[GitHub] vrahane commented on a change in pull request #1105: hw/drivers: Add TLC5971 driver

[GitBox <gi...@apache.org>]

vrahane commented on a change in pull request #1105: hw/drivers: Add TLC5971 driver
URL: https://github.com/apache/mynewt-core/pull/1105#discussion_r189127498
 
 

 ##########
 File path: hw/drivers/tlc5971/src/tlc5971.c
 ##########
 @@ -0,0 +1,270 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+#include <string.h>
+#include "os/mynewt.h"
+#include "tlc5971/tlc5971.h"
+#include "hal/hal_gpio.h"
+#include "hal/hal_spi.h"
+
+/**
+ * tlc5972 open
+ *
+ * Device open funtion.
+ *
+ * @param odev Pointer to OS device structure
+ * @param wait The amount of time to wait to open (if needed).
+ * @param arg device open arg (not used)
+ *
+ * @return int
+ */
+static int
+tlc5971_open(struct os_dev *odev, uint32_t wait, void *arg)
+{
+    int rc;
+    int spi_num;
+    struct tlc5971_dev *dev;
+    struct hal_spi_settings spi_cfg;
+
+    dev = (struct tlc5971_dev *)odev;
+
+    /* Configure the spi and enable it */
+    spi_cfg.baudrate = dev->tlc_itf.tpi_spi_freq;
+    spi_cfg.data_mode = HAL_SPI_MODE0;
+    spi_cfg.data_order = HAL_SPI_MSB_FIRST;
+    spi_cfg.word_size = HAL_SPI_WORD_SIZE_8BIT;
+
+    spi_num = dev->tlc_itf.tpi_spi_num;
+    hal_spi_disable(spi_num);
+    rc = hal_spi_config(spi_num, &spi_cfg);
+    if (rc) {
+        return rc;
+    }
+    hal_spi_enable(spi_num);
+
+    dev->is_enabled = true;
+    return 0;
+}
+
+static int
+tlc5971_close(struct os_dev *odev)
+{
+    struct tlc5971_dev *dev;
+
+    dev = (struct tlc5971_dev *)odev;
+
+    /* Disable the SPI */
+    hal_spi_disable(dev->tlc_itf.tpi_spi_num);
+
+    /* Device is no longer enabled */
+    dev->is_enabled = false;
+
+    return 0;
+}
+
+/**
+ * tlc5971 is enabled
+ *
+ * Returns device enabled flag
+ *
+ *
+ * @param dev Pointer to tlc5971 device
+ *
+ * @return uint8_t 0:not enabled, 1:enabled
+ */
+int
+tlc5971_is_enabled(struct tlc5971_dev *dev)
+{
+    return dev->is_enabled;
+}
+
+/**
+ * tlc5971 construct packet
+ *
+ * This routine constructs the 224-bit buffer to send to the device. Bit 224
+ * should get sent first. Since packet buffer byte 0 gets sent first to the
+ * spi, we construct the data packet in reverse order. On other words, byte 27
+ * gets placed into packet location 0, byte in location 1, etc.
+ *
+ * @param dev
+ */
+static void
+tlc5971_construct_packet(struct tlc5971_dev *dev)
+{
+    int i;
+    uint8_t *dptr;
+
+    dptr = dev->data_packet;
+
+    /* Place command, control and global brightness control into buffer */
+    dptr[0] = TLC5971_DATA_BYTE27(dev->control_data);
+    dptr[1] = TLC5971_DATA_BYTE26(dev->control_data, dev->bc.bc_blue);
+    dptr[2] = TLC5971_DATA_BYTE25(dev->bc.bc_blue, dev->bc.bc_green);
+    dptr[3] = TLC5971_DATA_BYTE24(dev->bc.bc_green, dev->bc.bc_red);
+    dptr += 4;
+
+    /* Now place 16-bit values into buffer*/
+    i = 3;
+    while (i >= 0) {
+        dptr[0] = (uint8_t)(dev->gs[i].gs_blue >> 8);
+        dptr[1] = (uint8_t)(dev->gs[i].gs_blue);
+        dptr[2] = (uint8_t)(dev->gs[i].gs_green >> 8);
+        dptr[3] = (uint8_t)(dev->gs[i].gs_green);
+        dptr[4] = (uint8_t)(dev->gs[i].gs_red >> 8);
+        dptr[5] = (uint8_t)(dev->gs[i].gs_red);
+        dptr += 6;
+        --i;
+    }
+}
+
+/**
+ * tlc5971 write
+ *
+ * Send the 224 bits to the device. Note that the device must be opened
+ * prior to calling this function
+ *
+ * @param dev   Pointer to tlc5971 device
+ *
+ * @return int  0: success; -1 error
+ */
+int
+tlc5971_write(struct tlc5971_dev *dev)
+{
+    int rc;
+    os_sr_t sr;
+
+    if (!dev->is_enabled) {
+        return -1;
+    }
+
+    /*
+     * XXX: for now, disable interrupts around write as it is possible that
+     * too long a gap will cause mis-program of device.
+     */
+    tlc5971_construct_packet(dev);
+
+    OS_ENTER_CRITICAL(sr);
 
 Review comment:
   This is not needed. The user/library/app should use a mutex to access the device anyways. The packet is really big (217 bits). Let me know what you think ?

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