|  | /* | 
|  | * OpenCores tiny SPI master driver | 
|  | * | 
|  | * http://opencores.org/project,tiny_spi | 
|  | * | 
|  | * Copyright (C) 2011 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> | 
|  | * | 
|  | * 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/interrupt.h> | 
|  | #include <linux/errno.h> | 
|  | #include <linux/module.h> | 
|  | #include <linux/platform_device.h> | 
|  | #include <linux/spi/spi.h> | 
|  | #include <linux/spi/spi_bitbang.h> | 
|  | #include <linux/spi/spi_oc_tiny.h> | 
|  | #include <linux/io.h> | 
|  | #include <linux/gpio.h> | 
|  | #include <linux/of.h> | 
|  |  | 
|  | #define DRV_NAME "spi_oc_tiny" | 
|  |  | 
|  | #define TINY_SPI_RXDATA 0 | 
|  | #define TINY_SPI_TXDATA 4 | 
|  | #define TINY_SPI_STATUS 8 | 
|  | #define TINY_SPI_CONTROL 12 | 
|  | #define TINY_SPI_BAUD 16 | 
|  |  | 
|  | #define TINY_SPI_STATUS_TXE 0x1 | 
|  | #define TINY_SPI_STATUS_TXR 0x2 | 
|  |  | 
|  | struct tiny_spi { | 
|  | /* bitbang has to be first */ | 
|  | struct spi_bitbang bitbang; | 
|  | struct completion done; | 
|  |  | 
|  | void __iomem *base; | 
|  | int irq; | 
|  | unsigned int freq; | 
|  | unsigned int baudwidth; | 
|  | unsigned int baud; | 
|  | unsigned int speed_hz; | 
|  | unsigned int mode; | 
|  | unsigned int len; | 
|  | unsigned int txc, rxc; | 
|  | const u8 *txp; | 
|  | u8 *rxp; | 
|  | int gpio_cs_count; | 
|  | int *gpio_cs; | 
|  | }; | 
|  |  | 
|  | static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev) | 
|  | { | 
|  | return spi_master_get_devdata(sdev->master); | 
|  | } | 
|  |  | 
|  | static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz) | 
|  | { | 
|  | struct tiny_spi *hw = tiny_spi_to_hw(spi); | 
|  |  | 
|  | return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1; | 
|  | } | 
|  |  | 
|  | static void tiny_spi_chipselect(struct spi_device *spi, int is_active) | 
|  | { | 
|  | struct tiny_spi *hw = tiny_spi_to_hw(spi); | 
|  |  | 
|  | if (hw->gpio_cs_count > 0) { | 
|  | gpio_set_value(hw->gpio_cs[spi->chip_select], | 
|  | (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); | 
|  | } | 
|  | } | 
|  |  | 
|  | static int tiny_spi_setup_transfer(struct spi_device *spi, | 
|  | struct spi_transfer *t) | 
|  | { | 
|  | struct tiny_spi *hw = tiny_spi_to_hw(spi); | 
|  | unsigned int baud = hw->baud; | 
|  |  | 
|  | if (t) { | 
|  | if (t->speed_hz && t->speed_hz != hw->speed_hz) | 
|  | baud = tiny_spi_baud(spi, t->speed_hz); | 
|  | } | 
|  | writel(baud, hw->base + TINY_SPI_BAUD); | 
|  | writel(hw->mode, hw->base + TINY_SPI_CONTROL); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int tiny_spi_setup(struct spi_device *spi) | 
|  | { | 
|  | struct tiny_spi *hw = tiny_spi_to_hw(spi); | 
|  |  | 
|  | if (spi->max_speed_hz != hw->speed_hz) { | 
|  | hw->speed_hz = spi->max_speed_hz; | 
|  | hw->baud = tiny_spi_baud(spi, hw->speed_hz); | 
|  | } | 
|  | hw->mode = spi->mode & (SPI_CPOL | SPI_CPHA); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static inline void tiny_spi_wait_txr(struct tiny_spi *hw) | 
|  | { | 
|  | while (!(readb(hw->base + TINY_SPI_STATUS) & | 
|  | TINY_SPI_STATUS_TXR)) | 
|  | cpu_relax(); | 
|  | } | 
|  |  | 
|  | static inline void tiny_spi_wait_txe(struct tiny_spi *hw) | 
|  | { | 
|  | while (!(readb(hw->base + TINY_SPI_STATUS) & | 
|  | TINY_SPI_STATUS_TXE)) | 
|  | cpu_relax(); | 
|  | } | 
|  |  | 
|  | static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) | 
|  | { | 
|  | struct tiny_spi *hw = tiny_spi_to_hw(spi); | 
|  | const u8 *txp = t->tx_buf; | 
|  | u8 *rxp = t->rx_buf; | 
|  | unsigned int i; | 
