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![Wolfram Sang](/assets/img/avatar_default.png)
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
505 lines
12 KiB
C
505 lines
12 KiB
C
/*
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* Copyright (C) 2012-2013 Uwe Kleine-Koenig for Pengutronix
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*
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* This program is free software; you can redistribute it and/or modify it under
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* the terms of the GNU General Public License version 2 as published by the
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* Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/io.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_bitbang.h>
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#include <linux/gpio.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/of_gpio.h>
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#include <linux/platform_data/efm32-spi.h>
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#define DRIVER_NAME "efm32-spi"
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#define MASK_VAL(mask, val) ((val << __ffs(mask)) & mask)
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#define REG_CTRL 0x00
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#define REG_CTRL_SYNC 0x0001
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#define REG_CTRL_CLKPOL 0x0100
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#define REG_CTRL_CLKPHA 0x0200
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#define REG_CTRL_MSBF 0x0400
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#define REG_CTRL_TXBIL 0x1000
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#define REG_FRAME 0x04
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#define REG_FRAME_DATABITS__MASK 0x000f
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#define REG_FRAME_DATABITS(n) ((n) - 3)
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#define REG_CMD 0x0c
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#define REG_CMD_RXEN 0x0001
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#define REG_CMD_RXDIS 0x0002
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#define REG_CMD_TXEN 0x0004
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#define REG_CMD_TXDIS 0x0008
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#define REG_CMD_MASTEREN 0x0010
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#define REG_STATUS 0x10
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#define REG_STATUS_TXENS 0x0002
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#define REG_STATUS_TXC 0x0020
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#define REG_STATUS_TXBL 0x0040
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#define REG_STATUS_RXDATAV 0x0080
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#define REG_CLKDIV 0x14
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#define REG_RXDATAX 0x18
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#define REG_RXDATAX_RXDATA__MASK 0x01ff
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#define REG_RXDATAX_PERR 0x4000
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#define REG_RXDATAX_FERR 0x8000
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#define REG_TXDATA 0x34
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#define REG_IF 0x40
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#define REG_IF_TXBL 0x0002
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#define REG_IF_RXDATAV 0x0004
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#define REG_IFS 0x44
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#define REG_IFC 0x48
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#define REG_IEN 0x4c
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#define REG_ROUTE 0x54
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#define REG_ROUTE_RXPEN 0x0001
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#define REG_ROUTE_TXPEN 0x0002
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#define REG_ROUTE_CLKPEN 0x0008
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#define REG_ROUTE_LOCATION__MASK 0x0700
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#define REG_ROUTE_LOCATION(n) MASK_VAL(REG_ROUTE_LOCATION__MASK, (n))
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struct efm32_spi_ddata {
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struct spi_bitbang bitbang;
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spinlock_t lock;
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struct clk *clk;
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void __iomem *base;
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unsigned int rxirq, txirq;
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struct efm32_spi_pdata pdata;
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/* irq data */
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struct completion done;
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const u8 *tx_buf;
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u8 *rx_buf;
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unsigned tx_len, rx_len;
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/* chip selects */
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unsigned csgpio[];
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};
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#define ddata_to_dev(ddata) (&(ddata->bitbang.master->dev))
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#define efm32_spi_vdbg(ddata, format, arg...) \
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dev_vdbg(ddata_to_dev(ddata), format, ##arg)
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static void efm32_spi_write32(struct efm32_spi_ddata *ddata,
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u32 value, unsigned offset)
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{
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writel_relaxed(value, ddata->base + offset);
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}
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static u32 efm32_spi_read32(struct efm32_spi_ddata *ddata, unsigned offset)
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{
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return readl_relaxed(ddata->base + offset);
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}
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static void efm32_spi_chipselect(struct spi_device *spi, int is_on)
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{
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struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
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int value = !(spi->mode & SPI_CS_HIGH) == !(is_on == BITBANG_CS_ACTIVE);
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gpio_set_value(ddata->csgpio[spi->chip_select], value);
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}
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static int efm32_spi_setup_transfer(struct spi_device *spi,
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struct spi_transfer *t)
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{
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struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
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unsigned bpw = t->bits_per_word ?: spi->bits_per_word;
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unsigned speed = t->speed_hz ?: spi->max_speed_hz;
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unsigned long clkfreq = clk_get_rate(ddata->clk);
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u32 clkdiv;
