treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / 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
20 static 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
29 static 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
78 err1:
79         pm_runtime_disable(&pdev->dev);
80
81 err0:
82         device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
83
84         return ret;
85 }
86
87 static 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
96 static const struct of_device_id omap_ocp2scp_id_table[] = {
97         { .compatible = "ti,omap-ocp2scp" },
98         { .compatible = "ti,am437x-ocp2scp" },
99         {}
100 };
101 MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);
102 #endif
103
104 static 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
113 module_platform_driver(omap_ocp2scp_driver);
114
115 MODULE_ALIAS("platform:omap-ocp2scp");
116 MODULE_AUTHOR("Texas Instruments Inc.");
117 MODULE_DESCRIPTION("OMAP OCP2SCP driver");
118 MODULE_LICENSE("GPL v2");