--- /dev/null
+/*
+ * drivers/cbus/cbus.c
+ *
+ * Support functions for CBUS serial protocol
+ *
+ * Copyright (C) 2004, 2005 Nokia Corporation
+ *
+ * Written by Juha Yrjölä <juha.yrjola@nokia.com>,
+ * David Weinehall <david.weinehall@nokia.com>, and
+ * Mikko Ylinen <mikko.k.ylinen@nokia.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/gpio.h>
+
+#include <mach/board.h>
+#include <mach/board-nokia.h>
+
+#include <asm/io.h>
+
+#include "cbus.h"
+
+struct cbus_host *cbus_host = NULL;
+
+#ifdef CONFIG_ARCH_OMAP1
+/* We use our own MPUIO functions to get closer to 1MHz bus speed */
+
+static inline void cbus_set_gpio_direction(u32 base, int mpuio, int is_input)
+{
+ u16 w;
+
+ mpuio &= 0x0f;
+ w = __raw_readw(base + OMAP_MPUIO_IO_CNTL);
+ if (is_input)
+ w |= 1 << mpuio;
+ else
+ w &= ~(1 << mpuio);
+ __raw_writew(w, base + OMAP_MPUIO_IO_CNTL);
+
+}
+
+static inline void cbus_set_gpio_dataout(u32 base, int mpuio, int enable)
+{
+ u16 w;
+
+ mpuio &= 0x0f;
+ w = __raw_readw(base + OMAP_MPUIO_OUTPUT);
+ if (enable)
+ w |= 1 << mpuio;
+ else
+ w &= ~(1 << mpuio);
+ __raw_writew(w, base + OMAP_MPUIO_OUTPUT);
+}
+
+static inline int cbus_get_gpio_datain(u32 base, int mpuio)
+{
+ mpuio &= 0x0f;
+
+ return (__raw_readw(base + OMAP_MPUIO_INPUT_LATCH) & (1 << mpuio)) != 0;
+}
+
+static void cbus_send_bit(struct cbus_host *host, u32 base, int bit,
+ int set_to_input)
+{
+ cbus_set_gpio_dataout(base, host->dat_gpio, bit ? 1 : 0);
+ cbus_set_gpio_dataout(base, host->clk_gpio, 1);
+
+ /* The data bit is read on the rising edge of CLK */
+ if (set_to_input)
+ cbus_set_gpio_direction(base, host->dat_gpio, 1);
+
+ cbus_set_gpio_dataout(base, host->clk_gpio, 0);
+}
+
+static u8 cbus_receive_bit(struct cbus_host *host, u32 base)
+{
+ u8 ret;
+
+ cbus_set_gpio_dataout(base, host->clk_gpio, 1);
+ ret = cbus_get_gpio_datain(base, host->dat_gpio);
+ cbus_set_gpio_dataout(base, host->clk_gpio, 0);
+
+ return ret;
+}
+
+#define cbus_output(base, gpio, val) cbus_set_gpio_direction(base, gpio, 0)
+
+#else
+
+#define cbus_output(base, gpio, val) gpio_direction_output(gpio, val)
+#define cbus_set_gpio_dataout(base, gpio, enable) gpio_set_value(gpio, enable)
+#define cbus_get_gpio_datain(base, int, gpio) gpio_get_value(gpio)
+
+static void _cbus_send_bit(struct cbus_host *host, int bit, int set_to_input)
+{
+ gpio_set_value(host->dat_gpio, bit ? 1 : 0);
+ gpio_set_value(host->clk_gpio, 1);
+
+ /* The data bit is read on the rising edge of CLK */
+ if (set_to_input)
+ gpio_direction_input(host->dat_gpio);
+
+ gpio_set_value(host->clk_gpio, 0);
+}
+
+static u8 _cbus_receive_bit(struct cbus_host *host)
+{
+ u8 ret;
+
+ gpio_set_value(host->clk_gpio, 1);
+ ret = gpio_get_value(host->dat_gpio);
+ gpio_set_value(host->clk_gpio, 0);
+
+ return ret;
+}
+
+#define cbus_send_bit(host, base, bit, set_to_input) _cbus_send_bit(host, bit, set_to_input)
+#define cbus_receive_bit(host, base) _cbus_receive_bit(host)
+
+#endif
+
+static int cbus_transfer(struct cbus_host *host, int dev, int reg, int data)
+{
+ int i;
+ int is_read = 0;
+ unsigned long flags;
+ u32 base;
+
+#ifdef CONFIG_ARCH_OMAP1
+ base = OMAP1_IO_ADDRESS(OMAP_MPUIO_BASE);
+#else
+ base = 0;
+#endif
+
+ if (data < 0)
+ is_read = 1;
+
+ /* We don't want interrupts disturbing our transfer */
+ spin_lock_irqsave(&host->lock, flags);
+
