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![Bhaktipriya Shridhar](/assets/img/avatar_default.png)
The workqueue has a single workitem(&ss->ws) and hence doesn't require ordering. Also, it is not being used on a memory reclaim path. Hence, the singlethreaded workqueue has been replaced with the use of system_wq. System workqueues have been able to handle high level of concurrency for a long time now and hence it's not required to have a singlethreaded workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue created with create_singlethread_workqueue(), system_wq allows multiple work items to overlap executions even on the same CPU; however, a per-cpu workqueue doesn't have any CPU locality or global ordering guarantee unless the target CPU is explicitly specified and thus the increase of local concurrency shouldn't make any difference. Work item has been flushed in spi_sh_remove() to ensure that there are no pending tasks while disconnecting the driver. Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
527 lines
12 KiB
C
527 lines
12 KiB
C
/*
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* SH SPI bus driver
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*
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* Copyright (C) 2011 Renesas Solutions Corp.
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*
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* Based on pxa2xx_spi.c:
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* Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <linux/timer.h>
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#include <linux/delay.h>
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#include <linux/list.h>
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#include <linux/workqueue.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/spi/spi.h>
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#define SPI_SH_TBR 0x00
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#define SPI_SH_RBR 0x00
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#define SPI_SH_CR1 0x08
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#define SPI_SH_CR2 0x10
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#define SPI_SH_CR3 0x18
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#define SPI_SH_CR4 0x20
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#define SPI_SH_CR5 0x28
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/* CR1 */
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#define SPI_SH_TBE 0x80
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#define SPI_SH_TBF 0x40
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#define SPI_SH_RBE 0x20
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#define SPI_SH_RBF 0x10
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#define SPI_SH_PFONRD 0x08
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#define SPI_SH_SSDB 0x04
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#define SPI_SH_SSD 0x02
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#define SPI_SH_SSA 0x01
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/* CR2 */
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#define SPI_SH_RSTF 0x80
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#define SPI_SH_LOOPBK 0x40
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#define SPI_SH_CPOL 0x20
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#define SPI_SH_CPHA 0x10
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#define SPI_SH_L1M0 0x08
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/* CR3 */
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#define SPI_SH_MAX_BYTE 0xFF
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/* CR4 */
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#define SPI_SH_TBEI 0x80
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#define SPI_SH_TBFI 0x40
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#define SPI_SH_RBEI 0x20
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#define SPI_SH_RBFI 0x10
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#define SPI_SH_WPABRT 0x04
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#define SPI_SH_SSS 0x01
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/* CR8 */
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#define SPI_SH_P1L0 0x80
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#define SPI_SH_PP1L0 0x40
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#define SPI_SH_MUXI 0x20
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#define SPI_SH_MUXIRQ 0x10
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#define SPI_SH_FIFO_SIZE 32
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#define SPI_SH_SEND_TIMEOUT (3 * HZ)
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#define SPI_SH_RECEIVE_TIMEOUT (HZ >> 3)
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#undef DEBUG
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struct spi_sh_data {
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void __iomem *addr;
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int irq;
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struct spi_master *master;
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struct list_head queue;
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struct work_struct ws;
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unsigned long cr1;
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wait_queue_head_t wait;
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spinlock_t lock;
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int width;
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};
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static void spi_sh_write(struct spi_sh_data *ss, unsigned long data,
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unsigned long offset)
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{
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if (ss->width == 8)
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iowrite8(data, ss->addr + (offset >> 2));
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else if (ss->width == 32)
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iowrite32(data, ss->addr + offset);
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}
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static unsigned long spi_sh_read(struct spi_sh_data *ss, unsigned long offset)
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{
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if (ss->width == 8)
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return ioread8(ss->addr + (offset >> 2));
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else if (ss->width == 32)
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return ioread32(ss->addr + offset);
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else
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return 0;
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}
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static void spi_sh_set_bit(struct spi_sh_data *ss, unsigned long val,
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unsigned long offset)
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{
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unsigned long tmp;
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tmp = spi_sh_read(ss, offset);
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tmp |= val;
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spi_sh_write(ss, tmp, offset);
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}
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static void spi_sh_clear_bit(struct spi_sh_data *ss, unsigned long val,
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unsigned long offset)
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{
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unsigned long tmp;
