRC)
 
 SNEK_LOCAL_INC = \

metro-snek/ao-pins.h

@@ -32,6 +32,9 @@
 #define USE_SERIAL_0_STDIN	0
 #define SERIAL_0_PA10_PA11	1
 
+#define HAS_I2C			1
+#define HAS_I2C_3		1
+
 #define HAS_USB			1
 #define AO_USB_OUT_HOOK		1
 #define USE_USB_FIFO		1

metro-snek/metro-snek.builtin

@@ -31,3 +31,5 @@ A2, -2, 16
 A3, -2, 17
 A4, -2, 18
 A5, -2, 19
+i2c.send, 2
+i2c.recv, 2

samd21/ao-i2c.c

@@ -0,0 +1,130 @@
+/*
+ * Copyright © 2019 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <ao.h>
+#include <ao-i2c.h>
+
+#define AO_I2C_CLOCK	400000
+#define AO_I2C_SERCOM	(&samd21_sercom3)
+#define AO_I2C_SERCOM_UNIT	3
+#define HAS_I2C_3	1
+
+void
+ao_i2c_start(uint8_t addr)
+{
+	struct samd21_sercom	*sercom = AO_I2C_SERCOM;
+
+	sercom->addr = ((addr << SAMD21_SERCOM_ADDR_ADDR) |
+			(0 << SAMD21_SERCOM_ADDR_LENEN) |
+			(0 << SAMD21_SERCOM_ADDR_HS) |
+			(0 << SAMD21_SERCOM_ADDR_TENBITEN) |
+			(0 << SAMD21_SERCOM_ADDR_LEN));
+}
+
+void
+ao_i2c_send(void *block, uint32_t len, bool stop)
+{
+	struct samd21_sercom	*sercom = AO_I2C_SERCOM;
+	uint8_t	*d = block;
+
+	while (len--) {
+		while ((sercom->intflag & (1 << SAMD21_SERCOM_INTFLAG_TXFE)) == 0)
+			;
+		sercom->data = *d++;
+	}
+	if (stop) {
+		sercom->ctrlb |= (SAMD21_SERCOM_CTRLB_CMD_STOP << SAMD21_SERCOM_CTRLB_CMD);
+		while (sercom->syncbusy & (1 << SAMD21_SERCOM_SYNCBUSY_SYSOP))
+			;
+	}
+}
+
+void
+ao_i2c_recv(void *block, uint32_t len, bool stop)
+{
+	struct samd21_sercom	*sercom = AO_I2C_SERCOM;
+	uint8_t	*d = block;
+
+	while (len--) {
+		while ((sercom->intflag & (1 << SAMD21_SERCOM_INTFLAG_RXFF)) == 0)
+			;
+		*d++ = sercom->data;
+	}
+	if (stop) {
+		sercom->ctrlb |= (SAMD21_SERCOM_CTRLB_CMD_STOP << SAMD21_SERCOM_CTRLB_CMD);
+		while (sercom->syncbusy & (1 << SAMD21_SERCOM_SYNCBUSY_SYSOP))
+			;
+	}
+}
+
+static void
+ao_i2c_sercom_init(struct samd21_sercom *sercom, int id)
+{
+	/* Send a clock along */
+	samd21_gclk_clkctrl(0, SAMD21_GCLK_CLKCTRL_ID_SERCOM0_CORE + id);
+
+	/* enable */
+	samd21_pm.apbcmask |= (1 << (SAMD21_PM_APBCMASK_SERCOM0 + id));
+
+	/* Reset */
+	sercom->ctrla = (1 << SAMD21_SERCOM_CTRLA_SWRST);
+
+	while ((sercom->ctrla & (1 << SAMD21_SERCOM_CTRLA_SWRST)) ||
+	       (sercom->syncbusy & (1 << SAMD21_SERCOM_SYNCBUSY_SWRST)))
+		;
+
+	/* Configure I2C master mode */
+	sercom->ctrla = ((0 << SAMD21_SERCOM_CTRLA_SWRST) |
+			 (0 << SAMD21_SERCOM_CTRLA_ENABLE) |
+			 (SAMD21_SERCOM_CTRLA_MODE_I2C_MASTER << SAMD21_SERCOM_CTRLA_MODE) |
+			 (1 << SAMD21_SERCOM_CTRLA_RUNSTDBY) |
+
+			 (0 << SAMD21_SERCOM_CTRLA_PINOUT) |
+			 (SAMD21_SERCOM_CTRLA_SDAHOLD_DIS << SAMD21_SERCOM_CTRLA_SDAHOLD) |
+			 (0 << SAMD21_SERCOM_CTRLA_MEXTTOEN) |
+			 (0 << SAMD21_SERCOM_CTRLA_SEXTTOEN) |
+			 (SAMD21_SERCOM_CTRLA_SPEED_STANDARD << SAMD21_SERCOM_CTRLA_SPEED) |
+			 (0 << SAMD21_SERCOM_CTRLA_SCLSM) |
+			 (SAMD21_SERCOM_CTRLA_INACTOUT_DIS << SAMD21_SERCOM_CTRLA_INACTOUT) |
+			 (0 << SAMD21_SERCOM_CTRLA_LOWTOUT));
+
+	sercom->ctrlb = ((1 << SAMD21_SERCOM_CTRLB_SMEN) |
+			 (0 << SAMD21_SERCOM_CTRLB_QCEN) |
+			 (SAMD21_SERCOM_CTRLB_CMD_NOP << SAMD21_SERCOM_CTRLB_CMD) |
+			 (SAMD21_SERCOM_CTRLB_ACKACT_ACK << SAMD21_SERCOM_CTRLB_ACKACT) |
+			 (3 << SAMD21_SERCOM_CTRLB_FIFOCLR));
+
+	sercom->intenclr = 0xff;
+
+	sercom->baud = AO_SYSCLK / AO_I2C_CLOCK - 1;
+
+	/* finish setup and enable the hardware */
+	sercom->ctrla |= (1 << SAMD21_SERCOM_CTRLA_ENABLE);
+}
+
+
+void
+ao_i2c_init(void)
+{
+#if HAS_I2C_3
+	ao_enable_port(&samd21_port_a);
+	samd21_port_pmux_set(&samd21_port_a, 22, SAMD21_PORT_PMUX_FUNC_C);
+	samd21_port_pmux_set(&samd21_port_a, 23, SAMD21_PORT_PMUX_FUNC_C);
+	ao_i2c_sercom_init(AO_I2C_SERCOM, AO_I2C_SERCOM_UNIT);
+#endif
+}

