Re: [PATCH 32/33] add omap 1-wire interface driver

["Madhusudhan Chikkature" <madhu.cr@ti.com>]

Hi,

The HDQ patchset that I posted to Tony were given ACK by Evgeniy Polyakov on the omap list. I hope that helps.

Regards,
Madhu

----- Original Message ----- 
From: "Felipe Balbi" <me@felipebalbi.com>
To: <linux-omap@vger.kernel.org>
Cc: "Felipe Balbi" <felipe.balbi@nokia.com>
Sent: Saturday, August 30, 2008 10:46 PM
Subject: [PATCH 32/33] add omap 1-wire interface driver


> From: Felipe Balbi <felipe.balbi@nokia.com>
> 
> Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
> ---
> arch/arm/plat-omap/include/mach/irqs.h |    2 +
> drivers/w1/masters/Kconfig             |    7 +
> drivers/w1/masters/Makefile            |    1 +
> drivers/w1/masters/omap_hdq.c          |  704 ++++++++++++++++++++++++++++++++
> 4 files changed, 714 insertions(+), 0 deletions(-)
> create mode 100644 drivers/w1/masters/omap_hdq.c
> 
> diff --git a/arch/arm/plat-omap/include/mach/irqs.h b/arch/arm/plat-omap/include/mach/irqs.h
> index 17248bb..c9e95a6 100644
> --- a/arch/arm/plat-omap/include/mach/irqs.h
> +++ b/arch/arm/plat-omap/include/mach/irqs.h
> @@ -54,6 +54,8 @@
> #define INT_TIMER2 30
> #define INT_LCD_CTRL 31
> 
> +#define INT_24XX_HDQ_IRQ 58 /* Temporarily here for driver to build */
> +
> /*
>  * OMAP-1510 specific IRQ numbers for interrupt handler 1
>  */
> diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig
> index c449309..636d4f7 100644
> --- a/drivers/w1/masters/Kconfig
> +++ b/drivers/w1/masters/Kconfig
> @@ -42,6 +42,13 @@ config W1_MASTER_DS1WM
>    in HP iPAQ devices like h5xxx, h2200, and ASIC3-based like
>    hx4700.
> 
> +config HDQ_MASTER_OMAP
> + tristate "OMAP HDQ driver"
> + depends on ARCH_OMAP2430 || ARCH_OMAP34XX
> + help
> +   Say Y here if you want support for the 1-wire or HDQ Interface
> +   on an OMAP processor.
> +
> config W1_MASTER_GPIO
>  tristate "GPIO 1-wire busmaster"
>  depends on GENERIC_GPIO
> diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile
> index 1420b5b..1daeb6e 100644
> --- a/drivers/w1/masters/Makefile
> +++ b/drivers/w1/masters/Makefile
> @@ -6,4 +6,5 @@ obj-$(CONFIG_W1_MASTER_MATROX) += matrox_w1.o
> obj-$(CONFIG_W1_MASTER_DS2490) += ds2490.o
> obj-$(CONFIG_W1_MASTER_DS2482) += ds2482.o
> obj-$(CONFIG_W1_MASTER_DS1WM) += ds1wm.o
> +obj-$(CONFIG_HDQ_MASTER_OMAP) += omap_hdq.o
> obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o
> diff --git a/drivers/w1/masters/omap_hdq.c b/drivers/w1/masters/omap_hdq.c
> new file mode 100644
> index 0000000..880e282
> --- /dev/null
> +++ b/drivers/w1/masters/omap_hdq.c
> @@ -0,0 +1,704 @@
> +/*
> + * drivers/w1/masters/omap_hdq.c
> + *
> + * Copyright (C) 2007 Texas Instruments, Inc.
> + *
> + * This file is licensed under the terms of the GNU General Public License
> + * version 2. This program is licensed "as is" without any warranty of any
> + * kind, whether express or implied.
