},
 };
 
+static inline unsigned int
+oxygen_substream_channel(struct snd_pcm_substream *substream)
+{
+       return (unsigned int)(uintptr_t)substream->runtime->private_data;
+}
+
 static int oxygen_open(struct snd_pcm_substream *substream,
                       unsigned int channel)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
        int err;
 
-       runtime->private_data = (void *)channel;
+       runtime->private_data = (void *)(uintptr_t)channel;
        runtime->hw = oxygen_hardware[channel];
        err = snd_pcm_hw_constraint_step(runtime, 0,
                                         SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 32);
 static int oxygen_close(struct snd_pcm_substream *substream)
 {
        struct oxygen *chip = snd_pcm_substream_chip(substream);
-       unsigned int channel = (unsigned int)substream->runtime->private_data;
+       unsigned int channel = oxygen_substream_channel(substream);
 
        mutex_lock(&chip->mutex);
        chip->pcm_active &= ~(1 << channel);
                            struct snd_pcm_hw_params *hw_params)
 {
        struct oxygen *chip = snd_pcm_substream_chip(substream);
-       unsigned int channel = (unsigned int)substream->runtime->private_data;
+       unsigned int channel = oxygen_substream_channel(substream);
        int err;
 
        err = snd_pcm_lib_malloc_pages(substream,
 static int oxygen_hw_free(struct snd_pcm_substream *substream)
 {
        struct oxygen *chip = snd_pcm_substream_chip(substream);
-       unsigned int channel = (unsigned int)substream->runtime->private_data;
+       unsigned int channel = oxygen_substream_channel(substream);
 
        spin_lock_irq(&chip->reg_lock);
        chip->interrupt_mask &= ~(1 << channel);
 static int oxygen_prepare(struct snd_pcm_substream *substream)
 {
        struct oxygen *chip = snd_pcm_substream_chip(substream);
-       unsigned int channel = (unsigned int)substream->runtime->private_data;
+       unsigned int channel = oxygen_substream_channel(substream);
        unsigned int channel_mask = 1 << channel;
 
        spin_lock_irq(&chip->reg_lock);
 
        snd_pcm_group_for_each_entry(s, substream) {
                if (snd_pcm_substream_chip(s) == chip) {
-                       mask |= 1 << (unsigned int)s->runtime->private_data;
+                       mask |= 1 << oxygen_substream_channel(s);
                        snd_pcm_trigger_done(s, substream);
                }
        }
 {
        struct oxygen *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
-       unsigned int channel = (unsigned int)runtime->private_data;
+       unsigned int channel = oxygen_substream_channel(substream);
        u32 curr_addr;
 
        /* no spinlock, this read should be atomic */