| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-id: <56A02A25.9050905@samsung.com>
Date: Thu, 21 Jan 2016 09:45:25 +0900
From: Krzysztof Kozlowski <k.kozlowski@...sung.com>
To: Javier Martinez Canillas <javier@....samsung.com>,
linux-kernel@...r.kernel.org
Cc: Kukjin Kim <kgene@...nel.org>, rtc-linux@...glegroups.com,
Chanwoo Choi <cw00.choi@...sung.com>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Laxman Dewangan <ldewangan@...dia.com>,
linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH 3/8] rtc: max77686: Use a driver data struct instead
hard-coded values
On 21.01.2016 02:14, Javier Martinez Canillas wrote:
> The driver has some hard-coded values such as the minimum delay needed
> before a RTC update or the mask used for the sec/min/hour/etc registers.
>
> Use a data structure that contains these values and pass as driver data
> using the platform device ID table for each device.
>
> This allows to make the driver's ops callbacks more generic so other RTC
> that are similar but don't have the same values can also be supported.
>
> Signed-off-by: Javier Martinez Canillas <javier@....samsung.com>
> ---
>
> drivers/rtc/rtc-max77686.c | 47 +++++++++++++++++++++++++++++-----------------
> 1 file changed, 30 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
> index ae4d61e7ce4b..441d163dcbeb 100644
> --- a/drivers/rtc/rtc-max77686.c
> +++ b/drivers/rtc/rtc-max77686.c
> @@ -41,8 +41,6 @@
> #define ALARM_ENABLE_SHIFT 7
> #define ALARM_ENABLE_MASK (1 << ALARM_ENABLE_SHIFT)
>
> -#define MAX77686_RTC_UPDATE_DELAY 16000
> -
> enum {
> RTC_SEC = 0,
> RTC_MIN,
> @@ -54,6 +52,11 @@ enum {
> RTC_NR_TIME
> };
>
> +struct rtc_driver_data {
1. This is only local structure so maybe: max77686_rtc_driver_data?
2. Can you put here a comment explaining the purpose of this delay
(quite generic name) and used units?
> + unsigned long delay;
A comment here - what 'mask'? Generic name so explanation would be welcomed.
> + int mask;
I think this should be u8 to avoid early promotions to int. It is used
directly with other u8 values. At the end effect of operation is
promoted to int anyway but using only u8 for operations looks more
consistent to me.
> +};
> +
> struct max77686_rtc_info {
> struct device *dev;
> struct max77686_dev *max77686;
> @@ -63,6 +66,8 @@ struct max77686_rtc_info {
>
> struct regmap *regmap;
>
> + struct rtc_driver_data *drv_data;
That may be pointer to const data. Actually not "may be" but
even "should be" because you allocate later really a const data and you
are discarding const-ness with cast.
> +
> int virq;
> int rtc_24hr_mode;
> };
> @@ -72,12 +77,19 @@ enum MAX77686_RTC_OP {
> MAX77686_RTC_READ,
> };
>
> +static const struct rtc_driver_data max77686_drv_data = {
> + .delay = 1600,
> + .mask = 0x7f,
> +};
> +
> static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
> - int rtc_24hr_mode)
> + struct max77686_rtc_info *info)
> {
> - tm->tm_sec = data[RTC_SEC] & 0x7f;
> - tm->tm_min = data[RTC_MIN] & 0x7f;
> - if (rtc_24hr_mode)
> + int mask = info->drv_data->mask;
> +
> + tm->tm_sec = data[RTC_SEC] & mask;
> + tm->tm_min = data[RTC_MIN] & mask;
> + if (info->rtc_24hr_mode)
> tm->tm_hour = data[RTC_HOUR] & 0x1f;
> else {
> tm->tm_hour = data[RTC_HOUR] & 0x0f;
> @@ -86,10 +98,10 @@ static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
> }
>
> /* Only a single bit is set in data[], so fls() would be equivalent */
> - tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0x7f) - 1;
> + tm->tm_wday = ffs(data[RTC_WEEKDAY] & mask) - 1;
> tm->tm_mday = data[RTC_DATE] & 0x1f;
> tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
> - tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;
> + tm->tm_year = (data[RTC_YEAR] & mask) + 100;
> tm->tm_yday = 0;
> tm->tm_isdst = 0;
> }
> @@ -117,6 +129,7 @@ static int max77686_rtc_update(struct max77686_rtc_info *info,
> {
> int ret;
> unsigned int data;
> + unsigned long delay = info->drv_data->delay;
>
> if (op == MAX77686_RTC_WRITE)
> data = 1 << RTC_UDR_SHIFT;
> @@ -129,9 +142,8 @@ static int max77686_rtc_update(struct max77686_rtc_info *info,
> dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
> __func__, ret, data);
> else {
> - /* Minimum 16ms delay required before RTC update. */
> - usleep_range(MAX77686_RTC_UPDATE_DELAY,
> - MAX77686_RTC_UPDATE_DELAY * 2);
> + /* Minimum delay required before RTC update. */
> + usleep_range(delay, delay * 2);
> }
>
> return ret;
> @@ -156,7 +168,7 @@ static int max77686_rtc_read_time(struct device *dev, struct rtc_time *tm)
> goto out;
> }
>
> - max77686_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
> + max77686_rtc_data_to_tm(data, tm, info);
>
> ret = rtc_valid_tm(tm);
>
> @@ -213,7 +225,7 @@ static int max77686_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> goto out;
> }
>
> - max77686_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
> + max77686_rtc_data_to_tm(data, &alrm->time, info);
>
> alrm->enabled = 0;
> for (i = 0; i < RTC_NR_TIME; i++) {
> @@ -260,7 +272,7 @@ static int max77686_rtc_stop_alarm(struct max77686_rtc_info *info)
> goto out;
> }
>
> - max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
> + max77686_rtc_data_to_tm(data, &tm, info);
>
> for (i = 0; i < RTC_NR_TIME; i++)
> data[i] &= ~ALARM_ENABLE_MASK;
> @@ -299,7 +311,7 @@ static int max77686_rtc_start_alarm(struct max77686_rtc_info *info)
> goto out;
> }
>
> - max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
> + max77686_rtc_data_to_tm(data, &tm, info);
>
> data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
> data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
> @@ -307,7 +319,7 @@ static int max77686_rtc_start_alarm(struct max77686_rtc_info *info)
> data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
> if (data[RTC_MONTH] & 0xf)
> data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
> - if (data[RTC_YEAR] & 0x7f)
> + if (data[RTC_YEAR] & info->drv_data->mask)
> data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
> if (data[RTC_DATE] & 0x1f)
> data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);
> @@ -436,6 +448,7 @@ static int max77686_rtc_probe(struct platform_device *pdev)
> info->dev = &pdev->dev;
> info->max77686 = max77686;
> info->rtc = max77686->rtc;
> + info->drv_data = (struct rtc_driver_data *)pdev->id_entry->driver_data;
That cast dropping constness is bad.
Best regards,
Krzysztof
>
> platform_set_drvdata(pdev, info);
>
> @@ -510,7 +523,7 @@ static SIMPLE_DEV_PM_OPS(max77686_rtc_pm_ops,
> max77686_rtc_suspend, max77686_rtc_resume);
>
> static const struct platform_device_id rtc_id[] = {
> - { "max77686-rtc", 0 },
> + { "max77686-rtc", .driver_data = (kernel_ulong_t)&max77686_drv_data, },
> {},
> };
> MODULE_DEVICE_TABLE(platform, rtc_id);
>
Powered by blists - more mailing lists