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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /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.c214
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
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+++ 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
26static 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 */
53int 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 */
81int 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 */
97void 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 */
111void 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 */
121void 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 */
132void 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 */
146void 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 */
165int 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 */
194void ssp_exit(void)
195{
196 Ser4SSCR0 &= ~SSCR0_SSE;
197
198 free_irq(IRQ_Ser4SSP, NULL);
199 release_mem_region(__PREG(Ser4SSCR0), 0x18);
200}
201
202MODULE_AUTHOR("Russell King");
203MODULE_DESCRIPTION("SA11x0 SSP PIO driver");
204MODULE_LICENSE("GPL");
205
206EXPORT_SYMBOL(ssp_write_word);
207EXPORT_SYMBOL(ssp_read_word);
208EXPORT_SYMBOL(ssp_flush);
209EXPORT_SYMBOL(ssp_enable);
210EXPORT_SYMBOL(ssp_disable);
211EXPORT_SYMBOL(ssp_save_state);
212EXPORT_SYMBOL(ssp_restore_state);
213EXPORT_SYMBOL(ssp_init);
214EXPORT_SYMBOL(ssp_exit);