1/*
2 * omap-ocp2scp.c - transform ocp interface protocol to scp protocol
3 *
4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * Author: Kishon Vijay Abraham I <kishon@ti.com>
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 */
18
19#include <linux/io.h>
20#include <linux/module.h>
21#include <linux/platform_device.h>
22#include <linux/err.h>
23#include <linux/pm_runtime.h>
24#include <linux/of.h>
25#include <linux/of_platform.h>
26
27#define OCP2SCP_TIMING 0x18
28#define SYNC2_MASK 0xf
29
30static int ocp2scp_remove_devices(struct device *dev, void *c)
31{
32	struct platform_device *pdev = to_platform_device(dev);
33
34	platform_device_unregister(pdev);
35
36	return 0;
37}
38
39static int omap_ocp2scp_probe(struct platform_device *pdev)
40{
41	int ret;
42	u32 reg;
43	void __iomem *regs;
44	struct resource *res;
45	struct device_node *np = pdev->dev.of_node;
46
47	if (np) {
48		ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
49		if (ret) {
50			dev_err(&pdev->dev,
51			    "failed to add resources for ocp2scp child\n");
52			goto err0;
53		}
54	}
55
56	pm_runtime_enable(&pdev->dev);
57	/*
58	 * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf
59	 * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution;
60	 * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf
61	 * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution;
62	 * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf
63	 * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution;
64	 * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249
65	 * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution;
66	 *
67	 * Read path of OCP2SCP is not working properly due to low reset value
68	 * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more.
69	 */
70	if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) {
71		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
72		regs = devm_ioremap_resource(&pdev->dev, res);
73		if (IS_ERR(regs))
74			goto err0;
75
76		pm_runtime_get_sync(&pdev->dev);
77		reg = readl_relaxed(regs + OCP2SCP_TIMING);
78		reg &= ~(SYNC2_MASK);
79		reg |= 0x6;
80		writel_relaxed(reg, regs + OCP2SCP_TIMING);
81		pm_runtime_put_sync(&pdev->dev);
82	}
83
84	return 0;
85
86err0:
87	device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
88
89	return ret;
90}
91
92static int omap_ocp2scp_remove(struct platform_device *pdev)
93{
94	pm_runtime_disable(&pdev->dev);
95	device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
96
97	return 0;
98}
99
100#ifdef CONFIG_OF
101static const struct of_device_id omap_ocp2scp_id_table[] = {
102	{ .compatible = "ti,omap-ocp2scp" },
103	{ .compatible = "ti,am437x-ocp2scp" },
104	{}
105};
106MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);
107#endif
108
109static struct platform_driver omap_ocp2scp_driver = {
110	.probe		= omap_ocp2scp_probe,
111	.remove		= omap_ocp2scp_remove,
112	.driver		= {
113		.name	= "omap-ocp2scp",
114		.of_match_table = of_match_ptr(omap_ocp2scp_id_table),
115	},
116};
117
118module_platform_driver(omap_ocp2scp_driver);
119
120MODULE_ALIAS("platform:omap-ocp2scp");
121MODULE_AUTHOR("Texas Instruments Inc.");
122MODULE_DESCRIPTION("OMAP OCP2SCP driver");
123MODULE_LICENSE("GPL v2");
124