On 03/13/2015 08:00 PM, Ville Syrjälä wrote:
> On Thu, Mar 12, 2015 at 10:01:33PM +0530, Shobhit Kumar wrote:
>> CC: Samuel Ortiz <[email protected]>
>> Cc: Linus Walleij <[email protected]>
>> Cc: Alexandre Courbot <[email protected]>
>> Cc: Thierry Reding <[email protected]>
>> Signed-off-by: Shobhit Kumar <[email protected]>
>> ---
>>  drivers/gpu/drm/i915/intel_dsi.c | 25 +++++++++++++++++++++++++
>>  drivers/gpu/drm/i915/intel_dsi.h |  3 +++
>>  2 files changed, 28 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_dsi.c 
>> b/drivers/gpu/drm/i915/intel_dsi.c
>> index 219421c..511446f 100644
>> --- a/drivers/gpu/drm/i915/intel_dsi.c
>> +++ b/drivers/gpu/drm/i915/intel_dsi.c
>> @@ -32,6 +32,7 @@
>>  #include <drm/drm_mipi_dsi.h>
>>  #include <linux/slab.h>
>>  #include <linux/gpio/consumer.h>
>> +#include <linux/pwm.h>
>>  #include "i915_drv.h"
>>  #include "intel_drv.h"
>>  #include "intel_dsi.h"
>> @@ -402,6 +403,10 @@ static void intel_dsi_enable(struct intel_encoder 
>> *encoder)
>>  
>>              intel_dsi_port_enable(encoder);
>>      }
>> +
>> +    /* Enable the backlight with default PWM as programmed by BIOS */
>> +    pwm_enable(intel_dsi->pwm);
>> +    pwm_config_alternate(intel_dsi->pwm, 0x7F, 100);
> 
> I suppose we migth want to wrap these in 'if (intel_dsi->pwm)' checks,
> or does the pwm subsystem take care of NULL checks for us?

PWM subsystem does make the checks. Actually this patch is kind of
prelim patch and I have to still hook up pwm usage in our back-light
infra in intel_panel.c. I have a working patch for that though not
posted yet. Will take care in that final patch for enabling this.

Regards
Shobhit

> 
>>  }
>>  
>>  static void intel_dsi_pre_enable(struct intel_encoder *encoder)
>> @@ -467,6 +472,11 @@ static void intel_dsi_pre_disable(struct intel_encoder 
>> *encoder)
>>  
>>      DRM_DEBUG_KMS("\n");
>>  
>> +    /* Disable the backlight */
>> +    pwm_config_alternate(intel_dsi->pwm, 0x7F, 0);
>> +    usleep_range(2000, 3000);
>> +    pwm_disable(intel_dsi->pwm);
> 
> ditto
> 
>> +
>>      if (is_vid_mode(intel_dsi)) {
>>              /* Send Shutdown command to the panel in LP mode */
>>              for_each_dsi_port(port, intel_dsi->ports)
>> @@ -971,6 +981,10 @@ static void intel_dsi_encoder_destroy(struct 
>> drm_encoder *encoder)
>>      if (intel_dsi->gpio_panel)
>>              gpiod_put(intel_dsi->gpio_panel);
>>  
>> +    /* dispose of the pwm */
>> +    if (intel_dsi->pwm)
>> +            pwm_put(intel_dsi->pwm);
>> +
>>      intel_encoder_destroy(encoder);
>>  }
>>  
>> @@ -1098,6 +1112,17 @@ void intel_dsi_init(struct drm_device *dev)
>>                      DRM_ERROR("Failed to own gpio for panel control\n");
>>                      intel_dsi->gpio_panel = NULL;
>>              }
>> +
>> +            /* Get the PWM chip for backlight control */
>> +            intel_dsi->pwm = pwm_get(dev->dev, "pwm_backlight");
>> +            if (IS_ERR(intel_dsi->pwm)) {
>> +                    DRM_ERROR("Faild to own the pwm chip\n");
>> +                    intel_dsi->pwm = NULL;
>> +            } else if (pwm_config_alternate(intel_dsi->pwm, 0x7F, 100) < 0) 
>> {
>> +                    DRM_ERROR("Failed to configure the pwm chip\n");
>> +                    pwm_put(intel_dsi->pwm);
>> +                    intel_dsi->pwm = NULL;
>> +            }
>>      }
>>  
>>      intel_encoder->type = INTEL_OUTPUT_DSI;
>> diff --git a/drivers/gpu/drm/i915/intel_dsi.h 
>> b/drivers/gpu/drm/i915/intel_dsi.h
>> index 8be75a7..d8ec9c1 100644
>> --- a/drivers/gpu/drm/i915/intel_dsi.h
>> +++ b/drivers/gpu/drm/i915/intel_dsi.h
>> @@ -52,6 +52,9 @@ struct intel_dsi {
>>      /* GPIO Desc for CRC based Panel control */
>>      struct gpio_desc *gpio_panel;
>>  
>> +    /* PWM chip */
>> +    struct pwm_device *pwm;
>> +
>>      struct intel_connector *attached_connector;
>>  
>>      /* bit mask of ports being driven */
>> -- 
>> 2.1.0
>>
>> _______________________________________________
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>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
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