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Diffstat (limited to 'nuttx/arch/z80/src/z8/z8_i2c.c')
-rwxr-xr-xnuttx/arch/z80/src/z8/z8_i2c.c1207
1 files changed, 604 insertions, 603 deletions
diff --git a/nuttx/arch/z80/src/z8/z8_i2c.c b/nuttx/arch/z80/src/z8/z8_i2c.c
index 1fb87d291..796f389ec 100755
--- a/nuttx/arch/z80/src/z8/z8_i2c.c
+++ b/nuttx/arch/z80/src/z8/z8_i2c.c
@@ -1,603 +1,604 @@
-/****************************************************************************
- * arch/z80/src/z8/z8_i2c.c
- *
- * Copyright(C) 2009 Gregory Nutt. All rights reserved.
- * Author: Gregory Nutt <spudmonkey@racsa.co.cr>
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- * 3. Neither the name NuttX nor the names of its contributors may be
- * used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- ****************************************************************************/
-
-/****************************************************************************
- * Included Files
- ****************************************************************************/
-
-#include <nuttx/config.h>
-
-#include <sys/types.h>
-#include <stdlib.h>
-#include <semaphore.h>
-#include <errno.h>
-#include <assert.h>
-#include <debug.h>
-
-#include <nuttx/i2c.h>
-#include <arch/board/board.h>
-
-#include <eZ8.h> /* eZ8 Register definitions */
-#include "chip.h" /* Register bit definitions */
-
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
-/****************************************************************************
- * Private Types
- ****************************************************************************/
-
-struct z8_i2cdev_s
-{
- const struct i2c_ops_s *ops; /* I2C vtable */
- uint16 brg; /* Baud rate generator value */
- ubyte addr; /* 8-bit address */
-};
-
-/****************************************************************************
- * Private Function Prototypes
- ****************************************************************************/
-
-/* Misc. Helpers */
-
-static void i2c_waittxempty(void);
-static void i2c_waitrxavail(void);
-static void i2c_setbrg(uint16 brg);
-static uint16 i2c_getbrg(uint32 frequency);
-
-/* I2C methods */
-
-static uint32 i2c_setfrequency(FAR struct i2c_dev_s *dev, uint32 frequency);
-static int i2c_setaddress(FAR struct i2c_dev_s *dev, int addr, int nbits);
-static int i2c_write(FAR struct i2c_dev_s *dev, const ubyte *buffer, int buflen);
-static int i2c_read(FAR struct i2c_dev_s *dev, ubyte *buffer, int buflen);
-
-/****************************************************************************
- * Public Function Prototypes
- ****************************************************************************/
-
-/* This function is normally prototyped int the ZiLOG header file sio.h */
-
-extern uint32 get_freq(void);
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
-
-static uint16 g_currbrg; /* Current BRG setting */
-static boolean g_initialized; /* TRUE:I2C has been initialized */
-static sem_t g_i2csem; /* Serialize I2C transfers */
-
-const struct i2c_ops_s g_ops =
-{
- i2c_setfrequency,
- i2c_setaddress,
- i2c_write,
- i2c_read,
-};
-
-/****************************************************************************
- * Private Functions
- ****************************************************************************/
-/****************************************************************************
- * Name: i2c_semtake/i2c_semgive
- *
- * Description:
- * Take/Give the I2C semaphore.
- *
- * Input Parameters:
- * None
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
-
-static void i2c_semtake(void)
-{
- /* Take the I2C semaphore (perhaps waiting) */
-
- while (sem_wait(&g_i2csem) != 0)
- {
- /* The only case that an error should occr here is if
- * the wait was awakened by a signal.
- */
-
- ASSERT(errno == EINTR);
- }
-}
-
-#define i2c_semgive() sem_post(&g_i2csem)
-
-/****************************************************************************
- * Name: i2c_waittxempty
- *
- * Description:
- * Wait for the transmit data register to become empty.
