Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Russell King | a09e64f | 2008-08-05 16:14:15 +0100 | [diff] [blame] | 23 | #include <mach/hardware.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <asm/hardware/ssp.h> |
| 25 | |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 26 | #define TIMEOUT 100000 |
| 27 | |
Linus Torvalds | 0cd61b6 | 2006-10-06 10:53:39 -0700 | [diff] [blame] | 28 | static irqreturn_t ssp_interrupt(int irq, void *dev_id) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | { |
| 30 | unsigned int status = Ser4SSSR; |
| 31 | |
Jeff Garzik | e8f2af1 | 2007-10-26 05:40:25 -0400 | [diff] [blame] | 32 | if (status & SSSR_ROR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | printk(KERN_WARNING "SSP: receiver overrun\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
| 35 | Ser4SSSR = SSSR_ROR; |
| 36 | |
| 37 | return status ? IRQ_HANDLED : IRQ_NONE; |
| 38 | } |
| 39 | |
| 40 | /** |
| 41 | * ssp_write_word - write a word to the SSP port |
| 42 | * @data: 16-bit, MSB justified data to write. |
| 43 | * |
| 44 | * Wait for a free entry in the SSP transmit FIFO, and write a data |
| 45 | * word to the SSP port. Wait for the SSP port to start sending |
| 46 | * the data. |
| 47 | * |
| 48 | * The caller is expected to perform the necessary locking. |
| 49 | * |
| 50 | * Returns: |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 51 | * %-ETIMEDOUT timeout occurred |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | * 0 success |
| 53 | */ |
| 54 | int ssp_write_word(u16 data) |
| 55 | { |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 56 | int timeout = TIMEOUT; |
| 57 | |
| 58 | while (!(Ser4SSSR & SSSR_TNF)) { |
| 59 | if (!--timeout) |
| 60 | return -ETIMEDOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | cpu_relax(); |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 62 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
| 64 | Ser4SSDR = data; |
| 65 | |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 66 | timeout = TIMEOUT; |
| 67 | while (!(Ser4SSSR & SSSR_BSY)) { |
| 68 | if (!--timeout) |
| 69 | return -ETIMEDOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | cpu_relax(); |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 71 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | |
| 73 | return 0; |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * ssp_read_word - read a word from the SSP port |
| 78 | * |
| 79 | * Wait for a data word in the SSP receive FIFO, and return the |
| 80 | * received data. Data is LSB justified. |
| 81 | * |
| 82 | * Note: Currently, if data is not expected to be received, this |
| 83 | * function will wait for ever. |
| 84 | * |
| 85 | * The caller is expected to perform the necessary locking. |
| 86 | * |
| 87 | * Returns: |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 88 | * %-ETIMEDOUT timeout occurred |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | * 16-bit data success |
| 90 | */ |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 91 | int ssp_read_word(u16 *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | { |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 93 | int timeout = TIMEOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 95 | while (!(Ser4SSSR & SSSR_RNE)) { |
| 96 | if (!--timeout) |
| 97 | return -ETIMEDOUT; |
| 98 | cpu_relax(); |
| 99 | } |
| 100 | |
| 101 | *data = (u16)Ser4SSDR; |
| 102 | |
| 103 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | } |
| 105 | |
| 106 | /** |
| 107 | * ssp_flush - flush the transmit and receive FIFOs |
| 108 | * |
| 109 | * Wait for the SSP to idle, and ensure that the receive FIFO |
| 110 | * is empty. |
| 111 | * |
| 112 | * The caller is expected to perform the necessary locking. |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 113 | * |
| 114 | * Returns: |
| 115 | * %-ETIMEDOUT timeout occurred |
