diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mach-sa1100/ssp.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/arm/mach-sa1100/ssp.c')
-rw-r--r-- | arch/arm/mach-sa1100/ssp.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/arch/arm/mach-sa1100/ssp.c b/arch/arm/mach-sa1100/ssp.c new file mode 100644 index 000000000000..1604dadf27fc --- /dev/null +++ b/arch/arm/mach-sa1100/ssp.c | |||
@@ -0,0 +1,214 @@ | |||
1 | /* | ||
2 | * linux/arch/arm/mach-sa1100/ssp.c | ||
3 | * | ||
4 | * Copyright (C) 2003 Russell King. | ||
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 | * Generic SSP driver. This provides the generic core for simple | ||
11 | * IO-based SSP applications. | ||
12 | */ | ||
13 | #include <linux/module.h> | ||
14 | #include <linux/kernel.h> | ||
15 | #include <linux/sched.h> | ||
16 | #include <linux/errno.h> | ||
17 | #include <linux/interrupt.h> | ||
18 | #include <linux/ioport.h> | ||
19 | #include <linux/init.h> | ||
20 | |||
21 | #include <asm/io.h> | ||
22 | #include <asm/irq.h> | ||
23 | #include <asm/hardware.h> | ||
24 | #include <asm/hardware/ssp.h> | ||
25 | |||
26 | static irqreturn_t ssp_interrupt(int irq, void *dev_id, struct pt_regs *regs) | ||
27 | { | ||
28 | unsigned int status = Ser4SSSR; | ||
29 | |||
30 | if (status & SSSR_ROR) { | ||
31 | printk(KERN_WARNING "SSP: receiver overrun\n"); | ||
32 | } | ||
33 | |||
34 | Ser4SSSR = SSSR_ROR; | ||
35 | |||
36 | return status ? IRQ_HANDLED : IRQ_NONE; | ||
37 | } | ||
38 | |||
39 | /** | ||
40 | * ssp_write_word - write a word to the SSP port | ||
41 | * @data: 16-bit, MSB justified data to write. | ||
42 | * | ||
43 | * Wait for a free entry in the SSP transmit FIFO, and write a data | ||
44 | * word to the SSP port. Wait for the SSP port to start sending | ||
45 | * the data. | ||
46 | * | ||
47 | * The caller is expected to perform the necessary locking. | ||
48 | * | ||
49 | * Returns: | ||
50 | * %-ETIMEDOUT timeout occurred (for future) | ||
51 | * 0 success | ||
52 | */ | ||
53 | int ssp_write_word(u16 data) | ||
54 | { | ||
55 | while (!(Ser4SSSR & SSSR_TNF)) | ||
56 | cpu_relax(); | ||
57 | |||
58 | Ser4SSDR = data; | ||
59 | |||
60 | while (!(Ser4SSSR & SSSR_BSY)) | ||
61 | cpu_relax(); | ||
62 | |||
63 | return 0; | ||
64 | } | ||
65 | |||
66 | /** | ||
67 | * ssp_read_word - read a word from the SSP port | ||
68 | * | ||
69 | * Wait for a data word in the SSP receive FIFO, and return the | ||
70 | * received data. Data is LSB justified. | ||
71 | * | ||
72 | * Note: Currently, if data is not expected to be received, this | ||
73 | * function will wait for ever. | ||
74 | * | ||
75 | * The caller is expected to perform the necessary locking. | ||
76 | * | ||
77 | * Returns: | ||
78 | * %-ETIMEDOUT timeout occurred (for future) | ||
79 | * 16-bit data success | ||
80 | */ | ||
81 | int ssp_read_word(void) | ||
82 | { | ||
83 | while (!(Ser4SSSR & SSSR_RNE)) | ||
84 | cpu_relax(); | ||
85 | |||
86 | return Ser4SSDR; | ||
87 | } | ||
88 | |||
89 | /** | ||
90 | * ssp_flush - flush the transmit and receive FIFOs | ||
91 | * | ||
92 | * Wait for the SSP to idle, and ensure that the receive FIFO | ||
93 | * is empty. | ||
94 | * | ||
95 | * The caller is expected to perform the necessary locking. | ||
96 | */ | ||
97 | void ssp_flush(void) | ||
98 | { | ||
99 | do { | ||
