diff mbox

[RFC,10/12] mmc: mmci: Add clock support for Qualcomm.

Message ID 1398116945-31640-1-git-send-email-srinivas.kandagatla@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Srinivas Kandagatla April 21, 2014, 9:49 p.m. UTC
From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

MCICLK going to card bus is directly driven by the clock controller, so the
driver has to set the required rates depending on the state of the card. This
bit of support is very much similar to bypass mode but there is no such thing
called bypass mode in MCICLK register of Qcom SD card controller. By default
the clock is directly driven by the clk controller.

This patch adds clock support for Qualcomm SDCC in the driver. This bit of
code is conditioned on hw designer.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/mmc/host/mmci.c |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

Comments

Stephen Boyd April 21, 2014, 10:20 p.m. UTC | #1
On 04/21/14 14:49, srinivas.kandagatla@linaro.org wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>
> MCICLK going to card bus is directly driven by the clock controller, so the
> driver has to set the required rates depending on the state of the card. This
> bit of support is very much similar to bypass mode but there is no such thing
> called bypass mode in MCICLK register of Qcom SD card controller. By default
> the clock is directly driven by the clk controller.
>
> This patch adds clock support for Qualcomm SDCC in the driver. This bit of
> code is conditioned on hw designer.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> ---
>  drivers/mmc/host/mmci.c |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index f465eb5..2cd3a8f 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -291,7 +291,18 @@ static void mmci_set_clkreg(struct mmci_host *host, unsigned int desired)
>  	host->cclk = 0;
>  
>  	if (desired) {
> -		if (desired >= host->mclk) {
> +		if (desired != host->mclk &&
> +		    host->hw_designer == AMBA_VENDOR_QCOM) {
> +			/* Qcom MCLKCLK register does not define bypass bits */
> +			int rc = clk_set_rate(host->clk, desired);

Please turn on lockdep (PROVE_LOCKING) and sleeping while atomic checks
(DEBUG_ATOMIC_SLEEP). You cannot call clk_set_rate() in atomic context.
Srinivas Kandagatla April 22, 2014, 10:03 a.m. UTC | #2
Thankyou Stephen,

On 21/04/14 23:20, Stephen Boyd wrote:
> Please turn on lockdep (PROVE_LOCKING) and sleeping while atomic checks
> (DEBUG_ATOMIC_SLEEP). You cannot call clk_set_rate() in atomic context.
You are correct, there is a spinlock taken just before entering this 
code. I will fix this in next version by moving clk_set_rate out of this 
lock.

Thanks,
srini
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index f465eb5..2cd3a8f 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -291,7 +291,18 @@  static void mmci_set_clkreg(struct mmci_host *host, unsigned int desired)
 	host->cclk = 0;
 
 	if (desired) {
-		if (desired >= host->mclk) {
+		if (desired != host->mclk &&
+		    host->hw_designer == AMBA_VENDOR_QCOM) {
+			/* Qcom MCLKCLK register does not define bypass bits */
+			int rc = clk_set_rate(host->clk, desired);
+			if (rc < 0) {
+				dev_err(mmc_dev(host->mmc),
+					"Error setting clock rate (%d)\n", rc);
+			} else {
+				host->mclk = clk_get_rate(host->clk);
+				host->cclk = host->mclk;
+			}
+		} else if (desired >= host->mclk) {
 			clk = MCI_CLK_BYPASS;
 			if (variant->st_clkdiv)
 				clk |= MCI_ST_UX500_NEG_EDGE;
@@ -1612,7 +1623,8 @@  static int mmci_probe(struct amba_device *dev,
 	 * of course.
 	 */
 	if (plat->f_max)
-		mmc->f_max = min(host->mclk, plat->f_max);
+		mmc->f_max = (host->hw_designer == AMBA_VENDOR_QCOM) ?
+				plat->f_max : min(host->mclk, plat->f_max);
 	else
 		mmc->f_max = min(host->mclk, fmax);
 	dev_dbg(mmc_dev(mmc), "clocking block at %u Hz\n", mmc->f_max);