高通MSM8953平台SPI6配置修改

/* * Simple synchronous userspace interface to SPI devices * * Copyright (C) 2006 SWAPP * Andrea Paterniani <a.paterniani@swapp-eng.it> * Copyright (C) 2007 David Brownell (simplification, cleanup) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/init.h> #include <linux/module.h> #include <linux/ioctl.h> #include <linux/fs.h> #include <linux/device.h> #include <linux/err.h> #include <linux/list.h> #include <linux/errno.h> #include <linux/mutex.h> #include <linux/slab.h> #include <linux/compat.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/spi/spi.h> #include <linux/spi/spidev.h> #include <linux/uaccess.h> /* * This supports access to SPI devices using normal userspace I/O calls. * Note that while traditional UNIX/POSIX I/O semantics are half duplex, * and often mask message boundaries, full SPI support requires full duplex * transfers. There are several kinds of internal message boundaries to * handle chipselect management and other protocol options. * * SPI has a character major number assigned. We allocate minor numbers * dynamically using a bitmask. You must use hotplug tools, such as udev * (or mdev with busybox) to create and destroy the /dev/spidevB.C device * nodes, since there is no fixed association of minor numbers with any * particular SPI bus or device. */ #define SPIDEV_MAJOR 153 /* assigned */ #define N_SPI_MINORS 32 /* ... up to 256 */ static DECLARE_BITMAP(minors, N_SPI_MINORS); /* Bit masks for spi_device.mode management. Note that incorrect * settings for some settings can cause *lots* of trouble for other * devices on a shared bus: * * - CS_HIGH ... this device will be active when it shouldn't be * - 3WIRE ... when active, it won't behave as it should * - NO_CS ... there will be no explicit message boundaries; this * is completely incompatible with the shared bus model * - READY ... transfers may proceed when they shouldn't. * * REVISIT should changing those flags be privileged? */ #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \ | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD) struct spidev_data { dev_t devt; spinlock_t spi_lock; struct spi_device *spi; struct list_head device_entry; /* TX/RX buffers are NULL unless this device is open (users > 0) */ struct mutex buf_lock; unsigned users; u8 *tx_buffer; u8 *rx_buffer; }; static LIST_HEAD(device_list); static DEFINE_MUTEX(device_list_lock); static unsigned bufsiz = 4096; module_param(bufsiz, uint, S_IRUGO); MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); /* * This can be used for testing the controller, given the busnum and the * cs required to use. If those parameters are used, spidev is * dynamically added as device on the busnum, and messages can be sent * via this interface. */ static int busnum = -1; module_param(busnum, int, S_IRUGO); MODULE_PARM_DESC(busnum, "bus num of the controller"); static int chipselect = -1; module_param(chipselect, int, S_IRUGO); MODULE_PARM_DESC(chipselect, "chip select of the desired device"); static int maxspeed = 10000000; module_param(maxspeed, int, S_IRUGO); MODULE_PARM_DESC(maxspeed, "max_speed of the desired device"); static int spimode = SPI_MODE_3; module_param(spimode, int, S_IRUGO); MODULE_PARM_DESC(spimode, "mode of the desired device"); static struct spi_device *spi; /*-------------------------------------------------------------------------*/ /* * We can't use the standard synchronous wrappers for file I/O; we * need to protect against async removal of the underlying spi_device. */ static void spidev_complete(void *arg) { complete(arg); } static ssize_t spidev_sync(struct spidev_data *spidev, struct spi_message *message) { DECLARE_COMPLETION_ONSTACK(done); int status; message->complete = spidev_complete; message->context = &done; spin_lock_irq(&spidev->spi_lock); if (spidev->spi == NULL) status = -ESHUTDOWN; else status = spi_async(spidev->spi, message); spin_unlock_irq(&spidev->spi_lock); if (status == 0) { wait_for_completion(&done); status = message->status; if (status == 0) status = message->actual_length; } return status; } static inline ssize_t spidev_sync_write(struct spidev_data *spidev, size_t len) { struct spi_transfer t = { .tx_buf = spidev->tx_buffer, .len = len, }; struct spi_message m; spi_message_init(&m); spi_message_add_tail(&t, &m); return spidev_sync(spidev, &m); } static inline ssize_t spidev_sync_read(struct spidev_data *spidev, size_t len) { struct spi_transfer t = { .rx_buf = spidev->rx_buffer, .len = len, }; struct spi_message m; spi_message_init(&m); spi_message_add_tail(&t, &m); return spidev_sync(spidev, &m); } /*-------------------------------------------------------------------------*/ /* Read-only message with current device setup */ static ssize_t spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) { struct spidev_data *spidev; ssize_t status = 0; /* chipselect only toggles at start or end of operation */ if (count > bufsiz) return -EMSGSIZE; spidev = filp->private_data; mutex_lock(&spidev->buf_lock); status = spidev_sync_read(spidev, count); if (status > 0) { unsigned long missing; missing = copy_to_user(buf, spidev->rx_buffer, status); if (missing == status) status = -EFAULT; else status = status - missing; } mutex_unlock(&spidev->buf_lock); return status; } /* Write-only message with current device setup */ static ssize_t spidev_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) { struct spidev_data *spidev; ssize_t status = 0; unsigned long missing; /* chipselect only toggles at start or end of operation */ if (count > bufsiz) return -EMSGSIZE; spidev = filp->private_data; mutex_lock(&spidev->buf_lock); missing = copy_from_user(spidev->tx_buffer, buf, count); if (missing == 0) status = spidev_sync_write(spidev, count); else status = -EFAULT; mutex_unlock(&spidev->buf_lock); return status; } static int spidev_message(struct spidev_data *spidev, struct spi_ioc_transfer *u_xfers, unsigned n_xfers) { struct spi_message msg; struct spi_transfer *k_xfers; struct spi_transfer *k_tmp; struct spi_ioc_transfer *u_tmp; unsigned n, total; u8 *tx_buf, *rx_buf; int status = -EFAULT; spi_message_init(&msg); k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); if (k_xfers == NULL) return -ENOMEM; /* Construct spi_message, copying any tx data to bounce buffer. * We walk the array of user-provided transfers, using each one * to initialize a kernel version of the same transfer. */ tx_buf = spidev->tx_buffer; rx_buf = spidev->rx_buffer; total = 0; for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; n; n--, k_tmp++, u_tmp++) { k_tmp->len = u_tmp->len; total += k_tmp->len; /* Check total length of transfers. Also check each * transfer length to avoid arithmetic overflow. */ if (total > bufsiz || k_tmp->len > bufsiz) { status = -EMSGSIZE; goto done; } if (u_tmp->rx_buf) { k_tmp->rx_buf = rx_buf; if (!access_ok(VERIFY_WRITE, (u8 __user *) (uintptr_t) u_tmp->rx_buf, u_tmp->len))