| 116 | * 0 success |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | */ |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 118 | int ssp_flush(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | { |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 120 | int timeout = TIMEOUT * 2; |
| 121 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | do { |
| 123 | while (Ser4SSSR & SSSR_RNE) { |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 124 | if (!--timeout) |
| 125 | return -ETIMEDOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | (void) Ser4SSDR; |
| 127 | } |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 128 | if (!--timeout) |
| 129 | return -ETIMEDOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | } while (Ser4SSSR & SSSR_BSY); |
Paul Sokolovsky | 8f1bf87 | 2006-08-27 12:54:56 +0100 | [diff] [blame] | 131 | |
| 132 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | } |
| 134 | |
| 135 | /** |
| 136 | * ssp_enable - enable the SSP port |
| 137 | * |
| 138 | * Turn on the SSP port. |
| 139 | */ |
| 140 | void ssp_enable(void) |
| 141 | { |
| 142 | Ser4SSCR0 |= SSCR0_SSE; |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * ssp_disable - shut down the SSP port |
| 147 | * |
| 148 | * Turn off the SSP port, optionally powering it down. |
| 149 | */ |
| 150 | void ssp_disable(void) |
| 151 | { |
| 152 | Ser4SSCR0 &= ~SSCR0_SSE; |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * ssp_save_state - save the SSP configuration |
| 157 | * @ssp: pointer to structure to save SSP configuration |
| 158 | * |
| 159 | * Save the configured SSP state for suspend. |
| 160 | */ |
| 161 | void ssp_save_state(struct ssp_state *ssp) |
| 162 | { |
| 163 | ssp->cr0 = Ser4SSCR0; |
| 164 | ssp->cr1 = Ser4SSCR1; |
| 165 | |
| 166 | Ser4SSCR0 &= ~SSCR0_SSE; |
| 167 | } |
| 168 | |
| 169 | /** |
| 170 | * ssp_restore_state - restore a previously saved SSP configuration |
| 171 | * @ssp: pointer to configuration saved by ssp_save_state |
| 172 | * |
| 173 | * Restore the SSP configuration saved previously by ssp_save_state. |
| 174 | */ |
| 175 | void ssp_restore_state(struct ssp_state *ssp) |
| 176 | { |
| 177 | Ser4SSSR = SSSR_ROR; |
| 178 | |
| 179 | Ser4SSCR0 = ssp->cr0 & ~SSCR0_SSE; |
| 180 | Ser4SSCR1 = ssp->cr1; |
| 181 | Ser4SSCR0 = ssp->cr0; |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * ssp_init - setup the SSP port |
| 186 | * |
| 187 | * initialise and claim resources for the SSP port. |
| 188 | * |
| 189 | * Returns: |
| 190 | * %-ENODEV if the SSP port is unavailable |
| 191 | * %-EBUSY if the resources are already in use |
| 192 | * %0 on success |
| 193 | */ |
| 194 | int ssp_init(void) |
| 195 | { |
| 196 | int ret; |
| 197 | |
| 198 | if (!(PPAR & PPAR_SPR) && (Ser4MCCR0 & MCCR0_MCE)) |
| 199 | return -ENODEV; |
| 200 | |
| 201 | if (!request_mem_region(__PREG(Ser4SSCR0), 0x18, "SSP")) { |
| 202 | return -EBUSY; |
| 203 | } |
| 204 | |
| 205 | Ser4SSSR = SSSR_ROR; |
| 206 | |
| 207 | ret = request_irq(IRQ_Ser4SSP, ssp_interrupt, 0, "SSP", NULL); |
| 208 | if (ret) |
| 209 | goto out_region; |
| 210 | |
| 211 | return 0; |
| 212 | |
| 213 | out_region: |
| 214 | release_mem_region(__PREG(Ser4SSCR0), 0x18); |
| 215 | return ret; |
| 216 | } |
| 217 | |
| 218 | /** |
| 219 | * ssp_exit - undo the effects of ssp_init |
| 220 | * |
| 221 | * release and free resources for the SSP port. |
| 222 | */ |
| 223 | void ssp_exit(void) |
| 224 | { |
| 225 | Ser4SSCR0 &= ~SSCR0_SSE; |
| 226 | |
| 227 | free_irq(IRQ_Ser4SSP, NULL); |
| 228 | release_mem_region(__PREG(Ser4SSCR0), 0x18); |
| 229 | } |
| 230 | |
| 231 | MODULE_AUTHOR("Russell King"); |
| 232 | MODULE_DESCRIPTION("SA11x0 SSP PIO driver"); |
| 233 | MODULE_LICENSE("GPL"); |
| 234 | |
| 235 | EXPORT_SYMBOL(ssp_write_word); |
| 236 | EXPORT_SYMBOL(ssp_read_word); |
| 237 | EXPORT_SYMBOL(ssp_flush); |
| 238 | EXPORT_SYMBOL(ssp_enable); |
| 239 | EXPORT_SYMBOL(ssp_disable); |
| 240 | EXPORT_SYMBOL(ssp_save_state); |
| 241 | EXPORT_SYMBOL(ssp_restore_state); |
| 242 | EXPORT_SYMBOL(ssp_init); |
| 243 | EXPORT_SYMBOL(ssp_exit); |