Re: [PATCH v2 3/3] mmc: pwrseq: convert to proper platform device

From: Ulf Hansson
Date: Tue Mar 01 2016 - 04:54:27 EST


On 1 March 2016 at 10:51, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
> On 28 January 2016 at 11:03, Srinivas Kandagatla
> <srinivas.kandagatla@xxxxxxxxxx> wrote:
>> simple-pwrseq and emmc-pwrseq drivers rely on platform_device
>> structure from of_find_device_by_node(), this works mostly. But, as there
>> is no driver associated with this devices, cases like default/init pinctrl
>> setup would never be performed by pwrseq. This becomes problem when the
>> gpios used in pwrseq require pinctrl setup.
>>
>> Currently most of the common pinctrl setup is done in
>> drivers/base/pinctrl.c by pinctrl_bind_pins().
>>
>> There are two ways to solve this issue on either convert pwrseq drivers
>> to a proper platform drivers or copy the exact code from
>> pcintrl_bind_pins(). I prefer converting pwrseq to proper drivers so that
>> other cases like setting up clks/parents from dt would also be possible.
>>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
>> ---
>> drivers/mmc/Kconfig | 2 +
>> drivers/mmc/core/Kconfig | 7 +++
>> drivers/mmc/core/Makefile | 4 +-
>> drivers/mmc/core/pwrseq.c | 115 +++++++++++++++++++++------------------
>> drivers/mmc/core/pwrseq.h | 19 +++++--
>> drivers/mmc/core/pwrseq_emmc.c | 81 +++++++++++++++++++--------
>> drivers/mmc/core/pwrseq_simple.c | 85 ++++++++++++++++++++---------
>> 7 files changed, 207 insertions(+), 106 deletions(-)
>>
>> diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
>> index f2eeb38..7b2412a 100644
>> --- a/drivers/mmc/Kconfig
>> +++ b/drivers/mmc/Kconfig
>> @@ -5,6 +5,8 @@
>> menuconfig MMC
>> tristate "MMC/SD/SDIO card support"
>> depends on HAS_IOMEM
>> + select PWRSEQ_SIMPLE if OF
>> + select PWRSEQ_EMMC if OF
>
> In general I don't like "select" and for this case I think there is a
> better way. See below.
>
>> help
>> This selects MultiMediaCard, Secure Digital and Secure
>> Digital I/O support.
>> diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
>> index 4c33d76..b26f756 100644
>> --- a/drivers/mmc/core/Kconfig
>> +++ b/drivers/mmc/core/Kconfig
>> @@ -1,3 +1,10 @@
>> #
>> # MMC core configuration
>> #
>> +config PWRSEQ_EMMC
>> + tristate "PwrSeq EMMC"
>
> I suggest change this to:
> bool "HW reset support for eMMC"
>
>> + depends on OF
>
> Add:
> default y
>
> Also I think some brief "help" text, describing the feature would be nice.
>
>> +
>> +config PWRSEQ_SIMPLE
>> + tristate "PwrSeq Simple"
>> + depends on OF
>
> Similar comments as above for PWRSEQ_EMMC.
>
>> diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
>> index 2c25138..f007151 100644
>> --- a/drivers/mmc/core/Makefile
>> +++ b/drivers/mmc/core/Makefile
>> @@ -8,5 +8,7 @@ mmc_core-y := core.o bus.o host.o \
>> sdio.o sdio_ops.o sdio_bus.o \
>> sdio_cis.o sdio_io.o sdio_irq.o \
