Hi Thomas,
On 08/29/2012 07:48 PM, Thomas Abraham wrote:
> Some platforms allow for clock gating and control of bus interface unit clock
> and card interface unit clock. Add support for clock lookup of optional biu
> and ciu clocks for clock gating and clock speed determination.
>
> Signed-off-by: Abhilash Kesavan <a.kesa...@samsung.com>
> Signed-off-by: Thomas Abraham <thomas.abra...@linaro.org>
> Acked-by: Will Newton <will.new...@imgtec.com>
> ---
> drivers/mmc/host/dw_mmc.c | 42 +++++++++++++++++++++++++++++++++++++++---
> include/linux/mmc/dw_mmc.h | 4 ++++
> 2 files changed, 43 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 227c42e..90c7c7b 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1960,18 +1960,38 @@ int dw_mci_probe(struct dw_mci *host)
> return -ENODEV;
> }
>
> - if (!host->pdata->bus_hz) {
> + host->biu_clk = clk_get(host->dev, "biu");
> + if (IS_ERR(host->biu_clk))
> + dev_dbg(host->dev, "biu clock not available\n");
> + else
> + clk_prepare_enable(host->biu_clk);
biu is clock for bus interface?
if didn't get "biu_clk" or didn't clk_prepare_enable(), then can we initialize
the card?
> +
> + host->ciu_clk = clk_get(host->dev, "ciu");
> + if (IS_ERR(host->ciu_clk))
> + dev_dbg(host->dev, "ciu clock not available\n");
> + else
> + clk_prepare_enable(host->ciu_clk);
> +
> + if (IS_ERR(host->ciu_clk))
> + host->bus_hz = host->pdata->bus_hz;
> + else
> + host->bus_hz = clk_get_rate(host->ciu_clk);
if clk_get_rate() is incorrect value(ex,400MHz),
then mmc->f_min value is too high.
because mmc->f_min is assigned to DIV_ROUND_UP(host->bus_hz, 510) into
dw_mc_init_slot.
Do you have any opinion for solving this?
> +
> + if (!host->bus_hz) {
> dev_err(host->dev,
> "Platform data must supply bus speed\n");
> - return -ENODEV;
> + ret = -ENODEV;
> + goto err_clk;
> }
>
> - host->bus_hz = host->pdata->bus_hz;
> host->quirks = host->pdata->quirks;
>
> spin_lock_init(&host->lock);
> INIT_LIST_HEAD(&host->queue);
>
> + host->dma_ops = host->pdata->dma_ops;
> + dw_mci_init_dma(host);
> +
> /*
> * Get the host data width - this assumes that HCON has been set with
> * the correct values.
> @@ -2116,6 +2136,16 @@ err_dmaunmap:
> regulator_disable(host->vmmc);
> regulator_put(host->vmmc);
> }
> +
> +err_clk:
> + if (!IS_ERR(host->ciu_clk)) {
> + clk_disable_unprepare(host->ciu_clk);
> + clk_put(host->ciu_clk);
> + }
> + if (!IS_ERR(host->biu_clk)) {
> + clk_disable_unprepare(host->biu_clk);
> + clk_put(host->biu_clk);
> + }
> return ret;
> }
> EXPORT_SYMBOL(dw_mci_probe);
> @@ -2149,6 +2179,12 @@ void dw_mci_remove(struct dw_mci *host)
> regulator_put(host->vmmc);
> }
>
> + if (!IS_ERR(host->ciu_clk))
> + clk_disable_unprepare(host->ciu_clk);
> + if (!IS_ERR(host->biu_clk))
> + clk_disable_unprepare(host->biu_clk);
> + clk_put(host->ciu_clk);
> + clk_put(host->biu_clk);
> }
> EXPORT_SYMBOL(dw_mci_remove);
>
> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
> index a37a573..787ad56 100644
> --- a/include/linux/mmc/dw_mmc.h
> +++ b/include/linux/mmc/dw_mmc.h
> @@ -78,6 +78,8 @@ struct mmc_data;
> * @data_offset: Set the offset of DATA register according to VERID.
> * @dev: Device associated with the MMC controller.
> * @pdata: Platform data associated with the MMC controller.
> + * @biu_clk: Pointer to bus interface unit clock instance.
> + * @ciu_clk: Pointer to card interface unit clock instance.
> * @slot: Slots sharing this MMC controller.
> * @fifo_depth: depth of FIFO.
> * @data_shift: log2 of FIFO item size.
> @@ -158,6 +160,8 @@ struct dw_mci {
> u16 data_offset;
> struct device *dev;
> struct dw_mci_board *pdata;
> + struct clk *biu_clk;
> + struct clk *ciu_clk;
> struct dw_mci_slot *slot[MAX_MCI_SLOTS];
>
> /* FIFO push and pull */
>
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