- *
- * Input Parameters:
- * None
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
-
-static void i2c_waittxempty(void)
-{
- int i;
- for (i = 0; i < 10000 && (I2CSTAT & I2C_STAT_TDRE) == 0; i++);
-}
-
-/****************************************************************************
- * Name: i2c_waitrxavail
- *
- * Description:
- * Wait until we have received a full byte of data.
- *
- * Input Parameters:
- * None
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
-
-static void i2c_waitrxavail(void)
-{
- int i;
- for (i = 0; i <= 10000 && (I2CSTAT & (I2C_STAT_RDRF | I2C_STAT_NCKI)) == 0; i++);
-}
-
-/****************************************************************************
- * Name: i2c_setbrg
- *
- * Description:
- * Set the current BRG value for this transaction
- *
- * Input Parameters:
- * brg - BRG to set
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
-
-static void i2c_setbrg(uint16 brg)
-{
- if (g_currbrg != brg)
- {
- I2CBRH = (ubyte)(brg >> 8);
- I2CBRL = (ubyte)(brg & 0xff);
- g_currbrg = brg;
- }
-}
-
-/****************************************************************************
- * Name: i2c_getbrg
- *
- * Description:
- * Calculate the BRG value
- *
- * Input Parameters:
- * frequency - The I2C frequency requested
- *
- * Returned Value:
- * Returns the actual frequency selected
- *
- ****************************************************************************/
-
-static uint16 i2c_getbrg(uint32 frequency)
-{
- uint32 sysclock = get_freq();
-
- /* Max is 400 Kb/sec */
-
- if (frequency > 400*1000)
- {
- dbg("Invalid inputs\n");
- frequency = 400*1000;
- }
-
- /* BRG = sysclock / (4 * frequency) */
-
- return ((sysclock >> 2) + (frequency >> 1)) / frequency;
-}
-
-/****************************************************************************
- * Name: i2c_setfrequency
- *
- * Description:
- * Set the I2C frequency. This frequency will be retained in the struct
- * i2c_dev_s instance and will be used with all transfers. Required.
- *
- * Input Parameters:
- * dev - Device-specific state data
- * frequency - The I2C frequency requested
- *
- * Returned Value:
- * Returns the actual frequency selected
- *
- ****************************************************************************/
-
-static uint32 i2c_setfrequency(FAR struct i2c_dev_s *dev, uint32 frequency)
-{
- FAR struct z8_i2cdev_s *priv = (FAR struct z8_i2cdev_s *)dev;
-
- /* Sanity Check */
-
-#ifdef CONFIG_DEBUG
- if (!dev)
- {
- dbg("Invalid inputs\n");
- return -EINVAL;
- }
-#endif
-
- /* Calculate and save the BRG (we won't apply it until the first transfer) */
-
- priv->brg = i2c_getbrg(frequency);
- return OK;
-}
-
-/****************************************************************************
- * Name: i2c_setaddress
- *
- * Description:
- * Set the I2C slave address. This frequency will be retained in the struct
- * i2c_dev_s instance and will be used with all transfers. Required.
- *
- * Input Parameters:
- * dev - Device-specific state data
- * address - The I2C slave address
- * nbits - The number of address bits provided (7 or 10)
- *
- * Returned Value:
- * Returns the actual frequency selected
- *
- ****************************************************************************/
-
-static int i2c_setaddress(FAR struct i2c_dev_s *dev, int addr, int nbits)
-{
- FAR struct z8_i2cdev_s *priv = (FAR struct z8_i2cdev_s *)dev;
-
- /* Sanity Check */
-
-#ifdef CONFIG_DEBUG
- if (!dev || (unsigned)addr > 0x7f)
- {
- dbg("Invalid inputs\n");
- return -EINVAL;
- }
-#endif
-
- /* Save the 7-bit address (10-bit address not yet supported) */
-
- DEBUGASSERT(nbits == 7);
- priv->addr = (ubyte)addr;
- return OK;
-}
-
-/****************************************************************************
- * Name: i2c_write
- *
- * Description:
- * Send a block of data on I2C using the previously selected I2C
- * frequency and slave address. Each write operational will be an 'atomic'
- * operation in the sense that any other I2C actions will be serialized
- * and pend until this write completes. Required.
