memory: tegra: Expose supported rates via debugfs

In order to ease testing, expose the list of supported EMC frequencies
via debugfs.

Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 40 insertions, 2 deletions

diff --git a/drivers/memory/tegra/tegra124-emc.c b/drivers/memory/tegra/tegra124-emc.c
index 8620355776fe..3dac7be39654 100644
--- a/drivers/memory/tegra/tegra124-emc.c
+++ b/drivers/memory/tegra/tegra124-emc.c
@@ -1027,7 +1027,40 @@ static int emc_debug_rate_set(void *data, u64 rate)
 DEFINE_SIMPLE_ATTRIBUTE(emc_debug_rate_fops, emc_debug_rate_get,
                         emc_debug_rate_set, "%lld\n");
 
-static void emc_debugfs_init(struct device *dev)
+static int emc_debug_supported_rates_show(struct seq_file *s, void *data)
+{
+        struct tegra_emc *emc = s->private;
+        const char *prefix = "";
+        unsigned int i;
+
+        for (i = 0; i < emc->num_timings; i++) {
+                struct emc_timing *timing = &emc->timings[i];
+
+                seq_printf(s, "%s%lu", prefix, timing->rate);
+
+                prefix = " ";
+        }
+
+        seq_puts(s, "\n");
+
+        return 0;
+}
+
+static int emc_debug_supported_rates_open(struct inode *inode,
+                                          struct file *file)
+{
+        return single_open(file, emc_debug_supported_rates_show,
+                           inode->i_private);
+}
+
+static const struct file_operations emc_debug_supported_rates_fops = {
+        .open = emc_debug_supported_rates_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = single_release,
+};
+
+static void emc_debugfs_init(struct device *dev, struct tegra_emc *emc)
 {
         struct dentry *root, *file;
         struct clk *clk;
@@ -1048,6 +1081,11 @@ static void emc_debugfs_init(struct device *dev)
                                    &emc_debug_rate_fops);
         if (!file)
                 dev_err(dev, "failed to create debugfs entry\n");
+
+        file = debugfs_create_file("supported_rates", S_IRUGO, root, emc,
+                                   &emc_debug_supported_rates_fops);
+        if (!file)
+                dev_err(dev, "failed to create debugfs entry\n");
 }
 
 static int tegra_emc_probe(struct platform_device *pdev)
@@ -1119,7 +1157,7 @@ static int tegra_emc_probe(struct platform_device *pdev)
         platform_set_drvdata(pdev, emc);
 
         if (IS_ENABLED(CONFIG_DEBUG_FS))
-                emc_debugfs_init(&pdev->dev);
+                emc_debugfs_init(&pdev->dev, emc);
 
         return 0;
 };