Loading...
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 __raw_writel(val, spi->regs + addr);
38}
39
40static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi,
41 unsigned addr)
42{
43 return __raw_readl(spi->regs + addr);
44}
45
46static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi)
47{
48 unsigned i;
49
50 for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) &&
51 i < BUSY_WAIT_US; ++i)
52 udelay(1);
53 WARN_ON_ONCE(i == BUSY_WAIT_US);
54}
55
56static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
57 u32 v, u8 bits)
58{
59 struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);
60
61 xspi->data = (xspi->data << bits) | (v & GENMASK(bits - 1, 0));
62 xspi->data_sz += bits;
63 if (xspi->data_sz >= 16) {
64 xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA,
65 xspi->data >> (xspi->data_sz - 16));
66 xspi->data_sz -= 16;
67 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1);
68 xtfpga_spi_wait_busy(xspi);
69 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
70 }
71
72 return 0;
73}
74
75static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on)
76{
77 struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);
78
79 WARN_ON(xspi->data_sz != 0);
80 xspi->data_sz = 0;
81}
82
83static int xtfpga_spi_probe(struct platform_device *pdev)
84{
85 struct xtfpga_spi *xspi;
86 struct resource *mem;
87 int ret;
88 struct spi_master *master;
89
90 master = spi_alloc_master(&pdev->dev, sizeof(struct xtfpga_spi));
91 if (!master)
92 return -ENOMEM;
93
94 master->flags = SPI_MASTER_NO_RX;
95 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
96 master->bus_num = pdev->dev.id;
97 master->dev.of_node = pdev->dev.of_node;
98
99 xspi = spi_master_get_devdata(master);
100 xspi->bitbang.master = master;
101 xspi->bitbang.chipselect = xtfpga_spi_chipselect;
102 xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word;
103
104 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
105 if (!mem) {
106 dev_err(&pdev->dev, "No memory resource\n");
107 ret = -ENODEV;
108 goto err;
109 }
110 xspi->regs = devm_ioremap_resource(&pdev->dev, mem);
111 if (IS_ERR(xspi->regs)) {
112 ret = PTR_ERR(xspi->regs);
113 goto err;
114 }
115
116 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
117 usleep_range(1000, 2000);
118 if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) {
119 dev_err(&pdev->dev, "Device stuck in busy state\n");
120 ret = -EBUSY;
121 goto err;
122 }
123
124 ret = spi_bitbang_start(&xspi->bitbang);
125 if (ret < 0) {
126 dev_err(&pdev->dev, "spi_bitbang_start failed\n");
127 goto err;
128 }
129
130 platform_set_drvdata(pdev, master);
131 return 0;
132err:
133 spi_master_put(master);
134 return ret;
135}
136
137static int xtfpga_spi_remove(struct platform_device *pdev)
138{
139 struct spi_master *master = platform_get_drvdata(pdev);
140 struct xtfpga_spi *xspi = spi_master_get_devdata(master);
141
142 spi_bitbang_stop(&xspi->bitbang);
143 spi_master_put(master);
144
145 return 0;
146}
147
148MODULE_ALIAS("platform:" XTFPGA_SPI_NAME);
149
150#ifdef CONFIG_OF
151static const struct of_device_id xtfpga_spi_of_match[] = {
152 { .compatible = "cdns,xtfpga-spi", },
153 {}
154};
155MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match);
156#endif
157
158static struct platform_driver xtfpga_spi_driver = {
159 .probe = xtfpga_spi_probe,
160 .remove = xtfpga_spi_remove,
161 .driver = {
162 .name = XTFPGA_SPI_NAME,
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");