Hi Andy,
On Wed, Oct 13, 2010 at 11:22:22AM +0300, Andy Shevchenko wrote:
> For debugging power managment features there is quite convenient to have a
> possibility to change MMC host controller clock at run time. This patch adds
> 'clock' file under MMC host root of debugfs.
>
> Usage as follows:
>
> # cat /sys/kernel/debug/mmc0/clock
> 52000000
>
> # echo "1000000000" > /sys/kernel/debug/mmc0/clock
> # cat /sys/kernel/debug/mmc0/clock
> 52000000
>
> # echo "48000000" > /sys/kernel/debug/mmc0/clock
> # cat /sys/kernel/debug/mmc0/clock
> 48000000
>
> The second piece of example shows limits which are applied accordingly to used
> host driver.
>
> Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@xxxxxxxxx>
> ---
> drivers/mmc/core/debugfs.c | 35 +++++++++++++++++++++++++++++++++--
> 1 files changed, 33 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
> index 96d10f4..9b6ec07 100644
> --- a/drivers/mmc/core/debugfs.c
> +++ b/drivers/mmc/core/debugfs.c
> @@ -133,6 +133,33 @@ static const struct file_operations mmc_ios_fops = {
> .release = single_release,
> };
>
> +static int mmc_clock_opt_get(void *data, u64 *val)
> +{
> + struct mmc_host *host = data;
> +
> + *val = host->ios.clock;
> +
> + return 0;
> +}
> +
> +static int mmc_clock_opt_set(void *data, u64 val)
> +{
> + struct mmc_host *host = data;
> +
> + /* We need this check due to input value is u64 */
> + if (val > host->f_max)
> + return -EINVAL;
> +
> + mmc_claim_host(host);
> + mmc_set_clock(host, (unsigned int) val);
> + mmc_release_host(host);
> +
> + return 0;
> +}
> +
> +DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
> + "%llu\n");
> +
> void mmc_add_host_debugfs(struct mmc_host *host)
> {
> struct dentry *root;
> @@ -149,11 +176,15 @@ void mmc_add_host_debugfs(struct mmc_host *host)
> host->debugfs_root = root;
>
> if (!debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops))
> - goto err_ios;
> + goto err_node;
> +
> + if (!debugfs_create_file("clock", S_IRUSR | S_IWUSR, root, host,
> + &mmc_clock_fops))
> + goto err_node;
>
> return;
>
> -err_ios:
> +err_node:
> debugfs_remove_recursive(root);
> host->debugfs_root = NULL;
> err_root:
> --
Thanks, looks good -- applied to mmc-next with minor changelog edits.
--
Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
One Laptop Per Child
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