spi: add OpenCores tiny SPI driver
This patch adds support of OpenCores tiny SPI driver. http://opencores.org/project,tiny_spi Signed-off-by: Thomas Chou <thomas@wytron.com.tw> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Thomas Chou
Grant Likely
parent
9bde36afca
commit
ce792580ea
5 changed files with 465 additions and 0 deletions
12
Documentation/devicetree/bindings/spi/spi_oc_tiny.txt
Normal file
12
Documentation/devicetree/bindings/spi/spi_oc_tiny.txt
Normal file
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@ -0,0 +1,12 @@
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OpenCores tiny SPI
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Required properties:
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- compatible : should be "opencores,tiny-spi-rtlsvn2".
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- gpios : should specify GPIOs used for chipselect.
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Optional properties:
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- clock-frequency : input clock frequency to the core.
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- baud-width: width, in bits, of the programmable divider used to scale
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the input clock to SCLK.
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The clock-frequency and baud-width properties are needed only if the divider
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is programmable. They are not needed if the divider is fixed.
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@ -231,6 +231,13 @@ config SPI_FSL_ESPI
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From MPC8536, 85xx platform uses the controller, and all P10xx,
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P20xx, P30xx,P40xx, P50xx uses this controller.
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config SPI_OC_TINY
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tristate "OpenCores tiny SPI"
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depends on GENERIC_GPIO
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select SPI_BITBANG
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help
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This is the driver for OpenCores tiny SPI master controller.
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config SPI_OMAP_UWIRE
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tristate "OMAP1 MicroWire"
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depends on ARCH_OMAP1
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@ -27,6 +27,7 @@ obj-$(CONFIG_SPI_IMX) += spi_imx.o
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obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o
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obj-$(CONFIG_SPI_PXA2XX) += pxa2xx_spi.o
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obj-$(CONFIG_SPI_PXA2XX_PCI) += pxa2xx_spi_pci.o
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obj-$(CONFIG_SPI_OC_TINY) += spi_oc_tiny.o
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obj-$(CONFIG_SPI_OMAP_UWIRE) += omap_uwire.o
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obj-$(CONFIG_SPI_OMAP24XX) += omap2_mcspi.o
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obj-$(CONFIG_SPI_OMAP_100K) += omap_spi_100k.o
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425
drivers/spi/spi_oc_tiny.c
Normal file
425
drivers/spi/spi_oc_tiny.c
Normal file
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@ -0,0 +1,425 @@
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/*
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* OpenCores tiny SPI master driver
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*
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* http://opencores.org/project,tiny_spi
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*
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* Copyright (C) 2011 Thomas Chou <thomas@wytron.com.tw>
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*
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* Based on spi_s3c24xx.c, which is:
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* Copyright (c) 2006 Ben Dooks
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* Copyright (c) 2006 Simtec Electronics
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* Ben Dooks <ben@simtec.co.uk>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/errno.h>
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#include <linux/platform_device.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/spi_bitbang.h>
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#include <linux/spi/spi_oc_tiny.h>
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#include <linux/io.h>
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#include <linux/gpio.h>
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#include <linux/of.h>
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#define DRV_NAME "spi_oc_tiny"
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#define TINY_SPI_RXDATA 0
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#define TINY_SPI_TXDATA 4
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#define TINY_SPI_STATUS 8
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#define TINY_SPI_CONTROL 12
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#define TINY_SPI_BAUD 16
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#define TINY_SPI_STATUS_TXE 0x1
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#define TINY_SPI_STATUS_TXR 0x2
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struct tiny_spi {
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/* bitbang has to be first */
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struct spi_bitbang bitbang;
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struct completion done;
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void __iomem *base;
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int irq;
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unsigned int freq;
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unsigned int baudwidth;
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unsigned int baud;
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unsigned int speed_hz;
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unsigned int mode;
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unsigned int len;
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unsigned int txc, rxc;
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const u8 *txp;
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u8 *rxp;
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unsigned int gpio_cs_count;
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int *gpio_cs;
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};
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static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev)
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{
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return spi_master_get_devdata(sdev->master);
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}
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static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz)
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{
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struct tiny_spi *hw = tiny_spi_to_hw(spi);
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return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1;
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}
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static void tiny_spi_chipselect(struct spi_device *spi, int is_active)
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{
