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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/arch/arm/mach-sa1100/ssp.c | |
4 | * | |
5 | * Copyright (C) 2003 Russell King. | |
6 | * | |
1da177e4 LT |
7 | * Generic SSP driver. This provides the generic core for simple |
8 | * IO-based SSP applications. | |
9 | */ | |
10 | #include <linux/module.h> | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/sched.h> | |
13 | #include <linux/errno.h> | |
14 | #include <linux/interrupt.h> | |
15 | #include <linux/ioport.h> | |
16 | #include <linux/init.h> | |
fced80c7 | 17 | #include <linux/io.h> |
1da177e4 | 18 | |
a09e64fb | 19 | #include <mach/hardware.h> |
f314f33b | 20 | #include <mach/irqs.h> |
1da177e4 LT |
21 | #include <asm/hardware/ssp.h> |
22 | ||
8f1bf874 PS |
23 | #define TIMEOUT 100000 |
24 | ||
0cd61b68 | 25 | static irqreturn_t ssp_interrupt(int irq, void *dev_id) |
1da177e4 LT |
26 | { |
27 | unsigned int status = Ser4SSSR; | |
28 | ||
e8f2af17 | 29 | if (status & SSSR_ROR) |
1da177e4 | 30 | printk(KERN_WARNING "SSP: receiver overrun\n"); |
1da177e4 LT |
31 | |
32 | Ser4SSSR = SSSR_ROR; | |
33 | ||
34 | return status ? IRQ_HANDLED : IRQ_NONE; | |
35 | } | |
36 | ||
37 | /** | |
38 | * ssp_write_word - write a word to the SSP port | |
39 | * @data: 16-bit, MSB justified data to write. | |
40 | * | |
41 | * Wait for a free entry in the SSP transmit FIFO, and write a data | |
42 | * word to the SSP port. Wait for the SSP port to start sending | |
43 | * the data. | |
44 | * | |
45 | * The caller is expected to perform the necessary locking. | |
46 | * | |
47 | * Returns: | |
8f1bf874 | 48 | * %-ETIMEDOUT timeout occurred |
1da177e4 LT |
49 | * 0 success |
50 | */ | |
51 | int ssp_write_word(u16 data) | |
52 | { | |
8f1bf874 PS |
53 | int timeout = TIMEOUT; |
54 | ||
55 | while (!(Ser4SSSR & SSSR_TNF)) { | |
56 | if (!--timeout) | |
57 | return -ETIMEDOUT; | |
1da177e4 | 58 | cpu_relax(); |
8f1bf874 | 59 | } |
1da177e4 LT |
60 | |
61 | Ser4SSDR = data; | |
62 | ||
8f1bf874 PS |
63 | timeout = TIMEOUT; |
64 | while (!(Ser4SSSR & SSSR_BSY)) { | |
65 | if (!--timeout) | |
66 | return -ETIMEDOUT; | |
1da177e4 | 67 | cpu_relax(); |
8f1bf874 | 68 | } |
1da177e4 LT |
69 | |
70 | return 0; | |
71 | } | |
72 | ||
73 | /** | |
74 | * ssp_read_word - read a word from the SSP port | |
75 | * | |
76 | * Wait for a data word in the SSP receive FIFO, and return the | |
77 | * received data. Data is LSB justified. | |
78 | * | |
79 | * Note: Currently, if data is not expected to be received, this | |
80 | * function will wait for ever. | |
81 | * | |
82 | * The caller is expected to perform the necessary locking. | |
83 | * | |
84 | * Returns: | |
8f1bf874 | 85 | * %-ETIMEDOUT timeout occurred |
1da177e4 LT |
86 | * 16-bit data success |
87 | */ | |
8f1bf874 | 88 | int ssp_read_word(u16 *data) |
1da177e4 | 89 | { |
8f1bf874 PS |
90 | int timeout = TIMEOUT; |
91 | ||
92 | while (!(Ser4SSSR & SSSR_RNE)) { | |
93 | if (!--timeout) | |
94 | return -ETIMEDOUT; | |
1da177e4 | 95 | cpu_relax(); |
8f1bf874 PS |
96 | } |
97 | ||
98 | *data = (u16)Ser4SSDR; | |
1da177e4 | 99 | |
8f1bf874 | 100 | return 0; |
1da177e4 LT |
101 | } |
102 | ||
103 | /** | |
104 | * ssp_flush - flush the transmit and receive FIFOs | |
105 | * | |
106 | * Wait for the SSP to idle, and ensure that the receive FIFO | |
107 | * is empty. | |
108 | * | |
109 | * The caller is expected to perform the necessary locking. | |
8f1bf874 PS |
110 | * |
111 | * Returns: | |
112 | * %-ETIMEDOUT timeout occurred | |
113 | * 0 success | |
1da177e4 | 114 | */ |