- *
- * Input Parameters:
- * dev - Device-specific state data
- * buffer - A pointer to the read-only buffer of data to be written to device
- * buflen - The number of bytes to send from the buffer
- *
- * Returned Value:
- * 0: success, <0: A negated errno
- *
- ****************************************************************************/
-
-static int i2c_write(FAR struct i2c_dev_s *dev, const ubyte *buffer, int buflen)
-{
- FAR struct z8_i2cdev_s *priv = (FAR struct z8_i2cdev_s *)dev;
- const ubyte *ptr;
- int retry;
- int count;
-
-#ifdef CONFIG_DEBUG
- if (!priv || !buffer || buflen < 1)
- {
- dbg("Invalid inputs\n");
- return -EINVAL;
- }
-#endif
-
- /* Get exclusive access */
-
- i2c_semtake();
-
- /* Set the frequency */
-
- i2c_setbrg(priv->brg);
-
- /* Retry as necessary to send this whole message */
-
- for (retry = 0; retry < 100; retry++)
- {
- /* Load the address into the transmit register. It is not sent
- * until the START bit is set.
- */
-
- I2CD = I2C_WRITEADDR8(priv->addr);
- I2CCTL |= I2C_CTL_START;
-
- /* Wait for the xmt buffer to become empty */
-
- i2c_waittxempty();
-
- /* Then send all of the bytes in the buffer */
-
- ptr = buffer;
- for (count = buflen; count; count--)
- {
- /* Send a byte of data and wait for it to be sent */
-
- I2CD = *ptr++;
- i2c_waittxempty();
-
- /* If this was the last byte, then send STOP immediately. This
- * is because the ACK will not be valid until the STOP clocks out
- * the last bit.. Hmmm. If this true then we will never be
- * able to send more than one data byte???
- */
-
- if (count == 1)
- {
- I2CCTL |= I2C_CTL_STOP;
-
- /* If this last byte was ACKed, then the whole buffer
- * was successfully sent and we can return success.
- */
-
- if ((I2CSTAT & I2C_STAT_ACK) != 0)
- {
- i2c_semgive();
- return OK;
- }
-
- /* If was was not ACKed, then this inner loop will
- * terminated (because count will decrement to zero
- * and the whole message will be resent
- */
- }
-
- /* Not the last byte... was this byte ACKed? */
-
- else if ((I2CSTAT & I2C_STAT_ACK) == 0)
- {
- /* No, flush the buffer and toggle the I2C on and off */
-
- I2CCTL |= I2C_CTL_FLUSH;
- I2CCTL &= ~I2C_CTL_IEN;
- I2CCTL |= I2C_CTL_IEN;
-
- /* Break out of the loop early and try again */
-
- break;
- }
- }
- }
- i2c_semgive();
- return -ETIMEDOUT;
-}
-
-/****************************************************************************
- * Name: i2c_read
- *
- * Description:
- * Receive a block of data from I2C using the previously selected I2C
- * frequency and slave address. Each read operational will be an 'atomic'
- * operation in the sense that any other I2C actions will be serialized
- * and pend until this read completes. Required.
