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    Subject[PATCH] davinci: MMC: add cpufreq support
    Date
    Add cpufreq support to MMC driver. The clock divider value has to be
    modified according to the controller input frequency.

    Signed-off-by: Chaithrika U S <chaithrika@ti.com>
    ---
    This patch applies on top of the following two patches submitted to LKML
    http://patchwork.kernel.org/patch/54013/
    http://patchwork.kernel.org/patch/50914/

    drivers/mmc/host/davinci_mmc.c | 100 +++++++++++++++++++++++++++++++++------
    1 files changed, 84 insertions(+), 16 deletions(-)

    diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
    index fe8f613..b54c779 100644
    --- a/drivers/mmc/host/davinci_mmc.c
    +++ b/drivers/mmc/host/davinci_mmc.c
    @@ -25,6 +25,7 @@
    #include <linux/platform_device.h>
    #include <linux/clk.h>
    #include <linux/err.h>
    +#include <linux/cpufreq.h>
    #include <linux/mmc/host.h>
    #include <linux/io.h>
    #include <linux/irq.h>
    @@ -200,6 +201,9 @@ struct mmc_davinci_host {
    u8 version;
    /* for ns in one cycle calculation */
    unsigned ns_in_one_cycle;
    +#ifdef CONFIG_CPU_FREQ
    + struct notifier_block freq_transition;
    +#endif
    };


    @@ -739,27 +743,12 @@ static unsigned int calculate_freq_for_card(struct mmc_davinci_host *host,
    return mmc_push_pull_divisor;
    }

    -static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
    +static void calculate_clk_divider(struct mmc_host *mmc, struct mmc_ios *ios)
    {
    unsigned int open_drain_freq = 0, mmc_pclk = 0;
    unsigned int mmc_push_pull_freq = 0;
    struct mmc_davinci_host *host = mmc_priv(mmc);

    - mmc_pclk = host->mmc_input_clk;
    - dev_dbg(mmc_dev(host->mmc),
    - "clock %dHz busmode %d powermode %d Vdd %04x\n",
    - ios->clock, ios->bus_mode, ios->power_mode,
    - ios->vdd);
    - if (ios->bus_width == MMC_BUS_WIDTH_4) {
    - dev_dbg(mmc_dev(host->mmc), "Enabling 4 bit mode\n");
    - writel(readl(host->base + DAVINCI_MMCCTL) | MMCCTL_WIDTH_4_BIT,
    - host->base + DAVINCI_MMCCTL);
    - } else {
    - dev_dbg(mmc_dev(host->mmc), "Disabling 4 bit mode\n");
    - writel(readl(host->base + DAVINCI_MMCCTL) & ~MMCCTL_WIDTH_4_BIT,
    - host->base + DAVINCI_MMCCTL);
    - }
    -
    if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN) {
    u32 temp;

    @@ -798,6 +787,29 @@ static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)

    udelay(10);
    }
    +}
    +
    +static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
    +{
    + unsigned int mmc_pclk = 0;
    + struct mmc_davinci_host *host = mmc_priv(mmc);
    +
    + mmc_pclk = host->mmc_input_clk;
    + dev_dbg(mmc_dev(host->mmc),
    + "clock %dHz busmode %d powermode %d Vdd %04x\n",
    + ios->clock, ios->bus_mode, ios->power_mode,
    + ios->vdd);
    + if (ios->bus_width == MMC_BUS_WIDTH_4) {
    + dev_dbg(mmc_dev(host->mmc), "Enabling 4 bit mode\n");
    + writel(readl(host->base + DAVINCI_MMCCTL) | MMCCTL_WIDTH_4_BIT,
    + host->base + DAVINCI_MMCCTL);
    + } else {
    + dev_dbg(mmc_dev(host->mmc), "Disabling 4 bit mode\n");
    + writel(readl(host->base + DAVINCI_MMCCTL) & ~MMCCTL_WIDTH_4_BIT,
    + host->base + DAVINCI_MMCCTL);
    + }
    +
    + calculate_clk_divider(mmc, ios);

    host->bus_mode = ios->bus_mode;
    if (ios->power_mode == MMC_POWER_UP) {
    @@ -1040,6 +1052,52 @@ static struct mmc_host_ops mmc_davinci_ops = {

    /*----------------------------------------------------------------------*/

    +#ifdef CONFIG_CPU_FREQ
    +static int mmc_davinci_cpufreq_transition(struct notifier_block *nb,
    + unsigned long val, void *data)
    +{
    + struct mmc_davinci_host *host;
    + unsigned int mmc_pclk;
    + struct mmc_host *mmc;
    + unsigned long flags;
    +
    + host = container_of(nb, struct mmc_davinci_host, freq_transition);
    + mmc = host->mmc;
    + mmc_pclk = clk_get_rate(host->clk);
    +
    + if (val == CPUFREQ_POSTCHANGE) {
    + spin_lock_irqsave(&mmc->lock, flags);
    + host->mmc_input_clk = mmc_pclk;
    + calculate_clk_divider(mmc, &mmc->ios);
    + spin_unlock_irqrestore(&mmc->lock, flags);
    + }
    +
    + return 0;
    +}
    +
    +static inline int mmc_davinci_cpufreq_register(struct mmc_davinci_host *host)
    +{
    + host->freq_transition.notifier_call = mmc_davinci_cpufreq_transition;
    +
    + return cpufreq_register_notifier(&host->freq_transition,
    + CPUFREQ_TRANSITION_NOTIFIER);
    +}
    +
    +static inline void mmc_davinci_cpufreq_deregister(struct mmc_davinci_host *host)
    +{
    + cpufreq_unregister_notifier(&host->freq_transition,
    + CPUFREQ_TRANSITION_NOTIFIER);
    +}
    +#else
    +static inline int mmc_davinci_cpufreq_register(struct mmc_davinci_host *host)
    +{
    + return 0;
    +}
    +
    +static inline void mmc_davinci_cpufreq_deregister(struct mmc_davinci_host *host)
    +{
    +}
    +#endif
    static void __init init_mmcsd_host(struct mmc_davinci_host *host)
    {
    /* DAT line portion is diabled and in reset state */
    @@ -1169,6 +1227,12 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)

    platform_set_drvdata(pdev, host);

    + ret = mmc_davinci_cpufreq_register(host);
    + if (ret) {
    + dev_err(&pdev->dev, "failed to register cpufreq\n");
    + goto cpu_freq_fail;
    + }
    +
    ret = mmc_add_host(mmc);
    if (ret < 0)
    goto out;
    @@ -1186,6 +1250,8 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
    return 0;

    out:
    + mmc_davinci_cpufreq_deregister(host);
    +cpu_freq_fail:
    if (host) {
    davinci_release_dma_channels(host);

    @@ -1215,6 +1281,8 @@ static int __exit davinci_mmcsd_remove(struct platform_device *pdev)

    platform_set_drvdata(pdev, NULL);
    if (host) {
    + mmc_davinci_cpufreq_deregister(host);
    +
    mmc_remove_host(host->mmc);
    free_irq(host->irq, host);

    --
    1.5.6


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