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struct tiny_spi *hw = tiny_spi_to_hw(spi);
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if (hw->gpio_cs_count) {
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gpio_set_value(hw->gpio_cs[spi->chip_select],
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(spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
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}
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}
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static int tiny_spi_setup_transfer(struct spi_device *spi,
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struct spi_transfer *t)
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{
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struct tiny_spi *hw = tiny_spi_to_hw(spi);
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unsigned int baud = hw->baud;
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if (t) {
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if (t->speed_hz && t->speed_hz != hw->speed_hz)
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baud = tiny_spi_baud(spi, t->speed_hz);
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}
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writel(baud, hw->base + TINY_SPI_BAUD);
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writel(hw->mode, hw->base + TINY_SPI_CONTROL);
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return 0;
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}
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static int tiny_spi_setup(struct spi_device *spi)
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{
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struct tiny_spi *hw = tiny_spi_to_hw(spi);
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if (spi->max_speed_hz != hw->speed_hz) {
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hw->speed_hz = spi->max_speed_hz;
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hw->baud = tiny_spi_baud(spi, hw->speed_hz);
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}
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hw->mode = spi->mode & (SPI_CPOL | SPI_CPHA);
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return 0;
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}
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static inline void tiny_spi_wait_txr(struct tiny_spi *hw)
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{
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while (!(readb(hw->base + TINY_SPI_STATUS) &
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TINY_SPI_STATUS_TXR))
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cpu_relax();
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}
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static inline void tiny_spi_wait_txe(struct tiny_spi *hw)
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{
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while (!(readb(hw->base + TINY_SPI_STATUS) &
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TINY_SPI_STATUS_TXE))
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cpu_relax();
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}
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static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
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{
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struct tiny_spi *hw = tiny_spi_to_hw(spi);
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const u8 *txp = t->tx_buf;
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u8 *rxp = t->rx_buf;
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unsigned int i;
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if (hw->irq >= 0) {
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/* use intrrupt driven data transfer */
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hw->len = t->len;
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hw->txp = t->tx_buf;
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hw->rxp = t->rx_buf;
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hw->txc = 0;
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hw->rxc = 0;
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/* send the first byte */
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if (t->len > 1) {
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writeb(hw->txp ? *hw->txp++ : 0,
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hw->base + TINY_SPI_TXDATA);
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hw->txc++;
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writeb(hw->txp ? *hw->txp++ : 0,
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hw->base + TINY_SPI_TXDATA);
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hw->txc++;
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writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS);
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} else {
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writeb(hw->txp ? *hw->txp++ : 0,
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hw->base + TINY_SPI_TXDATA);
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hw->txc++;
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writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS);
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}
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wait_for_completion(&hw->done);
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} else if (txp && rxp) {
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/* we need to tighten the transfer loop */
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writeb(*txp++, hw->base + TINY_SPI_TXDATA);
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if (t->len > 1) {
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writeb(*txp++, hw->base + TINY_SPI_TXDATA);
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for (i = 2; i < t->len; i++) {
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u8 rx, tx = *txp++;
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tiny_spi_wait_txr(hw);
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rx = readb(hw->base + TINY_SPI_TXDATA);
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writeb(tx, hw->base + TINY_SPI_TXDATA);
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*rxp++ = rx;
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}
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tiny_spi_wait_txr(hw);
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*rxp++ = readb(hw->base + TINY_SPI_TXDATA);
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}
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tiny_spi_wait_txe(hw);
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*rxp++ = readb(hw->base + TINY_SPI_RXDATA);
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} else if (rxp) {
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writeb(0, hw->base + TINY_SPI_TXDATA);
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if (t->len > 1) {
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writeb(0,
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hw->base + TINY_SPI_TXDATA);
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for (i = 2; i < t->len; i++) {
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u8 rx;
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tiny_spi_wait_txr(hw);
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rx = readb(hw->base + TINY_SPI_TXDATA);
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writeb(0, hw->base + TINY_SPI_TXDATA);
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*rxp++ = rx;
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}
