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Message-ID: <20081008195908.GA12636@2ka.mipt.ru>
Date: Wed, 8 Oct 2008 23:59:10 +0400
From: Evgeniy Polyakov <johnpol@....mipt.ru>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
"Chikkature Rajashekar, Madhusudhan" <madhu.cr@...com>,
"Gadiyar, Anand" <gadiyar@...com>
Subject: Re: [PATCH 1/5] HDQ Driver for OMAP2430/3430
Hi all.
Andrew, please apply the whole serie to the upcoming tree when merge
window is opened. Thank you.
On Wed, Oct 08, 2008 at 12:46:25PM +0530, Gadiyar, Anand (gadiyar@...com) wrote:
> From: Madhusudhan Chikkature <madhu.cr@...com>
>
> The HDQ/1-Wire module of TI OMAP2430/3430 platforms implement the hardware
> protocol of the master functions of the Benchmark HDQ and the Dallas
> Semiconductor 1-Wire protocols. These protocols use a single wire for
> communication between the master (HDQ/1-Wire controller) and the slave
> (HDQ/1-Wire external compliant device).
>
> This patch provides the HDQ driver to suppport TI OMAP2430/3430 platforms.
>
> Signed-off-by: Madhusudhan Chikkature <madhu.cr@...com>
> Acked-by: Felipe Balbi <felipe.balbi@...ia.com>
> Acked-by: Evgeniy Polyakov <johnpol@....mipt.ru>
> ---
> Sending this series on behalf of Madhusudhan.
>
> drivers/w1/masters/Kconfig | 7
> drivers/w1/masters/Makefile | 1
> drivers/w1/masters/omap_hdq.c | 730 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 738 insertions(+)
>
> Index: linux-2.6/drivers/w1/masters/Kconfig
> ===================================================================
> --- linux-2.6.orig/drivers/w1/masters/Kconfig 2008-09-19 13:39:41.000000000 +0530
> +++ linux-2.6/drivers/w1/masters/Kconfig 2008-09-26 14:39:26.000000000 +0530
> @@ -52,5 +52,12 @@ config W1_MASTER_GPIO
> This support is also available as a module. If so, the module
> will be called w1-gpio.ko.
>
> +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.
> +
> endmenu
>
> Index: linux-2.6/drivers/w1/masters/Makefile
> ===================================================================
> --- linux-2.6.orig/drivers/w1/masters/Makefile 2008-09-19 13:39:41.000000000 +0530
> +++ linux-2.6/drivers/w1/masters/Makefile 2008-09-26 14:40:25.000000000 +0530
> @@ -7,3 +7,4 @@ obj-$(CONFIG_W1_MASTER_DS2490) += ds249
> obj-$(CONFIG_W1_MASTER_DS2482) += ds2482.o
> obj-$(CONFIG_W1_MASTER_DS1WM) += ds1wm.o
> obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o
> +obj-$(CONFIG_HDQ_MASTER_OMAP) += omap_hdq.o
> Index: linux-2.6/drivers/w1/masters/omap_hdq.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/drivers/w1/masters/omap_hdq.c 2008-09-26 14:28:36.000000000 +0530
> @@ -0,0 +1,730 @@
> +/*
> + * 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
> +
> +static DECLARE_WAIT_QUEUE_HEAD(hdq_wait_queue);
> +static int w1_id;
> +
> +struct hdq_data {
> + struct device *dev;
> + void __iomem *hdq_base;
> + /* lock status update */
> + struct mutex hdq_mutex;
> + int hdq_usecount;
> + struct clk *hdq_ick;
> + struct clk *hdq_fck;
> + u8 hdq_irqstatus;
> + /* device lock */
> + spinlock_t hdq_spinlock;
> + /*
> + * 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.
