ext Varadarajan, Charu Latha wrote:
-----Original Message-----
From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap-
owner@xxxxxxxxxxxxxxx] On Behalf Of Kevin Hilman
Sent: Saturday, August 22, 2009 9:59 PM
To: Roger Quadros
Cc: Varadarajan, Charu Latha; linux-omap@xxxxxxxxxxxxxxx;
tony@xxxxxxxxxxx; david-b@xxxxxxxxxxx; sameo@xxxxxxxxxxxxxxx;
p_gortmaker@xxxxxxxxx
Subject: Re: [RFC][PATCH 1/3] RTC periodic interrupts enabling and msecure
init
Roger Quadros <ext-roger.quadros@xxxxxxxxx> writes:
ext charu@xxxxxx wrote:
Triton2 RTC code changes for fixing periodic interrupt feature in RTC.
rtc-twlcore.c does initialisation of the msecure gpio pin. Board
files indicate msecure gpio line through twl4030 platform
data. twl4030-core.c passes this information to RTC driver.
Board files does msecure gpio mux configuration.
Signed-off-by: Charulatha V <charu@xxxxxx>
Periodic interrupts and msecure are 2 different entities. I think they
should be implemented in different patches.
Agreed. The "fix" part of this should be a separated out with a
detailed description of both the problem and the fix.
Kevin
Okay.
---
drivers/rtc/rtc-twl4030.c | 63
++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 62 insertions(+), 1 deletions(-)
diff --git a/drivers/rtc/rtc-twl4030.c b/drivers/rtc/rtc-twl4030.c
index 9c8c70c..614adf0 100644
--- a/drivers/rtc/rtc-twl4030.c
+++ b/drivers/rtc/rtc-twl4030.c
@@ -29,7 +29,12 @@
#include <linux/interrupt.h>
#include <linux/i2c/twl4030.h>
+#include <linux/gpio.h>
+/*
+ * To find if the value is a power of two
+ */
+#define is_power_of_two(x) (!((x) & ((x)-1)))
/*
* RTC block register offsets (use TWL_MODULE_RTC)
@@ -86,6 +91,37 @@
/*--------------------------------------------------------------------
--*/
/*
+ * msecure line initialisation for TWL4030 RTC registers write access
+ */
+static int msecure_init(struct twl4030_rtc_platform_data *pdata)
+{
+ int ret = 0;
+ if (pdata == NULL)
+ goto out;
+
+ ret = gpio_request(pdata->msecure_gpio, "msecure");
+ if (ret < 0) {
if (ret) should suffice
+ pr_err("twl4030_rtc: can't reserve msecure GPIO:%d !\n"
+ "RTC functionality will not be available\n",
+ pdata->msecure_gpio);
+ goto out;
+ }
+ /*
+ * TWL4030 will be in secure mode if msecure line from OMAP is low.
+ * Make msecure line high in order to change the TWL4030 RTC time
+ * and calender registers.
+ */
+ ret = gpio_direction_output(pdata->msecure_gpio, 1);
+ if (ret < 0)
ditto
+ pr_err("twl4030_rtc: can't set msecure GPIO direction:%d !\n"
+ "RTC functionality will not be available\n",
+ pdata->msecure_gpio);
+
+out:
+ return ret;
+}
Agreed.
+
+/*
* Supports 1 byte read from TWL4030 RTC register.
*/
static int twl4030_rtc_read_u8(u8 *data, u8 reg)
@@ -128,7 +164,6 @@ static int set_rtc_irq_bit(unsigned char bit)
int ret;
val = rtc_irq_bits | bit;
- val &= ~BIT_RTC_INTERRUPTS_REG_EVERY_M;
ret = twl4030_rtc_write_u8(val, REG_RTC_INTERRUPTS_REG);
if (ret == 0)
rtc_irq_bits = val;
@@ -318,6 +353,25 @@ out:
return ret;
}
+static int twl4030_rtc_irq_set_freq(struct device *dev, int freq)
+{
+ int ret, val = 1;
+ int regbit = 0;
+
+ if ((!is_power_of_2(freq)) || (freq > 8) || (freq <= 0))
+ return -EINVAL;
0 is valid freq. it means disable periodic interrupts.
+
+ while ((freq & val) == 0) {
+ val = val << 1;
+ regbit++;
+ }
as per your implementation, if user sets interrupt rate of 4 Hz then
you will set regbit to 2 which means interrupt every hour?
i.e. 0.00027 Hz. no?
+ ret = set_rtc_irq_bit(regbit);
+ if (ret)
+ dev_err(dev, "rtc_irq_set_freq error %d\n", ret);
+
+ return ret;
+}
+
static irqreturn_t twl4030_rtc_interrupt(int irq, void *rtc)
{
unsigned long events = 0;
@@ -383,6 +437,7 @@ static struct rtc_class_ops twl4030_rtc_ops = {
.set_alarm = twl4030_rtc_set_alarm,
.alarm_irq_enable = twl4030_rtc_alarm_irq_enable,
.update_irq_enable = twl4030_rtc_update_irq_enable,
+ .irq_set_freq = twl4030_rtc_irq_set_freq,
IMHO this does not make sense.
twl4030 supports a max interrupt rate of 1 Hz (i.e. 1 sec). So you can
only support freq values of 0 and 1 i.e. 0 for disabled and 1 for 1
sec interrupt.
This functionality is already achieved by update_irq_enable.
-roger
--
Agreed that twl4030_rtc_update_irq_enable is enough if the periodic interrupt is required only for 1 Hz.
If this is enough, then any ioctl call with RTC_IRQP_SET to twl4030 chip's RTC can do only
1 Hz freq setting. This means that "RTC_IRQP_SET" is not required at all for twl4030 chip's RTC
and only "RTC_UIE_ON" is enough. Please clarify.
The twl4030 chip also supports interrupt every min, day and hour. Don't we need support for this?
RTC_IRQP_SET is not meant for hours, min and day. It is meant to set interrupt
rate of 1 Hz and up. If seconds and hours are required then alarm ioctl
(RTC_ALM_SET) can be used.
-V Charu Latha--
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