|  |  | 
|  | if (hw->irq >= 0) { | 
|  | /* use interrupt driven data transfer */ | 
|  | hw->len = t->len; | 
|  | hw->txp = t->tx_buf; | 
|  | hw->rxp = t->rx_buf; | 
|  | hw->txc = 0; | 
|  | hw->rxc = 0; | 
|  |  | 
|  | /* send the first byte */ | 
|  | if (t->len > 1) { | 
|  | writeb(hw->txp ? *hw->txp++ : 0, | 
|  | hw->base + TINY_SPI_TXDATA); | 
|  | hw->txc++; | 
|  | writeb(hw->txp ? *hw->txp++ : 0, | 
|  | hw->base + TINY_SPI_TXDATA); | 
|  | hw->txc++; | 
|  | writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS); | 
|  | } else { | 
|  | writeb(hw->txp ? *hw->txp++ : 0, | 
|  | hw->base + TINY_SPI_TXDATA); | 
|  | hw->txc++; | 
|  | writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS); | 
|  | } | 
|  |  | 
|  | wait_for_completion(&hw->done); | 
|  | } else { | 
|  | /* we need to tighten the transfer loop */ | 
|  | writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA); | 
|  | for (i = 1; i < t->len; i++) { | 
|  | writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA); | 
|  |  | 
|  | if (rxp || (i != t->len - 1)) | 
|  | tiny_spi_wait_txr(hw); | 
|  | if (rxp) | 
|  | *rxp++ = readb(hw->base + TINY_SPI_TXDATA); | 
|  | } | 
|  | tiny_spi_wait_txe(hw); | 
|  | if (rxp) | 
|  | *rxp++ = readb(hw->base + TINY_SPI_RXDATA); | 
|  | } | 
|  |  | 
|  | return t->len; | 
|  | } | 
|  |  | 
|  | static irqreturn_t tiny_spi_irq(int irq, void *dev) | 
|  | { | 
|  | struct tiny_spi *hw = dev; | 
|  |  | 
|  | writeb(0, hw->base + TINY_SPI_STATUS); | 
|  | if (hw->rxc + 1 == hw->len) { | 
|  | if (hw->rxp) | 
|  | *hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA); | 
|  | hw->rxc++; | 
|  | complete(&hw->done); | 
|  | } else { | 
|  | if (hw->rxp) | 
|  | *hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA); | 
|  | hw->rxc++; | 
|  | if (hw->txc < hw->len) { | 
|  | writeb(hw->txp ? *hw->txp++ : 0, | 
|  | hw->base + TINY_SPI_TXDATA); | 
|  | hw->txc++; | 
|  | writeb(TINY_SPI_STATUS_TXR, | 
|  | hw->base + TINY_SPI_STATUS); | 
|  | } else { | 
|  | writeb(TINY_SPI_STATUS_TXE, | 
|  | hw->base + TINY_SPI_STATUS); | 
|  | } | 
|  | } | 
|  | return IRQ_HANDLED; | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_OF | 
|  | #include <linux/of_gpio.h> | 
|  |  | 
|  | static int tiny_spi_of_probe(struct platform_device *pdev) | 
|  | { | 
|  | struct tiny_spi *hw = platform_get_drvdata(pdev); | 
|  | struct device_node *np = pdev->dev.of_node; | 
|  | unsigned int i; | 
|  | u32 val; | 
|  |  | 
|  | if (!np) | 
|  | return 0; | 
|  | hw->gpio_cs_count = of_gpio_count(np); | 
|  | if (hw->gpio_cs_count > 0) { | 
|  | hw->gpio_cs = devm_kcalloc(&pdev->dev, | 
|  | hw->gpio_cs_count, sizeof(unsigned int), | 
|  | GFP_KERNEL); | 
|  | if (!hw->gpio_cs) | 
|  | return -ENOMEM; | 
|  | } | 
|  | for (i = 0; i < hw->gpio_cs_count; i++) { | 
|  | hw->gpio_cs[i] = of_get_gpio_flags(np, i, NULL); | 
|  | if (hw->gpio_cs[i] < 0) | 
|  | return -ENODEV; | 
|  | } | 
|  | hw->bitbang.master->dev.of_node = pdev->dev.of_node; | 
|  | if (!of_property_read_u32(np, "clock-frequency", &val)) | 
|  | hw->freq = val; | 
|  | if (!of_property_read_u32(np, "baud-width", &val)) | 
|  | hw->baudwidth = val; | 
|  | return 0; | 
|  | } | 
|  | #else /* !CONFIG_OF */ | 
|  | static int tiny_spi_of_probe(struct platform_device *pdev) | 
|  | { | 
|  | return 0; | 
|  | } | 
|  | #endif /* CONFIG_OF */ | 
|  |  | 
|  | static int tiny_spi_probe(struct platform_device *pdev) | 
|  | { | 
|  | struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev); | 
|  | struct tiny_spi *hw; | 
|  | struct spi_master *master; | 
|  | struct resource *res; | 