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tmp = spi_sh_read(ss, offset);
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tmp &= ~val;
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spi_sh_write(ss, tmp, offset);
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}
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static void clear_fifo(struct spi_sh_data *ss)
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{
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spi_sh_set_bit(ss, SPI_SH_RSTF, SPI_SH_CR2);
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spi_sh_clear_bit(ss, SPI_SH_RSTF, SPI_SH_CR2);
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}
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static int spi_sh_wait_receive_buffer(struct spi_sh_data *ss)
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{
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int timeout = 100000;
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while (spi_sh_read(ss, SPI_SH_CR1) & SPI_SH_RBE) {
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udelay(10);
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if (timeout-- < 0)
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return -ETIMEDOUT;
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}
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return 0;
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}
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static int spi_sh_wait_write_buffer_empty(struct spi_sh_data *ss)
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{
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int timeout = 100000;
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while (!(spi_sh_read(ss, SPI_SH_CR1) & SPI_SH_TBE)) {
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udelay(10);
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if (timeout-- < 0)
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return -ETIMEDOUT;
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}
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return 0;
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}
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static int spi_sh_send(struct spi_sh_data *ss, struct spi_message *mesg,
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struct spi_transfer *t)
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{
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int i, retval = 0;
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int remain = t->len;
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int cur_len;
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unsigned char *data;
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long ret;
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if (t->len)
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spi_sh_set_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
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data = (unsigned char *)t->tx_buf;
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while (remain > 0) {
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cur_len = min(SPI_SH_FIFO_SIZE, remain);
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for (i = 0; i < cur_len &&
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!(spi_sh_read(ss, SPI_SH_CR4) &
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SPI_SH_WPABRT) &&
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!(spi_sh_read(ss, SPI_SH_CR1) & SPI_SH_TBF);
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i++)
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spi_sh_write(ss, (unsigned long)data[i], SPI_SH_TBR);
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if (spi_sh_read(ss, SPI_SH_CR4) & SPI_SH_WPABRT) {
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/* Abort SPI operation */
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spi_sh_set_bit(ss, SPI_SH_WPABRT, SPI_SH_CR4);
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retval = -EIO;
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break;
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}
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cur_len = i;
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remain -= cur_len;
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data += cur_len;
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if (remain > 0) {
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ss->cr1 &= ~SPI_SH_TBE;
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spi_sh_set_bit(ss, SPI_SH_TBE, SPI_SH_CR4);
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ret = wait_event_interruptible_timeout(ss->wait,
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ss->cr1 & SPI_SH_TBE,
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SPI_SH_SEND_TIMEOUT);
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if (ret == 0 && !(ss->cr1 & SPI_SH_TBE)) {
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printk(KERN_ERR "%s: timeout\n", __func__);
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return -ETIMEDOUT;
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}
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}
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}
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if (list_is_last(&t->transfer_list, &mesg->transfers)) {
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spi_sh_clear_bit(ss, SPI_SH_SSD | SPI_SH_SSDB, SPI_SH_CR1);
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spi_sh_set_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
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ss->cr1 &= ~SPI_SH_TBE;
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spi_sh_set_bit(ss, SPI_SH_TBE, SPI_SH_CR4);
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ret = wait_event_interruptible_timeout(ss->wait,
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ss->cr1 & SPI_SH_TBE,
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SPI_SH_SEND_TIMEOUT);
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if (ret == 0 && (ss->cr1 & SPI_SH_TBE)) {
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printk(KERN_ERR "%s: timeout\n", __func__);
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return -ETIMEDOUT;
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}
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}
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return retval;
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}
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static int spi_sh_receive(struct spi_sh_data *ss, struct spi_message *mesg,
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struct spi_transfer *t)
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{
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int i;
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int remain = t->len;
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int cur_len;
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unsigned char *data;
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long ret;
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if (t->len > SPI_SH_MAX_BYTE)
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spi_sh_write(ss, SPI_SH_MAX_BYTE, SPI_SH_CR3);
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else
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spi_sh_write(ss, t->len, SPI_SH_CR3);
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spi_sh_clear_bit(ss, SPI_SH_SSD | SPI_SH_SSDB, SPI_SH_CR1);
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spi_sh_set_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
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spi_sh_wait_write_buffer_empty(ss);
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data = (unsigned char *)t->rx_buf;
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while (remain > 0) {
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if (remain >= SPI_SH_FIFO_SIZE) {
