1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * i.MX IIM driver
4  *
5  * Copyright (c) 2017 Pengutronix, Michael Grzeschik <m.grzeschik@pengutronix.de>
6  *
7  * Based on the barebox iim driver,
8  * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
9  *	Orex Computed Radiography
10  */
11 
12 #include <linux/device.h>
13 #include <linux/io.h>
14 #include <linux/module.h>
15 #include <linux/nvmem-provider.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/clk.h>
21 
22 #define IIM_BANK_BASE(n)	(0x800 + 0x400 * (n))
23 
24 struct imx_iim_drvdata {
25 	unsigned int nregs;
26 };
27 
28 struct iim_priv {
29 	void __iomem *base;
30 	struct clk *clk;
31 };
32 
imx_iim_read(void * context,unsigned int offset,void * buf,size_t bytes)33 static int imx_iim_read(void *context, unsigned int offset,
34 			  void *buf, size_t bytes)
35 {
36 	struct iim_priv *iim = context;
37 	int i, ret;
38 	u8 *buf8 = buf;
39 
40 	ret = clk_prepare_enable(iim->clk);
41 	if (ret)
42 		return ret;
43 
44 	for (i = offset; i < offset + bytes; i++) {
45 		int bank = i >> 5;
46 		int reg = i & 0x1f;
47 
48 		*buf8++ = readl(iim->base + IIM_BANK_BASE(bank) + reg * 4);
49 	}
50 
51 	clk_disable_unprepare(iim->clk);
52 
53 	return 0;
54 }
55 
56 static struct imx_iim_drvdata imx27_drvdata = {
57 	.nregs = 2 * 32,
58 };
59 
60 static struct imx_iim_drvdata imx25_imx31_imx35_drvdata = {
61 	.nregs = 3 * 32,
62 };
63 
64 static struct imx_iim_drvdata imx51_drvdata = {
65 	.nregs = 4 * 32,
66 };
67 
68 static struct imx_iim_drvdata imx53_drvdata = {
69 	.nregs = 4 * 32 + 16,
70 };
71 
72 static const struct of_device_id imx_iim_dt_ids[] = {
73 	{
74 		.compatible = "fsl,imx25-iim",
75 		.data = &imx25_imx31_imx35_drvdata,
76 	}, {
77 		.compatible = "fsl,imx27-iim",
78 		.data = &imx27_drvdata,
79 	}, {
80 		.compatible = "fsl,imx31-iim",
81 		.data = &imx25_imx31_imx35_drvdata,
82 	}, {
83 		.compatible = "fsl,imx35-iim",
84 		.data = &imx25_imx31_imx35_drvdata,
85 	}, {
86 		.compatible = "fsl,imx51-iim",
87 		.data = &imx51_drvdata,
88 	}, {
89 		.compatible = "fsl,imx53-iim",
90 		.data = &imx53_drvdata,
91 	}, {
92 		/* sentinel */
93 	},
94 };
95 MODULE_DEVICE_TABLE(of, imx_iim_dt_ids);
96 
imx_iim_probe(struct platform_device * pdev)97 static int imx_iim_probe(struct platform_device *pdev)
98 {
99 	struct device *dev = &pdev->dev;
100 	struct iim_priv *iim;
101 	struct nvmem_device *nvmem;
102 	struct nvmem_config cfg = {};
103 	const struct imx_iim_drvdata *drvdata = NULL;
104 
105 	iim = devm_kzalloc(dev, sizeof(*iim), GFP_KERNEL);
106 	if (!iim)
107 		return -ENOMEM;
108 
109 	iim->base = devm_platform_ioremap_resource(pdev, 0);
110 	if (IS_ERR(iim->base))
111 		return PTR_ERR(iim->base);
112 
113 	drvdata = of_device_get_match_data(&pdev->dev);
114 
115 	iim->clk = devm_clk_get(dev, NULL);
116 	if (IS_ERR(iim->clk))
117 		return PTR_ERR(iim->clk);
118 
119 	cfg.name = "imx-iim",
120 	cfg.read_only = true,
121 	cfg.word_size = 1,
122 	cfg.stride = 1,
123 	cfg.reg_read = imx_iim_read,
124 	cfg.dev = dev;
125 	cfg.size = drvdata->nregs;
126 	cfg.priv = iim;
127 
128 	nvmem = devm_nvmem_register(dev, &cfg);
129 
130 	return PTR_ERR_OR_ZERO(nvmem);
131 }
132 
133 static struct platform_driver imx_iim_driver = {
134 	.probe	= imx_iim_probe,
135 	.driver = {
136 		.name	= "imx-iim",
137 		.of_match_table = imx_iim_dt_ids,
138 	},
139 };
140 module_platform_driver(imx_iim_driver);
141 
142 MODULE_AUTHOR("Michael Grzeschik <m.grzeschik@pengutronix.de>");
143 MODULE_DESCRIPTION("i.MX IIM driver");
144 MODULE_LICENSE("GPL v2");
145