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(root: np, NULL, NULL, parent: &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(dev: &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(device: np, "ti,am437x-ocp2scp")) {
61 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
62 regs = devm_ioremap_resource(dev: &pdev->dev, res);
63 if (IS_ERR(ptr: regs)) {
64 ret = PTR_ERR(ptr: regs);
65 goto err1;
66 }
67
68 pm_runtime_get_sync(dev: &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(dev: &pdev->dev);
74 }
75
76 return 0;
77
78err1:
79 pm_runtime_disable(dev: &pdev->dev);
80
81err0:
82 device_for_each_child(dev: &pdev->dev, NULL, fn: ocp2scp_remove_devices);
83
84 return ret;
85}
86
87static int omap_ocp2scp_remove(struct platform_device *pdev)
88{
89 pm_runtime_disable(dev: &pdev->dev);
90 device_for_each_child(dev: &pdev->dev, NULL, fn: 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

source code of linux/drivers/bus/omap-ocp2scp.c