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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Xtensa xtfpga SPI controller driver
4 *
5 * Copyright (c) 2014 Cadence Design Systems Inc.
6 */
7
8#include <linux/delay.h>
9#include <linux/io.h>
10#include <linux/module.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/spi/spi.h>
14#include <linux/spi/spi_bitbang.h>
15
16#define XTFPGA_SPI_NAME "xtfpga_spi"
17
18#define XTFPGA_SPI_START 0x0
19#define XTFPGA_SPI_BUSY 0x4
20#define XTFPGA_SPI_DATA 0x8
21
22#define BUSY_WAIT_US 100
23
24struct xtfpga_spi {
25 struct spi_bitbang bitbang;
26 void __iomem *regs;
27 u32 data;
28 unsigned data_sz;
29};
30
31static inline void xtfpga_spi_write32(const struct xtfpga_spi *spi,
32 unsigned addr, u32 val)
33{
34 __raw_writel(val, spi->regs + addr);
35}
36
37static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi,
38 unsigned addr)
39{
40 return __raw_readl(spi->regs + addr);
41}
42
43static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi)
44{
45 unsigned i;
46
47 for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) &&
48 i < BUSY_WAIT_US; ++i)
49 udelay(1);
50 WARN_ON_ONCE(i == BUSY_WAIT_US);
51}
52
53static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
54 u32 v, u8 bits, unsigned flags)
55{
56 struct xtfpga_spi *xspi = spi_controller_get_devdata(spi->controller);
57
58 xspi->data = (xspi->data << bits) | (v & GENMASK(bits - 1, 0));
59 xspi->data_sz += bits;
60 if (xspi->data_sz >= 16) {
61 xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA,
62 xspi->data >> (xspi->data_sz - 16));
63 xspi->data_sz -= 16;
64 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1);
65 xtfpga_spi_wait_busy(xspi);
66 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
67 }
68
69 return 0;
70}
71
72static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on)
73{
74 struct xtfpga_spi *xspi = spi_controller_get_devdata(spi->controller);
75
76 WARN_ON(xspi->data_sz != 0);
77 xspi->data_sz = 0;
78}
79
80static int xtfpga_spi_probe(struct platform_device *pdev)
81{
82 struct xtfpga_spi *xspi;
83 int ret;
84 struct spi_controller *host;
85
86 host = devm_spi_alloc_host(&pdev->dev, sizeof(struct xtfpga_spi));
87 if (!host)
88 return -ENOMEM;
89
90 host->flags = SPI_CONTROLLER_NO_RX;
91 host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
92 host->bus_num = pdev->dev.id;
93 host->dev.of_node = pdev->dev.of_node;
94
95 xspi = spi_controller_get_devdata(host);
96 xspi->bitbang.master = host;
97 xspi->bitbang.chipselect = xtfpga_spi_chipselect;
98 xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word;
99 xspi->regs = devm_platform_ioremap_resource(pdev, 0);
100 if (IS_ERR(xspi->regs))
101 return PTR_ERR(xspi->regs);
102
103 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
104 usleep_range(1000, 2000);
105 if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) {
106 dev_err(&pdev->dev, "Device stuck in busy state\n");
107 return -EBUSY;
108 }
109
110 ret = spi_bitbang_start(&xspi->bitbang);
111 if (ret < 0) {
112 dev_err(&pdev->dev, "spi_bitbang_start failed\n");
113 return ret;
114 }
115
116 platform_set_drvdata(pdev, host);
117 return 0;
118}
119
120static void xtfpga_spi_remove(struct platform_device *pdev)
121{
122 struct spi_controller *host = platform_get_drvdata(pdev);
123 struct xtfpga_spi *xspi = spi_controller_get_devdata(host);
124
125 spi_bitbang_stop(&xspi->bitbang);
126 spi_controller_put(host);
127}
128
129MODULE_ALIAS("platform:" XTFPGA_SPI_NAME);
130
131#ifdef CONFIG_OF
132static const struct of_device_id xtfpga_spi_of_match[] = {
133 { .compatible = "cdns,xtfpga-spi", },
134 {}
135};
136MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match);
137#endif
138
139static struct platform_driver xtfpga_spi_driver = {
140 .probe = xtfpga_spi_probe,
141 .remove_new = xtfpga_spi_remove,
142 .driver = {
143 .name = XTFPGA_SPI_NAME,
144 .of_match_table = of_match_ptr(xtfpga_spi_of_match),
145 },
146};
147module_platform_driver(xtfpga_spi_driver);
148
149MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");
150MODULE_DESCRIPTION("xtensa xtfpga SPI driver");
151MODULE_LICENSE("GPL");
1/*
2 * Xtensa xtfpga SPI controller driver
3 *
