Re: [PATCH V2 23/27] mmc: mmci: add variant property to request a reset

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hi Ulf

On 10/01/2018 11:30 AM, Ulf Hansson wrote:
On 21 September 2018 at 11:46, Ludovic Barre <ludovic.Barre@xxxxxx> wrote:
From: Ludovic Barre <ludovic.barre@xxxxxx>

Some variants could require a reset.
STM32 sdmmc variant needs to reset hardware block
during the power cycle procedure (for re-initialization)

Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
---
  Documentation/devicetree/bindings/mmc/mmci.txt | 2 ++
  drivers/mmc/host/mmci.c                        | 9 +++++++++
  drivers/mmc/host/mmci.h                        | 4 ++++
  3 files changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmci.txt b/Documentation/devicetree/bindings/mmc/mmci.txt
index 03796cf..e952707 100644
--- a/Documentation/devicetree/bindings/mmc/mmci.txt
+++ b/Documentation/devicetree/bindings/mmc/mmci.txt
@@ -11,6 +11,8 @@ Required properties:
  - compatible             : contains "arm,pl18x", "arm,primecell".
  - vmmc-supply            : phandle to the regulator device tree node, mentioned
                             as the VCC/VDD supply in the eMMC/SD specs.
+depend of variant:
+- resets                 : phandle to internal reset line.


This looks like a thing depending on the SoC, rather than on the
variant. Therefore, I suggest you move this to be an optional DT
property.

could be replaced by:

Optional properties:
- resets                 : phandle to internal reset line.
			   Should be defined for sdmmc variant.


Also, please move the DT doc update into a separate patch.

OK


  Optional properties:
  - arm,primecell-periphid : contains the PrimeCell Peripheral ID, it overrides
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index b1d5bc5..6b3c33f 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -37,6 +37,7 @@
  #include <linux/pm_runtime.h>
  #include <linux/types.h>
  #include <linux/pinctrl/consumer.h>
+#include <linux/reset.h>

  #include <asm/div64.h>
  #include <asm/io.h>
@@ -1854,6 +1855,14 @@ static int mmci_probe(struct amba_device *dev,

         dev_dbg(mmc_dev(mmc), "clocking block at %u Hz\n", mmc->f_max);

+       if (variant->reset) {
+               host->rst = devm_reset_control_get_exclusive(&dev->dev, NULL);

As suggested, let's make this optional and not depending on the variant.

I done like that because is required for my variant (if no reset, no power cycle for sdmmc).

If you prefer, I could move to optional with "devm_reset_control_get_optional_exclusive"
And I add a comment in mmci dt binding to specify that not optional
for sdmmc. (see above)


+               if (IS_ERR(host->rst)) {
+                       ret = PTR_ERR(host->rst);
+                       goto clk_disable;
+               }
+       }
+
         /* Get regulators and the supported OCR mask */
         ret = mmc_regulator_get_supply(mmc);
         if (ret)
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index e130689..f0fa185 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -247,6 +247,7 @@ struct mmci_host;
   * @start_err: bitmask identifying the STARTBITERR bit inside MMCISTATUS
   *            register.
   * @opendrain: bitmask identifying the OPENDRAIN bit inside MMCIPOWER register
+ * @reset: true if variant has need reset signal.
   */
  struct variant_data {
         unsigned int            clkreg;
@@ -285,6 +286,7 @@ struct variant_data {
         bool                    qcom_dml;
         bool                    reversed_irq_handling;
         bool                    mmcimask1;
+       bool                    reset;
         unsigned int            irq_pio_mask;
         u32                     start_err;
         u32                     opendrain;
@@ -318,6 +320,8 @@ struct mmci_host {
         struct clk              *clk;
         bool                    singleirq;

+       struct reset_control    *rst;
+
         spinlock_t              lock;

         unsigned int            mclk;
--
2.7.4


Kind regards
Uffe




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