> + *
> + */
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/interrupt.h>
> +#include <linux/err.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <asm/irq.h>
> +#include <mach/hardware.h>
> +
> +#include "../w1.h"
> +#include "../w1_int.h"
> +
> +#define MOD_NAME "OMAP_HDQ:"
> +
> +#define OMAP_HDQ_REVISION 0x00
> +#define OMAP_HDQ_TX_DATA 0x04
> +#define OMAP_HDQ_RX_DATA 0x08
> +#define OMAP_HDQ_CTRL_STATUS 0x0c
> +#define OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK (1<<6)
> +#define OMAP_HDQ_CTRL_STATUS_CLOCKENABLE (1<<5)
> +#define OMAP_HDQ_CTRL_STATUS_GO (1<<4)
> +#define OMAP_HDQ_CTRL_STATUS_INITIALIZATION (1<<2)
> +#define OMAP_HDQ_CTRL_STATUS_DIR (1<<1)
> +#define OMAP_HDQ_CTRL_STATUS_MODE (1<<0)
> +#define OMAP_HDQ_INT_STATUS 0x10
> +#define OMAP_HDQ_INT_STATUS_TXCOMPLETE (1<<2)
> +#define OMAP_HDQ_INT_STATUS_RXCOMPLETE (1<<1)
> +#define OMAP_HDQ_INT_STATUS_TIMEOUT (1<<0)
> +#define OMAP_HDQ_SYSCONFIG 0x14
> +#define OMAP_HDQ_SYSCONFIG_SOFTRESET (1<<1)
> +#define OMAP_HDQ_SYSCONFIG_AUTOIDLE (1<<0)
> +#define OMAP_HDQ_SYSSTATUS 0x18
> +#define OMAP_HDQ_SYSSTATUS_RESETDONE (1<<0)
> +
> +#define OMAP_HDQ_FLAG_CLEAR 0
> +#define OMAP_HDQ_FLAG_SET 1
> +#define OMAP_HDQ_TIMEOUT (HZ/5)
> +
> +#define OMAP_HDQ_MAX_USER 4
> +
> +DECLARE_WAIT_QUEUE_HEAD(hdq_wait_queue);
> +int W1_ID;
> +
> +struct hdq_data {
> + resource_size_t hdq_base;
> + struct semaphore hdq_semlock;
> + int hdq_usecount;
> + struct clk *hdq_ick;
> + struct clk *hdq_fck;
> + u8 hdq_irqstatus;
> + spinlock_t hdq_spinlock;
> +};
> +
> +static struct hdq_data *hdq_data;
> +
> +static int omap_hdq_get(void);
> +static int omap_hdq_put(void);
> +static int omap_hdq_break(void);
> +
> +static int __init omap_hdq_probe(struct platform_device *pdev);
> +static int omap_hdq_remove(struct platform_device *pdev);
> +
> +static struct platform_driver omap_hdq_driver = {
> + .probe = omap_hdq_probe,
> + .remove = omap_hdq_remove,
> + .suspend = NULL,
> + .resume = NULL,
> + .driver = {
> + .name = "omap_hdq",
> + },
> +};
> +
> +static u8 omap_w1_read_byte(void *data);
> +static void omap_w1_write_byte(void *data, u8 byte);
> +static u8 omap_w1_reset_bus(void *data);
> +static void omap_w1_search_bus(void *data, u8 search_type,
> + w1_slave_found_callback slave_found);
> +
> +static struct w1_bus_master omap_w1_master = {
> + .read_byte = omap_w1_read_byte,
> + .write_byte = omap_w1_write_byte,
> + .reset_bus = omap_w1_reset_bus,
> + .search = omap_w1_search_bus,
> +};
> +
> +/*
> + * HDQ register I/O routines
> + */
> +static inline u8
> +hdq_reg_in(u32 offset)
> +{
> + return omap_readb(hdq_data->hdq_base + offset);
> +}
> +
> +static inline u8
> +hdq_reg_out(u32 offset, u8 val)
> +{
> + omap_writeb(val, hdq_data->hdq_base + offset);
> + return val;
> +}
> +
> +static inline u8
> +hdq_reg_merge(u32 offset, u8 val, u8 mask)
> +{
> + u8 new_val = (omap_readb(hdq_data->hdq_base + offset) & ~mask)
> + | (val & mask);
> + omap_writeb(new_val, hdq_data->hdq_base + offset);
> + return new_val;
> +}
> +
> +/*
> + * Wait for one or more bits in flag change.
> + * HDQ_FLAG_SET: wait until any bit in the flag is set.
> + * HDQ_FLAG_CLEAR: wait until all bits in the flag are cleared.
> + * return 0 on success and -ETIMEDOUT in the case of timeout.