|  | unsigned int i; | 
|  | int err = -ENODEV; | 
|  |  | 
|  | master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi)); | 
|  | if (!master) | 
|  | return err; | 
|  |  | 
|  | /* setup the master state. */ | 
|  | master->bus_num = pdev->id; | 
|  | master->num_chipselect = 255; | 
|  | master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; | 
|  | master->setup = tiny_spi_setup; | 
|  |  | 
|  | hw = spi_master_get_devdata(master); | 
|  | platform_set_drvdata(pdev, hw); | 
|  |  | 
|  | /* setup the state for the bitbang driver */ | 
|  | hw->bitbang.master = master; | 
|  | hw->bitbang.setup_transfer = tiny_spi_setup_transfer; | 
|  | hw->bitbang.chipselect = tiny_spi_chipselect; | 
|  | hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs; | 
|  |  | 
|  | /* find and map our resources */ | 
|  | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | 
|  | hw->base = devm_ioremap_resource(&pdev->dev, res); | 
|  | if (IS_ERR(hw->base)) { | 
|  | err = PTR_ERR(hw->base); | 
|  | goto exit; | 
|  | } | 
|  | /* irq is optional */ | 
|  | hw->irq = platform_get_irq(pdev, 0); | 
|  | if (hw->irq >= 0) { | 
|  | init_completion(&hw->done); | 
|  | err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0, | 
|  | pdev->name, hw); | 
|  | if (err) | 
|  | goto exit; | 
|  | } | 
|  | /* find platform data */ | 
|  | if (platp) { | 
|  | hw->gpio_cs_count = platp->gpio_cs_count; | 
|  | hw->gpio_cs = platp->gpio_cs; | 
|  | if (platp->gpio_cs_count && !platp->gpio_cs) { | 
|  | err = -EBUSY; | 
|  | goto exit; | 
|  | } | 
|  | hw->freq = platp->freq; | 
|  | hw->baudwidth = platp->baudwidth; | 
|  | } else { | 
|  | err = tiny_spi_of_probe(pdev); | 
|  | if (err) | 
|  | goto exit; | 
|  | } | 
|  | for (i = 0; i < hw->gpio_cs_count; i++) { | 
|  | err = gpio_request(hw->gpio_cs[i], dev_name(&pdev->dev)); | 
|  | if (err) | 
|  | goto exit_gpio; | 
|  | gpio_direction_output(hw->gpio_cs[i], 1); | 
|  | } | 
|  | hw->bitbang.master->num_chipselect = max(1, hw->gpio_cs_count); | 
|  |  | 
|  | /* register our spi controller */ | 
|  | err = spi_bitbang_start(&hw->bitbang); | 
|  | if (err) | 
|  | goto exit; | 
|  | dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq); | 
|  |  | 
|  | return 0; | 
|  |  | 
|  | exit_gpio: | 
|  | while (i-- > 0) | 
|  | gpio_free(hw->gpio_cs[i]); | 
|  | exit: | 
|  | spi_master_put(master); | 
|  | return err; | 
|  | } | 
|  |  | 
|  | static int tiny_spi_remove(struct platform_device *pdev) | 
|  | { | 
|  | struct tiny_spi *hw = platform_get_drvdata(pdev); | 
|  | struct spi_master *master = hw->bitbang.master; | 
|  | unsigned int i; | 
|  |  | 
|  | spi_bitbang_stop(&hw->bitbang); | 
|  | for (i = 0; i < hw->gpio_cs_count; i++) | 
|  | gpio_free(hw->gpio_cs[i]); | 
|  | spi_master_put(master); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_OF | 
|  | static const struct of_device_id tiny_spi_match[] = { | 
|  | { .compatible = "opencores,tiny-spi-rtlsvn2", }, | 
|  | {}, | 
|  | }; | 
|  | MODULE_DEVICE_TABLE(of, tiny_spi_match); | 
|  | #endif /* CONFIG_OF */ | 
|  |  | 
|  | static struct platform_driver tiny_spi_driver = { | 
|  | .probe = tiny_spi_probe, | 
|  | .remove = tiny_spi_remove, | 
|  | .driver = { | 
|  | .name = DRV_NAME, | 
|  | .pm = NULL, | 
|  | .of_match_table = of_match_ptr(tiny_spi_match), | 
|  | }, | 
|  | }; | 
|  | module_platform_driver(tiny_spi_driver); | 
|  |  | 
|  | MODULE_DESCRIPTION("OpenCores tiny SPI driver"); | 
|  | MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); | 
|  | MODULE_LICENSE("GPL"); | 
|  | MODULE_ALIAS("platform:" DRV_NAME); |