ASoC: fsl_ssi: Move DT related code to a separate probe()

This patch cleans up probe() function by moving all Device Tree
related code into a separate function. It allows the probe() to
be Device Tree independent. This will be very useful for future
integration of imx-ssi driver which has similar functionalities
while exists only because it supports non-DT cases.

This patch also moves symmetric_channels of AC97 from the probe
to the structure snd_soc_dai_driver for simplification.

Additionally, since PowerPC and AC97 use the same pdev pointer
to register a platform device, this patch also unifies related
code.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Tested-by: Caleb Crome <caleb@crome.org>
Tested-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Reviewed-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 124 insertions, 95 deletions

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index b58fabe77c6f..5bc67ad8000f 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -239,8 +239,12 @@ struct fsl_ssi_soc_data {
  *
  * @fiq_params: FIQ stream filtering parameters
  *
- * @pdev: Pointer to pdev when using fsl-ssi as sound card (ppc only)
- *        TODO: Should be replaced with simple-sound-card
+ * @card_pdev: Platform_device pointer to register a sound card for PowerPC or
+ *             to register a CODEC platform device for AC97
+ * @card_name: Platform_device name to register a sound card for PowerPC or
+ *             to register a CODEC platform device for AC97
+ * @card_idx: The index of SSI to register a sound card for PowerPC or
+ *            to register a CODEC platform device for AC97
  *
  * @dbg_stats: Debugging statistics
  *
@@ -285,7 +289,9 @@ struct fsl_ssi {
 
         struct imx_pcm_fiq_params fiq_params;
 
-        struct platform_device *pdev;
+        struct platform_device *card_pdev;
+        char card_name[32];
+        u32 card_idx;
 
         struct fsl_ssi_dbg dbg_stats;
 
@@ -1134,6 +1140,7 @@ static const struct snd_soc_component_driver fsl_ssi_component = {
 
 static struct snd_soc_dai_driver fsl_ssi_ac97_dai = {
         .bus_control = true,
+        .symmetric_channels = 1,
         .probe = fsl_ssi_dai_probe,
         .playback = {
                 .stream_name = "AC97 Playback",
@@ -1291,9 +1298,7 @@ static void make_lowercase(char *s)
 static int fsl_ssi_imx_probe(struct platform_device *pdev,
                              struct fsl_ssi *ssi, void __iomem *iomem)
 {
-        struct device_node *np = pdev->dev.of_node;
         struct device *dev = &pdev->dev;
-        u32 dmas[4];
         int ret;
 
         /* Backward compatible for a DT without ipg clock name assigned */
@@ -1327,14 +1332,8 @@ static int fsl_ssi_imx_probe(struct platform_device *pdev,
         ssi->dma_params_tx.addr = ssi->ssi_phys + REG_SSI_STX0;
         ssi->dma_params_rx.addr = ssi->ssi_phys + REG_SSI_SRX0;
 
-        /* Set to dual FIFO mode according to the SDMA sciprt */
-        ret = of_property_read_u32_array(np, "dmas", dmas, 4);
-        if (ssi->use_dma && !ret && dmas[2] == IMX_DMATYPE_SSI_DUAL) {
-                ssi->use_dual_fifo = true;
-                /*
-                 * Use even numbers to avoid channel swap due to SDMA
-                 * script design
-                 */
+        /* Use even numbers to avoid channel swap due to SDMA script design */
+        if (ssi->use_dual_fifo) {
                 ssi->dma_params_tx.maxburst &= ~0x1;
                 ssi->dma_params_rx.maxburst &= ~0x1;
         }
@@ -1375,41 +1374,109 @@ static void fsl_ssi_imx_clean(struct platform_device *pdev, struct fsl_ssi *ssi)
                 clk_disable_unprepare(ssi->clk);
 }
 
-static int fsl_ssi_probe(struct platform_device *pdev)
+static int fsl_ssi_probe_from_dt(struct fsl_ssi *ssi)
 {
-        struct fsl_ssi *ssi;
-        int ret = 0;
-        struct device_node *np = pdev->dev.of_node;
-        struct device *dev = &pdev->dev;
+        struct device *dev = ssi->dev;
+        struct device_node *np = dev->of_node;
         const struct of_device_id *of_id;
         const char *p, *sprop;
         const __be32 *iprop;
-        struct resource *res;
-        void __iomem *iomem;
-        char name[64];
-        struct regmap_config regconfig = fsl_ssi_regconfig;
+        u32 dmas[4];
+        int ret;
 
         of_id = of_match_device(fsl_ssi_ids, dev);
         if (!of_id || !of_id->data)
                 return -EINVAL;
 