- *
- * Input Parameters:
- * dev - Device-specific state data
- * buffer - A pointer to a buffer of data to receive the data from the device
- * buflen - The requested number of bytes to be read
- *
- * Returned Value:
- * 0: success, <0: A negated errno
- *
- ****************************************************************************/
-
-static int i2c_read(FAR struct i2c_dev_s *dev, ubyte *buffer, int buflen)
-{
- FAR struct z8_i2cdev_s *priv = (FAR struct z8_i2cdev_s *)dev;
- ubyte *ptr;
- int retry;
- int count;
-
-#ifdef CONFIG_DEBUG
- if (!priv || !buffer || buflen < 1)
- {
- dbg("Invalid inputs\n");
- return -EINVAL;
- }
-#endif
-
- /* Get exclusive access */
-
- i2c_semtake();
-
- /* Set the frequency */
-
- i2c_setbrg(priv->brg);
-
- /* Retry as necessary to receive the whole message */
-
- for (retry = 0; retry < 100; retry++)
- {
- /* Load the address into the transmit register. It is not sent
- * until the START bit is set.
- */
-
- I2CD = I2C_READADDR8(priv->addr);
-
- /* If we want only a single byte of data, then set the NACK
- * bit now.
- */
-
- I2CCTL |= I2C_CTL_NAK;
-
- /* The START bit begins the transaction */
-
- I2CCTL |= I2C_CTL_START;
-
- /* Now loop to receive each data byte */
-
- ptr = buffer;
- for (count = buflen; count; count--)
- {
- /* Wait for the receive buffer to fill */
-
- i2c_waitrxavail();
-
- /* Did we get a byte? Or did an error occur? */
-
- if (I2CSTAT & I2C_STAT_RDRF)
- {
- /* Save the data byte */
-
- *ptr++ = I2CD;
-
- /* If the next byte is the last byte, then set NAK now */
-
- if (count == 2)
- {
- I2CCTL |= I2C_CTL_NAK;
- }
-
- /* If this was the last byte, then set STOP and return success */
-
- else if (count == 1)
- {
- I2CCTL |= I2C_CTL_STOP;
- i2c_semgive();
- return OK;
- }
- }
- /* An error occurred. Clear byte bus and break out of the loop
- * to retry now.
- */
-
- else
- {
- /* No, flush the buffer and toggle the I2C on and off */
-
- I2CCTL |= I2C_CTL_FLUSH;
- I2CCTL &= ~I2C_CTL_IEN;
- I2CCTL |= I2C_CTL_IEN;
-
- /* Break out of the loop early and try again */
-
- break;
- }
- }
- }
- i2c_semgive();
- return -ETIMEDOUT;
-}
-
-/****************************************************************************
- * Public Functions
- ****************************************************************************/
-
-/****************************************************************************
- * Name: up_i2cinitialize
- *
- * Description:
- * Initialize the selected I2C port. And return a unique instance of struct
- * struct i2c_dev_s. This function may be called to obtain multiple
- * instances of the interface, each of which may be set up with a
- * different frequency and slave address.
- *
- * Input Parameter:
- * Port number (for hardware that has mutiple I2C interfaces)
- *
- * Returned Value:
- * Valid I2C device structre reference on succcess; a NULL on failure
- *
- ****************************************************************************/
-
-FAR struct i2c_dev_s *up_i2cinitialize(int port)
-{
- FAR struct z8_i2cdev_s *i2c;
-
- if (!g_initialized)
- {
- /* Set up some initial BRG value */
-
- uint16 brg = i2c_getbrg(100*1000);
- i2c_setbrg(brg);
-
- /* Make sure that GPIOs are configured for the alternate function (this
- * varies with silicon revisions).
- */
-
- PAADDR = 0x02;
- PACTL |= 0xc0;
-
- /* This semaphore enforces serialized access for I2C transfers */
-
- sem_init(&g_i2csem, 0, 1);
-
- /* Enable I2C -- no interrupts */
-
- I2CCTL = I2C_CTL_IEN;
- }
-
- /* Now, allocate an I2C instance for this caller */
-
- i2c = (FAR struct z8_i2cdev_s *)malloc(sizeof(FAR struct z8_i2cdev_s));
- if (i2c)
- {
- /* Initialize the allocated instance */
-
- i2c->ops = &g_ops;
- i2c->brg = g_currbrg;
- }
- return (FAR struct i2c_dev_s *)i2c;
-}
+/****************************************************************************
+ * arch/z80/src/z8/z8_i2c.c
+ *
+ * Copyright(C) 2009 Gregory Nutt. All rights reserved.
+ * Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ * used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <semaphore.h>
+#include <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/i2c.h>
+#include <arch/board/board.h>
+
+#include <eZ8.h> /* eZ8 Register definitions */
+#include "chip.h" /* Register bit definitions */
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct z8_i2cdev_s
+{
+ const struct i2c_ops_s *ops; /* I2C vtable */
+ uint16_t brg; /* Baud rate generator value */
+ uint8_t addr; /* 8-bit address */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/* Misc. Helpers */
+
+static void i2c_waittxempty(void);
+static void i2c_waitrxavail(void);
+static void i2c_setbrg(uint16_t brg);
+static uint16_t i2c_getbrg(uint32_t frequency);
+
+/* I2C methods */
+
+static uint32_t i2c_setfrequency(FAR struct i2c_dev_s *dev, uint32_t frequency);
+static int i2c_setaddress(FAR struct i2c_dev_s *dev, int addr, int nbits);
+static int i2c_write(FAR struct i2c_dev_s *dev, const uint8_t *buffer, int buflen);
+static int i2c_read(FAR struct i2c_dev_s *dev, uint8_t *buffer, int buflen);
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/* This function is normally prototyped int the ZiLOG header file sio.h */
+
+extern uint32_t get_freq(void);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static uint16_t g_currbrg; /* Current BRG setting */
+static bool g_initialized; /* true:I2C has been initialized */
+static sem_t g_i2csem; /* Serialize I2C transfers */
+
+const struct i2c_ops_s g_ops =
+{
+ i2c_setfrequency,
+ i2c_setaddress,
+ i2c_write,
+ i2c_read,
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+/****************************************************************************
+ * Name: i2c_semtake/i2c_semgive
+ *
+ * Description:
+ * Take/Give the I2C semaphore.
+ *
+ * Input Parameters:
+ * None
+ *
+ * Returned Value:
+ * None
+ *
+ ****************************************************************************/
+
+static void i2c_semtake(void)
+{
+ /* Take the I2C semaphore (perhaps waiting) */
+
+ while (sem_wait(&g_i2csem) != 0)
+ {
+ /* The only case that an error should occr here is if
+ * the wait was awakened by a signal.
+ */
+
+ ASSERT(errno == EINTR);
+ }
+}
+
+#define i2c_semgive() sem_post(&g_i2csem)
+
+/****************************************************************************
+ * Name: i2c_waittxempty
+ *
+ * Description:
+ * Wait for the transmit data register to become empty.
+ *
+ * Input Parameters:
+ * None
+ *
+ * Returned Value:
+ * None
+ *
+ ****************************************************************************/
+
+static void i2c_waittxempty(void)
+{
+ int i;
+ for (i = 0; i < 10000 && (I2CSTAT & I2C_STAT_TDRE) == 0; i++);
+}
+
+/****************************************************************************
+ * Name: i2c_waitrxavail
+ *
+ * Description:
+ * Wait until we have received a full byte of data.
