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path: root/drivers/bus/omap-ocp2scp.c
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Diffstat (limited to 'drivers/bus/omap-ocp2scp.c')
-rw-r--r--drivers/bus/omap-ocp2scp.c123
1 files changed, 123 insertions, 0 deletions
diff --git a/drivers/bus/omap-ocp2scp.c b/drivers/bus/omap-ocp2scp.c
new file mode 100644
index 000000000..9f1856948
--- /dev/null
+++ b/drivers/bus/omap-ocp2scp.c
@@ -0,0 +1,123 @@
+/*
+ * omap-ocp2scp.c - transform ocp interface protocol to scp protocol
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+
+#define OCP2SCP_TIMING 0x18
+#define SYNC2_MASK 0xf
+
+static int ocp2scp_remove_devices(struct device *dev, void *c)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+
+ platform_device_unregister(pdev);
+
+ return 0;
+}
+
+static int omap_ocp2scp_probe(struct platform_device *pdev)
+{
+ int ret;
+ u32 reg;
+ void __iomem *regs;
+ struct resource *res;
+ struct device_node *np = pdev->dev.of_node;
+
+ if (np) {
+ ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to add resources for ocp2scp child\n");
+ goto err0;
+ }
+ }
+
+ pm_runtime_enable(&pdev->dev);
+ /*
+ * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf
+ * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution;
+ * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf
+ * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution;
+ * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf
+ * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution;
+ * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249
+ * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution;
+ *
+ * Read path of OCP2SCP is not working properly due to low reset value
+ * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more.
+ */
+ if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) {
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(regs))
+ goto err0;
+
+ pm_runtime_get_sync(&pdev->dev);
+ reg = readl_relaxed(regs + OCP2SCP_TIMING);
+ reg &= ~(SYNC2_MASK);
+ reg |= 0x6;
+ writel_relaxed(reg, regs + OCP2SCP_TIMING);
+ pm_runtime_put_sync(&pdev->dev);
+ }
+
+ return 0;
+
+err0:
+ device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
+
+ return ret;
+}
+
+static int omap_ocp2scp_remove(struct platform_device *pdev)
+{
+ pm_runtime_disable(&pdev->dev);
+ device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id omap_ocp2scp_id_table[] = {
+ { .compatible = "ti,omap-ocp2scp" },
+ { .compatible = "ti,am437x-ocp2scp" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);
+#endif
+
+static struct platform_driver omap_ocp2scp_driver = {
+ .probe = omap_ocp2scp_probe,
+ .remove = omap_ocp2scp_remove,
+ .driver = {
+ .name = "omap-ocp2scp",
+ .of_match_table = of_match_ptr(omap_ocp2scp_id_table),
+ },
+};
+
+module_platform_driver(omap_ocp2scp_driver);
+
+MODULE_ALIAS("platform: omap-ocp2scp");
+MODULE_AUTHOR("Texas Instruments Inc.");
+MODULE_DESCRIPTION("OMAP OCP2SCP driver");
+MODULE_LICENSE("GPL v2");