> + */
> +static int
> +hdq_wait_for_flag(u32 offset, u8 flag, u8 flag_set, u8 *status)
> +{
> + int ret = 0;
> + unsigned long timeout = jiffies + OMAP_HDQ_TIMEOUT;
> +
> + if (flag_set == OMAP_HDQ_FLAG_CLEAR) {
> + /* wait for the flag clear */
> + while (((*status = hdq_reg_in(offset)) & flag)
> + && time_before(jiffies, timeout)) {
> + set_current_state(TASK_UNINTERRUPTIBLE);
> + schedule_timeout(1);
> + }
> + if (unlikely(*status & flag))
> + ret = -ETIMEDOUT;
> + } else if (flag_set == OMAP_HDQ_FLAG_SET) {
> + /* wait for the flag set */
> + while (!((*status = hdq_reg_in(offset)) & flag)
> + && time_before(jiffies, timeout)) {
> + set_current_state(TASK_UNINTERRUPTIBLE);
> + schedule_timeout(1);
> + }
> + if (unlikely(!(*status & flag)))
> + ret = -ETIMEDOUT;
> + } else
> + return -EINVAL;
> +
> + return ret;
> +}
> +
> +/*
> + * write out a byte and fill *status with HDQ_INT_STATUS
> + */
> +static int
> +hdq_write_byte(u8 val, u8 *status)
> +{
> + int ret;
> + u8 tmp_status;
> + unsigned long irqflags;
> +
> + *status = 0;
> +
> + spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
> + /* clear interrupt flags via a dummy read */
> + hdq_reg_in(OMAP_HDQ_INT_STATUS);
> + /* ISR loads it with new INT_STATUS */
> + hdq_data->hdq_irqstatus = 0;
> + spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
> +
> + hdq_reg_out(OMAP_HDQ_TX_DATA, val);
> +
> + /* set the GO bit */
> + hdq_reg_merge(OMAP_HDQ_CTRL_STATUS, OMAP_HDQ_CTRL_STATUS_GO,
> + OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
> + /* wait for the TXCOMPLETE bit */
> + ret = wait_event_interruptible_timeout(hdq_wait_queue,
> + hdq_data->hdq_irqstatus, OMAP_HDQ_TIMEOUT);
> + if (unlikely(ret < 0)) {
> + pr_debug("wait interrupted");
> + return -EINTR;
> + }
> +
> + spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
> + *status = hdq_data->hdq_irqstatus;
> + spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
> + /* check irqstatus */
> + if (!(*status & OMAP_HDQ_INT_STATUS_TXCOMPLETE)) {
> + pr_debug("timeout waiting for TXCOMPLETE/RXCOMPLETE, %x",
> + *status);
> + return -ETIMEDOUT;
> + }
> +
> + /* wait for the GO bit return to zero */
> + ret = hdq_wait_for_flag(OMAP_HDQ_CTRL_STATUS, OMAP_HDQ_CTRL_STATUS_GO,
> + OMAP_HDQ_FLAG_CLEAR, &tmp_status);
> + if (ret) {
> + pr_debug("timeout waiting GO bit return to zero, %x",
> + tmp_status);
> + return ret;
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * HDQ Interrupt service routine.
> + */
> +static irqreturn_t
> +hdq_isr(int irq, void *arg)
> +{
> + unsigned long irqflags;
> +
> + spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
> + hdq_data->hdq_irqstatus = hdq_reg_in(OMAP_HDQ_INT_STATUS);
> + spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
> + pr_debug("hdq_isr: %x", hdq_data->hdq_irqstatus);
> +
> + if (hdq_data->hdq_irqstatus &
> + (OMAP_HDQ_INT_STATUS_TXCOMPLETE | OMAP_HDQ_INT_STATUS_RXCOMPLETE
> + | OMAP_HDQ_INT_STATUS_TIMEOUT)) {
> + /* wake up sleeping process */
> + wake_up_interruptible(&hdq_wait_queue);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +/*
> + * HDQ Mode: always return success.
> + */
> +static u8 omap_w1_reset_bus(void *data)
> +{
> + return 0;
> +}
> +
> +/*
> + * W1 search callback function.
> + */
> +static void omap_w1_search_bus(void *data, u8 search_type,
> + w1_slave_found_callback slave_found)
> +{
> + u64 module_id, rn_le, cs, id;
> +
> + if (W1_ID)
> + module_id = W1_ID;
> + else
> + module_id = 0x1;
> +
> + rn_le = cpu_to_le64(module_id);
> + /*
> + * HDQ might not obey truly the 1-wire spec.
> + * So calculate CRC based on module parameter.
