1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * SH SCI SPI interface
4 *
5 * Copyright (c) 2008 Magnus Damm
6 *
7 * Based on S3C24XX GPIO based SPI driver, which is:
8 * Copyright (c) 2006 Ben Dooks
9 * Copyright (c) 2006 Simtec Electronics
10 */
11
12#include <linux/kernel.h>
13#include <linux/delay.h>
14#include <linux/spinlock.h>
15#include <linux/platform_device.h>
16
17#include <linux/spi/spi.h>
18#include <linux/spi/spi_bitbang.h>
19#include <linux/module.h>
20
21#include <asm/spi.h>
22#include <asm/io.h>
23
24struct sh_sci_spi {
25 struct spi_bitbang bitbang;
26
27 void __iomem *membase;
28 unsigned char val;
29 struct sh_spi_info *info;
30 struct platform_device *dev;
31};
32
33#define SCSPTR(sp) (sp->membase + 0x1c)
34#define PIN_SCK (1 << 2)
35#define PIN_TXD (1 << 0)
36#define PIN_RXD PIN_TXD
37#define PIN_INIT ((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD)
38
39static inline void setbits(struct sh_sci_spi *sp, int bits, int on)
40{
41 /*
42 * We are the only user of SCSPTR so no locking is required.
43 * Reading bit 2 and 0 in SCSPTR gives pin state as input.
44 * Writing the same bits sets the output value.
45 * This makes regular read-modify-write difficult so we
46 * use sp->val to keep track of the latest register value.
47 */
48
49 if (on)
50 sp->val |= bits;
51 else
52 sp->val &= ~bits;
53
54 iowrite8(sp->val, SCSPTR(sp));
55}
56
57static inline void setsck(struct spi_device *dev, int on)
58{
59 setbits(sp: spi_controller_get_devdata(ctlr: dev->controller), PIN_SCK, on);
60}
61
62static inline void setmosi(struct spi_device *dev, int on)
63{
64 setbits(sp: spi_controller_get_devdata(ctlr: dev->controller), PIN_TXD, on);
65}
66
67static inline u32 getmiso(struct spi_device *dev)
68{
69 struct sh_sci_spi *sp = spi_controller_get_devdata(ctlr: dev->controller);
70
71 return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0;
72}
73
74#define spidelay(x) ndelay(x)
75
76#include "spi-bitbang-txrx.h"
77
78static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi,
79 unsigned nsecs, u32 word, u8 bits,
80 unsigned flags)
81{
82 return bitbang_txrx_be_cpha0(spi, nsecs, cpol: 0, flags, word, bits);
83}
84
85static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi,
86 unsigned nsecs, u32 word, u8 bits,
87 unsigned flags)
88{
89 return bitbang_txrx_be_cpha1(spi, nsecs, cpol: 0, flags, word, bits);
90}
91
92static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi,
93 unsigned nsecs, u32 word, u8 bits,
94 unsigned flags)
95{
96 return bitbang_txrx_be_cpha0(spi, nsecs, cpol: 1, flags, word, bits);
97}
98
99static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi,
100 unsigned nsecs, u32 word, u8 bits,
101 unsigned flags)
102{
103 return bitbang_txrx_be_cpha1(spi, nsecs, cpol: 1, flags, word, bits);
104}
105
106static void sh_sci_spi_chipselect(struct spi_device *dev, int value)
107{
108 struct sh_sci_spi *sp = spi_controller_get_devdata(ctlr: dev->controller);
109
110 if (sp->info->chip_select)
111 (sp->info->chip_select)(sp->info, spi_get_chipselect(spi: dev, idx: 0), value);
112}
113
114static int sh_sci_spi_probe(struct platform_device *dev)
115{
116 struct resource *r;
117 struct spi_controller *host;
118 struct sh_sci_spi *sp;
119 int ret;
120
121 host = spi_alloc_host(dev: &dev->dev, size: sizeof(struct sh_sci_spi));
122 if (host == NULL) {
123 dev_err(&dev->dev, "failed to allocate spi host\n");
124 ret = -ENOMEM;
125 goto err0;
126 }
127
128 sp = spi_controller_get_devdata(ctlr: host);
129
130 platform_set_drvdata(pdev: dev, data: sp);
131 sp->info = dev_get_platdata(dev: &dev->dev);
132 if (!sp->info) {
133 dev_err(&dev->dev, "platform data is missing\n");
134 ret = -ENOENT;
135 goto err1;
136 }
137
138 /* setup spi bitbang adaptor */
139 sp->bitbang.ctlr = host;
140 sp->bitbang.ctlr->bus_num = sp->info->bus_num;
141 sp->bitbang.ctlr->num_chipselect = sp->info->num_chipselect;
142 sp->bitbang.chipselect = sh_sci_spi_chipselect;
143
144 sp->bitbang.txrx_word[SPI_MODE_0] = sh_sci_spi_txrx_mode0;
145 sp->bitbang.txrx_word[SPI_MODE_1] = sh_sci_spi_txrx_mode1;
146 sp->bitbang.txrx_word[SPI_MODE_2] = sh_sci_spi_txrx_mode2;
147 sp->bitbang.txrx_word[SPI_MODE_3] = sh_sci_spi_txrx_mode3;
148
149 r = platform_get_resource(dev, IORESOURCE_MEM, 0);
150 if (r == NULL) {
151 ret = -ENOENT;
152 goto err1;
153 }
154 sp->membase = ioremap(offset: r->start, size: resource_size(res: r));
155 if (!sp->membase) {
156 ret = -ENXIO;
157 goto err1;
158 }
159 sp->val = ioread8(SCSPTR(sp));
160 setbits(sp, PIN_INIT, on: 1);
161
162 ret = spi_bitbang_start(spi: &sp->bitbang);
163 if (!ret)
164 return 0;
165
166 setbits(sp, PIN_INIT, on: 0);
167 iounmap(addr: sp->membase);
168 err1:
169 spi_controller_put(ctlr: sp->bitbang.ctlr);
170 err0:
171 return ret;
172}
173
174static void sh_sci_spi_remove(struct platform_device *dev)
175{
176 struct sh_sci_spi *sp = platform_get_drvdata(pdev: dev);
177
178 spi_bitbang_stop(spi: &sp->bitbang);
179 setbits(sp, PIN_INIT, on: 0);
180 iounmap(addr: sp->membase);
181 spi_controller_put(ctlr: sp->bitbang.ctlr);
182}
183
184static struct platform_driver sh_sci_spi_drv = {
185 .probe = sh_sci_spi_probe,
186 .remove_new = sh_sci_spi_remove,
187 .driver = {
188 .name = "spi_sh_sci",
189 },
190};
191module_platform_driver(sh_sci_spi_drv);
192
193MODULE_DESCRIPTION("SH SCI SPI Driver");
194MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
195MODULE_LICENSE("GPL");
196MODULE_ALIAS("platform:spi_sh_sci");
197

source code of linux/drivers/spi/spi-sh-sci.c