summaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi-dw-mmio.c
blob: e80f60ed6fdf73d4cac750898eec8ef605d30694 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
/*
 * Memory-mapped interface driver for DW SPI Core
 *
 * Copyright (c) 2010, Octasic semiconductor.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/scatterlist.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/of_platform.h>
#include <linux/property.h>
#include <linux/regmap.h>

#include "spi-dw.h"

#define DRIVER_NAME "dw_spi_mmio"

struct dw_spi_mmio {
	struct dw_spi  dws;
	struct clk     *clk;
	void           *priv;
};

#define MSCC_CPU_SYSTEM_CTRL_GENERAL_CTRL	0x24
#define OCELOT_IF_SI_OWNER_MASK			GENMASK(5, 4)
#define OCELOT_IF_SI_OWNER_OFFSET		4
#define MSCC_IF_SI_OWNER_SISL			0
#define MSCC_IF_SI_OWNER_SIBM			1
#define MSCC_IF_SI_OWNER_SIMC			2

#define MSCC_SPI_MST_SW_MODE			0x14
#define MSCC_SPI_MST_SW_MODE_SW_PIN_CTRL_MODE	BIT(13)
#define MSCC_SPI_MST_SW_MODE_SW_SPI_CS(x)	(x << 5)

struct dw_spi_mscc {
	struct regmap       *syscon;
	void __iomem        *spi_mst;
};

/*
 * The Designware SPI controller (referred to as master in the documentation)
 * automatically deasserts chip select when the tx fifo is empty. The chip
 * selects then needs to be either driven as GPIOs or, for the first 4 using the
 * the SPI boot controller registers. the final chip select is an OR gate
 * between the Designware SPI controller and the SPI boot controller.
 */
static void dw_spi_mscc_set_cs(struct spi_device *spi, bool enable)
{
	struct dw_spi *dws = spi_master_get_devdata(spi->master);
	struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
	struct dw_spi_mscc *dwsmscc = dwsmmio->priv;
	u32 cs = spi->chip_select;

	if (cs < 4) {
		u32 sw_mode = MSCC_SPI_MST_SW_MODE_SW_PIN_CTRL_MODE;

		if (!enable)
			sw_mode |= MSCC_SPI_MST_SW_MODE_SW_SPI_CS(BIT(cs));

		writel(sw_mode, dwsmscc->spi_mst + MSCC_SPI_MST_SW_MODE);
	}

	dw_spi_set_cs(spi, enable);
}

static int dw_spi_mscc_init(struct platform_device *pdev,
			    struct dw_spi_mmio *dwsmmio)
{
	struct dw_spi_mscc *dwsmscc;
	struct resource *res;

	dwsmscc = devm_kzalloc(&pdev->dev, sizeof(*dwsmscc), GFP_KERNEL);
	if (!dwsmscc)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	dwsmscc->spi_mst = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(dwsmscc->spi_mst)) {
		dev_err(&pdev->dev, "SPI_MST region map failed\n");
		return PTR_ERR(dwsmscc->spi_mst);
	}

	dwsmscc->syscon = syscon_regmap_lookup_by_compatible("mscc,ocelot-cpu-syscon");
	if (IS_ERR(dwsmscc->syscon))
		return PTR_ERR(dwsmscc->syscon);

	/* Deassert all CS */
	writel(0, dwsmscc->spi_mst + MSCC_SPI_MST_SW_MODE);

	/* Select the owner of the SI interface */
	regmap_update_bits(dwsmscc->syscon, MSCC_CPU_SYSTEM_CTRL_GENERAL_CTRL,
			   OCELOT_IF_SI_OWNER_MASK,
			   MSCC_IF_SI_OWNER_SIMC << OCELOT_IF_SI_OWNER_OFFSET);

	dwsmmio->dws.set_cs = dw_spi_mscc_set_cs;
	dwsmmio->priv = dwsmscc;

	return 0;
}

static int dw_spi_mmio_probe(struct platform_device *pdev)
{
	int (*init_func)(struct platform_device *pdev,
			 struct dw_spi_mmio *dwsmmio);
	struct dw_spi_mmio *dwsmmio;
	struct dw_spi *dws;
	struct resource *mem;
	int ret;
	int num_cs;

	dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
			GFP_KERNEL);
	if (!dwsmmio)
		return -ENOMEM;

	dws = &dwsmmio->dws;

	/* Get basic io resource and map it */
	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	dws->regs = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(dws->regs)) {
		dev_err(&pdev->dev, "SPI region map failed\n");
		return PTR_ERR(dws->regs);
	}

	dws->irq = platform_get_irq(pdev, 0);
	if (dws->irq < 0) {
		dev_err(&pdev->dev, "no irq resource?\n");
		return dws->irq; /* -ENXIO */
	}

	dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(dwsmmio->clk))
		return PTR_ERR(dwsmmio->clk);
	ret = clk_prepare_enable(dwsmmio->clk);
	if (ret)
		return ret;

	dws->bus_num = pdev->id;

	dws->max_freq = clk_get_rate(dwsmmio->clk);

	device_property_read_u32(&pdev->dev, "reg-io-width", &dws->reg_io_width);

	num_cs = 4;

	device_property_read_u32(&pdev->dev, "num-cs", &num_cs);

	dws->num_cs = num_cs;

	if (pdev->dev.of_node) {
		int i;

		for (i = 0; i < dws->num_cs; i++) {
			int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
					"cs-gpios", i);

			if (cs_gpio == -EPROBE_DEFER) {
				ret = cs_gpio;
				goto out;
			}

			if (gpio_is_valid(cs_gpio)) {
				ret = devm_gpio_request(&pdev->dev, cs_gpio,
						dev_name(&pdev->dev));
				if (ret)
					goto out;
			}
		}
	}

	init_func = device_get_match_data(&pdev->dev);
	if (init_func) {
		ret = init_func(pdev, dwsmmio);
		if (ret)
			goto out;
	}

	ret = dw_spi_add_host(&pdev->dev, dws);
	if (ret)
		goto out;

	platform_set_drvdata(pdev, dwsmmio);
	return 0;

out:
	clk_disable_unprepare(dwsmmio->clk);
	return ret;
}

static int dw_spi_mmio_remove(struct platform_device *pdev)
{
	struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);

	dw_spi_remove_host(&dwsmmio->dws);
	clk_disable_unprepare(dwsmmio->clk);

	return 0;
}

static const struct of_device_id dw_spi_mmio_of_match[] = {
	{ .compatible = "snps,dw-apb-ssi", },
	{ .compatible = "mscc,ocelot-spi", .data = dw_spi_mscc_init},
	{ /* end of table */}
};
MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);

static struct platform_driver dw_spi_mmio_driver = {
	.probe		= dw_spi_mmio_probe,
	.remove		= dw_spi_mmio_remove,
	.driver		= {
		.name	= DRIVER_NAME,
		.of_match_table = dw_spi_mmio_of_match,
	},
};
module_platform_driver(dw_spi_mmio_driver);

MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
MODULE_LICENSE("GPL v2");