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efm32_spi_write32(ddata, REG_CTRL_SYNC | REG_CTRL_MSBF |
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(spi->mode & SPI_CPHA ? REG_CTRL_CLKPHA : 0) |
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(spi->mode & SPI_CPOL ? REG_CTRL_CLKPOL : 0), REG_CTRL);
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efm32_spi_write32(ddata,
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REG_FRAME_DATABITS(bpw), REG_FRAME);
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if (2 * speed >= clkfreq)
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clkdiv = 0;
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else
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clkdiv = 64 * (DIV_ROUND_UP(2 * clkfreq, speed) - 4);
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if (clkdiv > (1U << 21))
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return -EINVAL;
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efm32_spi_write32(ddata, clkdiv, REG_CLKDIV);
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efm32_spi_write32(ddata, REG_CMD_MASTEREN, REG_CMD);
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efm32_spi_write32(ddata, REG_CMD_RXEN | REG_CMD_TXEN, REG_CMD);
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return 0;
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}
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static void efm32_spi_tx_u8(struct efm32_spi_ddata *ddata)
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{
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u8 val = 0;
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if (ddata->tx_buf) {
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val = *ddata->tx_buf;
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ddata->tx_buf++;
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}
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ddata->tx_len--;
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efm32_spi_write32(ddata, val, REG_TXDATA);
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efm32_spi_vdbg(ddata, "%s: tx 0x%x\n", __func__, val);
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}
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static void efm32_spi_rx_u8(struct efm32_spi_ddata *ddata)
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{
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u32 rxdata = efm32_spi_read32(ddata, REG_RXDATAX);
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efm32_spi_vdbg(ddata, "%s: rx 0x%x\n", __func__, rxdata);
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if (ddata->rx_buf) {
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*ddata->rx_buf = rxdata;
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ddata->rx_buf++;
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}
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ddata->rx_len--;
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}
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static void efm32_spi_filltx(struct efm32_spi_ddata *ddata)
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{
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while (ddata->tx_len &&
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ddata->tx_len + 2 > ddata->rx_len &&
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efm32_spi_read32(ddata, REG_STATUS) & REG_STATUS_TXBL) {
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efm32_spi_tx_u8(ddata);
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}
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}
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static int efm32_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
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{
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struct efm32_spi_ddata *ddata = spi_master_get_devdata(spi->master);
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int ret = -EBUSY;
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spin_lock_irq(&ddata->lock);
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if (ddata->tx_buf || ddata->rx_buf)
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goto out_unlock;
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ddata->tx_buf = t->tx_buf;
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ddata->rx_buf = t->rx_buf;
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ddata->tx_len = ddata->rx_len =
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t->len * DIV_ROUND_UP(t->bits_per_word, 8);
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efm32_spi_filltx(ddata);
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reinit_completion(&ddata->done);
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efm32_spi_write32(ddata, REG_IF_TXBL | REG_IF_RXDATAV, REG_IEN);
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spin_unlock_irq(&ddata->lock);
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wait_for_completion(&ddata->done);
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spin_lock_irq(&ddata->lock);
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ret = t->len - max(ddata->tx_len, ddata->rx_len);
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efm32_spi_write32(ddata, 0, REG_IEN);
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ddata->tx_buf = ddata->rx_buf = NULL;
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out_unlock:
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spin_unlock_irq(&ddata->lock);
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return ret;
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}
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static irqreturn_t efm32_spi_rxirq(int irq, void *data)
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{
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struct efm32_spi_ddata *ddata = data;
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irqreturn_t ret = IRQ_NONE;
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spin_lock(&ddata->lock);
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while (ddata->rx_len > 0 &&
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efm32_spi_read32(ddata, REG_STATUS) &
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REG_STATUS_RXDATAV) {
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efm32_spi_rx_u8(ddata);
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ret = IRQ_HANDLED;
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}
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if (!ddata->rx_len) {
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u32 ien = efm32_spi_read32(ddata, REG_IEN);
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ien &= ~REG_IF_RXDATAV;
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efm32_spi_write32(ddata, ien, REG_IEN);
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complete(&ddata->done);
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}
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spin_unlock(&ddata->lock);
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return ret;
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}
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static irqreturn_t efm32_spi_txirq(int irq, void *data)
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{
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struct efm32_spi_ddata *ddata = data;
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efm32_spi_vdbg(ddata,
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"%s: txlen = %u, rxlen = %u, if=0x%08x, stat=0x%08x\n",
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__func__, ddata->tx_len, ddata->rx_len,
