ASoC: sh: Replace tasklet with work

The tasklet is an old API that should be deprecated, usually can be
converted to another decent API.  In ASoC SH SIU driver, a tasklet is
still used for offloading the hardware reset function.  It can be
achieved gracefully with a work queued, too.

This patch replaces the tasklet usage in SH SIU driver with a simple
work.  The conversion is fairly straightforward.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20200903104749.21435-3-tiwai@suse.de
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/siu.h

@@ -96,7 +96,7 @@ struct siu_info {
 };
 
 struct siu_stream {
-	struct tasklet_struct		tasklet;
+	struct work_struct		work;
 	struct snd_pcm_substream	*substream;
 	snd_pcm_format_t		format;
 	size_t				buf_bytes;

sound/soc/sh/siu_pcm.c

@@ -70,7 +70,7 @@ static int siu_pcm_stmwrite_start(struct siu_port *port_info)
 	siu_stream->rw_flg = RWF_STM_WT;
 
 	/* DMA transfer start */
-	tasklet_schedule(&siu_stream->tasklet);
+	queue_work(system_highpri_wq, &siu_stream->work);
 
 	return 0;
 }
@@ -93,7 +93,7 @@ static void siu_dma_tx_complete(void *arg)
 		siu_stream->cur_period * siu_stream->period_bytes,
 		siu_stream->buf_bytes, siu_stream->cookie);
 
-	tasklet_schedule(&siu_stream->tasklet);
+	queue_work(system_highpri_wq, &siu_stream->work);
 
 	/* Notify alsa: a period is done */
 	snd_pcm_period_elapsed(siu_stream->substream);
@@ -198,9 +198,10 @@ static int siu_pcm_rd_set(struct siu_port *port_info,
 	return 0;
 }
 
-static void siu_io_tasklet(struct tasklet_struct *t)
+static void siu_io_work(struct work_struct *work)
 {
-	struct siu_stream *siu_stream = from_tasklet(siu_stream, t, tasklet);
+	struct siu_stream *siu_stream = container_of(work, struct siu_stream,
+						     work);
 	struct snd_pcm_substream *substream = siu_stream->substream;
 	struct device *dev = substream->pcm->card->dev;
 	struct snd_pcm_runtime *rt = substream->runtime;
@@ -253,7 +254,7 @@ static int siu_pcm_stmread_start(struct siu_port *port_info)
 	/* during stmread flag set */
 	siu_stream->rw_flg = RWF_STM_RD;
 
-	tasklet_schedule(&siu_stream->tasklet);
+	queue_work(system_highpri_wq, &siu_stream->work);
 
 	return 0;
 }
@@ -519,9 +520,9 @@ static int siu_pcm_new(struct snd_soc_component *component,
 
 		(*port_info)->pcm = pcm;
 
-		/* IO tasklets */
-		tasklet_setup(&(*port_info)->playback.tasklet, siu_io_tasklet);
-		tasklet_setup(&(*port_info)->capture.tasklet, siu_io_tasklet);
+		/* IO works */
+		INIT_WORK(&(*port_info)->playback.work, siu_io_work);
+		INIT_WORK(&(*port_info)->capture.work, siu_io_work);
 	}
 
 	dev_info(card->dev, "SuperH SIU driver initialized.\n");
@@ -534,8 +535,8 @@ static void siu_pcm_free(struct snd_soc_component *component,
 	struct platform_device *pdev = to_platform_device(pcm->card->dev);
 	struct siu_port *port_info = siu_ports[pdev->id];
 
-	tasklet_kill(&port_info->capture.tasklet);
-	tasklet_kill(&port_info->playback.tasklet);
+	cancel_work_sync(&port_info->capture.work);
+	cancel_work_sync(&port_info->playback.work);
 
 	siu_free_port(port_info);