memory: tegra30-emc: Continue probing if timings are missing in device-tree

EMC driver will become mandatory after turning it into interconnect
provider because interconnect users, like display controller driver, will
fail to probe using newer device-trees that have interconnect properties.
Thus make EMC driver to probe even if timings are missing in device-tree.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20201111011456.7875-9-digetx@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

diff --git a/drivers/memory/tegra/tegra30-emc.c b/drivers/memory/tegra/tegra30-emc.c
index d092608..3488786 100644 (file)
--- a/drivers/memory/tegra/tegra30-emc.c
+++ b/drivers/memory/tegra/tegra30-emc.c
@@ -988,6 +988,11 @@ static struct device_node *emc_find_node_by_ram_code(struct device *dev)
        u32 value, ram_code;
        int err;
 
+       if (of_get_child_count(dev->of_node) == 0) {
+               dev_info(dev, "device-tree doesn't have memory timings\n");
+               return NULL;
+       }
+
        ram_code = tegra_read_ram_code();
 
        for_each_child_of_node(dev->of_node, np) {
@@ -1057,6 +1062,9 @@ static long emc_round_rate(unsigned long rate,
        struct tegra_emc *emc = arg;
        unsigned int i;
 
+       if (!emc->num_timings)
+               return clk_get_rate(emc->clk);
+
        min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate);
 
        for (i = 0; i < emc->num_timings; i++) {
@@ -1262,16 +1270,6 @@ static int tegra_emc_probe(struct platform_device *pdev)
        struct tegra_emc *emc;
        int err;
 
-       if (of_get_child_count(pdev->dev.of_node) == 0) {
-               dev_info(&pdev->dev,
-                        "device-tree node doesn't have memory timings\n");
-               return -ENODEV;
-       }
-
-       np = emc_find_node_by_ram_code(&pdev->dev);
-       if (!np)
-               return -EINVAL;
-
        emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
        if (!emc) {
                of_node_put(np);
@@ -1285,10 +1283,13 @@ static int tegra_emc_probe(struct platform_device *pdev)
        emc->clk_nb.notifier_call = emc_clk_change_notify;
        emc->dev = &pdev->dev;
 
-       err = emc_load_timings_from_dt(emc, np);
-       of_node_put(np);
-       if (err)
-               return err;
+       np = emc_find_node_by_ram_code(&pdev->dev);
+       if (np) {
+               err = emc_load_timings_from_dt(emc, np);
+               of_node_put(np);
+               if (err)
+                       return err;
+       }
 
        emc->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(emc->regs))