linux-kernel - [PATCH v2 13/22] memory: tegra20-emc: Continue probing if timings are missing in device-tree

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Date:   Mon, 30 Mar 2020 04:08:55 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Artur Świgoń <a.swigon@...sung.com>,
        Georgi Djakov <georgi.djakov@...aro.org>,
        Rob Herring <robh+dt@...nel.org>
Cc:     linux-tegra@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        devicetree@...r.kernel.org
Subject: [PATCH v2 13/22] memory: tegra20-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@...il.com>
---
 drivers/memory/tegra/tegra20-emc.c | 37 +++++++++++++++---------------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
index ef3abc18a3f4..3a6eb5cc5c29 100644
--- a/drivers/memory/tegra/tegra20-emc.c
+++ b/drivers/memory/tegra/tegra20-emc.c
@@ -383,6 +383,11 @@ tegra_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;
+	}
+
 	if (!of_property_read_bool(dev->of_node, "nvidia,use-ram-code"))
 		return of_node_get(dev->of_node);
 
@@ -451,6 +456,9 @@ 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++) {
@@ -656,13 +664,6 @@ static int tegra_emc_probe(struct platform_device *pdev)
 	struct tegra_emc *emc;
 	int irq, err;
 
-	/* driver has nothing to do in a case of memory timing absence */
-	if (of_get_child_count(pdev->dev.of_node) == 0) {
-		dev_info(&pdev->dev,
-			 "EMC device tree node doesn't have memory timings\n");
-		return 0;
-	}
-
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		dev_err(&pdev->dev, "interrupt not specified\n");
@@ -670,23 +671,20 @@ static int tegra_emc_probe(struct platform_device *pdev)
 		return irq;
 	}
 
-	np = tegra_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);
+	if (!emc)
 		return -ENOMEM;
-	}
 
 	emc->clk_nb.notifier_call = tegra_emc_clk_change_notify;
 	emc->dev = &pdev->dev;
 
-	err = tegra_emc_load_timings_from_dt(emc, np);
-	of_node_put(np);
-	if (err)
-		return err;
+	np = tegra_emc_find_node_by_ram_code(&pdev->dev);
+	if (np) {
+		err = tegra_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))
@@ -699,7 +697,8 @@ static int tegra_emc_probe(struct platform_device *pdev)
 	err = devm_request_irq(&pdev->dev, irq, tegra_emc_isr, 0,
 			       dev_name(&pdev->dev), emc);
 	if (err) {
-		dev_err(&pdev->dev, "failed to request IRQ#%u: %d\n", irq, err);
+		dev_err(&pdev->dev, "failed to request IRQ#%u: %d\n",
+			irq, err);
 		return err;
 	}
 
-- 
2.25.1