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 void 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
93#ifdef CONFIG_OF
94static const struct of_device_id omap_ocp2scp_id_table[] = {
95	{ .compatible = "ti,omap-ocp2scp" },
96	{ .compatible = "ti,am437x-ocp2scp" },
97	{}
98};
99MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);
100#endif
101
102static struct platform_driver omap_ocp2scp_driver = {
103	.probe		= omap_ocp2scp_probe,
104	.remove_new	= omap_ocp2scp_remove,
105	.driver		= {
106		.name	= "omap-ocp2scp",
107		.of_match_table = of_match_ptr(omap_ocp2scp_id_table),
108	},
109};
110
111module_platform_driver(omap_ocp2scp_driver);
112
113MODULE_ALIAS("platform:omap-ocp2scp");
114MODULE_AUTHOR("Texas Instruments Inc.");
115MODULE_DESCRIPTION("OMAP OCP2SCP driver");
116MODULE_LICENSE("GPL v2");
117