Samsung YP-R0/YP-R1: use Linux i2c-dev for radio chip access

Linux offers the high-level i2c-dev driver to directly access the
i2c bus(ses) on the system. This system device is used to get rid
of the (rather silly) radio chip kernel module for ypr0 target and
correctly enables radio access also for the ypr1 target.
fm-radio chip is located on i2c-0 bus on the ypr0 target while it
is located on i2c-1 bus on the ypr1 target.
Power-up (RST) pin is also handled for both targets, which is wired
to another GPIO of the i.MX 37 platform.
Additionally, this patch simplifies the RDS low-level handling by
exploiting the Si4709 debug interface which comes with a mutex
protection as free bonus.

Change-Id: I839282bec4a27ad0ad8403c5a8dd86963b77e1bf

5 files changed, 144 insertions, 107 deletions

diff --git a/firmware/target/hosted/samsungypr/radio-ypr.c b/firmware/target/hosted/samsungypr/radio-ypr.c
index 4fccf2616f..42d485231d 100644
--- a/firmware/target/hosted/samsungypr/radio-ypr.c
+++ b/firmware/target/hosted/samsungypr/radio-ypr.c
@@ -21,58 +21,116 @@
  *
  ****************************************************************************/
 
+/* system includes */
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
+#include <linux/i2c-dev.h>
 #include "stdint.h"
 #include "string.h"
-#include "kernel.h"
 
+/* application includes */
+#include "kernel.h"
 #include "radio-ypr.h"
-#include "si4700.h"
 #include "power.h"
+#include "gpio-target.h"
+#include "gpio-ypr.h"
+#include "panic.h"
+#include "i2c-target.h"
+
+/* 7bits I2C address for Si4709
+ * (apparently not selectable by pins or revisions) */
+#define SI4709_I2C_SLAVE_ADDR   0x10
 
+/** i2c file handle */
 static int radio_dev = -1;
 
-void radiodev_open(void) {
-    radio_dev = open("/dev/si470x", O_RDWR);
+/* toggle radio RST pin */
+static void power_toggle(bool set)
+{
+    /* setup the GPIO port, as in OF */
+    gpio_set_iomux(GPIO_FM_BUS_EN, CONFIG_ALT3);
+    gpio_set_pad(GPIO_FM_BUS_EN, PAD_CTL_SRE_FAST | PAD_CTL_DRV_HIGH);
+    gpio_direction_output(GPIO_FM_BUS_EN);
+    gpio_set(GPIO_FM_BUS_EN, set);
 }
 
-void radiodev_close(void) {
-    close(radio_dev);
-}
+void radiodev_open(void)
+{
+    int retval = -1;    /* ioctl return value */
+
+    /* open the I2C bus where the chip is attached to */
+    radio_dev = open(I2C_BUS_FM_RADIO, O_RDWR);
+
+    if (radio_dev == -1)
+    {
+        panicf("%s: failed to open /dev/i2c-1 device - %d", __FUNCTION__, retval);
+    }
+    else
+    {
+        /* device is open, go on */
+
+        /* set the slave address for the handle.
+         * Some other modules might have set the same slave address
+         * e.g. another module. Let's do a I2C_SLAVE_FORCE which does
+         * not care about looking for other init'ed i2c slaves */
+        retval = ioctl(radio_dev, I2C_SLAVE_FORCE, SI4709_I2C_SLAVE_ADDR);
+
+        if (retval == -1)
+        {
+            /* the ioctl call should never fail, if radio_dev is valid */
+            panicf("%s: failed to set slave address - %d", __FUNCTION__, retval);
+        }
+        else
+        {
+            /* initialization completed */
+        }
+    }
+
+    /* i2c subsystem ready, now toggle power to the chip */
+    power_toggle(true);
+    /* 100ms reset delay */
+    sleep(HZ/10);
 
-/* High-level registers access */
-void si4709_write_reg(int addr, uint16_t value) {
-    sSi4709_t r = { .addr = addr, .value = value };
-    ioctl(radio_dev, IOCTL_SI4709_WRITE_BYTE, &r);
 }
 
-uint16_t si4709_read_reg(int addr) {
-    sSi4709_t r = { .addr = addr, .value = 0 };
-    ioctl(radio_dev, IOCTL_SI4709_READ_BYTE, &r);
-    return r.value;
+void radiodev_close(void)
+{
+    /* power the chip down */
+    power_toggle(false);
+
+    /* close the i2c subsystem */
+    if (radio_dev != -1)
+    {
+        (void)close(radio_dev);
+    }
+    else
+    {
+        /* not opened */
+    }
+
+    /* set back to safe error value */
+    radio_dev = -1;
 }
 
