1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Altera SPI driver
4  *
5  * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
6  *
7  * Based on spi_s3c24xx.c, which is:
8  * Copyright (c) 2006 Ben Dooks
9  * Copyright (c) 2006 Simtec Electronics
10  *	Ben Dooks <ben@simtec.co.uk>
11  */
12 
13 #include <linux/interrupt.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 #include <linux/spi/altera.h>
18 #include <linux/spi/spi.h>
19 #include <linux/io.h>
20 #include <linux/of.h>
21 
22 #define DRV_NAME "spi_altera"
23 
24 enum altera_spi_type {
25 	ALTERA_SPI_TYPE_UNKNOWN,
26 	ALTERA_SPI_TYPE_SUBDEV,
27 };
28 
29 static const struct regmap_config spi_altera_config = {
30 	.reg_bits = 32,
31 	.reg_stride = 4,
32 	.val_bits = 32,
33 	.fast_io = true,
34 };
35 
36 static int altera_spi_probe(struct platform_device *pdev)
37 {
38 	const struct platform_device_id *platid = platform_get_device_id(pdev);
39 	struct altera_spi_platform_data *pdata = dev_get_platdata(&pdev->dev);
40 	enum altera_spi_type type = ALTERA_SPI_TYPE_UNKNOWN;
41 	struct altera_spi *hw;
42 	struct spi_controller *host;
43 	int err = -ENODEV;
44 	u16 i;
45 
46 	host = spi_alloc_host(&pdev->dev, sizeof(struct altera_spi));
47 	if (!host)
48 		return err;
49 
50 	/* setup the host state. */
51 	host->bus_num = -1;
52 
53 	if (pdata) {
54 		if (pdata->num_chipselect > ALTERA_SPI_MAX_CS) {
55 			dev_err(&pdev->dev,
56 				"Invalid number of chipselect: %u\n",
57 				pdata->num_chipselect);
58 			err = -EINVAL;
59 			goto exit;
60 		}
61 
62 		host->num_chipselect = pdata->num_chipselect;
63 		host->mode_bits = pdata->mode_bits;
64 		host->bits_per_word_mask = pdata->bits_per_word_mask;
65 	} else {
66 		host->num_chipselect = 16;
67 		host->mode_bits = SPI_CS_HIGH;
68 		host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
69 	}
70 
71 	host->dev.of_node = pdev->dev.of_node;
72 
73 	hw = spi_controller_get_devdata(host);
74 	hw->dev = &pdev->dev;
75 
76 	if (platid)
77 		type = platid->driver_data;
78 
79 	/* find and map our resources */
80 	if (type == ALTERA_SPI_TYPE_SUBDEV) {
81 		struct resource *regoff;
82 
83 		hw->regmap = dev_get_regmap(pdev->dev.parent, NULL);
84 		if (!hw->regmap) {
85 			dev_err(&pdev->dev, "get regmap failed\n");
86 			goto exit;
87 		}
88 
89 		regoff = platform_get_resource(pdev, IORESOURCE_REG, 0);
90 		if (regoff)
91 			hw->regoff = regoff->start;
92 	} else {
93 		void __iomem *res;
94 
95 		res = devm_platform_ioremap_resource(pdev, 0);
96 		if (IS_ERR(res)) {
97 			err = PTR_ERR(res);
98 			goto exit;
99 		}
100 
101 		hw->regmap = devm_regmap_init_mmio(&pdev->dev, res,
102 						   &spi_altera_config);
103 		if (IS_ERR(hw->regmap)) {
104 			dev_err(&pdev->dev, "regmap mmio init failed\n");
105 			err = PTR_ERR(hw->regmap);
106 			goto exit;
107 		}
108 	}
109 
110 	altera_spi_init_host(host);
111 
112 	/* irq is optional */
113 	hw->irq = platform_get_irq(pdev, 0);
114 	if (hw->irq >= 0) {
115 		err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
116 				       pdev->name, host);
117 		if (err)
118 			goto exit;
119 	}
120 
121 	err = devm_spi_register_controller(&pdev->dev, host);
122 	if (err)
123 		goto exit;
124 
125 	if (pdata) {
126 		for (i = 0; i < pdata->num_devices; i++) {
127 			if (!spi_new_device(host, pdata->devices + i))
128 				dev_warn(&pdev->dev,
129 					 "unable to create SPI device: %s\n",
130 					 pdata->devices[i].modalias);
131 		}
132 	}
133 
134 	dev_info(&pdev->dev, "regoff %u, irq %d\n", hw->regoff, hw->irq);
135 
136 	return 0;
137 exit:
138 	spi_controller_put(host);
139 	return err;
140 }
141 
142 #ifdef CONFIG_OF
143 static const struct of_device_id altera_spi_match[] = {
144 	{ .compatible = "ALTR,spi-1.0", },
145 	{ .compatible = "altr,spi-1.0", },
146 	{},
147 };
148 MODULE_DEVICE_TABLE(of, altera_spi_match);
149 #endif /* CONFIG_OF */
150 
151 static const struct platform_device_id altera_spi_ids[] = {
152 	{ DRV_NAME,		ALTERA_SPI_TYPE_UNKNOWN },
153 	{ "subdev_spi_altera",	ALTERA_SPI_TYPE_SUBDEV },
154 	{ }
155 };
156 MODULE_DEVICE_TABLE(platform, altera_spi_ids);
157 
158 static struct platform_driver altera_spi_driver = {
159 	.probe = altera_spi_probe,
160 	.driver = {
161 		.name = DRV_NAME,
162 		.pm = NULL,
163 		.of_match_table = of_match_ptr(altera_spi_match),
164 	},
165 	.id_table	= altera_spi_ids,
166 };
167 module_platform_driver(altera_spi_driver);
168 
169 MODULE_DESCRIPTION("Altera SPI driver");
170 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
171 MODULE_LICENSE("GPL");
172 MODULE_ALIAS("platform:" DRV_NAME);
173