This includes fixing some Coding Style issues and re-ordering and/or
simplifying a little code.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[thierry.reding@gmail.com: applied some bikeshedding>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Setting up the STI PWM IP as capture only, with zero PWM output devices
is a perfectly valid configuration. It is no longer okay to assume that
there must be at least 1 PWM output device. In this patch we make the
default number of PWM output devices zero and only configure channels
explicitly requested.
Reported-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Once a PWM capture has been initiated, the capture call enables a rising
edge detection interrupt, then waits. Once each of the 3 phase changes
have been recorded the thread then wakes. The remaining part of the call
carries out the relevant calculations and returns a structure filled out
with the capture data.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Here we're requesting the PWM capture IRQ and supplying the handler that
will be called in the event of an interrupt to handle it.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Each PWM capture device is allocated a structure to hold its own state.
During a capture the device may be partaking in one of 3 phases. Initial
(rising) phase change, a subsequent (falling) phase change indicating
end of the duty-cycle phase and finally a final (rising) phase change
indicating the end of the period. The timer value snapshot each event is
held in a variable of the same name, and the phase number (0, 1, 2) is
contained in the index variable. Other device specific information, such
as GPIO pin, the IRQ wait queue and locking is also contained in the
structure. This patch initialises this structure for each of the
available devices.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
ST's PWM IP is supplied by 2 different clocks. One for PWM output and
the other for capture. This patch provides clock handling for the
latter.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This is in preparation for subsequent patches that add support for PWM
capture to this driver.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
In the original code the clock rate was only obtained during
initialisation; however, the rate may change between then and
its use. This patch ensures the correct rate is acquired just
before use.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Exciting functionality is on the way to this device. But
before we can add it, we need to do some basic housekeeping
so the additions can be added cleanly.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This is to bring the terminology used in the STi PWM driver more
into line with the PWM subsystem.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This patch introduces a bitmap which is used to keep track of the
pwm channels which have been configured in a pwm chip.
The method used earlier to find the number of configured channels,
was to count the pwmdevices with PWMF_REQUESTED field set
and period value configured. This was not correct and failed
when of_pwm_get()/pwm_get() and then pwm_config() was used.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Removes the PWM period table. Instead the prescaler is computed
from the period value passed in the config() function.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
ST PWM IP has a common enable/disable control for all the PWM
channels on a PWM cell. Disables PWM output on the PWM HW only
when disable is called for the last channel.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
ST PWM IP shares the same clock prescaler across all the PWM
channels. Hence configuration requests which change the period
will affect all the channels. Do not allow period changes which
will stomp period settings of the already configured channels.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This patch fixes the pwm driver to write the complete 8 bits of
the prescaler value to the PWM Control register.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This driver supports all current STi platforms' PWM IPs.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[thierry.reding: rename module to pwm-sti, fix build breakage]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Lee Jones
Ajit Pal Singh