> + */
> + cs = w1_calc_crc8((u8 *)&rn_le, 7);
> + id = (cs << 56) | module_id;
> +
> + slave_found(data, id);
> +}
> +
> +static int
> +_omap_hdq_reset(void)
> +{
> + int ret;
> + u8 tmp_status;
> +
> + hdq_reg_out(OMAP_HDQ_SYSCONFIG, OMAP_HDQ_SYSCONFIG_SOFTRESET);
> + /*
> + * Select HDQ mode & enable clocks.
> + * It is observed that INT flags can't be cleared via a read and GO/INIT
> + * won't return to zero if interrupt is disabled. So we always enable
> + * interrupt.
> + */
> + hdq_reg_out(OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
> + OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
> +
> + /* wait for reset to complete */
> + ret = hdq_wait_for_flag(OMAP_HDQ_SYSSTATUS,
> + OMAP_HDQ_SYSSTATUS_RESETDONE, OMAP_HDQ_FLAG_SET, &tmp_status);
> + if (ret)
> + pr_debug("timeout waiting HDQ reset, %x", tmp_status);
> + else {
> + hdq_reg_out(OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
> + OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
> + hdq_reg_out(OMAP_HDQ_SYSCONFIG, OMAP_HDQ_SYSCONFIG_AUTOIDLE);
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * Issue break pulse to the device.
> + */
> +static int
> +omap_hdq_break()
> +{
> + int ret;
> + u8 tmp_status;
> + unsigned long irqflags;
> +
> + ret = down_interruptible(&hdq_data->hdq_semlock);
> + if (ret < 0)
> + return -EINTR;
> +
> + if (!hdq_data->hdq_usecount) {
> + up(&hdq_data->hdq_semlock);
> + return -EINVAL;
> + }
> +
> + spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
> + /* clear interrupt flags via a dummy read */
> + hdq_reg_in(OMAP_HDQ_INT_STATUS);
> + /* ISR loads it with new INT_STATUS */
> + hdq_data->hdq_irqstatus = 0;
> + spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
> +
> + /* set the INIT and GO bit */
> + hdq_reg_merge(OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_INITIALIZATION | OMAP_HDQ_CTRL_STATUS_GO,
> + OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
> + OMAP_HDQ_CTRL_STATUS_GO);
> +
> + /* wait for the TIMEOUT bit */
> + ret = wait_event_interruptible_timeout(hdq_wait_queue,
> + hdq_data->hdq_irqstatus, OMAP_HDQ_TIMEOUT);
> + if (unlikely(ret < 0)) {
> + pr_debug("wait interrupted");
> + up(&hdq_data->hdq_semlock);
> + return -EINTR;
> + }
> +
> + spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
> + tmp_status = hdq_data->hdq_irqstatus;
> + spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
> + /* check irqstatus */
> + if (!(tmp_status & OMAP_HDQ_INT_STATUS_TIMEOUT)) {
> + pr_debug("timeout waiting for TIMEOUT, %x", tmp_status);
> + up(&hdq_data->hdq_semlock);
> + return -ETIMEDOUT;
> + }
> + /*
> + * wait for both INIT and GO bits rerurn to zero.
> + * zero wait time expected for interrupt mode.
> + */
> + ret = hdq_wait_for_flag(OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
> + OMAP_HDQ_CTRL_STATUS_GO, OMAP_HDQ_FLAG_CLEAR,
> + &tmp_status);
> + if (ret)
> + pr_debug("timeout waiting INIT&GO bits return to zero, %x",
> + tmp_status);
> +
> + up(&hdq_data->hdq_semlock);
> + return ret;
> +}
> +
> +static int hdq_read_byte(u8 *val)
> +{
> + int ret;
> + u8 status;
> + unsigned long irqflags;
> +
> + ret = down_interruptible(&hdq_data->hdq_semlock);
> + if (ret < 0)
> + return -EINTR;
> +
> + if (!hdq_data->hdq_usecount) {
> + up(&hdq_data->hdq_semlock);
> + return -EINVAL;
> + }
> +
> + if (!(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
> + hdq_reg_merge(OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO,
> + OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
> + /*
> + * The RX comes immediately after TX. It
> + * triggers another interrupt before we
> + * sleep. So we have to wait for RXCOMPLETE bit.