-        ssi = devm_kzalloc(dev, sizeof(*ssi), GFP_KERNEL);
-        if (!ssi)
-                return -ENOMEM;
-
         ssi->soc = of_id->data;
-        ssi->dev = dev;
+
+        ret = of_property_match_string(np, "clock-names", "ipg");
+        /* Get error code if not found */
+        ssi->has_ipg_clk_name = ret >= 0;
 
         /* Check if being used in AC97 mode */
         sprop = of_get_property(np, "fsl,mode", NULL);
-        if (sprop) {
-                if (!strcmp(sprop, "ac97-slave"))
-                        ssi->dai_fmt = FSLSSI_AC97_DAIFMT;
+        if (sprop && !strcmp(sprop, "ac97-slave")) {
+                ssi->dai_fmt = FSLSSI_AC97_DAIFMT;
+
+                ret = of_property_read_u32(np, "cell-index", &ssi->card_idx);
+                if (ret) {
+                        dev_err(dev, "failed to get SSI index property\n");
+                        return -EINVAL;
+                }
+                strcpy(ssi->card_name, "ac97-codec");
+        } else if (!of_find_property(np, "fsl,ssi-asynchronous", NULL)) {
+                /*
+                 * In synchronous mode, STCK and STFS ports are used by RX
+                 * as well. So the software should limit the sample rates,
+                 * sample bits and channels to be symmetric.
+                 *
+                 * This is exclusive with FSLSSI_AC97_FORMATS as AC97 runs
+                 * in the SSI synchronous mode however it does not have to
+                 * limit symmetric sample rates and sample bits.
+                 */
+                ssi->synchronous = true;
         }
 
         /* Select DMA or FIQ */
         ssi->use_dma = !of_property_read_bool(np, "fsl,fiq-stream-filter");
 
+        /* Fetch FIFO depth; Set to 8 for older DT without this property */
+        iprop = of_get_property(np, "fsl,fifo-depth", NULL);
+        if (iprop)
+                ssi->fifo_depth = be32_to_cpup(iprop);
+        else
+                ssi->fifo_depth = 8;
+
+        /* Use dual FIFO mode depending on the support from SDMA script */
+        ret = of_property_read_u32_array(np, "dmas", dmas, 4);
+        if (ssi->use_dma && !ret && dmas[2] == IMX_DMATYPE_SSI_DUAL)
+                ssi->use_dual_fifo = true;
+
+        /*
+         * Backward compatible for older bindings by manually triggering the
+         * machine driver's probe(). Use /compatible property, including the
+         * address of CPU DAI driver structure, as the name of machine driver
+         *
+         * If card_name is set by AC97 earlier, bypass here since it uses a
+         * different name to register the device.
+         */
+        if (!ssi->card_name[0] && of_get_property(np, "codec-handle", NULL)) {
+                sprop = of_get_property(of_find_node_by_path("/"),
+                                        "compatible", NULL);
+                /* Strip "fsl," in the compatible name if applicable */
+                p = strrchr(sprop, ',');
+                if (p)
+                        sprop = p + 1;
+                snprintf(ssi->card_name, sizeof(ssi->card_name),
+                         "snd-soc-%s", sprop);
+                make_lowercase(ssi->card_name);
+                ssi->card_idx = 0;
+        }
+
+        return 0;
+}
+
+static int fsl_ssi_probe(struct platform_device *pdev)
+{
+        struct regmap_config regconfig = fsl_ssi_regconfig;
+        struct device *dev = &pdev->dev;
+        struct fsl_ssi *ssi;
+        struct resource *res;
+        void __iomem *iomem;
+        int ret = 0;
+
+        ssi = devm_kzalloc(dev, sizeof(*ssi), GFP_KERNEL);
+        if (!ssi)
+                return -ENOMEM;
+
+        ssi->dev = dev;
+
+        /* Probe from DT */
+        ret = fsl_ssi_probe_from_dt(ssi);
+        if (ret)
+                return ret;
+
         if (fsl_ssi_is_ac97(ssi)) {
                 memcpy(&ssi->cpu_dai_drv, &fsl_ssi_ac97_dai,
                        sizeof(fsl_ssi_ac97_dai));
@@ -1433,15 +1500,11 @@ static int fsl_ssi_probe(struct platform_device *pdev)
                         REG_SSI_SRMSK / sizeof(uint32_t) + 1;
         }
 
-        ret = of_property_match_string(np, "clock-names", "ipg");
-        if (ret < 0) {
-                ssi->has_ipg_clk_name = false;
-                ssi->regs = devm_regmap_init_mmio(dev, iomem, &regconfig);
-        } else {
-                ssi->has_ipg_clk_name = true;
+        if (ssi->has_ipg_clk_name)
                 ssi->regs = devm_regmap_init_mmio_clk(dev, "ipg", iomem,
                                                       &regconfig);
-        }
+        else
+                ssi->regs = devm_regmap_init_mmio(dev, iomem, &regconfig);
         if (IS_ERR(ssi->regs)) {
                 dev_err(dev, "failed to init register map\n");
                 return PTR_ERR(ssi->regs);
@@ -1453,24 +1516,13 @@ static int fsl_ssi_probe(struct platform_device *pdev)
                 return ssi->irq;
         }
 