> + */
> + int init_trans;
> +};
> +
> +static int omap_hdq_get(struct hdq_data *hdq_data);
> +static int omap_hdq_put(struct hdq_data *hdq_data);
> +static int omap_hdq_break(struct hdq_data *hdq_data);
> +
> +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,
> + .driver = {
> + .name = "omap_hdq",
> + },
> +};
> +
> +static u8 omap_w1_read_byte(void *_hdq);
> +static void omap_w1_write_byte(void *_hdq, u8 byte);
> +static u8 omap_w1_reset_bus(void *_hdq);
> +static void omap_w1_search_bus(void *_hdq, 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(struct hdq_data *hdq_data, u32 offset)
> +{
> + return __raw_readb(hdq_data->hdq_base + offset);
> +}
> +
> +static inline void hdq_reg_out(struct hdq_data *hdq_data, u32 offset, u8 val)
> +{
> + __raw_writeb(val, hdq_data->hdq_base + offset);
> +}
> +
> +static inline u8 hdq_reg_merge(struct hdq_data *hdq_data, u32 offset,
> + u8 val, u8 mask)
> +{
> + u8 new_val = (__raw_readb(hdq_data->hdq_base + offset) & ~mask)
> + | (val & mask);
> + __raw_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(struct hdq_data *hdq_data, 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(hdq_data, offset)) & flag)
> + && time_before(jiffies, timeout)) {
> + set_current_state(TASK_UNINTERRUPTIBLE);
> + schedule_timeout(1);
> + }
> + if (*status & flag)
> + ret = -ETIMEDOUT;
> + } else if (flag_set == OMAP_HDQ_FLAG_SET) {
> + /* wait for the flag set */
> + while (!((*status = hdq_reg_in(hdq_data, offset)) & flag)
> + && time_before(jiffies, timeout)) {
> + set_current_state(TASK_UNINTERRUPTIBLE);
> + schedule_timeout(1);
> + }
> + if (!(*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(struct hdq_data *hdq_data, 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(hdq_data, 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(hdq_data, OMAP_HDQ_TX_DATA, val);
> +
> + /* set the GO bit */
> + hdq_reg_merge(hdq_data, 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 (ret < 0) {
> + dev_dbg(hdq_data->dev, "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)) {
> + dev_dbg(hdq_data->dev, "timeout waiting for"
> + "TXCOMPLETE/RXCOMPLETE, %x", *status);
> + return -ETIMEDOUT;
> + }
> +
> + /* wait for the GO bit return to zero */
> + ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_GO,
> + OMAP_HDQ_FLAG_CLEAR, &tmp_status);
> + if (ret) {
> + dev_dbg(hdq_data->dev, "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 *_hdq)
> +{
> + struct hdq_data *hdq_data = _hdq;
> + unsigned long irqflags;
> +
> + spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
> + hdq_data->hdq_irqstatus = hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
> + spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
> + dev_dbg(hdq_data->dev, "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 *_hdq)
> +{
> + return 0;
> +}
> +
> +/* W1 search callback function */
> +static void omap_w1_search_bus(void *_hdq, 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(_hdq, id);
> +}
> +
> +static int _omap_hdq_reset(struct hdq_data *hdq_data)
> +{
> + int ret;
> + u8 tmp_status;
> +
> + hdq_reg_out(hdq_data, 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(hdq_data, OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
> + OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
> +
> + /* wait for reset to complete */
> + ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_SYSSTATUS,
> + OMAP_HDQ_SYSSTATUS_RESETDONE, OMAP_HDQ_FLAG_SET, &tmp_status);
> + if (ret)
> + dev_dbg(hdq_data->dev, "timeout waiting HDQ reset, %x",
> + tmp_status);
> + else {
> + hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
> + OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
> + hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
> + OMAP_HDQ_SYSCONFIG_AUTOIDLE);
> + }
> +
> + return ret;
> +}
> +
> +/* Issue break pulse to the device */
> +static int omap_hdq_break(struct hdq_data *hdq_data)
> +{
> + int ret;
> + u8 tmp_status;
> + unsigned long irqflags;
> +
> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
> + if (ret < 0)
> + return -EINTR;
> +
> + if (!hdq_data->hdq_usecount) {
> + mutex_unlock(&hdq_data->hdq_mutex);
> + return -EINVAL;
> + }
> +
> + spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
> + /* clear interrupt flags via a dummy read */
> + hdq_reg_in(hdq_data, 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(hdq_data, 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 (ret < 0) {
> + dev_dbg(hdq_data->dev, "wait interrupted");
> + mutex_unlock(&hdq_data->hdq_mutex);
> + 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)) {
> + dev_dbg(hdq_data->dev, "timeout waiting for TIMEOUT, %x",
> + tmp_status);
> + mutex_unlock(&hdq_data->hdq_mutex);
> + return -ETIMEDOUT;
> + }
> + /*
> + * wait for both INIT and GO bits rerurn to zero.