+ *
+ * Input Parameters:
+ * None
+ *
+ * Returned Value:
+ * None
+ *
+ ****************************************************************************/
+
+static void i2c_waitrxavail(void)
+{
+ int i;
+ for (i = 0; i <= 10000 && (I2CSTAT & (I2C_STAT_RDRF | I2C_STAT_NCKI)) == 0; i++);
+}
+
+/****************************************************************************
+ * Name: i2c_setbrg
+ *
+ * Description:
+ * Set the current BRG value for this transaction
+ *
+ * Input Parameters:
+ * brg - BRG to set
+ *
+ * Returned Value:
+ * None
+ *
+ ****************************************************************************/
+
+static void i2c_setbrg(uint16_t brg)
+{
+ if (g_currbrg != brg)
+ {
+ I2CBRH = (uint8_t)(brg >> 8);
+ I2CBRL = (uint8_t)(brg & 0xff);
+ g_currbrg = brg;
+ }
+}
+
+/****************************************************************************
+ * Name: i2c_getbrg
+ *
+ * Description:
+ * Calculate the BRG value
+ *
+ * Input Parameters:
+ * frequency - The I2C frequency requested
+ *
+ * Returned Value:
+ * Returns the actual frequency selected
+ *
+ ****************************************************************************/
+
+static uint16_t i2c_getbrg(uint32_t frequency)
+{
+ uint32_t sysclock = get_freq();
+
+ /* Max is 400 Kb/sec */
+
+ if (frequency > 400*1000)
+ {
+ dbg("Invalid inputs\n");
+ frequency = 400*1000;
+ }
+
+ /* BRG = sysclock / (4 * frequency) */
+
+ return ((sysclock >> 2) + (frequency >> 1)) / frequency;
+}
+
+/****************************************************************************
+ * Name: i2c_setfrequency
+ *
+ * Description:
+ * Set the I2C frequency. This frequency will be retained in the struct
+ * i2c_dev_s instance and will be used with all transfers. Required.
+ *
+ * Input Parameters:
+ * dev - Device-specific state data
+ * frequency - The I2C frequency requested
+ *
+ * Returned Value:
+ * Returns the actual frequency selected
+ *
+ ****************************************************************************/
+
+static uint32_t i2c_setfrequency(FAR struct i2c_dev_s *dev, uint32_t frequency)
+{
+ FAR struct z8_i2cdev_s *priv = (FAR struct z8_i2cdev_s *)dev;
+
+ /* Sanity Check */
+
+#ifdef CONFIG_DEBUG
+ if (!dev)
+ {
+ dbg("Invalid inputs\n");
+ return -EINVAL;
+ }
+#endif
+
+ /* Calculate and save the BRG (we won't apply it until the first transfer) */
+
+ priv->brg = i2c_getbrg(frequency);
+ return OK;
+}
+
+/****************************************************************************
+ * Name: i2c_setaddress
+ *
+ * Description:
+ * Set the I2C slave address. This frequency will be retained in the struct
+ * i2c_dev_s instance and will be used with all transfers. Required.
+ *
+ * Input Parameters:
+ * dev - Device-specific state data
+ * address - The I2C slave address
+ * nbits - The number of address bits provided (7 or 10)
+ *
+ * Returned Value:
+ * Returns the actual frequency selected
+ *
+ ****************************************************************************/
+
+static int i2c_setaddress(FAR struct i2c_dev_s *dev, int addr, int nbits)
+{
+ FAR struct z8_i2cdev_s *priv = (FAR struct z8_i2cdev_s *)dev;
+
+ /* Sanity Check */
+
+#ifdef CONFIG_DEBUG
+ if (!dev || (unsigned)addr > 0x7f)
+ {
+ dbg("Invalid inputs\n");
+ return -EINVAL;
+ }
+#endif
+
+ /* Save the 7-bit address (10-bit address not yet supported) */
+
+ DEBUGASSERT(nbits == 7);
+ priv->addr = (uint8_t)addr;
+ return OK;
+}
+
+/****************************************************************************
+ * Name: i2c_write
+ *
+ * Description:
+ * Send a block of data on I2C using the previously selected I2C
+ * frequency and slave address. Each write operational will be an 'atomic'
+ * operation in the sense that any other I2C actions will be serialized
+ * and pend until this write completes. Required.
