diff options
Diffstat (limited to 'drivers/spi/spi-altera-core.c')
| -rw-r--r-- | drivers/spi/spi-altera-core.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/drivers/spi/spi-altera-core.c b/drivers/spi/spi-altera-core.c new file mode 100644 index 000000000..de4d31c53 --- /dev/null +++ b/drivers/spi/spi-altera-core.c @@ -0,0 +1,222 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Altera SPI driver + * + * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw> + * + * Based on spi_s3c24xx.c, which is: + * Copyright (c) 2006 Ben Dooks + * Copyright (c) 2006 Simtec Electronics + * Ben Dooks <ben@simtec.co.uk> + */ + +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/spi/altera.h> +#include <linux/spi/spi.h> +#include <linux/io.h> +#include <linux/of.h> + +#define DRV_NAME "spi_altera" + +#define ALTERA_SPI_RXDATA 0 +#define ALTERA_SPI_TXDATA 4 +#define ALTERA_SPI_STATUS 8 +#define ALTERA_SPI_CONTROL 12 +#define ALTERA_SPI_SLAVE_SEL 20 + +#define ALTERA_SPI_STATUS_ROE_MSK 0x8 +#define ALTERA_SPI_STATUS_TOE_MSK 0x10 +#define ALTERA_SPI_STATUS_TMT_MSK 0x20 +#define ALTERA_SPI_STATUS_TRDY_MSK 0x40 +#define ALTERA_SPI_STATUS_RRDY_MSK 0x80 +#define ALTERA_SPI_STATUS_E_MSK 0x100 + +#define ALTERA_SPI_CONTROL_IROE_MSK 0x8 +#define ALTERA_SPI_CONTROL_ITOE_MSK 0x10 +#define ALTERA_SPI_CONTROL_ITRDY_MSK 0x40 +#define ALTERA_SPI_CONTROL_IRRDY_MSK 0x80 +#define ALTERA_SPI_CONTROL_IE_MSK 0x100 +#define ALTERA_SPI_CONTROL_SSO_MSK 0x400 + +static int altr_spi_writel(struct altera_spi *hw, unsigned int reg, + unsigned int val) +{ + int ret; + + ret = regmap_write(hw->regmap, hw->regoff + reg, val); + if (ret) + dev_err(hw->dev, "fail to write reg 0x%x val 0x%x: %d\n", + reg, val, ret); + + return ret; +} + +static int altr_spi_readl(struct altera_spi *hw, unsigned int reg, + unsigned int *val) +{ + int ret; + + ret = regmap_read(hw->regmap, hw->regoff + reg, val); + if (ret) + dev_err(hw->dev, "fail to read reg 0x%x: %d\n", reg, ret); + + return ret; +} + +static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev) +{ + return spi_master_get_devdata(sdev->master); +} + +static void altera_spi_set_cs(struct spi_device *spi, bool is_high) +{ + struct altera_spi *hw = altera_spi_to_hw(spi); + + if (is_high) { + hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK; + altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); + altr_spi_writel(hw, ALTERA_SPI_SLAVE_SEL, 0); + } else { + altr_spi_writel(hw, ALTERA_SPI_SLAVE_SEL, + BIT(spi->chip_select)); + hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK; + altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); + } +} + +static void altera_spi_tx_word(struct altera_spi *hw) +{ + unsigned int txd = 0; + + if (hw->tx) { + switch (hw->bytes_per_word) { + case 1: + txd = hw->tx[hw->count]; + break; + case 2: + txd = (hw->tx[hw->count * 2] + | (hw->tx[hw->count * 2 + 1] << 8)); + break; + case 4: + txd = (hw->tx[hw->count * 4] + | (hw->tx[hw->count * 4 + 1] << 8) + | (hw->tx[hw->count * 4 + 2] << 16) + | (hw->tx[hw->count * 4 + 3] << 24)); + break; + + } + } + + altr_spi_writel(hw, ALTERA_SPI_TXDATA, txd); +} + +static void altera_spi_rx_word(struct altera_spi *hw) +{ + unsigned int rxd; + + altr_spi_readl(hw, ALTERA_SPI_RXDATA, &rxd); + if (hw->rx) { + switch (hw->bytes_per_word) { + case 1: + hw->rx[hw->count] = rxd; + break; + case 2: + hw->rx[hw->count * 2] = rxd; + hw->rx[hw->count * 2 + 1] = rxd >> 8; + break; + case 4: + hw->rx[hw->count * 4] = rxd; + hw->rx[hw->count * 4 + 1] = rxd >> 8; + hw->rx[hw->count * 4 + 2] = rxd >> 16; + hw->rx[hw->count * 4 + 3] = rxd >> 24; + break; + + } + } + + hw->count++; +} + +static int altera_spi_txrx(struct spi_master *master, + struct spi_device *spi, struct spi_transfer *t) +{ + struct altera_spi *hw = spi_master_get_devdata(master); + u32 val; + + hw->tx = t->tx_buf; + hw->rx = t->rx_buf; + hw->count = 0; + hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8); + hw->len = t->len / hw->bytes_per_word; + + if (hw->irq >= 0) { + /* enable receive interrupt */ + hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK; + altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); + + /* send the first byte */ + altera_spi_tx_word(hw); + + return 1; + } + + while (hw->count < hw->len) { + altera_spi_tx_word(hw); + + for (;;) { + altr_spi_readl(hw, ALTERA_SPI_STATUS, &val); + if (val & ALTERA_SPI_STATUS_RRDY_MSK) + break; + + cpu_relax(); + } + + altera_spi_rx_word(hw); + } + spi_finalize_current_transfer(master); + + return 0; +} + +irqreturn_t altera_spi_irq(int irq, void *dev) +{ + struct spi_master *master = dev; + struct altera_spi *hw = spi_master_get_devdata(master); + + altera_spi_rx_word(hw); + + if (hw->count < hw->len) { + altera_spi_tx_word(hw); + } else { + /* disable receive interrupt */ + hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK; + altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); + + spi_finalize_current_transfer(master); + } + + return IRQ_HANDLED; +} +EXPORT_SYMBOL_GPL(altera_spi_irq); + +void altera_spi_init_master(struct spi_master *master) +{ + struct altera_spi *hw = spi_master_get_devdata(master); + u32 val; + + master->transfer_one = altera_spi_txrx; + master->set_cs = altera_spi_set_cs; + + /* program defaults into the registers */ + hw->imr = 0; /* disable spi interrupts */ + altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr); + altr_spi_writel(hw, ALTERA_SPI_STATUS, 0); /* clear status reg */ + altr_spi_readl(hw, ALTERA_SPI_STATUS, &val); + if (val & ALTERA_SPI_STATUS_RRDY_MSK) + altr_spi_readl(hw, ALTERA_SPI_RXDATA, &val); /* flush rxdata */ +} +EXPORT_SYMBOL_GPL(altera_spi_init_master); + +MODULE_LICENSE("GPL"); |