8f1bf874 | 115 | int ssp_flush(void) |
1da177e4 | 116 | { |
8f1bf874 PS |
117 | int timeout = TIMEOUT * 2; |
118 | ||
1da177e4 LT |
119 | do { |
120 | while (Ser4SSSR & SSSR_RNE) { | |
8f1bf874 PS |
121 | if (!--timeout) |
122 | return -ETIMEDOUT; | |
1da177e4 LT |
123 | (void) Ser4SSDR; |
124 | } | |
8f1bf874 PS |
125 | if (!--timeout) |
126 | return -ETIMEDOUT; | |
1da177e4 | 127 | } while (Ser4SSSR & SSSR_BSY); |
8f1bf874 PS |
128 | |
129 | return 0; | |
1da177e4 LT |
130 | } |
131 | ||
132 | /** | |
133 | * ssp_enable - enable the SSP port | |
134 | * | |
135 | * Turn on the SSP port. | |
136 | */ | |
137 | void ssp_enable(void) | |
138 | { | |
139 | Ser4SSCR0 |= SSCR0_SSE; | |
140 | } | |
141 | ||
142 | /** | |
143 | * ssp_disable - shut down the SSP port | |
144 | * | |
145 | * Turn off the SSP port, optionally powering it down. | |
146 | */ | |
147 | void ssp_disable(void) | |
148 | { | |
149 | Ser4SSCR0 &= ~SSCR0_SSE; | |
150 | } | |
151 | ||
152 | /** | |
153 | * ssp_save_state - save the SSP configuration | |
154 | * @ssp: pointer to structure to save SSP configuration | |
155 | * | |
156 | * Save the configured SSP state for suspend. | |
157 | */ | |
158 | void ssp_save_state(struct ssp_state *ssp) | |
159 | { | |
160 | ssp->cr0 = Ser4SSCR0; | |
161 | ssp->cr1 = Ser4SSCR1; | |
162 | ||
163 | Ser4SSCR0 &= ~SSCR0_SSE; | |
164 | } | |
165 | ||
166 | /** | |
167 | * ssp_restore_state - restore a previously saved SSP configuration | |
168 | * @ssp: pointer to configuration saved by ssp_save_state | |
169 | * | |
170 | * Restore the SSP configuration saved previously by ssp_save_state. | |
171 | */ | |
172 | void ssp_restore_state(struct ssp_state *ssp) | |
173 | { | |
174 | Ser4SSSR = SSSR_ROR; | |
175 | ||
176 | Ser4SSCR0 = ssp->cr0 & ~SSCR0_SSE; | |
177 | Ser4SSCR1 = ssp->cr1; | |
178 | Ser4SSCR0 = ssp->cr0; | |
179 | } | |
180 | ||
181 | /** | |
182 | * ssp_init - setup the SSP port | |
183 | * | |
184 | * initialise and claim resources for the SSP port. | |
185 | * | |
186 | * Returns: | |
187 | * %-ENODEV if the SSP port is unavailable | |
188 | * %-EBUSY if the resources are already in use | |
189 | * %0 on success | |
190 | */ | |
191 | int ssp_init(void) | |
192 | { | |
193 | int ret; | |
194 | ||
195 | if (!(PPAR & PPAR_SPR) && (Ser4MCCR0 & MCCR0_MCE)) | |
196 | return -ENODEV; | |
197 | ||
198 | if (!request_mem_region(__PREG(Ser4SSCR0), 0x18, "SSP")) { | |
199 | return -EBUSY; | |
200 | } | |
201 | ||
202 | Ser4SSSR = SSSR_ROR; | |
203 | ||
204 | ret = request_irq(IRQ_Ser4SSP, ssp_interrupt, 0, "SSP", NULL); | |
205 | if (ret) | |
206 | goto out_region; | |
207 | ||
208 | return 0; | |
209 | ||
210 | out_region: | |
211 | release_mem_region(__PREG(Ser4SSCR0), 0x18); | |
212 | return ret; | |
213 | } | |
214 | ||
215 | /** | |
216 | * ssp_exit - undo the effects of ssp_init | |
217 | * | |
218 | * release and free resources for the SSP port. | |
219 | */ | |
220 | void ssp_exit(void) | |
221 | { | |
222 | Ser4SSCR0 &= ~SSCR0_SSE; | |
223 | ||
224 | free_irq(IRQ_Ser4SSP, NULL); | |
225 | release_mem_region(__PREG(Ser4SSCR0), 0x18); | |
226 | } | |
227 | ||
228 | MODULE_AUTHOR("Russell King"); | |
229 | MODULE_DESCRIPTION("SA11x0 SSP PIO driver"); | |
230 | MODULE_LICENSE("GPL"); | |
231 | ||
232 | EXPORT_SYMBOL(ssp_write_word); | |
233 | EXPORT_SYMBOL(ssp_read_word); | |
234 | EXPORT_SYMBOL(ssp_flush); | |
235 | EXPORT_SYMBOL(ssp_enable); | |
236 | EXPORT_SYMBOL(ssp_disable); | |
237 | EXPORT_SYMBOL(ssp_save_state); | |
238 | EXPORT_SYMBOL(ssp_restore_state); | |
239 | EXPORT_SYMBOL(ssp_init); | |
240 | EXPORT_SYMBOL(ssp_exit); |