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tiny_spi_wait_txr(hw);
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*rxp++ = readb(hw->base + TINY_SPI_TXDATA);
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}
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tiny_spi_wait_txe(hw);
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*rxp++ = readb(hw->base + TINY_SPI_RXDATA);
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} else if (txp) {
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writeb(*txp++, hw->base + TINY_SPI_TXDATA);
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if (t->len > 1) {
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writeb(*txp++, hw->base + TINY_SPI_TXDATA);
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for (i = 2; i < t->len; i++) {
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u8 tx = *txp++;
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tiny_spi_wait_txr(hw);
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writeb(tx, hw->base + TINY_SPI_TXDATA);
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}
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}
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tiny_spi_wait_txe(hw);
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} else {
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writeb(0, hw->base + TINY_SPI_TXDATA);
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if (t->len > 1) {
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writeb(0, hw->base + TINY_SPI_TXDATA);
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for (i = 2; i < t->len; i++) {
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tiny_spi_wait_txr(hw);
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writeb(0, hw->base + TINY_SPI_TXDATA);
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}
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}
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tiny_spi_wait_txe(hw);
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}
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return t->len;
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}
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static irqreturn_t tiny_spi_irq(int irq, void *dev)
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{
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struct tiny_spi *hw = dev;
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writeb(0, hw->base + TINY_SPI_STATUS);
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if (hw->rxc + 1 == hw->len) {
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if (hw->rxp)
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*hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA);
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hw->rxc++;
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complete(&hw->done);
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} else {
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if (hw->rxp)
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*hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA);
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hw->rxc++;
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if (hw->txc < hw->len) {
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writeb(hw->txp ? *hw->txp++ : 0,
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hw->base + TINY_SPI_TXDATA);
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hw->txc++;
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writeb(TINY_SPI_STATUS_TXR,
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hw->base + TINY_SPI_STATUS);
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} else {
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writeb(TINY_SPI_STATUS_TXE,
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hw->base + TINY_SPI_STATUS);
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}
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}
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return IRQ_HANDLED;
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}
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#ifdef CONFIG_OF
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#include <linux/of_gpio.h>
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static int __devinit tiny_spi_of_probe(struct platform_device *pdev)
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{
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struct tiny_spi *hw = platform_get_drvdata(pdev);
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struct device_node *np = pdev->dev.of_node;
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unsigned int i;
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const __be32 *val;
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int len;
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if (!np)
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return 0;
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hw->gpio_cs_count = of_gpio_count(np);
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if (hw->gpio_cs_count) {
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hw->gpio_cs = devm_kzalloc(&pdev->dev,
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hw->gpio_cs_count * sizeof(unsigned int),
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GFP_KERNEL);
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if (!hw->gpio_cs)
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return -ENOMEM;
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}
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for (i = 0; i < hw->gpio_cs_count; i++) {
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hw->gpio_cs[i] = of_get_gpio_flags(np, i, NULL);
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if (hw->gpio_cs[i] < 0)
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return -ENODEV;
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}
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hw->bitbang.master->dev.of_node = pdev->dev.of_node;
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val = of_get_property(pdev->dev.of_node,
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"clock-frequency", &len);
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if (val && len >= sizeof(__be32))
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hw->freq = be32_to_cpup(val);
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val = of_get_property(pdev->dev.of_node, "baud-width", &len);
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if (val && len >= sizeof(__be32))
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hw->baudwidth = be32_to_cpup(val);
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return 0;
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}
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#else /* !CONFIG_OF */
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static int __devinit tiny_spi_of_probe(struct platform_device *pdev)
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{
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return 0;
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}
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#endif /* CONFIG_OF */
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static int __devinit tiny_spi_probe(struct platform_device *pdev)
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{
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struct tiny_spi_platform_data *platp = pdev->dev.platform_data;
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struct tiny_spi *hw;
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struct spi_master *master;
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struct resource *res;
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unsigned int i;