+ *
+ * Input Parameters:
+ * dev - Device-specific state data
+ * buffer - A pointer to the read-only buffer of data to be written to device
+ * buflen - The number of bytes to send from the buffer
+ *
+ * Returned Value:
+ * 0: success, <0: A negated errno
+ *
+ ****************************************************************************/
+
+static int i2c_write(FAR struct i2c_dev_s *dev, const uint8_t *buffer, int buflen)
+{
+ FAR struct z8_i2cdev_s *priv = (FAR struct z8_i2cdev_s *)dev;
+ const uint8_t *ptr;
+ int retry;
+ int count;
+
+#ifdef CONFIG_DEBUG
+ if (!priv || !buffer || buflen < 1)
+ {
+ dbg("Invalid inputs\n");
+ return -EINVAL;
+ }
+#endif
+
+ /* Get exclusive access */
+
+ i2c_semtake();
+
+ /* Set the frequency */
+
+ i2c_setbrg(priv->brg);
+
+ /* Retry as necessary to send this whole message */
+
+ for (retry = 0; retry < 100; retry++)
+ {
+ /* Load the address into the transmit register. It is not sent
+ * until the START bit is set.
+ */
+
+ I2CD = I2C_WRITEADDR8(priv->addr);
+ I2CCTL |= I2C_CTL_START;
+
+ /* Wait for the xmt buffer to become empty */
+
+ i2c_waittxempty();
+
+ /* Then send all of the bytes in the buffer */
+
+ ptr = buffer;
+ for (count = buflen; count; count--)
+ {
+ /* Send a byte of data and wait for it to be sent */
+
+ I2CD = *ptr++;
+ i2c_waittxempty();
+
+ /* If this was the last byte, then send STOP immediately. This
+ * is because the ACK will not be valid until the STOP clocks out
+ * the last bit.. Hmmm. If this true then we will never be
+ * able to send more than one data byte???
+ */
+
+ if (count == 1)
+ {
+ I2CCTL |= I2C_CTL_STOP;
+
+ /* If this last byte was ACKed, then the whole buffer
+ * was successfully sent and we can return success.
+ */
+
+ if ((I2CSTAT & I2C_STAT_ACK) != 0)
+ {
+ i2c_semgive();
+ return OK;
+ }
+
+ /* If was was not ACKed, then this inner loop will
+ * terminated (because count will decrement to zero
+ * and the whole message will be resent
+ */
+ }
+
+ /* Not the last byte... was this byte ACKed? */
+
+ else if ((I2CSTAT & I2C_STAT_ACK) == 0)
+ {
+ /* No, flush the buffer and toggle the I2C on and off */
+
+ I2CCTL |= I2C_CTL_FLUSH;
+ I2CCTL &= ~I2C_CTL_IEN;
+ I2CCTL |= I2C_CTL_IEN;
+
+ /* Break out of the loop early and try again */
+
+ break;
+ }
+ }
+ }
+ i2c_semgive();
+ return -ETIMEDOUT;
+}
+
+/****************************************************************************
+ * Name: i2c_read
+ *
+ * Description:
+ * Receive a block of data from I2C using the previously selected I2C
+ * frequency and slave address. Each read operational will be an 'atomic'
+ * operation in the sense that any other I2C actions will be serialized
+ * and pend until this read completes. Required.
+ *
+ * Input Parameters:
+ * dev - Device-specific state data
+ * buffer - A pointer to a buffer of data to receive the data from the device
+ * buflen - The requested number of bytes to be read
+ *
+ * Returned Value:
+ * 0: success, <0: A negated errno
+ *
+ ****************************************************************************/
+
+static int i2c_read(FAR struct i2c_dev_s *dev, uint8_t *buffer, int buflen)
+{
+ FAR struct z8_i2cdev_s *priv = (FAR struct z8_i2cdev_s *)dev;
+ uint8_t *ptr;
+ int retry;
+ int count;
+
+#ifdef CONFIG_DEBUG
+ if (!priv || !buffer || buflen < 1)
+ {
+ dbg("Invalid inputs\n");
+ return -EINVAL;
+ }
+#endif
+
+ /* Get exclusive access */
+
+ i2c_semtake();
+
+ /* Set the frequency */
+
+ i2c_setbrg(priv->brg);
+
+ /* Retry as necessary to receive the whole message */
+
+ for (retry = 0; retry < 100; retry++)
+ {
+ /* Load the address into the transmit register. It is not sent
+ * until the START bit is set.
