diff options
| -rw-r--r-- | Documentation/devicetree/bindings/spi/spi_oc_tiny.txt | 12 | ||||
| -rw-r--r-- | drivers/spi/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/spi/Makefile | 1 | ||||
| -rw-r--r-- | drivers/spi/spi_oc_tiny.c | 425 | ||||
| -rw-r--r-- | include/linux/spi/spi_oc_tiny.h | 20 |
5 files changed, 465 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/spi/spi_oc_tiny.txt b/Documentation/devicetree/bindings/spi/spi_oc_tiny.txt new file mode 100644 index 0000000..d95c0b3 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/spi_oc_tiny.txt @@ -0,0 +1,12 @@ +OpenCores tiny SPI + +Required properties: +- compatible : should be "opencores,tiny-spi-rtlsvn2". +- gpios : should specify GPIOs used for chipselect. +Optional properties: +- clock-frequency : input clock frequency to the core. +- baud-width: width, in bits, of the programmable divider used to scale + the input clock to SCLK. + +The clock-frequency and baud-width properties are needed only if the divider +is programmable. They are not needed if the divider is fixed. diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index bb233a9..8faa57a 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -231,6 +231,13 @@ config SPI_FSL_ESPI From MPC8536, 85xx platform uses the controller, and all P10xx, P20xx, P30xx,P40xx, P50xx uses this controller. +config SPI_OC_TINY + tristate "OpenCores tiny SPI" + depends on GENERIC_GPIO + select SPI_BITBANG + help + This is the driver for OpenCores tiny SPI master controller. + config SPI_OMAP_UWIRE tristate "OMAP1 MicroWire" depends on ARCH_OMAP1 diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 86d1b5f..c7e4c23 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -27,6 +27,7 @@ obj-$(CONFIG_SPI_IMX) += spi_imx.o obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o obj-$(CONFIG_SPI_PXA2XX) += pxa2xx_spi.o obj-$(CONFIG_SPI_PXA2XX_PCI) += pxa2xx_spi_pci.o +obj-$(CONFIG_SPI_OC_TINY) += spi_oc_tiny.o obj-$(CONFIG_SPI_OMAP_UWIRE) += omap_uwire.o obj-$(CONFIG_SPI_OMAP24XX) += omap2_mcspi.o obj-$(CONFIG_SPI_OMAP_100K) += omap_spi_100k.o diff --git a/drivers/spi/spi_oc_tiny.c b/drivers/spi/spi_oc_tiny.c new file mode 100644 index 0000000..f1bde66 --- /dev/null +++ b/drivers/spi/spi_oc_tiny.c @@ -0,0 +1,425 @@ +/* + * 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/init.h> +#include <linux/interrupt.h> +#include <linux/errno.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; + unsigned 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) { + 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 intrrupt 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 if (txp && rxp) { + /* we need to tighten the transfer loop */ + writeb(*txp++, hw->base + TINY_SPI_TXDATA); + if (t->len > 1) { + writeb(*txp++, hw->base + TINY_SPI_TXDATA); + for (i = 2; i < t->len; i++) { + u8 rx, tx = *txp++; + tiny_spi_wait_txr(hw); + rx = readb(hw->base + TINY_SPI_TXDATA); + writeb(tx, hw->base + TINY_SPI_TXDATA); + *rxp++ = rx; + } + tiny_spi_wait_txr(hw); + *rxp++ = readb(hw->base + TINY_SPI_TXDATA); + } + tiny_spi_wait_txe(hw); + *rxp++ = readb(hw->base + TINY_SPI_RXDATA); + } else if (rxp) { + writeb(0, hw->base + TINY_SPI_TXDATA); + if (t->len > 1) { + writeb(0, + hw->base + TINY_SPI_TXDATA); + for (i = 2; i < t->len; i++) { + u8 rx; + tiny_spi_wait_txr(hw); + rx = readb(hw->base + TINY_SPI_TXDATA); + writeb(0, hw->base + TINY_SPI_TXDATA); + *rxp++ = rx; + } + tiny_spi_wait_txr(hw); + *rxp++ = readb(hw->base + TINY_SPI_TXDATA); + } + tiny_spi_wait_txe(hw); + *rxp++ = readb(hw->base + TINY_SPI_RXDATA); + } else if (txp) { + writeb(*txp++, hw->base + TINY_SPI_TXDATA); + if (t->len > 1) { + writeb(*txp++, hw->base + TINY_SPI_TXDATA); + for (i = 2; i < t->len; i++) { + u8 tx = *txp++; + tiny_spi_wait_txr(hw); + writeb(tx, hw->base + TINY_SPI_TXDATA); + } + } + tiny_spi_wait_txe(hw); + } else { + writeb(0, hw->base + TINY_SPI_TXDATA); + if (t->len > 1) { + writeb(0, hw->base + TINY_SPI_TXDATA); + for (i = 2; i < t->len; i++) { + tiny_spi_wait_txr(hw); + writeb(0, hw->base + TINY_SPI_TXDATA); + } + } + tiny_spi_wait_txe(hw); + } + 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 __devinit 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; + const __be32 *val; + int len; + + if (!np) + return 0; + hw->gpio_cs_count = of_gpio_count(np); + if (hw->gpio_cs_count) { + hw->gpio_cs = devm_kzalloc(&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; + val = of_get_property(pdev->dev.of_node, + "clock-frequency", &len); + if (val && len >= sizeof(__be32)) + hw->freq = be32_to_cpup(val); + val = of_get_property(pdev->dev.of_node, "baud-width", &len); + if (val && len >= sizeof(__be32)) + hw->baudwidth = be32_to_cpup(val); + return 0; +} +#else /* !CONFIG_OF */ +static int __devinit tiny_spi_of_probe(struct platform_device *pdev) +{ + return 0; +} +#endif /* CONFIG_OF */ + +static int __devinit tiny_spi_probe(struct platform_device *pdev) +{ + struct tiny_spi_platform_data *platp = pdev->dev.platform_data; + 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 = spi_master_get(master); + if (!hw->bitbang.master) + return err; + 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); + if (!res) + goto exit_busy; + if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res), + pdev->name)) + goto exit_busy; + hw->base = devm_ioremap_nocache(&pdev->dev, res->start, + resource_size(res)); + if (!hw->base) + goto exit_busy; + /* 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) + goto exit_busy; + 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(1U, 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_busy: + err = -EBUSY; +exit: + platform_set_drvdata(pdev, NULL); + spi_master_put(master); + return err; +} + +static int __devexit 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]); + platform_set_drvdata(pdev, NULL); + 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); +#else /* CONFIG_OF */ +#define tiny_spi_match NULL +#endif /* CONFIG_OF */ + +static struct platform_driver tiny_spi_driver = { + .probe = tiny_spi_probe, + .remove = __devexit_p(tiny_spi_remove), + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + .pm = NULL, + .of_match_table = tiny_spi_match, + }, +}; + +static int __init tiny_spi_init(void) +{ + return platform_driver_register(&tiny_spi_driver); +} +module_init(tiny_spi_init); + +static void __exit tiny_spi_exit(void) +{ + platform_driver_unregister(&tiny_spi_driver); +} +module_exit(tiny_spi_exit); + +MODULE_DESCRIPTION("OpenCores tiny SPI driver"); +MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); diff --git a/include/linux/spi/spi_oc_tiny.h b/include/linux/spi/spi_oc_tiny.h new file mode 100644 index 0000000..1ac529c --- /dev/null +++ b/include/linux/spi/spi_oc_tiny.h @@ -0,0 +1,20 @@ +#ifndef _LINUX_SPI_SPI_OC_TINY_H +#define _LINUX_SPI_SPI_OC_TINY_H + +/** + * struct tiny_spi_platform_data - platform data of the OpenCores tiny SPI + * @freq: input clock freq to the core. + * @baudwidth: baud rate divider width of the core. + * @gpio_cs_count: number of gpio pins used for chipselect. + * @gpio_cs: array of gpio pins used for chipselect. + * + * freq and baudwidth are used only if the divider is programmable. + */ +struct tiny_spi_platform_data { + unsigned int freq; + unsigned int baudwidth; + unsigned int gpio_cs_count; + int *gpio_cs; +}; + +#endif /* _LINUX_SPI_SPI_OC_TINY_H */ |