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

["Rajendra Nayak" <rnayak@codeaurora.org>]

> "Rajendra Nayak" <rnayak@codeaurora.org> writes:
>
>>> On 23 April 2015 at 10:45, Rajendra Nayak <rnayak@codeaurora.org>
>>> 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 <rnayak@codeaurora.org>
>>>> Cc: <linux-mmc@vger.kernel.org>
>>>> ---
>>>>  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;
[]..
>>>
>>> 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.

so I just looked at what pm_clk_notify() does in !CONFIG_PM case and it
seems to do just that, leaves all the clocks enabled on
BUS_NOTIFY_BIND_DRIVER case and disables them for BUS_NOTIFY_UNBOUND_DRIVER
case. So looks like things are already in place to handle this :)

Ulf, does that address your concern or did I miss anything?

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