ALSA: oxygen: add UART I/O functions

Add functions to allow model drivers to communicate with external chips
by doing I/O with the not-used-for-MIDI UART.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

diff --git a/sound/pci/oxygen/oxygen.h b/sound/pci/oxygen/oxygen.h
index f82a962..19107c6 100644 (file)
--- a/sound/pci/oxygen/oxygen.h
+++ b/sound/pci/oxygen/oxygen.h
@@ -79,6 +79,7 @@ struct oxygen_model {
        void (*update_dac_volume)(struct oxygen *chip);
        void (*update_dac_mute)(struct oxygen *chip);
        void (*gpio_changed)(struct oxygen *chip);
+       void (*uart_input)(struct oxygen *chip);
        void (*ac97_switch)(struct oxygen *chip,
                            unsigned int reg, unsigned int mute);
        const unsigned int *dac_tlv;
@@ -125,6 +126,8 @@ struct oxygen {
                __le32 _32[OXYGEN_IO_SIZE / 4];
        } saved_registers;
        u16 saved_ac97_registers[2][0x40];
+       unsigned int uart_input_count;
+       u8 uart_input[32];
        struct oxygen_model model;
 };
 
@@ -174,6 +177,9 @@ void oxygen_write_ac97_masked(struct oxygen *chip, unsigned int codec,
 void oxygen_write_spi(struct oxygen *chip, u8 control, unsigned int data);
 void oxygen_write_i2c(struct oxygen *chip, u8 device, u8 map, u8 data);
 
+void oxygen_reset_uart(struct oxygen *chip);
+void oxygen_write_uart(struct oxygen *chip, u8 data);
+
 static inline void oxygen_set_bits8(struct oxygen *chip,
                                    unsigned int reg, u8 value)
 {

diff --git a/sound/pci/oxygen/oxygen_io.c b/sound/pci/oxygen/oxygen_io.c
index 83f135f..deba738 100644 (file)
--- a/sound/pci/oxygen/oxygen_io.c
+++ b/sound/pci/oxygen/oxygen_io.c
@@ -20,6 +20,7 @@
 #include <linux/delay.h>
 #include <linux/sched.h>
 #include <sound/core.h>
+#include <sound/mpu401.h>
 #include <asm/io.h>
 #include "oxygen.h"
 
@@ -232,3 +233,23 @@ void oxygen_write_i2c(struct oxygen *chip, u8 device, u8 map, u8 data)
                      device | OXYGEN_2WIRE_DIR_WRITE);
 }
 EXPORT_SYMBOL(oxygen_write_i2c);
+
+static void _write_uart(struct oxygen *chip, unsigned int port, u8 data)
+{
+       if (oxygen_read8(chip, OXYGEN_MPU401 + 1) & MPU401_TX_FULL)
+               msleep(1);
+       oxygen_write8(chip, OXYGEN_MPU401 + port, data);
+}
+
+void oxygen_reset_uart(struct oxygen *chip)
+{
+       _write_uart(chip, 1, MPU401_RESET);
+       _write_uart(chip, 1, MPU401_ENTER_UART);
+}
+EXPORT_SYMBOL(oxygen_reset_uart);
+
+void oxygen_write_uart(struct oxygen *chip, u8 data)
+{
+       _write_uart(chip, 0, data);
+}
+EXPORT_SYMBOL(oxygen_write_uart);

diff --git a/sound/pci/oxygen/oxygen_lib.c b/sound/pci/oxygen/oxygen_lib.c
index b199721..84f481d 100644 (file)
--- a/sound/pci/oxygen/oxygen_lib.c
+++ b/sound/pci/oxygen/oxygen_lib.c
@@ -35,6 +35,30 @@ MODULE_DESCRIPTION("C-Media CMI8788 helper library");
 MODULE_LICENSE("GPL v2");
 
 
+static inline int oxygen_uart_input_ready(struct oxygen *chip)
+{
+       return !(oxygen_read8(chip, OXYGEN_MPU401 + 1) & MPU401_RX_EMPTY);
+}
+
+static void oxygen_read_uart(struct oxygen *chip)
+{
+       if (unlikely(!oxygen_uart_input_ready(chip))) {
+               /* no data, but read it anyway to clear the interrupt */
+               oxygen_read8(chip, OXYGEN_MPU401);
+               return;
+       }
+       do {
+               u8 data = oxygen_read8(chip, OXYGEN_MPU401);
+               if (data == MPU401_ACK)
+                       continue;
+               if (chip->uart_input_count >= ARRAY_SIZE(chip->uart_input))
+                       chip->uart_input_count = 0;
+               chip->uart_input[chip->uart_input_count++] = data;
+       } while (oxygen_uart_input_ready(chip));
+       if (chip->model.uart_input)
+               chip->model.uart_input(chip);
+}
+
 static irqreturn_t oxygen_interrupt(int dummy, void *dev_id)
 {
        struct oxygen *chip = dev_id;
@@ -87,8 +111,12 @@ static irqreturn_t oxygen_interrupt(int dummy, void *dev_id)
        if (status & OXYGEN_INT_GPIO)
                schedule_work(&chip->gpio_work);
 
-       if ((status & OXYGEN_INT_MIDI) && chip->midi)
-               snd_mpu401_uart_interrupt(0, chip->midi->private_data);
+       if (status & OXYGEN_INT_MIDI) {
+               if (chip->midi)
+                       snd_mpu401_uart_interrupt(0, chip->midi->private_data);
+               else
+                       oxygen_read_uart(chip);
+       }
 
        if (status & OXYGEN_INT_AC97)
                wake_up(&chip->ac97_waitqueue);