xref: /openbmc/linux/drivers/memory/pl353-smc.c (revision 2010776f)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * ARM PL353 SMC driver
4  *
5  * Copyright (C) 2012 - 2018 Xilinx, Inc
6  * Author: Punnaiah Choudary Kalluri <punnaiah@xilinx.com>
7  * Author: Naga Sureshkumar Relli <nagasure@xilinx.com>
8  */
9 
10 #include <linux/clk.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/of_platform.h>
14 #include <linux/platform_device.h>
15 #include <linux/amba/bus.h>
16 
17 /**
18  * struct pl353_smc_data - Private smc driver structure
19  * @memclk:		Pointer to the peripheral clock
20  * @aclk:		Pointer to the AXI peripheral clock
21  */
22 struct pl353_smc_data {
23 	struct clk		*memclk;
24 	struct clk		*aclk;
25 };
26 
27 static int __maybe_unused pl353_smc_suspend(struct device *dev)
28 {
29 	struct pl353_smc_data *pl353_smc = dev_get_drvdata(dev);
30 
31 	clk_disable(pl353_smc->memclk);
32 	clk_disable(pl353_smc->aclk);
33 
34 	return 0;
35 }
36 
37 static int __maybe_unused pl353_smc_resume(struct device *dev)
38 {
39 	struct pl353_smc_data *pl353_smc = dev_get_drvdata(dev);
40 	int ret;
41 
42 	ret = clk_enable(pl353_smc->aclk);
43 	if (ret) {
44 		dev_err(dev, "Cannot enable axi domain clock.\n");
45 		return ret;
46 	}
47 
48 	ret = clk_enable(pl353_smc->memclk);
49 	if (ret) {
50 		dev_err(dev, "Cannot enable memory clock.\n");
51 		clk_disable(pl353_smc->aclk);
52 		return ret;
53 	}
54 
55 	return ret;
56 }
57 
58 static SIMPLE_DEV_PM_OPS(pl353_smc_dev_pm_ops, pl353_smc_suspend,
59 			 pl353_smc_resume);
60 
61 static const struct of_device_id pl353_smc_supported_children[] = {
62 	{
63 		.compatible = "cfi-flash"
64 	},
65 	{
66 		.compatible = "arm,pl353-nand-r2p1",
67 	},
68 	{}
69 };
70 
71 static int pl353_smc_probe(struct amba_device *adev, const struct amba_id *id)
72 {
73 	struct device_node *of_node = adev->dev.of_node;
74 	const struct of_device_id *match = NULL;
75 	struct pl353_smc_data *pl353_smc;
76 	struct device_node *child;
77 	int err;
78 
79 	pl353_smc = devm_kzalloc(&adev->dev, sizeof(*pl353_smc), GFP_KERNEL);
80 	if (!pl353_smc)
81 		return -ENOMEM;
82 
83 	pl353_smc->aclk = devm_clk_get(&adev->dev, "apb_pclk");
84 	if (IS_ERR(pl353_smc->aclk)) {
85 		dev_err(&adev->dev, "aclk clock not found.\n");
86 		return PTR_ERR(pl353_smc->aclk);
87 	}
88 
89 	pl353_smc->memclk = devm_clk_get(&adev->dev, "memclk");
90 	if (IS_ERR(pl353_smc->memclk)) {
91 		dev_err(&adev->dev, "memclk clock not found.\n");
92 		return PTR_ERR(pl353_smc->memclk);
93 	}
94 
95 	err = clk_prepare_enable(pl353_smc->aclk);
96 	if (err) {
97 		dev_err(&adev->dev, "Unable to enable AXI clock.\n");
98 		return err;
99 	}
100 
101 	err = clk_prepare_enable(pl353_smc->memclk);
102 	if (err) {
103 		dev_err(&adev->dev, "Unable to enable memory clock.\n");
104 		goto disable_axi_clk;
105 	}
106 
107 	amba_set_drvdata(adev, pl353_smc);
108 
109 	/* Find compatible children. Only a single child is supported */
110 	for_each_available_child_of_node(of_node, child) {
111 		match = of_match_node(pl353_smc_supported_children, child);
112 		if (!match) {
113 			dev_warn(&adev->dev, "unsupported child node\n");
114 			continue;
115 		}
116 		break;
117 	}
118 	if (!match) {
119 		err = -ENODEV;
120 		dev_err(&adev->dev, "no matching children\n");
121 		goto disable_mem_clk;
122 	}
123 
124 	of_platform_device_create(child, NULL, &adev->dev);
125 
126 	return 0;
127 
128 disable_mem_clk:
129 	clk_disable_unprepare(pl353_smc->memclk);
130 disable_axi_clk:
131 	clk_disable_unprepare(pl353_smc->aclk);
132 
133 	return err;
134 }
135 
136 static void pl353_smc_remove(struct amba_device *adev)
137 {
138 	struct pl353_smc_data *pl353_smc = amba_get_drvdata(adev);
139 
140 	clk_disable_unprepare(pl353_smc->memclk);
141 	clk_disable_unprepare(pl353_smc->aclk);
142 }
143 
144 static const struct amba_id pl353_ids[] = {
145 	{
146 		.id = 0x00041353,
147 		.mask = 0x000fffff,
148 	},
149 	{ 0, 0 },
150 };
151 MODULE_DEVICE_TABLE(amba, pl353_ids);
152 
153 static struct amba_driver pl353_smc_driver = {
154 	.drv = {
155 		.owner = THIS_MODULE,
156 		.name = "pl353-smc",
157 		.pm = &pl353_smc_dev_pm_ops,
158 	},
159 	.id_table = pl353_ids,
160 	.probe = pl353_smc_probe,
161 	.remove = pl353_smc_remove,
162 };
163 
164 module_amba_driver(pl353_smc_driver);
165 
166 MODULE_AUTHOR("Xilinx, Inc.");
167 MODULE_DESCRIPTION("ARM PL353 SMC Driver");
168 MODULE_LICENSE("GPL");
169