+ */
+
+ I2CD = I2C_READADDR8(priv->addr);
+
+ /* If we want only a single byte of data, then set the NACK
+ * bit now.
+ */
+
+ I2CCTL |= I2C_CTL_NAK;
+
+ /* The START bit begins the transaction */
+
+ I2CCTL |= I2C_CTL_START;
+
+ /* Now loop to receive each data byte */
+
+ ptr = buffer;
+ for (count = buflen; count; count--)
+ {
+ /* Wait for the receive buffer to fill */
+
+ i2c_waitrxavail();
+
+ /* Did we get a byte? Or did an error occur? */
+
+ if (I2CSTAT & I2C_STAT_RDRF)
+ {
+ /* Save the data byte */
+
+ *ptr++ = I2CD;
+
+ /* If the next byte is the last byte, then set NAK now */
+
+ if (count == 2)
+ {
+ I2CCTL |= I2C_CTL_NAK;
+ }
+
+ /* If this was the last byte, then set STOP and return success */
+
+ else if (count == 1)
+ {
+ I2CCTL |= I2C_CTL_STOP;
+ i2c_semgive();
+ return OK;
+ }
+ }
+ /* An error occurred. Clear byte bus and break out of the loop
+ * to retry now.
+ */
+
+ else
+ {
+ /* No, flush the buffer and toggle the I2C on and off */
+
+ I2CCTL |= I2C_CTL_FLUSH;
+ I2CCTL &= ~I2C_CTL_IEN;
+ I2CCTL |= I2C_CTL_IEN;
+
+ /* Break out of the loop early and try again */
+
+ break;
+ }
+ }
+ }
+ i2c_semgive();
+ return -ETIMEDOUT;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_i2cinitialize
+ *
+ * Description:
+ * Initialize the selected I2C port. And return a unique instance of struct
+ * struct i2c_dev_s. This function may be called to obtain multiple
+ * instances of the interface, each of which may be set up with a
+ * different frequency and slave address.
+ *
+ * Input Parameter:
+ * Port number (for hardware that has mutiple I2C interfaces)
+ *
+ * Returned Value:
+ * Valid I2C device structre reference on succcess; a NULL on failure
+ *
+ ****************************************************************************/
+
+FAR struct i2c_dev_s *up_i2cinitialize(int port)
+{
+ FAR struct z8_i2cdev_s *i2c;
+
+ if (!g_initialized)
+ {
+ /* Set up some initial BRG value */
+
+ uint16_t brg = i2c_getbrg(100*1000);
+ i2c_setbrg(brg);
+
+ /* Make sure that GPIOs are configured for the alternate function (this
+ * varies with silicon revisions).
+ */
+
+ PAADDR = 0x02;
+ PACTL |= 0xc0;
+
+ /* This semaphore enforces serialized access for I2C transfers */
+
+ sem_init(&g_i2csem, 0, 1);
+
+ /* Enable I2C -- no interrupts */
+
+ I2CCTL = I2C_CTL_IEN;
+ }
+
+ /* Now, allocate an I2C instance for this caller */
+
+ i2c = (FAR struct z8_i2cdev_s *)malloc(sizeof(FAR struct z8_i2cdev_s));
+ if (i2c)
+ {
+ /* Initialize the allocated instance */
+
+ i2c->ops = &g_ops;
+ i2c->brg = g_currbrg;
+ }
+ return (FAR struct i2c_dev_s *)i2c;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-01 08:09:54 +0000