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