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    SubjectRe: [PATCH 1/3] Driver for user access to internal clocks
    From
    > Same comments here as for your "timer.c" file:
    > - too generic of a name
    > - needs proper documentation
    > - send any kernel api changes also to linux-api@vger.kernel.org
    >
    > thanks,
    >
    > greg k-h
    >

    This is the modified Samsung S3c implementation for user mode clock driver.

    This is a proposal for adding 2 functions to clk interface to allow higher
    level drivers to enumerate and list all clocks, and to modify clk_get
    to accept device specific clk names in the form "name.id"
    There is also the implementation for Samsung S3C24xx platform.

    Signed-off-by: Davide Rizzo <elpa.rizzo@gmail.com>
    ---diff -urpN linux-2.6.29-rc2/arch/arm/plat-s3c/clock.c
    linux-2.6.29-rc2.elpa/arch/arm/plat-s3c/clock.c
    --- linux-2.6.29-rc2/arch/arm/plat-s3c/clock.c 2009-01-17
    11:32:38.000000000 +0100
    +++ linux-2.6.29-rc2.elpa/arch/arm/plat-s3c/clock.c 2009-01-28
    19:32:08.000000000 +0100
    @@ -69,11 +69,19 @@ static int clk_null_enable(struct clk *c

    struct clk *clk_get(struct device *dev, const char *id)
    {
    + long idno;
    + char *name = (char *)id;
    + char *dotpos = strrchr(id, '.');
    struct clk *p;
    struct clk *clk = ERR_PTR(-ENOENT);
    - int idno;

    - if (dev == NULL || dev->bus != &platform_bus_type)
    + if (dotpos) {
    + int err = strict_strtol(dotpos + 1, 10, &idno);
    + if (err)
    + return ERR_PTR(err);
    + name = kstrdup(id, GFP_KERNEL);
    + name[dotpos - id] = '\0';
    + } else if (dev == NULL || dev->bus != &platform_bus_type)
    idno = -1;
    else
    idno = to_platform_device(dev)->id;
    @@ -82,7 +90,7 @@ struct clk *clk_get(struct device *dev,

    list_for_each_entry(p, &clocks, list) {
    if (p->id == idno &&
    - strcmp(id, p->name) == 0 &&
    + strcmp(name, p->name) == 0 &&
    try_module_get(p->owner)) {
    clk = p;
    break;
    @@ -94,7 +102,7 @@ struct clk *clk_get(struct device *dev,

    if (IS_ERR(clk)) {
    list_for_each_entry(p, &clocks, list) {
    - if (p->id == -1 && strcmp(id, p->name) == 0 &&
    + if (p->id == -1 && strcmp(name, p->name) == 0 &&
    try_module_get(p->owner)) {
    clk = p;
    break;
    @@ -103,6 +111,8 @@ struct clk *clk_get(struct device *dev,
    }

    spin_unlock(&clocks_lock);
    + if (dotpos)
    + kfree(name);
    return clk;
    }

    @@ -222,6 +232,42 @@ EXPORT_SYMBOL(clk_set_rate);
    EXPORT_SYMBOL(clk_get_parent);
    EXPORT_SYMBOL(clk_set_parent);

    +int clk_for_each(int(*fn)(struct clk *, void *), void *data)
    + {
    + struct clk *clk;
    + int ret = 0;
    +
    + list_for_each_entry(clk, &clocks, list)
    + {
    + ret = fn(clk, data);
    + if (ret)
    + break;
    + }
    + return ret;
    +}
    +EXPORT_SYMBOL(clk_for_each);
    +
    +/* Returned pointer must be deallocated with kfree() */
    +const char *clk_get_name(struct clk *clk)
    +{
    + char *s;
    + int len;
    +
    + if (IS_ERR(clk))
    + return ERR_PTR(-EINVAL);
    +
    + len = strlen(clk->name) + 8;
    + s = kmalloc(len, GFP_KERNEL);
    + if (!s)
    + return ERR_PTR(-ENOMEM);
    + if (clk->id == -1)
    + strlcpy(s, clk->name, len);
    + else if (snprintf(s, len, "%s.%d", clk->name, clk->id) > len)
    + s[len - 1] = '\0';
    + return s;
    +}
    +EXPORT_SYMBOL(clk_get_name);
    +
    /* base clocks */

    static int clk_default_setrate(struct clk *clk, unsigned long rate)
    diff -urpN linux-2.6.29-rc2/include/linux/clk.h
    linux-2.6.29-rc2.elpa/include/linux/clk.h
    --- linux-2.6.29-rc2/include/linux/clk.h 2008-12-25 00:26:37.000000000 +0100
    +++ linux-2.6.29-rc2.elpa/include/linux/clk.h 2009-01-28
    19:21:43.000000000 +0100
    @@ -125,4 +125,22 @@ int clk_set_parent(struct clk *clk, stru
    */
    struct clk *clk_get_parent(struct clk *clk);

    +/**
    + * clk_for_each - calls fn, iterating between registered clocks
    + * @fn: function to be called, passing each clk structure in 1st argument
    + * @data: 2nd argument to pass to fn function
    + *
    + * Returns 0 or the called fn return code if != 0
    + */
    +int clk_for_each(int(*fn)(struct clk *, void *), void *data);
    +
    +/**
    + * clk_name - get clock name
    + * @clk: clock source
    + *
    + * Returns clock's name that must be deallocated with kfree(), or valid
    + * IS_ERR() condition containing errno.
    + */
    +const char *clk_get_name(struct clk *clk);
    +
    #endif

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