-/* Low-level i2c channel access */
+/* Low-level i2c channel access: write */
 int fmradio_i2c_write(unsigned char address, unsigned char* buf, int count)
 {
     (void)address;
-    sSi4709_i2c_t r = { .size = count, .buf = buf };
-    return ioctl(radio_dev, IOCTL_SI4709_I2C_WRITE, &r);
+    return write(radio_dev, buf, count);
 }
 
+/* Low-level i2c channel access: read */
 int fmradio_i2c_read(unsigned char address, unsigned char* buf, int count)
 {
     (void)address;
-    sSi4709_i2c_t r = { .size = count, .buf = buf };
-    return ioctl(radio_dev, IOCTL_SI4709_I2C_READ, &r);
+    return read(radio_dev, buf, count);
 }
 
 #ifdef HAVE_RDS_CAP
 
 /* Register we are going to poll */
-#define STATUSRSSI  0xA
+#define STATUSRSSI          (0xA)
 #define STATUSRSSI_RDSR     (0x1 << 15)
 
 /* Low-level RDS Support */
@@ -89,6 +147,7 @@ static void NORETURN_ATTR rds_thread(void)
     int timeout = TIMEOUT_BLOCK;
     struct queue_event ev;
     bool rds_rdy = false;
+    struct si4700_dbg_info radio_regs;
 
     while (true) {
         queue_wait_w_tmo(&rds_queue, &ev, timeout);
@@ -97,9 +156,10 @@ static void NORETURN_ATTR rds_thread(void)
                 /* power up: timeout after 1 tick, else block indefinitely */
                 timeout = ev.data ? 1 : TIMEOUT_BLOCK;
                 break;
-            case SYS_TIMEOUT:;
+            case SYS_TIMEOUT:
                 /* Captures RDS data and processes it */
-                bool rdsr = si4709_read_reg(STATUSRSSI) & STATUSRSSI_RDSR;
+                si4700_dbg_info(&radio_regs);
+                bool rdsr = radio_regs.regs[STATUSRSSI] & STATUSRSSI_RDSR;
                 if (rdsr != rds_rdy) {
                     rds_rdy = rdsr;
                     if (rdsr) {
diff --git a/firmware/target/hosted/samsungypr/radio-ypr.h b/firmware/target/hosted/samsungypr/radio-ypr.h
index 13bcb6dc72..15aeb526ef 100644
--- a/firmware/target/hosted/samsungypr/radio-ypr.h
+++ b/firmware/target/hosted/samsungypr/radio-ypr.h
@@ -23,7 +23,6 @@
 #ifndef __RADIO_YPR0_H__
 #define __RADIO_YPR0_H__
 
-#include "si4709.h"
 #include "stdint.h"
 #include "rds.h"
 #include "si4700.h"
@@ -33,4 +32,4 @@ void radiodev_close(void);
 void si4709_write_reg(int addr, uint16_t value);
 uint16_t si4709_read_reg(int addr);
 