> + * zero wait time expected for interrupt mode.
> + */
> + ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
> + OMAP_HDQ_CTRL_STATUS_GO, OMAP_HDQ_FLAG_CLEAR,
> + &tmp_status);
> + if (ret)
> + dev_dbg(hdq_data->dev, "timeout waiting INIT&GO bits"
> + "return to zero, %x", tmp_status);
> +
> + mutex_unlock(&hdq_data->hdq_mutex);
> +
> + return ret;
> +}
> +
> +static int hdq_read_byte(struct hdq_data *hdq_data, u8 *val)
> +{
> + int ret;
> + u8 status;
> + unsigned long irqflags;
> + unsigned long timeout = jiffies + OMAP_HDQ_TIMEOUT;
> +
> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
> + if (ret < 0)
> + return -EINTR;
> +
> + if (!hdq_data->hdq_usecount) {
> + mutex_unlock(&hdq_data->hdq_mutex);
> + return -EINVAL;
> + }
> +
> + if (!(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
> + hdq_reg_merge(hdq_data, 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.
> + */
> + 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(hdq_data, 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)) {
> + dev_dbg(hdq_data->dev, "timeout waiting for"
> + "RXCOMPLETE, %x", status);
> + mutex_unlock(&hdq_data->hdq_mutex);
> + return -ETIMEDOUT;
> + }
> + }
> + /* the data is ready. Read it in! */
> + *val = hdq_reg_in(hdq_data, OMAP_HDQ_RX_DATA);
> + mutex_unlock(&hdq_data->hdq_mutex);
> +
> + return 0;
> +
> +}
> +
> +/* Enable clocks and set the controller to HDQ mode */
> +static int omap_hdq_get(struct hdq_data *hdq_data)
> +{
> + int ret = 0;
> +
> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
> + if (ret < 0)
> + return -EINTR;
> +
> + if (OMAP_HDQ_MAX_USER == hdq_data->hdq_usecount) {
> + dev_dbg(hdq_data->dev, "attempt to exceed the max use count");
> + mutex_unlock(&hdq_data->hdq_mutex);
> + 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)) {
> + dev_dbg(hdq_data->dev, "Can not enable ick\n");
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + mutex_unlock(&hdq_data->hdq_mutex);
> + return -ENODEV;
> + }
> + if (clk_enable(hdq_data->hdq_fck)) {
> + dev_dbg(hdq_data->dev, "Can not enable fck\n");
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + mutex_unlock(&hdq_data->hdq_mutex);
> + return -ENODEV;
> + }
> +
> + /* make sure HDQ is out of reset */
> + if (!(hdq_reg_in(hdq_data, OMAP_HDQ_SYSSTATUS) &
> + OMAP_HDQ_SYSSTATUS_RESETDONE)) {
> + ret = _omap_hdq_reset(hdq_data);
> + if (ret)
> + /* back up the count */
> + hdq_data->hdq_usecount--;
> + } else {
> + /* select HDQ mode & enable clocks */
> + hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
> + OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
> + OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
> + hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
> + OMAP_HDQ_SYSCONFIG_AUTOIDLE);
> + hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
> + }
> + }
> + }
> + mutex_unlock(&hdq_data->hdq_mutex);
> +
> + return ret;
> +}
> +
> +/* Disable clocks to the module */
> +static int omap_hdq_put(struct hdq_data *hdq_data)
> +{
> + int ret = 0;
> +
> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
> + if (ret < 0)
> + return -EINTR;
> +
> + if (0 == hdq_data->hdq_usecount) {
> + dev_dbg(hdq_data->dev, "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);
> + }
> + }
> + mutex_unlock(&hdq_data->hdq_mutex);
> +
> + return ret;
> +}
> +
> +/* Read a byte of data from the device */
> +static u8 omap_w1_read_byte(void *_hdq)
> +{
> + struct hdq_data *hdq_data = _hdq;
> + u8 val;
> + int ret;
> +
> + ret = hdq_read_byte(hdq_data, &val);
> + if (ret) {
> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
> + if (ret < 0) {
> + dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
> + return -EINTR;
> + }
> + hdq_data->init_trans = 0;
> + mutex_unlock(&hdq_data->hdq_mutex);
> + omap_hdq_put(hdq_data);
> + return -1;
> + }
> +
> + /* Write followed by a read, release the module */
> + if (hdq_data->init_trans) {
> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
> + if (ret < 0) {
> + dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
> + return -EINTR;
> + }
> + hdq_data->init_trans = 0;
> + mutex_unlock(&hdq_data->hdq_mutex);
> + omap_hdq_put(hdq_data);
> + }
> +
> + return val;
> +}
> +
> +/* Write a byte of data to the device */
> +static void omap_w1_write_byte(void *_hdq, u8 byte)
> +{
> + struct hdq_data *hdq_data = _hdq;
> + int ret;
> + u8 status;
> +
> + /* First write to initialize the transfer */
> + if (hdq_data->init_trans == 0)
> + omap_hdq_get(hdq_data);
> +
> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
> + if (ret < 0) {
> + dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
> + return;
> + }
> + hdq_data->init_trans++;
> + mutex_unlock(&hdq_data->hdq_mutex);
> +
> + hdq_write_byte(hdq_data, byte, &status);
> + dev_dbg(hdq_data->dev, "Ctrl status %x\n", status);
> +
> + /* Second write, data transfered. Release the module */
> + if (hdq_data->init_trans > 1) {
> + omap_hdq_put(hdq_data);
> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
> + if (ret < 0) {
> + dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
> + return;
> + }
> + hdq_data->init_trans = 0;
> + mutex_unlock(&hdq_data->hdq_mutex);
> + }
> +
> + return;
> +}
> +
> +static int __init omap_hdq_probe(struct platform_device *pdev)
> +{
> + struct hdq_data *hdq_data;
> + struct resource *res;
> + int ret, irq;
> + u8 rev;
> +
> + if (!pdev)
> + return -ENODEV;
> +
> + hdq_data = kmalloc(sizeof(*hdq_data), GFP_KERNEL);
> + if (!hdq_data) {
> + dev_dbg(&pdev->dev, "unable to allocate memory\n");
> + ret = -ENODEV;
> + goto err_kmalloc;
> + }
> +
> + hdq_data->dev = &pdev->dev;
> + platform_set_drvdata(pdev, hdq_data);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_dbg(&pdev->dev, "unable to get resource\n");
> + ret = ENXIO;
> + goto err_resource;
> + }
> +
> + hdq_data->hdq_base = ioremap(res->start, SZ_4K);
> + if (!hdq_data->hdq_base) {
> + dev_dbg(&pdev->dev, "ioremap failed\n");
> + ret = -EINVAL;
> + goto err_ioremap;
> + }
> +
> + /* 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)) {
> + dev_dbg(&pdev->dev, "Can't get HDQ clock objects\n");