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efm32_spi_read32(ddata, REG_IF),
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efm32_spi_read32(ddata, REG_STATUS));
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spin_lock(&ddata->lock);
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efm32_spi_filltx(ddata);
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efm32_spi_vdbg(ddata, "%s: txlen = %u, rxlen = %u\n",
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__func__, ddata->tx_len, ddata->rx_len);
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if (!ddata->tx_len) {
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u32 ien = efm32_spi_read32(ddata, REG_IEN);
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ien &= ~REG_IF_TXBL;
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efm32_spi_write32(ddata, ien, REG_IEN);
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efm32_spi_vdbg(ddata, "disable TXBL\n");
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}
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spin_unlock(&ddata->lock);
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return IRQ_HANDLED;
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}
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static u32 efm32_spi_get_configured_location(struct efm32_spi_ddata *ddata)
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{
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u32 reg = efm32_spi_read32(ddata, REG_ROUTE);
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return (reg & REG_ROUTE_LOCATION__MASK) >> __ffs(REG_ROUTE_LOCATION__MASK);
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}
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static void efm32_spi_probe_dt(struct platform_device *pdev,
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struct spi_master *master, struct efm32_spi_ddata *ddata)
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{
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struct device_node *np = pdev->dev.of_node;
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u32 location;
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int ret;
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ret = of_property_read_u32(np, "energymicro,location", &location);
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if (ret)
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/* fall back to wrongly namespaced property */
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ret = of_property_read_u32(np, "efm32,location", &location);
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if (ret)
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/* fall back to old and (wrongly) generic property "location" */
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ret = of_property_read_u32(np, "location", &location);
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if (!ret) {
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dev_dbg(&pdev->dev, "using location %u\n", location);
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} else {
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/* default to location configured in hardware */
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location = efm32_spi_get_configured_location(ddata);
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dev_info(&pdev->dev, "fall back to location %u\n", location);
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}
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ddata->pdata.location = location;
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}
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static int efm32_spi_probe(struct platform_device *pdev)
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{
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struct efm32_spi_ddata *ddata;
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struct resource *res;
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int ret;
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struct spi_master *master;
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struct device_node *np = pdev->dev.of_node;
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int num_cs, i;
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if (!np)
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return -EINVAL;
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num_cs = of_gpio_named_count(np, "cs-gpios");
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if (num_cs < 0)
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return num_cs;
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master = spi_alloc_master(&pdev->dev,
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sizeof(*ddata) + num_cs * sizeof(unsigned));
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if (!master) {
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dev_dbg(&pdev->dev,
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"failed to allocate spi master controller\n");
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return -ENOMEM;
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}
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platform_set_drvdata(pdev, master);
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master->dev.of_node = pdev->dev.of_node;
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master->num_chipselect = num_cs;
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master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
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master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
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ddata = spi_master_get_devdata(master);
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ddata->bitbang.master = master;
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ddata->bitbang.chipselect = efm32_spi_chipselect;
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ddata->bitbang.setup_transfer = efm32_spi_setup_transfer;
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ddata->bitbang.txrx_bufs = efm32_spi_txrx_bufs;
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spin_lock_init(&ddata->lock);
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init_completion(&ddata->done);
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ddata->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(ddata->clk)) {
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ret = PTR_ERR(ddata->clk);
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dev_err(&pdev->dev, "failed to get clock: %d\n", ret);
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goto err;
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}
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for (i = 0; i < num_cs; ++i) {
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ret = of_get_named_gpio(np, "cs-gpios", i);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to get csgpio#%u (%d)\n",
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i, ret);
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goto err;
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}
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ddata->csgpio[i] = ret;
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dev_dbg(&pdev->dev, "csgpio#%u = %u\n", i, ddata->csgpio[i]);
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ret = devm_gpio_request_one(&pdev->dev, ddata->csgpio[i],
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GPIOF_OUT_INIT_LOW, DRIVER_NAME);
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if (ret < 0) {
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dev_err(&pdev->dev,
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"failed to configure csgpio#%u (%d)\n",
