[PATCH v5 2/2] sdhci-s3c: Add support no internal clock divider in host controller

[kmpark@infradead.org (Kyungmin Park)]

Hi Chris,

we make a conclusion use this patch. Can you merge it for 2.6.37?

Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

On Mon, Oct 11, 2010 at 4:50 PM, Kukjin Kim <kgene.kim@samsung.com> wrote:
> From: Jeongbae Seo <jeongbae.seo@samsung.com>
>
> This patch adds to support no internal clock divider in SDHCI.
> The external clock divider can be used to make a proper clock
> because SDHCI doesn't support internal clock divider by itself.
>
> If external clock divider type is selected, some functions related
> with clock control will be overridened by other functions.
>
> The current clock control index is added to let you know which
> clock bus is used for SDHCI when using overriding functions.
>
> The checking functions is added into sdhci_s3c_consider_clock,
> because clock divider step is different from that of host controller.
>
> Signed-off-by: Jeongbae Seo <jeongbae.seo@samsung.com>
> Cc: Jaehoon Chung <jh80.chung@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Ben Dooks <ben-linux@fluff.org>
> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
> ---
> Changes since v4:
> - Added missing change
>
> Changes since v3:
> - Modified comparision condition as per Kyungmin Park's suggestion
>
> Changes since v2:
> - Changed clock control method to overriding from using quirk
> - This patch is referred from that of Jaehoon Chung's support non-standard clock setting
>
> Changes since v1:
> - Separated to each topic
>
> NOTE :
> - This patch depends on following.
> ?[PATCH 4/5] ARM: SAMSUNG : Add clock types into platform data
>
> ?drivers/mmc/host/sdhci-s3c.c | ? 62 ++++++++++++++++++++++++++++++++++++++++++
> ?1 files changed, 62 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
> index a7710f5..e7208f6 100644
> --- a/drivers/mmc/host/sdhci-s3c.c
> +++ b/drivers/mmc/host/sdhci-s3c.c
> @@ -130,6 +130,15 @@ static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
> ? ? ? ?if (!clksrc)
> ? ? ? ? ? ? ? ?return UINT_MAX;
>
> + ? ? ? /*
> + ? ? ? ?* Clock divider's step is different as 1 from that of host controller
> + ? ? ? ?* when 'clk_type' is S3C_SDHCI_CLK_DIV_EXTERNAL.
> + ? ? ? ?*/
> + ? ? ? if (ourhost->pdata->clk_type == S3C_SDHCI_CLK_DIV_EXTERNAL) {
> + ? ? ? ? ? ? ? rate = clk_round_rate(clksrc, wanted);
> + ? ? ? ? ? ? ? return wanted - rate;
> + ? ? ? }
> +
> ? ? ? ?rate = clk_get_rate(clksrc);
>
> ? ? ? ?for (div = 1; div < 256; div *= 2) {
> @@ -232,6 +241,42 @@ static unsigned int sdhci_s3c_get_min_clock(struct sdhci_host *host)
> ? ? ? ?return min;
> ?}
>
> +/* sdhci_cmu_get_max_clk - callback to get maximum clock frequency.*/
> +static unsigned int sdhci_cmu_get_max_clock(struct sdhci_host *host)
> +{
> + ? ? ? struct sdhci_s3c *ourhost = to_s3c(host);
> +
> + ? ? ? return clk_round_rate(ourhost->clk_bus[ourhost->cur_clk], UINT_MAX);
> +}
> +
> +/* sdhci_cmu_get_min_clock - callback to get minimal supported clock value. */
> +static unsigned int sdhci_cmu_get_min_clock(struct sdhci_host *host)
> +{
> + ? ? ? struct sdhci_s3c *ourhost = to_s3c(host);
> +
> + ? ? ? /*
> + ? ? ? ?* initial clock can be in the frequency range of
> + ? ? ? ?* 100KHz-400KHz, so we set it as max value.
> + ? ? ? ?*/
> + ? ? ? return clk_round_rate(ourhost->clk_bus[ourhost->cur_clk], 400000);
> +}
> +
> +/* sdhci_cmu_set_clock - callback on clock change.*/
> +static void sdhci_cmu_set_clock(struct sdhci_host *host, unsigned int clock)
> +{
> + ? ? ? struct sdhci_s3c *ourhost = to_s3c(host);
> +
> + ? ? ? /* don't bother if the clock is going off */
> + ? ? ? if (clock == 0)
> + ? ? ? ? ? ? ? return;
> +
> + ? ? ? sdhci_s3c_set_clock(host, clock);
> +
> + ? ? ? clk_set_rate(ourhost->clk_bus[ourhost->cur_clk], clock);
> +
> + ? ? ? host->clock = clock;
> +}
> +
> ?static struct sdhci_ops sdhci_s3c_ops = {
> ? ? ? ?.get_max_clock ? ? ? ? ?= sdhci_s3c_get_max_clk,
> ? ? ? ?.set_clock ? ? ? ? ? ? ?= sdhci_s3c_set_clock,
> @@ -361,6 +406,13 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
>
> ? ? ? ? ? ? ? ?clks++;
> ? ? ? ? ? ? ? ?sc->clk_bus[ptr] = clk;
> +
> + ? ? ? ? ? ? ? /*
> + ? ? ? ? ? ? ? ?* save current clock index to know which clock bus
> + ? ? ? ? ? ? ? ?* is used later in overriding functions.
> + ? ? ? ? ? ? ? ?*/
> + ? ? ? ? ? ? ? sc->cur_clk = ptr;
> +
> ? ? ? ? ? ? ? ?clk_enable(clk);
>
> ? ? ? ? ? ? ? ?dev_info(dev, "clock source %d: %s (%ld Hz)\n",
> @@ -427,6 +479,16 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
> ? ? ? ?/* HSMMC on Samsung SoCs uses SDCLK as timeout clock */
> ? ? ? ?host->quirks |= SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK;
>
> + ? ? ? /*
> + ? ? ? ?* If controller does not have internal clock divider,
> + ? ? ? ?* we can use overriding functions instead of default.
> + ? ? ? ?*/
> + ? ? ? if (pdata->clk_type == S3C_SDHCI_CLK_DIV_EXTERNAL) {
> + ? ? ? ? ? ? ? sdhci_s3c_ops.set_clock = sdhci_cmu_set_clock;
> + ? ? ? ? ? ? ? sdhci_s3c_ops.get_min_clock = sdhci_cmu_get_min_clock;
> + ? ? ? ? ? ? ? sdhci_s3c_ops.get_max_clock = sdhci_cmu_get_max_clock;
> + ? ? ? }
> +
> ? ? ? ?/* It supports additional host capabilities if needed */
> ? ? ? ?if (pdata->host_caps)
> ? ? ? ? ? ? ? ?host->mmc->caps |= pdata->host_caps;
> --
> 1.6.2.5
>
> --
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