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Magnus Damm37e46642008-02-06 01:38:15 -08001/*
2 * SH SCI SPI interface
3 *
4 * Copyright (c) 2008 Magnus Damm
5 *
6 * Based on S3C24XX GPIO based SPI driver, which is:
7 * Copyright (c) 2006 Ben Dooks
8 * Copyright (c) 2006 Simtec Electronics
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 *
14 */
15
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/delay.h>
19#include <linux/spinlock.h>
20#include <linux/workqueue.h>
21#include <linux/platform_device.h>
22
23#include <linux/spi/spi.h>
24#include <linux/spi/spi_bitbang.h>
Paul Gortmakerd7614de2011-07-03 15:44:29 -040025#include <linux/module.h>
Magnus Damm37e46642008-02-06 01:38:15 -080026
27#include <asm/spi.h>
28#include <asm/io.h>
29
30struct sh_sci_spi {
31 struct spi_bitbang bitbang;
32
33 void __iomem *membase;
34 unsigned char val;
35 struct sh_spi_info *info;
36 struct platform_device *dev;
37};
38
39#define SCSPTR(sp) (sp->membase + 0x1c)
40#define PIN_SCK (1 << 2)
41#define PIN_TXD (1 << 0)
42#define PIN_RXD PIN_TXD
43#define PIN_INIT ((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD)
44
45static inline void setbits(struct sh_sci_spi *sp, int bits, int on)
46{
47 /*
48 * We are the only user of SCSPTR so no locking is required.
49 * Reading bit 2 and 0 in SCSPTR gives pin state as input.
50 * Writing the same bits sets the output value.
51 * This makes regular read-modify-write difficult so we
52 * use sp->val to keep track of the latest register value.
53 */
54
55 if (on)
56 sp->val |= bits;
57 else
58 sp->val &= ~bits;
59
60 iowrite8(sp->val, SCSPTR(sp));
61}
62
63static inline void setsck(struct spi_device *dev, int on)
64{
65 setbits(spi_master_get_devdata(dev->master), PIN_SCK, on);
66}
67
68static inline void setmosi(struct spi_device *dev, int on)
69{
70 setbits(spi_master_get_devdata(dev->master), PIN_TXD, on);
71}
72
73static inline u32 getmiso(struct spi_device *dev)
74{
75 struct sh_sci_spi *sp = spi_master_get_devdata(dev->master);
76
77 return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0;
78}
79
80#define spidelay(x) ndelay(x)
81
Grant Likelyca632f52011-06-06 01:16:30 -060082#include "spi-bitbang-txrx.h"
Magnus Damm37e46642008-02-06 01:38:15 -080083
84static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi,
85 unsigned nsecs, u32 word, u8 bits)
86{
Marek Szyprowski04bb2a02010-06-30 14:27:32 -060087 return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
Magnus Damm37e46642008-02-06 01:38:15 -080088}
89
90static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi,
91 unsigned nsecs, u32 word, u8 bits)
92{
Marek Szyprowski04bb2a02010-06-30 14:27:32 -060093 return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
Magnus Damm37e46642008-02-06 01:38:15 -080094}
95
96static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi,
97 unsigned nsecs, u32 word, u8 bits)
98{
Marek Szyprowski04bb2a02010-06-30 14:27:32 -060099 return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
Magnus Damm37e46642008-02-06 01:38:15 -0800100}
101
102static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi,
103 unsigned nsecs, u32 word, u8 bits)
104{
Marek Szyprowski04bb2a02010-06-30 14:27:32 -0600105 return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
Magnus Damm37e46642008-02-06 01:38:15 -0800106}
107
108static void sh_sci_spi_chipselect(struct spi_device *dev, int value)
109{
110 struct sh_sci_spi *sp = spi_master_get_devdata(dev->master);
111
112 if (sp->info && sp->info->chip_select)
113 (sp->info->chip_select)(sp->info, dev->chip_select, value);
114}
115
116static int sh_sci_spi_probe(struct platform_device *dev)
117{
118 struct resource *r;
119 struct spi_master *master;
120 struct sh_sci_spi *sp;
121 int ret;
122
123 master = spi_alloc_master(&dev->dev, sizeof(struct sh_sci_spi));
124 if (master == NULL) {
125 dev_err(&dev->dev, "failed to allocate spi master\n");
126 ret = -ENOMEM;
127 goto err0;
128 }
129
130 sp = spi_master_get_devdata(master);
131
132 platform_set_drvdata(dev, sp);
133 sp->info = dev->dev.platform_data;
134
135 /* setup spi bitbang adaptor */
136 sp->bitbang.master = spi_master_get(master);
137 sp->bitbang.master->bus_num = sp->info->bus_num;
138 sp->bitbang.master->num_chipselect = sp->info->num_chipselect;
139 sp->bitbang.chipselect = sh_sci_spi_chipselect;
140
141 sp->bitbang.txrx_word[SPI_MODE_0] = sh_sci_spi_txrx_mode0;
142 sp->bitbang.txrx_word[SPI_MODE_1] = sh_sci_spi_txrx_mode1;
143 sp->bitbang.txrx_word[SPI_MODE_2] = sh_sci_spi_txrx_mode2;
144 sp->bitbang.txrx_word[SPI_MODE_3] = sh_sci_spi_txrx_mode3;
145
146 r = platform_get_resource(dev, IORESOURCE_MEM, 0);
147 if (r == NULL) {
148 ret = -ENOENT;
149 goto err1;
150 }
hartleys76b6fdd2009-12-14 22:40:05 +0000151 sp->membase = ioremap(r->start, resource_size(r));
Magnus Damm37e46642008-02-06 01:38:15 -0800152 if (!sp->membase) {
153 ret = -ENXIO;
154 goto err1;
155 }
156 sp->val = ioread8(SCSPTR(sp));
157 setbits(sp, PIN_INIT, 1);
158
159 ret = spi_bitbang_start(&sp->bitbang);
160 if (!ret)
161 return 0;
162
163 setbits(sp, PIN_INIT, 0);
164 iounmap(sp->membase);
165 err1:
166 spi_master_put(sp->bitbang.master);
167 err0:
168 return ret;
169}
170
171static int sh_sci_spi_remove(struct platform_device *dev)
172{
173 struct sh_sci_spi *sp = platform_get_drvdata(dev);
174
175 iounmap(sp->membase);
176 setbits(sp, PIN_INIT, 0);
177 spi_bitbang_stop(&sp->bitbang);
178 spi_master_put(sp->bitbang.master);
179 return 0;
180}
181
182static struct platform_driver sh_sci_spi_drv = {
183 .probe = sh_sci_spi_probe,
184 .remove = sh_sci_spi_remove,
185 .driver = {
186 .name = "spi_sh_sci",
187 .owner = THIS_MODULE,
188 },
189};
Grant Likely940ab882011-10-05 11:29:49 -0600190module_platform_driver(sh_sci_spi_drv);
Magnus Damm37e46642008-02-06 01:38:15 -0800191
192MODULE_DESCRIPTION("SH SCI SPI Driver");
193MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
194MODULE_LICENSE("GPL");
Kay Sievers7e38c3c2008-04-10 21:29:20 -0700195MODULE_ALIAS("platform:spi_sh_sci");