sam3: Merge sam4e8e support into sam3 code

Most of the peripherals on the sam4e8e are similar to the ones on the
sam3x8e mcu.  Merge the code together and use just one code directory.

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

1 files changed, 180 insertions, 0 deletions

diff --git a/src/sam3/i2c.c b/src/sam3/i2c.c
new file mode 100644
index 00000000..caf05f0a
--- /dev/null
+++ b/src/sam3/i2c.c
@@ -0,0 +1,180 @@
+// SAM4 I2C Port
+//
+// Copyright (C) 2018  Florian Heilmann <Florian.Heilmann@gmx.net>
+// Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "autoconf.h" // CONFIG_CLOCK_FREQ
+#include "board/misc.h" // timer_from_us
+#include "command.h" // shutdown
+#include "gpio.h" // i2c_setup
+#include "internal.h" // gpio_peripheral
+#include "sam4e.h" // TWI0
+#include "sched.h" // sched_shutdown
+
+// I2C pin definitions
+#define TWI0_SCL_GPIO GPIO('A', 4)
+#define TWI0_SCL_PERIPH 'A'
+
+#define TWI0_SDA_GPIO GPIO('A', 3)
+#define TWI0_SDA_PERIPH 'A'
+
+#define TWI1_SCL_GPIO GPIO('B', 5)
+#define TWI1_SCL_PERIPH 'A'
+
+#define TWI1_SDA_GPIO GPIO('B', 4)
+#define TWI1_SDA_PERIPH 'A'
+
+void
+i2c_init(Twi *p_twi, uint32_t rate)
+{
+    uint32_t twi_id = (p_twi == TWI0) ? ID_TWI0 : ID_TWI1;
+    if ((PMC->PMC_PCSR0 & (1u << twi_id)) == 0) {
+        PMC->PMC_PCER0 = 1 << twi_id;
+    }
+    if (p_twi == TWI0) {
+        gpio_peripheral(TWI0_SCL_GPIO, TWI0_SCL_PERIPH, 0);
+        gpio_peripheral(TWI0_SDA_GPIO, TWI0_SDA_PERIPH, 0);
+    } else {
+        gpio_peripheral(TWI1_SCL_GPIO, TWI1_SCL_PERIPH, 0);
+        gpio_peripheral(TWI1_SDA_GPIO, TWI1_SDA_PERIPH, 0);
+    }
+    p_twi->TWI_IDR = 0xFFFFFFFF;
+    (void)p_twi->TWI_SR;
+    p_twi->TWI_CR = TWI_CR_SWRST;
+    (void)p_twi->TWI_RHR;
+    p_twi->TWI_CR = TWI_CR_MSDIS;
+    p_twi->TWI_CR = TWI_CR_SVDIS;
+    p_twi->TWI_CR = TWI_CR_MSEN;
+
+    uint32_t cldiv = 0;
+    uint32_t chdiv = 0;
+    uint32_t ckdiv = 0;
+
+    cldiv = CONFIG_CLOCK_FREQ / ((rate > 384000 ? 384000 : rate) * 2) - 4;
+
+    while((cldiv > 255) && (ckdiv < 7)) {
+        ckdiv++;
+        cldiv /= 2;
+    }
+
+    if (rate > 348000) {
+        chdiv = CONFIG_CLOCK_FREQ / ((2 * rate - 384000) * 2) - 4;
+        while((chdiv > 255) && (ckdiv < 7)) {
+            ckdiv++;
+            chdiv /= 2;
+        }
+    } else {
+        chdiv = cldiv;
+    }
+    p_twi->TWI_CWGR = TWI_CWGR_CLDIV(cldiv) | \
+                      TWI_CWGR_CHDIV(chdiv) | \
+                      TWI_CWGR_CKDIV(ckdiv);
+}
+
+uint32_t
+addr_to_u32(uint8_t addr_len, uint8_t *addr)
+{
+    uint32_t address = addr[0];
+    if (addr_len > 1) {
+        address <<= 8;
+        address |= addr[1];
+    }
+    if (addr_len > 2) {
+        address <<= 8;
+        address |= addr[2];
+    }
+    if (addr_len > 3) {
+        shutdown("Addresses larger than 3 bytes are not supported");
+    }
+    return address;
+}
+
+struct i2c_config
+i2c_setup(uint32_t bus, uint32_t rate, uint8_t addr)
+{
+    if ((bus > 1) | (rate > 400000))
+        shutdown("Invalid i2c_setup parameters!");
+    Twi *p_twi = (bus == 0) ? TWI0 : TWI1;
+    i2c_init(p_twi, rate);
+    return (struct i2c_config){ .twi=p_twi, .addr=addr};
+}
+
+void
+i2c_write(struct i2c_config config,
+                uint8_t write_len, uint8_t *write)
+{
+    Twi *p_twi = config.twi;
+    uint32_t status;
+    uint32_t bytes_to_send = write_len;
+    p_twi->TWI_MMR = TWI_MMR_DADR(config.addr);
+    for(;;) {
+        status = p_twi->TWI_SR;
+        if (status & TWI_SR_NACK)
+            shutdown("I2C NACK error encountered!");
+        if (!(status & TWI_SR_TXRDY))
+            continue;
+        if (!bytes_to_send)
+            break;
+        p_twi->TWI_THR = *write++;
+        bytes_to_send--;
+    }
+    p_twi->TWI_CR = TWI_CR_STOP;
+    while(!(p_twi->TWI_SR& TWI_SR_TXCOMP)) {
+    }
+}
+
+static void
+i2c_wait(Twi* p_twi, uint32_t bit, uint32_t timeout)
+{
+    for (;;) {
+        uint32_t flags = p_twi->TWI_SR;
+        if (flags & bit)
+            break;
+        if (!timer_is_before(timer_read_time(), timeout))
+            shutdown("I2C timeout occured");
+    }
+}
+
+void
+i2c_read(struct i2c_config config,
+              uint8_t reg_len, uint8_t *reg,
+              uint8_t read_len, uint8_t *read)
+{
+    Twi *p_twi = config.twi;
+    uint32_t status;
+    uint32_t bytes_to_send=read_len;
+    uint8_t stop = 0;
+    p_twi->TWI_MMR = 0;
+    p_twi->TWI_MMR = TWI_MMR_MREAD | TWI_MMR_DADR(config.addr) |
+                     ((reg_len << TWI_MMR_IADRSZ_Pos) &
+                     TWI_MMR_IADRSZ_Msk);
+    p_twi->TWI_IADR = 0;
+    p_twi->TWI_IADR = addr_to_u32(reg_len, reg);
+    if (bytes_to_send == 1) {
+        p_twi->TWI_CR = TWI_CR_START | TWI_CR_STOP;
+        stop = 1;
+    } else {
+        p_twi->TWI_CR = TWI_CR_START;
+        stop = 0;
+    }
+    while (bytes_to_send > 0) {
+        status = p_twi->TWI_SR;
+        if (status & TWI_SR_NACK) {
+            shutdown("I2C NACK error encountered!");
+        }
+        if (bytes_to_send == 1 && !stop) {
+            p_twi->TWI_CR = TWI_CR_STOP;
+            stop = 1;
+        }
+        i2c_wait(p_twi, TWI_SR_RXRDY, timer_read_time() + timer_from_us(5000));
+        if (!(status & TWI_SR_RXRDY)) {
+            continue;
+        }
+        *read++ = p_twi->TWI_RHR;
+        bytes_to_send--;
+    }
+    while (!(p_twi->TWI_SR & TWI_SR_TXCOMP)) {}
+    (void)p_twi->TWI_SR;
+}