diff options
Diffstat (limited to 'drivers/spi/spi-efm32.c')
| -rw-r--r-- | drivers/spi/spi-efm32.c | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/drivers/spi/spi-efm32.c b/drivers/spi/spi-efm32.c new file mode 100644 index 000000000..065fe8744 --- /dev/null +++ b/drivers/spi/spi-efm32.c @@ -0,0 +1,505 @@ +/* + * 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); |