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ss->cr1 &= ~SPI_SH_RBF;
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spi_sh_set_bit(ss, SPI_SH_RBF, SPI_SH_CR4);
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ret = wait_event_interruptible_timeout(ss->wait,
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ss->cr1 & SPI_SH_RBF,
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SPI_SH_RECEIVE_TIMEOUT);
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if (ret == 0 &&
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spi_sh_read(ss, SPI_SH_CR1) & SPI_SH_RBE) {
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printk(KERN_ERR "%s: timeout\n", __func__);
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return -ETIMEDOUT;
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}
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}
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cur_len = min(SPI_SH_FIFO_SIZE, remain);
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for (i = 0; i < cur_len; i++) {
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if (spi_sh_wait_receive_buffer(ss))
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break;
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data[i] = (unsigned char)spi_sh_read(ss, SPI_SH_RBR);
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}
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remain -= cur_len;
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data += cur_len;
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}
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/* deassert CS when SPI is receiving. */
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if (t->len > SPI_SH_MAX_BYTE) {
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clear_fifo(ss);
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spi_sh_write(ss, 1, SPI_SH_CR3);
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} else {
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spi_sh_write(ss, 0, SPI_SH_CR3);
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}
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return 0;
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}
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static void spi_sh_work(struct work_struct *work)
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{
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struct spi_sh_data *ss = container_of(work, struct spi_sh_data, ws);
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struct spi_message *mesg;
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struct spi_transfer *t;
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unsigned long flags;
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int ret;
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pr_debug("%s: enter\n", __func__);
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spin_lock_irqsave(&ss->lock, flags);
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while (!list_empty(&ss->queue)) {
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mesg = list_entry(ss->queue.next, struct spi_message, queue);
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list_del_init(&mesg->queue);
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spin_unlock_irqrestore(&ss->lock, flags);
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list_for_each_entry(t, &mesg->transfers, transfer_list) {
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pr_debug("tx_buf = %p, rx_buf = %p\n",
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t->tx_buf, t->rx_buf);
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pr_debug("len = %d, delay_usecs = %d\n",
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t->len, t->delay_usecs);
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if (t->tx_buf) {
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ret = spi_sh_send(ss, mesg, t);
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if (ret < 0)
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goto error;
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}
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if (t->rx_buf) {
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ret = spi_sh_receive(ss, mesg, t);
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if (ret < 0)
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goto error;
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}
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mesg->actual_length += t->len;
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}
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spin_lock_irqsave(&ss->lock, flags);
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mesg->status = 0;
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if (mesg->complete)
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mesg->complete(mesg->context);
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}
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clear_fifo(ss);
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spi_sh_set_bit(ss, SPI_SH_SSD, SPI_SH_CR1);
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udelay(100);
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spi_sh_clear_bit(ss, SPI_SH_SSA | SPI_SH_SSDB | SPI_SH_SSD,
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SPI_SH_CR1);
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clear_fifo(ss);
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spin_unlock_irqrestore(&ss->lock, flags);
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return;
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error:
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mesg->status = ret;
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if (mesg->complete)
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mesg->complete(mesg->context);
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spi_sh_clear_bit(ss, SPI_SH_SSA | SPI_SH_SSDB | SPI_SH_SSD,
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SPI_SH_CR1);
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clear_fifo(ss);
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}
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static int spi_sh_setup(struct spi_device *spi)
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{
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struct spi_sh_data *ss = spi_master_get_devdata(spi->master);
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pr_debug("%s: enter\n", __func__);
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spi_sh_write(ss, 0xfe, SPI_SH_CR1); /* SPI sycle stop */
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spi_sh_write(ss, 0x00, SPI_SH_CR1); /* CR1 init */
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spi_sh_write(ss, 0x00, SPI_SH_CR3); /* CR3 init */
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clear_fifo(ss);
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/* 1/8 clock */
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spi_sh_write(ss, spi_sh_read(ss, SPI_SH_CR2) | 0x07, SPI_SH_CR2);
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udelay(10);
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return 0;
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}
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static int spi_sh_transfer(struct spi_device *spi, struct spi_message *mesg)
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{
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struct spi_sh_data *ss = spi_master_get_devdata(spi->master);
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unsigned long flags;
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pr_debug("%s: enter\n", __func__);
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pr_debug("\tmode = %02x\n", spi->mode);
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spin_lock_irqsave(&ss->lock, flags);
