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 | |
24 | struct 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 | |
39 | static 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 | |
57 | static 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 | |
62 | static 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 | |
67 | static 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 | |
78 | static 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 | |
85 | static 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 | |
92 | static 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 | |
99 | static 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 | |
106 | static 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 | |
114 | static 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 | |
174 | static 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 | |
184 | static 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 | }; |
191 | module_platform_driver(sh_sci_spi_drv); |
192 | |
193 | MODULE_DESCRIPTION("SH SCI SPI Driver" ); |
194 | MODULE_AUTHOR("Magnus Damm <damm@opensource.se>" ); |
195 | MODULE_LICENSE("GPL" ); |
196 | MODULE_ALIAS("platform:spi_sh_sci" ); |
197 | |