-        /* Set software limitations for synchronous mode */
-        if (!of_find_property(np, "fsl,ssi-asynchronous", NULL)) {
-                if (!fsl_ssi_is_ac97(ssi)) {
-                        ssi->cpu_dai_drv.symmetric_rates = 1;
-                        ssi->cpu_dai_drv.symmetric_samplebits = 1;
-                        ssi->synchronous = true;
-                }
-
+        /* Set software limitations for synchronous mode except AC97 */
+        if (ssi->synchronous && !fsl_ssi_is_ac97(ssi)) {
+                ssi->cpu_dai_drv.symmetric_rates = 1;
                 ssi->cpu_dai_drv.symmetric_channels = 1;
+                ssi->cpu_dai_drv.symmetric_samplebits = 1;
         }
 
-        /* Fetch FIFO depth; Set to 8 for older DT without this property */
-        iprop = of_get_property(np, "fsl,fifo-depth", NULL);
-        if (iprop)
-                ssi->fifo_depth = be32_to_cpup(iprop);
-        else
-                ssi->fifo_depth = 8;
-
         /*
          * Configure TX and RX DMA watermarks -- when to send a DMA request
          *
@@ -1535,50 +1587,27 @@ static int fsl_ssi_probe(struct platform_device *pdev)
         if (ret)
                 goto error_asoc_register;
 
-        /* Bypass it if using newer DT bindings of ASoC machine drivers */
-        if (!of_get_property(np, "codec-handle", NULL))
-                goto done;
-
-        /*
-         * Backward compatible for older bindings by manually triggering the
-         * machine driver's probe(). Use /compatible property, including the
-         * address of CPU DAI driver structure, as the name of machine driver.
-         */
-        sprop = of_get_property(of_find_node_by_path("/"), "compatible", NULL);
-        /* Sometimes the compatible name has a "fsl," prefix, so we strip it. */
-        p = strrchr(sprop, ',');
-        if (p)
-                sprop = p + 1;
-        snprintf(name, sizeof(name), "snd-soc-%s", sprop);
-        make_lowercase(name);
-
-        ssi->pdev = platform_device_register_data(dev, name, 0, NULL, 0);
-        if (IS_ERR(ssi->pdev)) {
-                ret = PTR_ERR(ssi->pdev);
-                dev_err(dev, "failed to register platform: %d\n", ret);
-                goto error_sound_card;
-        }
-
-done:
         /* Initially configures SSI registers */
         fsl_ssi_hw_init(ssi);
 
-        if (fsl_ssi_is_ac97(ssi)) {
-                u32 ssi_idx;
-
-                ret = of_property_read_u32(np, "cell-index", &ssi_idx);
-                if (ret) {
-                        dev_err(dev, "failed to get SSI index property\n");
-                        goto error_sound_card;
-                }
-
-                ssi->pdev = platform_device_register_data(NULL, "ac97-codec",
-                                                          ssi_idx, NULL, 0);
-                if (IS_ERR(ssi->pdev)) {
-                        ret = PTR_ERR(ssi->pdev);
-                        dev_err(dev,
-                                "failed to register AC97 codec platform: %d\n",
-                                ret);
+        /* Register a platform device for older bindings or AC97 */
+        if (ssi->card_name[0]) {
+                struct device *parent = dev;
+                /*
+                 * Do not set SSI dev as the parent of AC97 CODEC device since
+                 * it does not have a DT node. Otherwise ASoC core will assume
+                 * CODEC has the same DT node as the SSI, so it may bypass the
+                 * dai_probe() of SSI and then cause NULL DMA data pointers.
+                 */
+                if (fsl_ssi_is_ac97(ssi))
+                        parent = NULL;
+
+                ssi->card_pdev = platform_device_register_data(parent,
+                                ssi->card_name, ssi->card_idx, NULL, 0);
+                if (IS_ERR(ssi->card_pdev)) {
+                        ret = PTR_ERR(ssi->card_pdev);
+                        dev_err(dev, "failed to register %s: %d\n",
+                                ssi->card_name, ret);
                         goto error_sound_card;
                 }
         }
@@ -1606,8 +1635,8 @@ static int fsl_ssi_remove(struct platform_device *pdev)
 
         fsl_ssi_debugfs_remove(&ssi->dbg_stats);
 
-        if (ssi->pdev)
-                platform_device_unregister(ssi->pdev);
+        if (ssi->card_pdev)
+                platform_device_unregister(ssi->card_pdev);
 
         /* Clean up SSI registers */
         fsl_ssi_hw_clean(ssi);