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@ -17,10 +17,13 @@ |
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#include <linux/spi/spi_bitbang.h> |
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#include <linux/gfp.h> |
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#include <linux/delay.h> |
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#include <linux/crc16.h> |
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#define PFX "ucmb: " |
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#define DEBUG |
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MODULE_LICENSE("GPL"); |
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MODULE_DESCRIPTION("Microcontroller Message Bus"); |
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@ -28,6 +31,8 @@ MODULE_AUTHOR("Michael Buesch"); |
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struct ucmb { |
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unsigned int msg_delay_ms; |
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/* Misc character device driver */ |
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struct miscdevice mdev; |
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struct file_operations mdev_fops; |
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@ -45,6 +50,10 @@ struct ucmb_message_hdr { |
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__le16 len; /* Payload length (excluding header) */ |
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} __attribute__((packed)); |
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struct ucmb_message_footer { |
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__le16 crc; /* CRC of the header + payload. */ |
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} __attribute__((packed)); |
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struct ucmb_status { |
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__le16 magic; /* UCMB_MAGIC */ |
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__le16 code; /* enum ucmb_status_code */ |
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@ -58,6 +67,7 @@ enum ucmb_status_code { |
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UCMB_STAT_EPROTO, /* Protocol format error */ |
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UCMB_STAT_ENOMEM, /* Out of memory */ |
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UCMB_STAT_E2BIG, /* Message too big */ |
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UCMB_STAT_ECRC, /* CRC error */ |
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}; |
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@ -71,6 +81,9 @@ static struct ucmb_platform_data ucmb_list[] = { |
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.gpio_sck = 0, |
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.gpio_miso = 1, |
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.gpio_mosi = 2, |
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.mode = SPI_MODE_0, |
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.max_speed_hz = 128000, /* Hz */ |
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.msg_delay_ms = 1, /* mS */ |
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}, |
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}; |
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@ -106,6 +119,8 @@ static int ucmb_status_code_to_errno(enum ucmb_status_code code) |
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return -ENOMEM; |
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case UCMB_STAT_E2BIG: |
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return -E2BIG; |
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case UCMB_STAT_ECRC: |
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return -EBADMSG; |
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} |
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return -EBUSY; |
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} |
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@ -115,7 +130,6 @@ static inline struct ucmb * filp_to_ucmb(struct file *filp) |
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return container_of(filp->f_op, struct ucmb, mdev_fops); |
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} |
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/* FIXME offp */ |
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static ssize_t ucmb_read(struct file *filp, char __user *user_buf, |
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size_t size, loff_t *offp) |
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{ |
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@ -123,13 +137,11 @@ static ssize_t ucmb_read(struct file *filp, char __user *user_buf, |
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u8 *buf; |
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int res, err; |
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struct ucmb_message_hdr hdr; |
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struct ucmb_message_footer footer; |
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struct ucmb_status status = { .magic = cpu_to_le16(UCMB_MAGIC), }; |
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u16 crc = 0xFFFF; |
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err = -E2BIG; |
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if (size > PAGE_SIZE) |
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goto out; |
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if (size > UCMB_MAX_MSG_LEN) |
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goto out; |
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size = min_t(size_t, size, PAGE_SIZE); |
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err = -ENOMEM; |
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buf = (char *)__get_free_page(GFP_KERNEL); |
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@ -139,6 +151,10 @@ static ssize_t ucmb_read(struct file *filp, char __user *user_buf, |
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err = spi_read(ucmb->sdev, (u8 *)&hdr, sizeof(hdr)); |
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if (err) |
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goto out_free; |
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#ifdef DEBUG |
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printk(KERN_DEBUG PFX "Received message header 0x%04X 0x%04X\n", |
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le16_to_cpu(hdr.magic), le16_to_cpu(hdr.len)); |
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#endif |
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err = -EPROTO; |
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if (hdr.magic != cpu_to_le16(UCMB_MAGIC)) |
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goto out_free; |
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@ -147,17 +163,31 @@ static ssize_t ucmb_read(struct file *filp, char __user *user_buf, |
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goto out_free; |
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size = le16_to_cpu(hdr.len); |
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err = spi_read(ucmb->sdev, buf, size); |
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if (err) |
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goto out_free; |
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err = spi_read(ucmb->sdev, (u8 *)&footer, sizeof(footer)); |
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if (err) |
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goto out_free; |
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err = -EFAULT; |
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if (copy_to_user(user_buf, buf, size)) |
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crc = crc16(crc, &hdr, sizeof(hdr)); |