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mesg->actual_length = 0;
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mesg->status = -EINPROGRESS;
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spi_sh_clear_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
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list_add_tail(&mesg->queue, &ss->queue);
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schedule_work(&ss->ws);
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spin_unlock_irqrestore(&ss->lock, flags);
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return 0;
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}
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static void spi_sh_cleanup(struct spi_device *spi)
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{
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struct spi_sh_data *ss = spi_master_get_devdata(spi->master);
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pr_debug("%s: enter\n", __func__);
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spi_sh_clear_bit(ss, SPI_SH_SSA | SPI_SH_SSDB | SPI_SH_SSD,
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SPI_SH_CR1);
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}
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static irqreturn_t spi_sh_irq(int irq, void *_ss)
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{
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struct spi_sh_data *ss = (struct spi_sh_data *)_ss;
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unsigned long cr1;
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cr1 = spi_sh_read(ss, SPI_SH_CR1);
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if (cr1 & SPI_SH_TBE)
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ss->cr1 |= SPI_SH_TBE;
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if (cr1 & SPI_SH_TBF)
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ss->cr1 |= SPI_SH_TBF;
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if (cr1 & SPI_SH_RBE)
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ss->cr1 |= SPI_SH_RBE;
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if (cr1 & SPI_SH_RBF)
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ss->cr1 |= SPI_SH_RBF;
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if (ss->cr1) {
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spi_sh_clear_bit(ss, ss->cr1, SPI_SH_CR4);
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wake_up(&ss->wait);
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}
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return IRQ_HANDLED;
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}
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static int spi_sh_remove(struct platform_device *pdev)
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{
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struct spi_sh_data *ss = platform_get_drvdata(pdev);
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spi_unregister_master(ss->master);
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flush_work(&ss->ws);
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free_irq(ss->irq, ss);
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return 0;
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}
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static int spi_sh_probe(struct platform_device *pdev)
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{
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struct resource *res;
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struct spi_master *master;
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struct spi_sh_data *ss;
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int ret, irq;
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/* get base addr */
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (unlikely(res == NULL)) {
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dev_err(&pdev->dev, "invalid resource\n");
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return -EINVAL;
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}
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irq = platform_get_irq(pdev, 0);
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if (irq < 0) {
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dev_err(&pdev->dev, "platform_get_irq error\n");
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return -ENODEV;
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}
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master = spi_alloc_master(&pdev->dev, sizeof(struct spi_sh_data));
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if (master == NULL) {
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dev_err(&pdev->dev, "spi_alloc_master error.\n");
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return -ENOMEM;
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}
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ss = spi_master_get_devdata(master);
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platform_set_drvdata(pdev, ss);
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switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
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case IORESOURCE_MEM_8BIT:
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ss->width = 8;
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break;
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case IORESOURCE_MEM_32BIT:
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ss->width = 32;
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break;
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default:
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dev_err(&pdev->dev, "No support width\n");
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ret = -ENODEV;
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goto error1;
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}
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ss->irq = irq;
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ss->master = master;
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ss->addr = devm_ioremap(&pdev->dev, res->start, resource_size(res));
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if (ss->addr == NULL) {
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dev_err(&pdev->dev, "ioremap error.\n");
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ret = -ENOMEM;
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goto error1;
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}
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INIT_LIST_HEAD(&ss->queue);
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spin_lock_init(&ss->lock);
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INIT_WORK(&ss->ws, spi_sh_work);
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init_waitqueue_head(&ss->wait);
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ret = request_irq(irq, spi_sh_irq, 0, "spi_sh", ss);
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if (ret < 0) {
|
|
dev_err(&pdev->dev, "request_irq error\n");
|
|
goto error1;
|
|
}
|
|
|
|
master->num_chipselect = 2;
|
|
master->bus_num = pdev->id;
|
|
master->setup = spi_sh_setup;
|
|
master->transfer = spi_sh_transfer;
|
|
master->cleanup = spi_sh_cleanup;
|
|
|
|
ret = spi_register_master(master);
|
|
if (ret < 0) {
|
|
printk(KERN_ERR "spi_register_master error.\n");
|
|
goto error3;
|
|
}
|
|
|
|
return 0;
|
|
|
|
error3:
|
|
free_irq(irq, ss);
|
|
error1:
|
|
spi_master_put(master);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct platform_driver spi_sh_driver = {
|
|
.probe = spi_sh_probe,
|
|
.remove = spi_sh_remove,
|
|
.driver = {
|
|
.name = "sh_spi",
|
|
},
|
|
};
|
|
module_platform_driver(spi_sh_driver);
|
|
|
|
MODULE_DESCRIPTION("SH SPI bus driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Yoshihiro Shimoda");
|
|
MODULE_ALIAS("platform:sh_spi");
|