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i, ret);
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goto err;
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}
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}
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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ret = -ENODEV;
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dev_err(&pdev->dev, "failed to determine base address\n");
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goto err;
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}
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if (resource_size(res) < 0x60) {
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ret = -EINVAL;
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dev_err(&pdev->dev, "memory resource too small\n");
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goto err;
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}
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ddata->base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(ddata->base)) {
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ret = PTR_ERR(ddata->base);
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goto err;
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}
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ret = platform_get_irq(pdev, 0);
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if (ret <= 0) {
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dev_err(&pdev->dev, "failed to get rx irq (%d)\n", ret);
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goto err;
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}
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ddata->rxirq = ret;
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ret = platform_get_irq(pdev, 1);
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if (ret <= 0)
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ret = ddata->rxirq + 1;
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ddata->txirq = ret;
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ret = clk_prepare_enable(ddata->clk);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret);
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goto err;
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}
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efm32_spi_probe_dt(pdev, master, ddata);
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efm32_spi_write32(ddata, 0, REG_IEN);
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efm32_spi_write32(ddata, REG_ROUTE_TXPEN | REG_ROUTE_RXPEN |
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REG_ROUTE_CLKPEN |
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REG_ROUTE_LOCATION(ddata->pdata.location), REG_ROUTE);
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ret = request_irq(ddata->rxirq, efm32_spi_rxirq,
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0, DRIVER_NAME " rx", ddata);
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if (ret) {
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dev_err(&pdev->dev, "failed to register rxirq (%d)\n", ret);
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goto err_disable_clk;
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}
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ret = request_irq(ddata->txirq, efm32_spi_txirq,
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0, DRIVER_NAME " tx", ddata);
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if (ret) {
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dev_err(&pdev->dev, "failed to register txirq (%d)\n", ret);
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goto err_free_rx_irq;
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}
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ret = spi_bitbang_start(&ddata->bitbang);
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if (ret) {
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dev_err(&pdev->dev, "spi_bitbang_start failed (%d)\n", ret);
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free_irq(ddata->txirq, ddata);
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err_free_rx_irq:
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free_irq(ddata->rxirq, ddata);
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err_disable_clk:
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clk_disable_unprepare(ddata->clk);
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err:
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spi_master_put(master);
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}
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return ret;
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}
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static int efm32_spi_remove(struct platform_device *pdev)
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{
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struct spi_master *master = platform_get_drvdata(pdev);
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struct efm32_spi_ddata *ddata = spi_master_get_devdata(master);
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spi_bitbang_stop(&ddata->bitbang);
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efm32_spi_write32(ddata, 0, REG_IEN);
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free_irq(ddata->txirq, ddata);
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free_irq(ddata->rxirq, ddata);
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clk_disable_unprepare(ddata->clk);
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spi_master_put(master);
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return 0;
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}
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static const struct of_device_id efm32_spi_dt_ids[] = {
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{
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.compatible = "energymicro,efm32-spi",
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}, {
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/* doesn't follow the "vendor,device" scheme, don't use */
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.compatible = "efm32,spi",
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}, {
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/* sentinel */
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}
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};
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MODULE_DEVICE_TABLE(of, efm32_spi_dt_ids);
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static struct platform_driver efm32_spi_driver = {
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.probe = efm32_spi_probe,
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.remove = efm32_spi_remove,
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|
|
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.driver = {
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|
.name = DRIVER_NAME,
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.of_match_table = efm32_spi_dt_ids,
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},
|
|
};
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module_platform_driver(efm32_spi_driver);
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|
|
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MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
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MODULE_DESCRIPTION("EFM32 SPI driver");
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|
MODULE_LICENSE("GPL v2");
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|
MODULE_ALIAS("platform:" DRIVER_NAME);
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