+ /* Reset state and start of transfer, SEL stays down during transfer */
+ cbus_set_gpio_dataout(base, host->sel_gpio, 0);
+
+ /* Set the DAT pin to output */
+ cbus_output(base, host->dat_gpio, 1);
+
+ /* Send the device address */
+ for (i = 3; i > 0; i--)
+ cbus_send_bit(host, base, dev & (1 << (i - 1)), 0);
+
+ /* Send the rw flag */
+ cbus_send_bit(host, base, is_read, 0);
+
+ /* Send the register address */
+ for (i = 5; i > 0; i--) {
+ int set_to_input = 0;
+
+ if (is_read && i == 1)
+ set_to_input = 1;
+
+ cbus_send_bit(host, base, reg & (1 << (i - 1)), set_to_input);
+ }
+
+ if (!is_read) {
+ for (i = 16; i > 0; i--)
+ cbus_send_bit(host, base, data & (1 << (i - 1)), 0);
+ } else {
+ cbus_set_gpio_dataout(base, host->clk_gpio, 1);
+ data = 0;
+
+ for (i = 16; i > 0; i--) {
+ u8 bit = cbus_receive_bit(host, base);
+
+ if (bit)
+ data |= 1 << (i - 1);
+ }
+ }
+
+ /* Indicate end of transfer, SEL goes up until next transfer */
+ cbus_set_gpio_dataout(base, host->sel_gpio, 1);
+ cbus_set_gpio_dataout(base, host->clk_gpio, 1);
+ cbus_set_gpio_dataout(base, host->clk_gpio, 0);
+
+ spin_unlock_irqrestore(&host->lock, flags);
+
+ return is_read ? data : 0;
+}
+
+/*
+ * Read a given register from the device
+ */
+int cbus_read_reg(struct cbus_host *host, int dev, int reg)
+{
+ return cbus_host ? cbus_transfer(host, dev, reg, -1) : -ENODEV;
+}
+
+/*
+ * Write to a given register of the device
+ */
+int cbus_write_reg(struct cbus_host *host, int dev, int reg, u16 val)
+{
+ return cbus_host ? cbus_transfer(host, dev, reg, (int)val) : -ENODEV;
+}
+
+int __init cbus_bus_init(void)
+{
+ const struct omap_cbus_config * cbus_config;
+ struct cbus_host *chost;
+ int ret;
+
+ chost = kmalloc(sizeof (*chost), GFP_KERNEL);
+ if (chost == NULL)
+ return -ENOMEM;
+
+ memset(chost, 0, sizeof (*chost));
+
+ spin_lock_init(&chost->lock);
+
+ cbus_config = omap_get_config(OMAP_TAG_CBUS, struct omap_cbus_config);
+
+ if (cbus_config == NULL) {
+ printk(KERN_ERR "cbus: Unable to retrieve config data\n");
+ return -ENODATA;
+ }
+
+ chost->clk_gpio = cbus_config->clk_gpio;
+ chost->dat_gpio = cbus_config->dat_gpio;
+ chost->sel_gpio = cbus_config->sel_gpio;
+
+#ifdef CONFIG_ARCH_OMAP1
+ if (!OMAP_GPIO_IS_MPUIO(chost->clk_gpio) ||
+ !OMAP_GPIO_IS_MPUIO(chost->dat_gpio) ||
+ !OMAP_GPIO_IS_MPUIO(chost->sel_gpio)) {
+ printk(KERN_ERR "cbus: Only MPUIO pins supported\n");
+ ret = -ENODEV;
+ goto exit1;
+ }
+#endif
+
+ if ((ret = gpio_request(chost->clk_gpio, "CBUS clk")) < 0)
+ goto exit1;
+
+ if ((ret = gpio_request(chost->dat_gpio, "CBUS data")) < 0)
+ goto exit2;
+
+ if ((ret = gpio_request(chost->sel_gpio, "CBUS sel")) < 0)
+ goto exit3;
+
+ gpio_direction_output(chost->clk_gpio, 0);
+ gpio_direction_input(chost->dat_gpio);
+ gpio_direction_output(chost->sel_gpio, 1);
+
+ gpio_set_value(chost->clk_gpio, 1);
+ gpio_set_value(chost->clk_gpio, 0);
+
+ cbus_host = chost;
+
+ return 0;
+exit3:
+ gpio_free(chost->dat_gpio);
+exit2:
+ gpio_free(chost->clk_gpio);
+exit1:
+ kfree(chost);
+ return ret;
+}
+
+subsys_initcall(cbus_bus_init);
+
+EXPORT_SYMBOL(cbus_host);
+EXPORT_SYMBOL(cbus_read_reg);
+EXPORT_SYMBOL(cbus_write_reg);
+
+MODULE_DESCRIPTION("CBUS serial protocol");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Juha Yrjölä, David Weinehall, and Mikko Ylinen");
projects / linux-2.6-omap-h63xx.git / blobdiff