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crc = crc16(crc, buf, size); |
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crc ^= 0xFFFF; |
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if (crc != le16_to_cpu(footer.crc)) { |
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err = -EPROTO; |
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status.code = UCMB_STAT_ECRC; |
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goto out_send_status; |
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} |
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if (copy_to_user(user_buf, buf, size)) { |
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err = -EFAULT; |
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status.code = UCMB_STAT_ENOMEM; |
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goto out_send_status; |
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} |
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status.code = UCMB_STAT_OK; |
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err = 0; |
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out_send_status: |
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status.code = err ? UCMB_STAT_ENOMEM : UCMB_STAT_OK; |
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res = spi_write(ucmb->sdev, (u8 *)&status, sizeof(status)); |
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if (res && !err) |
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err = res; |
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@ -167,7 +197,6 @@ out: |
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return err ? err : size; |
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} |
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/* FIXME offp */ |
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static ssize_t ucmb_write(struct file *filp, const char __user *user_buf, |
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size_t size, loff_t *offp) |
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{ |
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@ -175,8 +204,10 @@ static ssize_t ucmb_write(struct file *filp, const char __user *user_buf, |
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u8 *buf; |
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int err; |
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struct ucmb_message_hdr hdr = { .magic = cpu_to_le16(UCMB_MAGIC), }; |
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struct ucmb_message_footer footer = { .crc = 0xFFFF, }; |
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struct ucmb_status status; |
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struct spi_transfer spi_hdr_xfer; |
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struct spi_transfer spi_footer_xfer; |
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struct spi_transfer spi_data_xfer; |
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struct spi_message spi_msg; |
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@ -192,6 +223,10 @@ static ssize_t ucmb_write(struct file *filp, const char __user *user_buf, |
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goto out_free; |
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hdr.len = cpu_to_le16(size); |
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footer.crc = crc16(footer.crc, &hdr, sizeof(hdr)); |
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footer.crc = crc16(footer.crc, buf, size); |
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footer.crc ^= 0xFFFF; |
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spi_message_init(&spi_msg); |
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memset(&spi_hdr_xfer, 0, sizeof(spi_hdr_xfer)); |
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@ -204,18 +239,28 @@ static ssize_t ucmb_write(struct file *filp, const char __user *user_buf, |
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spi_data_xfer.len = size; |
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spi_message_add_tail(&spi_data_xfer, &spi_msg); |
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memset(&spi_footer_xfer, 0, sizeof(spi_footer_xfer)); |
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spi_footer_xfer.tx_buf = &footer; |
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spi_footer_xfer.len = sizeof(footer); |
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spi_message_add_tail(&spi_footer_xfer, &spi_msg); |
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/* Send the message, including header. */ |
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err = spi_sync(ucmb->sdev, &spi_msg); |
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if (err) |
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goto out_free; |
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/* The microcontroller deserves some time to process the message. */ |
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msleep(1); |
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if (ucmb->msg_delay_ms) |
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msleep(ucmb->msg_delay_ms); |
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/* Get the status code. */ |
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err = spi_read(ucmb->sdev, (u8 *)&status, sizeof(status)); |
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if (err) |
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goto out_free; |
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#ifdef DEBUG |
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printk(KERN_DEBUG PFX "Sent message. Status report: 0x%04X 0x%04X\n", |
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le16_to_cpu(status.magic), le16_to_cpu(status.code)); |
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#endif |
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err = -EPROTO; |
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if (status.magic != cpu_to_le16(UCMB_MAGIC)) |
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goto out_free; |
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@ -244,6 +289,7 @@ static int __devinit ucmb_probe(struct platform_device *pdev) |
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ucmb = kzalloc(sizeof(struct ucmb), GFP_KERNEL); |
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if (!ucmb) |
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return -ENOMEM; |
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ucmb->msg_delay_ms = pdata->msg_delay_ms; |
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/* Create the SPI GPIO bus master. */ |
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@ -280,9 +326,9 @@ static int __devinit ucmb_probe(struct platform_device *pdev) |
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printk(KERN_ERR PFX "Failed to allocate SPI device\n"); |
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goto err_unreg_spi_gpio_pdev; |
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} |
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ucmb->sdev->max_speed_hz = 500000; |
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ucmb->sdev->max_speed_hz = pdata->max_speed_hz; |
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ucmb->sdev->chip_select = 0; |
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ucmb->sdev->mode = SPI_MODE_0; |
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ucmb->sdev->mode = pdata->mode; |
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strlcpy(ucmb->sdev->modalias, "ucmb", /* We are the SPI driver. */ |
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sizeof(ucmb->sdev->modalias)); |
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ucmb->sdev->controller_data = (void *)pdata->gpio_cs; |