samd21/ao-i2c.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright © 2019 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef _AO_I2C_H_
+#define _AO_I2C_H_
+
+void
+ao_i2c_start(uint8_t addr);
+
+void
+ao_i2c_send(void *block, uint32_t len, bool stop);
+
+void
+ao_i2c_recv(void *block, uint32_t len, bool stop);
+
+void
+ao_i2c_init(void);
+
+#endif /* _AO_I2C_H_ */

samd21/ao-snek.c

@@ -19,6 +19,9 @@
 #include <ao-tcc-samd21.h>
 #include <ao-tc-samd21.h>
 #include <ao-adc-samd21.h>
+#if HAS_I2C
+#include <ao-i2c.h>
+#endif
 #include <setjmp.h>
 
 void
@@ -148,6 +151,9 @@ main(void)
 	ao_tc_samd21_init();
 	ao_adc_init();
 	ao_usb_init();
+#if HAS_I2C
+	ao_i2c_init();
+#endif
 
 	setjmp(snek_reset_buf);
 	ao_snek_port_init();

samd21/snek-altos.c

@@ -59,3 +59,55 @@ snek_builtin_random_randrange(snek_poly_t a)
 	random_x = (random_x >> 32) | (random_x << 32);
 	return snek_float_to_poly(random_x % snek_poly_get_soffset(a));
 }
+
+#if HAS_I2C
+#include <ao-i2c.h>
+
+snek_poly_t
+snek_builtin_i2c_recv(snek_poly_t addr, snek_poly_t data)
+{
+	snek_offset_t	a = (snek_poly_get_soffset(addr) << 1) | 1;
+	snek_list_t	*list;
+	uint8_t		tmp[32];
+	uint8_t		i;
+
+	if (snek_poly_type(data) != snek_list ||
+	    snek_list_type(list = snek_poly_to_list(data)) != snek_list_list ||
+	    list->size > sizeof (data))
+	{
+		return snek_error_type_1(data);
+	}
+	if (snek_abort)
+		return SNEK_NULL;
+	ao_i2c_start(a);
+	ao_i2c_recv(tmp, list->size, true);
+	snek_poly_t	*d = snek_list_data(list);
+	for (i = 0; i < list->size; i++)
+		d[i] = snek_float_to_poly(tmp[i]);
+	return snek_float_to_poly(list->size);
+}
+
+snek_poly_t
+snek_builtin_i2c_send(snek_poly_t addr, snek_poly_t data)
+{
+	snek_offset_t	a = (snek_poly_get_soffset(addr) << 1) | 0;
+	snek_list_t	*list;
+	uint8_t		tmp[32];
+	uint8_t		i;
+
+	if (snek_poly_type(data) != snek_list ||
+	    snek_list_type(list = snek_poly_to_list(data)) != snek_list_list ||
+	    list->size > sizeof (data))
+	{
+		return snek_error_type_1(data);
+	}
+	snek_poly_t	*d = snek_list_data(list);
+	for (i = 0; i < list->size; i++)
+		tmp[i] = snek_poly_get_soffset(d[i]);
+	if (snek_abort)
+		return SNEK_NULL;
+	ao_i2c_start(a);
+	ao_i2c_send(tmp, list->size, true);
+	return snek_float_to_poly(list->size);
+}
+#endif