Subject: [RFC/RFT 4/6] mmc: sdhci-msm: convert driver to use runtime PM apis

From: [email-masked] (Kevin Hilman)
Date: Thu, 23 Apr 2015 14:15:21 -0700

"Rajendra Nayak" <[email-masked]> writes:

>> On 23 April 2015 at 10:45, Rajendra Nayak <[email-masked]> wrote:
>>> With platform support now in place to manage clocks from within runtime
>>> PM
>>> callbacks, get rid of all clock handling from the driver and convert the
>>> driver to use runtime PM apis.
>>>
>>> Signed-off-by: Rajendra Nayak <[email-masked]>
>>> Cc: <[email-masked]>
>>> ---
>>>  drivers/mmc/host/sdhci-msm.c | 46
>>> +++++++++++---------------------------------
>>>  1 file changed, 11 insertions(+), 35 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
>>> index 4a09f76..3c62a77 100644
>>> --- a/drivers/mmc/host/sdhci-msm.c
>>> +++ b/drivers/mmc/host/sdhci-msm.c
>>> @@ -19,6 +19,7 @@
>>>  #include <linux/delay.h>
>>>  #include <linux/mmc/mmc.h>
>>>  #include <linux/slab.h>
>>> +#include <linux/pm_runtime.h>
>>>
>>>  #include "sdhci-pltfm.h"
>>>
>>> @@ -56,8 +57,6 @@
>>>  struct sdhci_msm_host {
>>>         struct platform_device *pdev;
>>>         void __iomem *core_mem; /* MSM SDCC mapped address */
>>> -       struct clk *clk;        /* main SD/MMC bus clock */
>>> -       struct clk *pclk;       /* SDHC peripheral bus clock */
>>>         struct clk *bus_clk;    /* SDHC bus voter clock */
>>>         struct mmc_host *mmc;
>>>         struct sdhci_pltfm_data sdhci_msm_pdata;
>>> @@ -469,29 +468,8 @@ static int sdhci_msm_probe(struct platform_device
>>> *pdev)
>>>                         goto pltfm_free;
>>>         }
>>>
>>> -       /* Setup main peripheral bus clock */
>>> -       msm_host->pclk = devm_clk_get(&pdev->dev, "iface");
>>> -       if (IS_ERR(msm_host->pclk)) {
>>> -               ret = PTR_ERR(msm_host->pclk);
>>> -               dev_err(&pdev->dev, "Perpheral clk setup failed (%d)\n",
>>> ret);
>>> -               goto bus_clk_disable;
>>> -       }
>>> -
>>> -       ret = clk_prepare_enable(msm_host->pclk);
>>> -       if (ret)
>>> -               goto bus_clk_disable;
>>> -
>>> -       /* Setup SDC MMC clock */
>>> -       msm_host->clk = devm_clk_get(&pdev->dev, "core");
>>> -       if (IS_ERR(msm_host->clk)) {
>>> -               ret = PTR_ERR(msm_host->clk);
>>> -               dev_err(&pdev->dev, "SDC MMC clk setup failed (%d)\n",
>>> ret);
>>> -               goto pclk_disable;
>>> -       }
>>> -
>>> -       ret = clk_prepare_enable(msm_host->clk);
>>> -       if (ret)
>>> -               goto pclk_disable;
>>> +       pm_runtime_enable(&pdev->dev);
>>> +       pm_runtime_get_sync(&pdev->dev);
>>>
>>>         core_memres = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>>>         msm_host->core_mem = devm_ioremap_resource(&pdev->dev,
>>> core_memres);
>>> @@ -499,7 +477,7 @@ static int sdhci_msm_probe(struct platform_device
>>> *pdev)
>>>         if (IS_ERR(msm_host->core_mem)) {
>>>                 dev_err(&pdev->dev, "Failed to remap registers\n");
>>>                 ret = PTR_ERR(msm_host->core_mem);
>>> -               goto clk_disable;
>>> +               goto err;
>>>         }
>>>
>>>         /* Reset the core and Enable SDHC mode */
>>> @@ -511,7 +489,7 @@ static int sdhci_msm_probe(struct platform_device
>>> *pdev)
>>>         if (readl(msm_host->core_mem + CORE_POWER) & CORE_SW_RST) {
>>>                 dev_err(&pdev->dev, "Stuck in reset\n");
>>>                 ret = -ETIMEDOUT;
>>> -               goto clk_disable;
>>> +               goto err;
>>>         }
>>>
>>>         /* Set HC_MODE_EN bit in HC_MODE register */
>>> @@ -545,15 +523,13 @@ static int sdhci_msm_probe(struct platform_device
>>> *pdev)
>>>
>>>         ret = sdhci_add_host(host);
>>>         if (ret)
>>> -               goto clk_disable;
>>> +               goto err;
>>>
>>>         return 0;
>>>
>>> -clk_disable:
>>> -       clk_disable_unprepare(msm_host->clk);
>>> -pclk_disable:
>>> -       clk_disable_unprepare(msm_host->pclk);
>>> -bus_clk_disable:
>>> +err:
>>> +       pm_runtime_put_sync(&pdev->dev);
>>> +       pm_runtime_disable(&pdev->dev);
>>>         if (!IS_ERR(msm_host->bus_clk))
>>>                 clk_disable_unprepare(msm_host->bus_clk);
>>>  pltfm_free:
>>> @@ -571,8 +547,8 @@ static int sdhci_msm_remove(struct platform_device
>>> *pdev)
>>>
>>>         sdhci_remove_host(host, dead);
>>>         sdhci_pltfm_free(pdev);
>>> -       clk_disable_unprepare(msm_host->clk);
>>> -       clk_disable_unprepare(msm_host->pclk);
>>> +       pm_runtime_put_sync(&pdev->dev);
>>> +       pm_runtime_disable(&pdev->dev);
>>>         if (!IS_ERR(msm_host->bus_clk))
>>>                 clk_disable_unprepare(msm_host->bus_clk);
>>>         return 0;
>>> --
>>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
>>> member
>>> of Code Aurora Forum, hosted by The Linux Foundation
>>>
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>>
>> This all looks wrong. The driver will no longer work unless CONFIG_PM is
>> set.
>
> Right, I seem to have completely ignored the !CONFIG_PM case.
> Will look at how to handle that.

IMO, don't complicate the driver with that.  Just enable (or leave
enabled) all the clocks in the clock driver in the !CONFIG_PM case.

Kevin