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int err = -ENODEV;
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master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi));
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if (!master)
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return err;
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/* setup the master state. */
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master->bus_num = pdev->id;
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master->num_chipselect = 255;
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master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
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master->setup = tiny_spi_setup;
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hw = spi_master_get_devdata(master);
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platform_set_drvdata(pdev, hw);
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/* setup the state for the bitbang driver */
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hw->bitbang.master = spi_master_get(master);
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if (!hw->bitbang.master)
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return err;
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hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
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hw->bitbang.chipselect = tiny_spi_chipselect;
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hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
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/* find and map our resources */
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res)
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goto exit_busy;
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if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
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pdev->name))
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goto exit_busy;
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hw->base = devm_ioremap_nocache(&pdev->dev, res->start,
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resource_size(res));
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if (!hw->base)
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goto exit_busy;
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/* irq is optional */
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hw->irq = platform_get_irq(pdev, 0);
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if (hw->irq >= 0) {
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init_completion(&hw->done);
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err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0,
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pdev->name, hw);
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if (err)
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goto exit;
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}
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/* find platform data */
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if (platp) {
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hw->gpio_cs_count = platp->gpio_cs_count;
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hw->gpio_cs = platp->gpio_cs;
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if (platp->gpio_cs_count && !platp->gpio_cs)
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goto exit_busy;
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hw->freq = platp->freq;
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hw->baudwidth = platp->baudwidth;
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} else {
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err = tiny_spi_of_probe(pdev);
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if (err)
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goto exit;
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}
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for (i = 0; i < hw->gpio_cs_count; i++) {
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err = gpio_request(hw->gpio_cs[i], dev_name(&pdev->dev));
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if (err)
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goto exit_gpio;
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gpio_direction_output(hw->gpio_cs[i], 1);
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}
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hw->bitbang.master->num_chipselect = max(1U, hw->gpio_cs_count);
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/* register our spi controller */
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err = spi_bitbang_start(&hw->bitbang);
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if (err)
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goto exit;
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dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
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return 0;
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exit_gpio:
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while (i-- > 0)
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gpio_free(hw->gpio_cs[i]);
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exit_busy:
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err = -EBUSY;
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exit:
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platform_set_drvdata(pdev, NULL);
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spi_master_put(master);
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return err;
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}
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static int __devexit tiny_spi_remove(struct platform_device *pdev)
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{
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struct tiny_spi *hw = platform_get_drvdata(pdev);
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struct spi_master *master = hw->bitbang.master;
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unsigned int i;
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spi_bitbang_stop(&hw->bitbang);
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for (i = 0; i < hw->gpio_cs_count; i++)
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gpio_free(hw->gpio_cs[i]);
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platform_set_drvdata(pdev, NULL);
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spi_master_put(master);
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return 0;
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}
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#ifdef CONFIG_OF
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static const struct of_device_id tiny_spi_match[] = {
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{ .compatible = "opencores,tiny-spi-rtlsvn2", },
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{},
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};
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MODULE_DEVICE_TABLE(of, tiny_spi_match);
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#else /* CONFIG_OF */
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#define tiny_spi_match NULL
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#endif /* CONFIG_OF */
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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);
|
||||
20
include/linux/spi/spi_oc_tiny.h
Normal file
20
include/linux/spi/spi_oc_tiny.h
Normal file
|
|
@ -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 */
|
||||
Loading…
Reference in a new issue