100 | while (Ser4SSSR & SSSR_RNE) { | ||
101 | (void) Ser4SSDR; | ||
102 | } | ||
103 | } while (Ser4SSSR & SSSR_BSY); | ||
104 | } | ||
105 | |||
106 | /** | ||
107 | * ssp_enable - enable the SSP port | ||
108 | * | ||
109 | * Turn on the SSP port. | ||
110 | */ | ||
111 | void ssp_enable(void) | ||
112 | { | ||
113 | Ser4SSCR0 |= SSCR0_SSE; | ||
114 | } | ||
115 | |||
116 | /** | ||
117 | * ssp_disable - shut down the SSP port | ||
118 | * | ||
119 | * Turn off the SSP port, optionally powering it down. | ||
120 | */ | ||
121 | void ssp_disable(void) | ||
122 | { | ||
123 | Ser4SSCR0 &= ~SSCR0_SSE; | ||
124 | } | ||
125 | |||
126 | /** | ||
127 | * ssp_save_state - save the SSP configuration | ||
128 | * @ssp: pointer to structure to save SSP configuration | ||
129 | * | ||
130 | * Save the configured SSP state for suspend. | ||
131 | */ | ||
132 | void ssp_save_state(struct ssp_state *ssp) | ||
133 | { | ||
134 | ssp->cr0 = Ser4SSCR0; | ||
135 | ssp->cr1 = Ser4SSCR1; | ||
136 | |||
137 | Ser4SSCR0 &= ~SSCR0_SSE; | ||
138 | } | ||
139 | |||
140 | /** | ||
141 | * ssp_restore_state - restore a previously saved SSP configuration | ||
142 | * @ssp: pointer to configuration saved by ssp_save_state | ||
143 | * | ||
144 | * Restore the SSP configuration saved previously by ssp_save_state. | ||
145 | */ | ||
146 | void ssp_restore_state(struct ssp_state *ssp) | ||
147 | { | ||
148 | Ser4SSSR = SSSR_ROR; | ||
149 | |||
150 | Ser4SSCR0 = ssp->cr0 & ~SSCR0_SSE; | ||
151 | Ser4SSCR1 = ssp->cr1; | ||
152 | Ser4SSCR0 = ssp->cr0; | ||
153 | } | ||
154 | |||
155 | /** | ||
156 | * ssp_init - setup the SSP port | ||
157 | * | ||
158 | * initialise and claim resources for the SSP port. | ||
159 | * | ||
160 | * Returns: | ||
161 | * %-ENODEV if the SSP port is unavailable | ||
162 | * %-EBUSY if the resources are already in use | ||
163 | * %0 on success | ||
164 | */ | ||
165 | int ssp_init(void) | ||
166 | { | ||
167 | int ret; | ||
168 | |||
169 | if (!(PPAR & PPAR_SPR) && (Ser4MCCR0 & MCCR0_MCE)) | ||
170 | return -ENODEV; | ||
171 | |||
172 | if (!request_mem_region(__PREG(Ser4SSCR0), 0x18, "SSP")) { | ||
173 | return -EBUSY; | ||
174 | } | ||
175 | |||
176 | Ser4SSSR = SSSR_ROR; | ||
177 | |||
178 | ret = request_irq(IRQ_Ser4SSP, ssp_interrupt, 0, "SSP", NULL); | ||
179 | if (ret) | ||
180 | goto out_region; | ||
181 | |||
182 | return 0; | ||
183 | |||
184 | out_region: | ||
185 | release_mem_region(__PREG(Ser4SSCR0), 0x18); | ||
186 | return ret; | ||
187 | } | ||
188 | |||
189 | /** | ||
190 | * ssp_exit - undo the effects of ssp_init | ||
191 | * | ||
192 | * release and free resources for the SSP port. | ||
193 | */ | ||
194 | void ssp_exit(void) | ||
195 | { | ||
196 | Ser4SSCR0 &= ~SSCR0_SSE; | ||
197 | |||
198 | free_irq(IRQ_Ser4SSP, NULL); | ||
199 | release_mem_region(__PREG(Ser4SSCR0), 0x18); | ||
200 | } | ||
201 | |||
202 | MODULE_AUTHOR("Russell King"); | ||
203 | MODULE_DESCRIPTION("SA11x0 SSP PIO driver"); | ||
204 | MODULE_LICENSE("GPL"); | ||
205 | |||
206 | EXPORT_SYMBOL(ssp_write_word); | ||
207 | EXPORT_SYMBOL(ssp_read_word); | ||
208 | EXPORT_SYMBOL(ssp_flush); | ||
209 | EXPORT_SYMBOL(ssp_enable); | ||
210 | EXPORT_SYMBOL(ssp_disable); | ||
211 | EXPORT_SYMBOL(ssp_save_state); | ||
212 | EXPORT_SYMBOL(ssp_restore_state); | ||
213 | EXPORT_SYMBOL(ssp_init); | ||
214 | EXPORT_SYMBOL(ssp_exit); | ||