LXR linux/drivers/bus/omap-ocp2scp.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * omap-ocp2scp.c - transform ocp interface protocol to scp protocol
   4 *
   5 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
   6 * Author: Kishon Vijay Abraham I <kishon@ti.com>
   7 */
   8
   9#include <linux/io.h>
  10#include <linux/module.h>
  11#include <linux/platform_device.h>
  12#include <linux/err.h>
  13#include <linux/pm_runtime.h>
  14#include <linux/of.h>
  15#include <linux/of_platform.h>
  16
  17#define OCP2SCP_TIMING 0x18
  18#define SYNC2_MASK 0xf
  19
  20static int ocp2scp_remove_devices(struct device *dev, void *c)
  21{
  22        struct platform_device *pdev = to_platform_device(dev);
  23
  24        platform_device_unregister(pdev);
  25
  26        return 0;
  27}
  28
  29static int omap_ocp2scp_probe(struct platform_device *pdev)
  30{
  31        int ret;
  32        u32 reg;
  33        void __iomem *regs;
  34        struct resource *res;
  35        struct device_node *np = pdev->dev.of_node;
  36
  37        if (np) {
  38                ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
  39                if (ret) {
  40                        dev_err(&pdev->dev,
  41                            "failed to add resources for ocp2scp child\n");
  42                        goto err0;
  43                }
  44        }
  45
  46        pm_runtime_enable(&pdev->dev);
  47        /*
  48         * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf
  49         * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution;
  50         * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf
  51         * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution;
  52         * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf
  53         * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution;
  54         * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249
  55         * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution;
  56         *
  57         * Read path of OCP2SCP is not working properly due to low reset value
  58         * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more.
  59         */
  60        if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) {
  61                res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  62                regs = devm_ioremap_resource(&pdev->dev, res);
  63                if (IS_ERR(regs)) {
  64                        ret = PTR_ERR(regs);
  65                        goto err1;
  66                }
  67
  68                pm_runtime_get_sync(&pdev->dev);
  69                reg = readl_relaxed(regs + OCP2SCP_TIMING);
  70                reg &= ~(SYNC2_MASK);
  71                reg |= 0x6;
  72                writel_relaxed(reg, regs + OCP2SCP_TIMING);
  73                pm_runtime_put_sync(&pdev->dev);
  74        }
  75
  76        return 0;
  77
  78err1:
  79        pm_runtime_disable(&pdev->dev);
  80
  81err0:
  82        device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
  83
  84        return ret;
  85}
  86
  87static int omap_ocp2scp_remove(struct platform_device *pdev)
  88{
  89        pm_runtime_disable(&pdev->dev);
  90        device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
  91
  92        return 0;
  93}
  94
  95#ifdef CONFIG_OF
  96static const struct of_device_id omap_ocp2scp_id_table[] = {
  97        { .compatible = "ti,omap-ocp2scp" },
  98        { .compatible = "ti,am437x-ocp2scp" },
  99        {}
 100};
 101MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);
 102#endif
 103
 104static struct platform_driver omap_ocp2scp_driver = {
 105        .probe          = omap_ocp2scp_probe,
 106        .remove         = omap_ocp2scp_remove,
 107        .driver         = {
 108                .name   = "omap-ocp2scp",
 109                .of_match_table = of_match_ptr(omap_ocp2scp_id_table),
 110        },
 111};
 112
 113module_platform_driver(omap_ocp2scp_driver);
 114
 115MODULE_ALIAS("platform:omap-ocp2scp");
 116MODULE_AUTHOR("Texas Instruments Inc.");
 117MODULE_DESCRIPTION("OMAP OCP2SCP driver");
 118MODULE_LICENSE("GPL v2");
 119