> + */
> + {
> + unsigned long timeout = jiffies + OMAP_HDQ_TIMEOUT;
> + while (!(hdq_data->hdq_irqstatus
> + & OMAP_HDQ_INT_STATUS_RXCOMPLETE)
> + && time_before(jiffies, timeout)) {
> + set_current_state(TASK_UNINTERRUPTIBLE);
> + schedule_timeout(1);
> + }
> + }
> + hdq_reg_merge(OMAP_HDQ_CTRL_STATUS, 0,
> + OMAP_HDQ_CTRL_STATUS_DIR);
> + spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
> + status = hdq_data->hdq_irqstatus;
> + spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
> + /* check irqstatus */
> + if (!(status & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
> + pr_debug("timeout waiting for RXCOMPLETE, %x", status);
> + up(&hdq_data->hdq_semlock);
> + return -ETIMEDOUT;
> + }
> + }
> + /* the data is ready. Read it in! */
> + *val = hdq_reg_in(OMAP_HDQ_RX_DATA);
> + up(&hdq_data->hdq_semlock);
> +
> + return 0;
> +
> +}
> +
> +/*
> + * Enable clocks and set the controller to HDQ mode.
> + */
> +static int
> +omap_hdq_get()
> +{
> + int ret = 0;
> +
> + ret = down_interruptible(&hdq_data->hdq_semlock);
> + if (ret < 0)
> + return -EINTR;
> +
> + if (OMAP_HDQ_MAX_USER == hdq_data->hdq_usecount) {
> + pr_debug("attempt to exceed the max use count");
> + up(&hdq_data->hdq_semlock);
> + ret = -EINVAL;
> + } else {
> + hdq_data->hdq_usecount++;
> + try_module_get(THIS_MODULE);
> + if (1 == hdq_data->hdq_usecount) {
> + if (clk_enable(hdq_data->hdq_ick)) {
> + pr_debug("Can not enable ick\n");
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + up(&hdq_data->hdq_semlock);
> + return -ENODEV;
> + }
> + if (clk_enable(hdq_data->hdq_fck)) {
> + pr_debug("Can not enable fck\n");
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + up(&hdq_data->hdq_semlock);
> + return -ENODEV;
> + }
> +
> + /* make sure HDQ is out of reset */
> + if (!(hdq_reg_in(OMAP_HDQ_SYSSTATUS) &
> + OMAP_HDQ_SYSSTATUS_RESETDONE)) {
> + ret = _omap_hdq_reset();
> + if (ret)
> + /* back up the count */
> + hdq_data->hdq_usecount--;
> + } else {
> + /* select HDQ mode & enable clocks */
> + hdq_reg_out(OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
> + OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
> + hdq_reg_out(OMAP_HDQ_SYSCONFIG,
> + OMAP_HDQ_SYSCONFIG_AUTOIDLE);
> + hdq_reg_in(OMAP_HDQ_INT_STATUS);
> + }
> + }
> + }
> + up(&hdq_data->hdq_semlock);
> + return ret;
> +}
> +
> +/*
> + * Disable clocks to the module.
> + */
> +static int
> +omap_hdq_put()
> +{
> + int ret = 0;
> +
> + ret = down_interruptible(&hdq_data->hdq_semlock);
> + if (ret < 0)
> + return -EINTR;
> +
> + if (0 == hdq_data->hdq_usecount) {
> + pr_debug("attempt to decrement use count when it is zero");
> + ret = -EINVAL;
> + } else {
> + hdq_data->hdq_usecount--;
> + module_put(THIS_MODULE);
> + if (0 == hdq_data->hdq_usecount) {
> + clk_disable(hdq_data->hdq_ick);
> + clk_disable(hdq_data->hdq_fck);
> + }
> + }
> + up(&hdq_data->hdq_semlock);
> + return ret;
> +}
> +
> +/*
> + * Used to control the call to omap_hdq_get and omap_hdq_put.
> + * HDQ Protocol: Write the CMD|REG_address first, followed by
> + * the data wrire or read.
> + */
> +static int init_trans;
> +
> +/*
> + * Read a byte of data from the device.
> + */
> +static u8 omap_w1_read_byte(void *data)
> +{
> + u8 val;
> + int ret;
> +
> + ret = hdq_read_byte(&val);
> + if (ret) {
> + init_trans = 0;
> + omap_hdq_put();
> + return -1;
> + }
> +
> + /* Write followed by a read, release the module */
> + if (init_trans) {
> + init_trans = 0;
> + omap_hdq_put();
> + }
> +
> + return val;
> +}
> +
> +/*
> + * Write a byte of data to the device.
