x86: Add PCA9685 support

This patch adds pwm-pca9685.c and pwm-pca9685.h files,
which support access to I2C-based PCA9685 PWM controller
configuration register through a function interface.

The PCA9685 is an I2C-bus controlled 16-channel LED controller
optimized for Red/Green/Blue/Amber (RGBA) color backlighting
applications. Each LED output has its own 12-bit resolution
(4096 steps) fixed frequency individual PWM controller that
operates at a programmable frequency from a typical of 24 Hz to
1526 Hz with a duty cycle that is adjustable from 0 % to 100 %
to allow the LED to be set to a specific brightness value.
More about PCA9685 can be found in its datasheet[1].

This driver is needed in order to configure Galileo pinmux.

[1] - http://www.nxp.com/documents/data_sheet/PCA9685.pdf

platform/galileo/Makefile.galileo

@@ -5,7 +5,7 @@ LIBGCC_PATH = /usr/lib/gcc/$(shell gcc -dumpmachine)/$(shell gcc -dumpversion)
 
 CONTIKI_TARGET_DIRS = . core/sys/ drivers/
 CONTIKI_TARGET_MAIN = ${addprefix $(OBJECTDIR)/,contiki-main.o}
-CONTIKI_SOURCEFILES += contiki-main.c clock.c rtimer-arch.c gpio-pcal9535a.c
+CONTIKI_SOURCEFILES += contiki-main.c clock.c rtimer-arch.c gpio-pcal9535a.c pwm-pca9685.c
 
 PROJECT_SOURCEFILES += newlib-syscalls.c
 

platform/galileo/drivers/pwm-pca9685.c

@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2015, Intel Corporation. All rights reserved.
+ *
+ * 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 of the copyright holder 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 HOLDER 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.
+ */
+
+#include "i2c.h"
+#include "pwm-pca9685.h"
+
+#define REG_MODE1 0x00
+#define REG_MODE2 0x01
+
+#define REG_LED_ON_L(n)  ((4 * n) + 0x06)
+#define REG_LED_ON_H(n)  ((4 * n) + 0x07)
+#define REG_LED_OFF_L(n) ((4 * n) + 0x08)
+#define REG_LED_OFF_H(n) ((4 * n) + 0x09)
+
+#define MAX_PWM_OUT          16
+#define PWM_ONE_PERIOD_TICKS 4096
+
+int
+pwm_pca9685_set_values(struct pwm_pca9685_data *data, uint32_t pwm, uint32_t on, uint32_t off)
+{
+  uint8_t buf[5] = { 0 };
+
+  if (!quarkX1000_i2c_is_available())
+    return -1;
+
+  if (pwm > MAX_PWM_OUT)
+    return -1;
+
+  buf[0] = REG_LED_ON_L(pwm);
+
+  if ((on >= PWM_ONE_PERIOD_TICKS) || (off >= PWM_ONE_PERIOD_TICKS)) {
+    /* Treat as 100% */
+    buf[1] = 0x0;
+    buf[2] = (1 << 4);
+    buf[3] = 0x0;
+    buf[4] = 0x0;
+  } else if (off == 0) {
+    /* Treat it as 0% */
+    buf[1] = 0x0;
+    buf[2] = 0x0;
+    buf[3] = 0x0;
+    buf[4] = (1 << 4);
+  } else {
+    /* Populate registers accordingly */
+    buf[0] = (on & 0xFF);
+    buf[1] = ((on >> 8) & 0x0F);
+    buf[2] = (off & 0xFF);
+    buf[3] = ((off >> 8) & 0x0F);
+  }
+
+  return quarkX1000_i2c_polling_write(buf, sizeof(buf), data->i2c_slave_addr);
+}
+
+int
+pwm_pca9685_set_duty_cycle(struct pwm_pca9685_data *data, uint32_t pwm, uint8_t duty)
+{
+  uint32_t on, off;
+
+  if (duty == 0) {
+    on = 0;
+    off = 0;
+  } else if (duty >= 100) {
+    on = PWM_ONE_PERIOD_TICKS + 1;
+    off = PWM_ONE_PERIOD_TICKS + 1;
+  } else {
+    on = PWM_ONE_PERIOD_TICKS * duty / 100;
+    off = PWM_ONE_PERIOD_TICKS - 1;
+  }
+
+  return pwm_pca9685_set_values(data, pwm, on, off);
+}
+
+int
+pwm_pca9685_init(struct pwm_pca9685_data *data, uint16_t i2c_slave_addr)
+{
+  uint8_t buf[2] = { 0 };
+
+  /* has to init after I2C master */
+  if (!quarkX1000_i2c_is_available())
+    return -1;
+
+  data->i2c_slave_addr = i2c_slave_addr;
+
+  buf[0] = REG_MODE1;
+  buf[1] = (1 << 5);
+
+  if (quarkX1000_i2c_polling_write(buf, 2, i2c_slave_addr) < 0)
+    return -1;
+
+  return 0;
+}

platform/galileo/drivers/pwm-pca9685.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2015, Intel Corporation. All rights reserved.
+ *
+ * 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 of the copyright holder 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 HOLDER 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.
+ */
+
+#ifndef CPU_X86_DRIVERS_PWM_PCA9685_H_
+#define CPU_X86_DRIVERS_PWM_PCA9685_H_
+
+#include <stdint.h>
+
+struct pwm_pca9685_data {
+  uint16_t i2c_slave_addr;
+};
+
+int pwm_pca9685_init(struct pwm_pca9685_data *data, uint16_t i2c_slave_addr);
+int pwm_pca9685_set_duty_cycle(struct pwm_pca9685_data *data, uint32_t pwm, uint8_t duty);
+int pwm_pca9685_set_values(struct pwm_pca9685_data *data, uint32_t pwm, uint32_t on, uint32_t off);
+
+#endif /* CPU_X86_DRIVERS_PWM_PCA9685_H_ */