-#endif /*__RADIO-YPR0_H__*/
\ No newline at end of file
+#endif /*__RADIO-YPR0_H__*/
diff --git a/firmware/target/hosted/samsungypr/si4709.h b/firmware/target/hosted/samsungypr/si4709.h
deleted file mode 100644
index c27472e856..0000000000
--- a/firmware/target/hosted/samsungypr/si4709.h
+++ /dev/null
@@ -1,82 +0,0 @@
-/***************************************************************************
- *             __________               __   ___.
- *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
- *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
- *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
- *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
- *                     \/            \/     \/    \/            \/
- *
- * Module header for SI4709 FM Radio Chip, using /dev/si470x (si4709.ko) of Samsung YP-R0
- *
- * Copyright (c) 2012 Lorenzo Miori
- *
- * 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 2
- * of the License, or (at your option) any later version.
- *
- * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
- * KIND, either express or implied.
- *
- ****************************************************************************/
-
-#ifndef __SI4709_H__
-#define __SI4709_H__
-
-#include "stdint.h"
-
-/* 7bits I2C address */
-#define SI4709_I2C_SLAVE_ADDR       0x10
-
-#define SI4702_DEVICEID     0x00
-#define SI4702_CHIPID       0x01
-#define SI4702_POWERCFG     0x02
-#define SI4702_CHANNEL      0x03
-#define SI4702_SYSCONFIG1   0x04
-#define SI4702_SYSCONFIG2   0x05
-#define SI4702_SYSCONFIG3   0x06
-#define SI4702_TEST1        0x07
-#define SI4702_TEST2        0x08
-#define SI4702_B00TCONFIG   0x09
-#define SI4702_STATUSRSSI   0x0A
-#define SI4702_READCHAN     0x0B
-#define SI4709_REG_NUM      0x10
-#define SI4702_REG_BYTE     (SI4709_REG_NUM * 2)
-#define SI4702_DEVICE_ID    0x1242
-#define SI4702_RW_REG_NUM   (SI4702_STATUSRSSI - SI4702_POWERCFG)
-#define SI4702_RW_OFFSET    \
-    (SI4709_REG_NUM - SI4702_STATUSRSSI + SI4702_POWERCFG)
-#define BYTE_TO_WORD(hi, lo)    (((hi) << 8) & 0xFF00) | ((lo) & 0x00FF)
-
-typedef struct {
-    int addr;
-    uint16_t value;
-}__attribute__((packed)) sSi4709_t;
-
-typedef struct {
-    int size;
-    unsigned char *buf;
-}__attribute__((packed)) sSi4709_i2c_t;
-
-typedef enum
-{
-    IOCTL_SI4709_INIT = 0,
-    IOCTL_SI4709_CLOSE,
-    IOCTL_SI4709_WRITE_BYTE,
-    IOCTL_SI4709_READ_BYTE,
-    IOCTL_SI4709_I2C_WRITE,
-    IOCTL_SI4709_I2C_READ,
-
-    E_IOCTL_SI4709_MAX
-} eSi4709_ioctl_t;
-
-#define DRV_IOCTL_SI4709_MAGIC     'S'
-
-#define IOCTL_SI4709_INIT          _IO(DRV_IOCTL_SI4709_MAGIC, IOCTL_SI4709_INIT)
-#define IOCTL_SI4709_CLOSE         _IO(DRV_IOCTL_SI4709_MAGIC, IOCTL_SI4709_CLOSE)
-#define IOCTL_SI4709_WRITE_BYTE    _IOW(DRV_IOCTL_SI4709_MAGIC, IOCTL_SI4709_WRITE_BYTE, sSi4709_t)
-#define IOCTL_SI4709_READ_BYTE     _IOR(DRV_IOCTL_SI4709_MAGIC, IOCTL_SI4709_READ_BYTE, sSi4709_t)
-#define IOCTL_SI4709_I2C_WRITE     _IOW(DRV_IOCTL_SI4709_MAGIC, IOCTL_SI4709_I2C_WRITE, sSi4709_i2c_t)
-#define IOCTL_SI4709_I2C_READ      _IOR(DRV_IOCTL_SI4709_MAGIC, IOCTL_SI4709_I2C_READ, sSi4709_i2c_t)
-
-#endif /* __SI4709_H__ */
\ No newline at end of file
diff --git a/firmware/target/hosted/samsungypr/ypr0/i2c-target.h b/firmware/target/hosted/samsungypr/ypr0/i2c-target.h
new file mode 100644
index 0000000000..351988844e
--- /dev/null
+++ b/firmware/target/hosted/samsungypr/ypr0/i2c-target.h
@@ -0,0 +1,30 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ *
+ * Module wrapper for SI4709 FM Radio Chip, using /dev/si470x (si4709.ko)
+ *      Samsung YP-R0 & Samsung YP-R1
+ *
+ * Copyright (c) 2017 Lorenzo Miori
+ *
+ * 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#ifndef I2C_TARGET_H_
+#define I2C_TARGET_H_
+
+/** Define the FM Radio Chip I2C bus */
+#define I2C_BUS_FM_RADIO        ("/dev/i2c-0")
+
+#endif /* I2C_TARGET_H_ */
diff --git a/firmware/target/hosted/samsungypr/ypr1/i2c-target.h b/firmware/target/hosted/samsungypr/ypr1/i2c-target.h
new file mode 100644
index 0000000000..f1fed01cc7
--- /dev/null
+++ b/firmware/target/hosted/samsungypr/ypr1/i2c-target.h
@@ -0,0 +1,30 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ *
+ * Module wrapper for SI4709 FM Radio Chip, using /dev/si470x (si4709.ko)
+ *      Samsung YP-R0 & Samsung YP-R1
+ *
+ * Copyright (c) 2017 Lorenzo Miori
+ *
+ * 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#ifndef I2C_TARGET_H_
+#define I2C_TARGET_H_
+
+/** Define the FM Radio Chip I2C bus */
+#define I2C_BUS_FM_RADIO        ("/dev/i2c-1")
+
+#endif /* I2C_TARGET_H_ */