> + */
> +static void omap_w1_write_byte(void *data, u8 byte)
> +{
> + u8 status;
> +
> + /* First write to initialize the transfer */
> + if (init_trans == 0)
> + omap_hdq_get();
> +
> + init_trans++;
> +
> + hdq_write_byte(byte, &status);
> + pr_debug("Ctrl status %x\n", status);
> +
> + /* Second write, data transfered. Release the module */
> + if (init_trans > 1) {
> + omap_hdq_put();
> + init_trans = 0;
> + }
> +
> + return;
> +}
> +
> +static int __init omap_hdq_probe(struct platform_device *pdev)
> +{
> + struct resource *res;
> + int ret, irq;
> + u8 rev;
> +
> + if (!pdev)
> + return -ENODEV;
> +
> + hdq_data = kmalloc(sizeof(*hdq_data), GFP_KERNEL);
> + if (!hdq_data)
> + return -ENODEV;
> +
> + platform_set_drvdata(pdev, hdq_data);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (res == NULL) {
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> + return -ENXIO;
> + }
> +
> + hdq_data->hdq_base = res->start;
> +
> + /* get interface & functional clock objects */
> + hdq_data->hdq_ick = clk_get(&pdev->dev, "hdq_ick");
> + hdq_data->hdq_fck = clk_get(&pdev->dev, "hdq_fck");
> +
> + if (IS_ERR(hdq_data->hdq_ick) || IS_ERR(hdq_data->hdq_fck)) {
> + pr_debug("Can't get HDQ clock objects\n");
> + if (IS_ERR(hdq_data->hdq_ick)) {
> + ret = PTR_ERR(hdq_data->hdq_ick);
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> + return ret;
> + }
> + if (IS_ERR(hdq_data->hdq_fck)) {
> + ret = PTR_ERR(hdq_data->hdq_fck);
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> + return ret;
> + }
> + }
> +
> + hdq_data->hdq_usecount = 0;
> + sema_init(&hdq_data->hdq_semlock, 1);
> +
> + if (clk_enable(hdq_data->hdq_ick)) {
> + pr_debug("Can not enable ick\n");
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> + return -ENODEV;
> + }
> +
> + if (clk_enable(hdq_data->hdq_fck)) {
> + pr_debug("Can not enable fck\n");
> + clk_disable(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> + return -ENODEV;
> + }
> +
> + rev = hdq_reg_in(OMAP_HDQ_REVISION);
> + pr_info("OMAP HDQ Hardware Revision %c.%c. Driver in %s mode.\n",
> + (rev >> 4) + '0', (rev & 0x0f) + '0', "Interrupt");
> +
> + spin_lock_init(&hdq_data->hdq_spinlock);
> + omap_hdq_break();
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> + return -ENXIO;
> + }
> +
> + if (request_irq(irq, hdq_isr, IRQF_DISABLED, "OMAP HDQ",
> + &hdq_data->hdq_semlock)) {
> + pr_debug("request_irq failed\n");
> + clk_disable(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> + return -ENODEV;
> + }
> +
> + /* don't clock the HDQ until it is needed */
> + clk_disable(hdq_data->hdq_ick);
> + clk_disable(hdq_data->hdq_fck);
> +
> + ret = w1_add_master_device(&omap_w1_master);
> + if (ret) {
> + pr_debug("Failure in registering w1 master\n");
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int omap_hdq_remove(struct platform_device *pdev)
> +{
> + down_interruptible(&hdq_data->hdq_semlock);
> + if (0 != hdq_data->hdq_usecount) {
> + pr_debug("removed when use count is not zero\n");
> + return -EBUSY;
> + }
> + up(&hdq_data->hdq_semlock);
> +
> + /* remove module dependency */
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + free_irq(INT_24XX_HDQ_IRQ, &hdq_data->hdq_semlock);
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> +
> + return 0;
> +}
> +
> +static int __init
> +omap_hdq_init(void)
> +{
> + return platform_driver_register(&omap_hdq_driver);
> +}
> +
> +static void __exit
> +omap_hdq_exit(void)
> +{
> + platform_driver_unregister(&omap_hdq_driver);
> +}
> +
> +module_init(omap_hdq_init);
> +module_exit(omap_hdq_exit);
> +
> +module_param(W1_ID, int, S_IRUSR);
> +
> +MODULE_AUTHOR("Texas Instruments");
> +MODULE_DESCRIPTION("HDQ driver Library");
> +MODULE_LICENSE("GPL");
> -- 
> 1.6.0.1.141.g445ca
> 
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