4 * Copyright (c) 2014 Cadence Design Systems Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/delay.h>
12#include <linux/io.h>
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/platform_device.h>
16#include <linux/spi/spi.h>
17#include <linux/spi/spi_bitbang.h>
18
19#define XTFPGA_SPI_NAME "xtfpga_spi"
20
21#define XTFPGA_SPI_START 0x0
22#define XTFPGA_SPI_BUSY 0x4
23#define XTFPGA_SPI_DATA 0x8
24
25#define BUSY_WAIT_US 100
26
27struct xtfpga_spi {
28 struct spi_bitbang bitbang;
29 void __iomem *regs;
30 u32 data;
31 unsigned data_sz;
32};
33
34static inline void xtfpga_spi_write32(const struct xtfpga_spi *spi,
35 unsigned addr, u32 val)
36{
37 iowrite32(val, spi->regs + addr);
38}
39
40static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi,
41 unsigned addr)
42{
43 return ioread32(spi->regs + addr);
44}
45
46static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi)
47{
48 unsigned i;
49 for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) &&
50 i < BUSY_WAIT_US; ++i)
51 udelay(1);
52 WARN_ON_ONCE(i == BUSY_WAIT_US);
53}
54
55static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
56 u32 v, u8 bits)
57{
58 struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);
59
60 xspi->data = (xspi->data << bits) | (v & GENMASK(bits - 1, 0));
61 xspi->data_sz += bits;
62 if (xspi->data_sz >= 16) {
63 xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA,
64 xspi->data >> (xspi->data_sz - 16));
65 xspi->data_sz -= 16;
66 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1);
67 xtfpga_spi_wait_busy(xspi);
68 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
69 }
70
71 return 0;
72}
73
74static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on)
75{
76 struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);
77
78 WARN_ON(xspi->data_sz != 0);
79 xspi->data_sz = 0;
80}
81
82static int xtfpga_spi_probe(struct platform_device *pdev)
83{
84 struct xtfpga_spi *xspi;
85 struct resource *mem;
86 int ret;
87 struct spi_master *master;
88
89 master = spi_alloc_master(&pdev->dev, sizeof(struct xtfpga_spi));
90 if (!master)
91 return -ENOMEM;
92
93 master->flags = SPI_MASTER_NO_RX;
94 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
95 master->bus_num = pdev->dev.id;
96 master->dev.of_node = pdev->dev.of_node;
97
98 xspi = spi_master_get_devdata(master);
99 xspi->bitbang.master = master;
100 xspi->bitbang.chipselect = xtfpga_spi_chipselect;
101 xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word;
102
103 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
104 if (!mem) {
105 dev_err(&pdev->dev, "No memory resource\n");
106 ret = -ENODEV;
107 goto err;
108 }
109 xspi->regs = devm_ioremap_resource(&pdev->dev, mem);
110 if (IS_ERR(xspi->regs)) {
111 ret = PTR_ERR(xspi->regs);
112 goto err;
113 }
114
115 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
116 usleep_range(1000, 2000);
117 if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) {
118 dev_err(&pdev->dev, "Device stuck in busy state\n");
119 ret = -EBUSY;
120 goto err;
121 }
122
123 ret = spi_bitbang_start(&xspi->bitbang);
124 if (ret < 0) {
125 dev_err(&pdev->dev, "spi_bitbang_start failed\n");
126 goto err;
127 }
128
129 platform_set_drvdata(pdev, master);
130 return 0;
131err:
132 spi_master_put(master);
133 return ret;
134}
135
136static int xtfpga_spi_remove(struct platform_device *pdev)
137{
138 struct spi_master *master = platform_get_drvdata(pdev);
139 struct xtfpga_spi *xspi = spi_master_get_devdata(master);
140
141 spi_bitbang_stop(&xspi->bitbang);
142 spi_master_put(master);
143
144 return 0;
145}
146
147MODULE_ALIAS("platform:" XTFPGA_SPI_NAME);
148
149#ifdef CONFIG_OF
150static const struct of_device_id xtfpga_spi_of_match[] = {
151 { .compatible = "cdns,xtfpga-spi", },
152 {}
153};
154MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match);
155#endif
156
157static struct platform_driver xtfpga_spi_driver = {
158 .probe = xtfpga_spi_probe,
159 .remove = xtfpga_spi_remove,
160 .driver = {
161 .name = XTFPGA_SPI_NAME,
162 .owner = THIS_MODULE,
163 .of_match_table = of_match_ptr(xtfpga_spi_of_match),
164 },
165};
166module_platform_driver(xtfpga_spi_driver);
167
168MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");
169MODULE_DESCRIPTION("xtensa xtfpga SPI driver");
170MODULE_LICENSE("GPL");