>> quirks.o slot-gpio.o
>> -mmc_core-$(CONFIG_OF) += pwrseq.o pwrseq_simple.o pwrseq_emmc.o
>> +mmc_core-$(CONFIG_OF) += pwrseq.o
>> +obj-$(CONFIG_PWRSEQ_SIMPLE) += pwrseq_simple.o
>> +obj-$(CONFIG_PWRSEQ_EMMC) += pwrseq_emmc.o
>> mmc_core-$(CONFIG_DEBUG_FS) += debugfs.o
>> diff --git a/drivers/mmc/core/pwrseq.c b/drivers/mmc/core/pwrseq.c
>> index 4c1d175..64c7c79 100644
>> --- a/drivers/mmc/core/pwrseq.c
>> +++ b/drivers/mmc/core/pwrseq.c
>> @@ -8,80 +8,64 @@
>> * MMC power sequence management
>> */
>> #include <linux/kernel.h>
>> -#include <linux/platform_device.h>
>> #include <linux/err.h>
>> +#include <linux/module.h>
>> #include <linux/of.h>
>> -#include <linux/of_platform.h>
>>
>> #include <linux/mmc/host.h>
>>
>> #include "pwrseq.h"
>>
>> -struct mmc_pwrseq_match {
>> - const char *compatible;
>> - struct mmc_pwrseq *(*alloc)(struct mmc_host *host, struct device *dev);
>> -};
>> -
>> -static struct mmc_pwrseq_match pwrseq_match[] = {
>> - {
>> - .compatible = "mmc-pwrseq-simple",
>> - .alloc = mmc_pwrseq_simple_alloc,
>> - }, {
>> - .compatible = "mmc-pwrseq-emmc",
>> - .alloc = mmc_pwrseq_emmc_alloc,
>> - },
>> -};
>> -
>> -static struct mmc_pwrseq_match *mmc_pwrseq_find(struct device_node *np)
>> +static DEFINE_MUTEX(pwrseq_list_mutex);
>> +static LIST_HEAD(pwrseq_list);
>> +
>> +static struct mmc_pwrseq *of_find_mmc_pwrseq(struct mmc_host *host)
>> {
>> - struct mmc_pwrseq_match *match = ERR_PTR(-ENODEV);
>> - int i;
>> + struct device_node *np;
>> + struct mmc_pwrseq *p, *pwrseq = NULL;
>>
>> - for (i = 0; i < ARRAY_SIZE(pwrseq_match); i++) {
>> - if (of_device_is_compatible(np, pwrseq_match[i].compatible)) {
>> - match = &pwrseq_match[i];
>> + np = of_parse_phandle(host->parent->of_node, "mmc-pwrseq", 0);
>> + if (!np)
>> + return NULL;
>> +
>> + mutex_lock(&pwrseq_list_mutex);
>> + list_for_each_entry(p, &pwrseq_list, list) {
>> + if (p->dev->of_node == np) {
>> + pwrseq = p;
>> break;
>> }
>> }
>>
>> - return match;
>> + of_node_put(np);
>> + mutex_unlock(&pwrseq_list_mutex);
>> +
>> + return pwrseq ? : ERR_PTR(-EPROBE_DEFER);
>> }
>>
>> int mmc_pwrseq_alloc(struct mmc_host *host)
>> {
>> - struct platform_device *pdev;
>> - struct device_node *np;
>> - struct mmc_pwrseq_match *match;
>> struct mmc_pwrseq *pwrseq;
>> int ret = 0;
>>
>> - np = of_parse_phandle(host->parent->of_node, "mmc-pwrseq", 0);
>> - if (!np)
>> - return 0;
>> + pwrseq = of_find_mmc_pwrseq(host);
>>
>
> I think you can remove another empty line here.
>
>> - pdev = of_find_device_by_node(np);
>> - if (!pdev) {
>> - ret = -ENODEV;
>> - goto err;
>> - }
>> + if (IS_ERR_OR_NULL(pwrseq))
>> + return PTR_ERR(pwrseq);
>
> You need "return PTR_ERR_OR_ZERO(pwrseq)", as pwrse is what you want here.
>

Argh, slipped with my fingers in the middle of review and manage to
send on half the review. Please ignore it, I will send a new one with
a full review.

Sorry for noise.

Kind regards
Uffe