> + if (IS_ERR(hdq_data->hdq_ick)) {
> + ret = PTR_ERR(hdq_data->hdq_ick);
> + goto err_clk;
> + }
> + if (IS_ERR(hdq_data->hdq_fck)) {
> + ret = PTR_ERR(hdq_data->hdq_fck);
> + clk_put(hdq_data->hdq_ick);
> + goto err_clk;
> + }
> + }
> +
> + hdq_data->hdq_usecount = 0;
> + mutex_init(&hdq_data->hdq_mutex);
> +
> + if (clk_enable(hdq_data->hdq_ick)) {
> + dev_dbg(&pdev->dev, "Can not enable ick\n");
> + ret = -ENODEV;
> + goto err_ick;
> + }
> +
> + if (clk_enable(hdq_data->hdq_fck)) {
> + dev_dbg(&pdev->dev, "Can not enable fck\n");
> + ret = -ENODEV;
> + goto err_fck;
> + }
> +
> + rev = hdq_reg_in(hdq_data, OMAP_HDQ_REVISION);
> + dev_info(&pdev->dev, "OMAP HDQ Hardware Rev %c.%c. Driver in %s mode\n",
> + (rev >> 4) + '0', (rev & 0x0f) + '0', "Interrupt");
> +
> + spin_lock_init(&hdq_data->hdq_spinlock);
> + omap_hdq_break(hdq_data);
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + ret = -ENXIO;
> + goto err_irq;
> + }
> +
> + ret = request_irq(irq, hdq_isr, IRQF_DISABLED, "omap_hdq", hdq_data);
> + if (ret < 0) {
> + dev_dbg(&pdev->dev, "could not request irq\n");
> + goto err_irq;
> + }
> +
> + /* don't clock the HDQ until it is needed */
> + clk_disable(hdq_data->hdq_ick);
> + clk_disable(hdq_data->hdq_fck);
> +
> + omap_w1_master.data = hdq_data;
> +
> + ret = w1_add_master_device(&omap_w1_master);
> + if (ret) {
> + dev_dbg(&pdev->dev, "Failure in registering w1 master\n");
> + goto err_w1;
> + }
> +
> + return 0;
> +
> +err_w1:
> +err_irq:
> + clk_disable(hdq_data->hdq_fck);
> +
> +err_fck:
> + clk_disable(hdq_data->hdq_ick);
> +
> +err_ick:
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> +
> +err_clk:
> + iounmap(hdq_data->hdq_base);
> +
> +err_ioremap:
> +err_resource:
> + platform_set_drvdata(pdev, NULL);
> + kfree(hdq_data);
> +
> +err_kmalloc:
> + return ret;
> +
> +}
> +
> +static int omap_hdq_remove(struct platform_device *pdev)
> +{
> + struct hdq_data *hdq_data = platform_get_drvdata(pdev);
> +
> + mutex_lock(&hdq_data->hdq_mutex);
> +
> + if (0 != hdq_data->hdq_usecount) {
> + dev_dbg(&pdev->dev, "removed when use count is not zero\n");
> + return -EBUSY;
> + }
> +
> + mutex_unlock(&hdq_data->hdq_mutex);
> +
> + /* remove module dependency */
> + clk_put(hdq_data->hdq_ick);
> + clk_put(hdq_data->hdq_fck);
> + free_irq(INT_24XX_HDQ_IRQ, hdq_data);
> + platform_set_drvdata(pdev, NULL);
> + iounmap(hdq_data->hdq_base);
> + kfree(hdq_data);
> +
> + return 0;
> +}
> +
> +static int __init
> +omap_hdq_init(void)
> +{
> + return platform_driver_register(&omap_hdq_driver);
> +}
> +module_init(omap_hdq_init);
> +
> +static void __exit
> +omap_hdq_exit(void)
> +{
> + platform_driver_unregister(&omap_hdq_driver);
> +}
> +module_exit(omap_hdq_exit);
> +
> +module_param(w1_id, int, S_IRUSR);
> +MODULE_PARM_DESC(w1_id, "1-wire id for the slave detection");
> +
> +MODULE_AUTHOR("Texas Instruments");
> +MODULE_DESCRIPTION("HDQ driver Library");
> +MODULE_LICENSE("GPL");
--
Evgeniy Polyakov
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