[Intel-gfx] [PATCH 11/15] drm/i915: Adding the parsing logic for the i2c element

[Jani Nikula]

On Mon, 11 Jan 2016, Jani Nikula <jani.nikula at intel.com> wrote:
> On Thu, 07 Jan 2016, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
>> On Mon, Dec 21, 2015 at 03:11:02PM +0200, Jani Nikula wrote:
>>> From: vkorjani <vikas.korjani at intel.com>
>>> 
>>> New sequence element for i2c is been added in the
>>> mipi sequence block of the VBT. This patch parses
>>> and executes the i2c sequence.
>>> 
>>> v2: Add i2c_put_adapter call(Jani), rebase
>>> 
>>> v3: corrected the retry loop(Jani), rebase
>>> 
>>> v4 by Jani:
>>>  - don't put the adapter if get fails
>>>  - print an error message if all retries exhausted
>>>  - use a for loop
>>>  - fix warnings for unused variables
>>> 
>>> Cc: Jani Nikula <jani.nikula at intel.com>
>>> Signed-off-by: vkorjani <vikas.korjani at intel.com>
>>> Signed-off-by: Deepak M <m.deepak at intel.com>
>>> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
>>> ---
>>>  drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 58 ++++++++++++++++++++++++++++++
>>>  1 file changed, 58 insertions(+)
>>> 
>>> diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>>> index ba5355506590..8fcfb0f63dc1 100644
>>> --- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>>> +++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>>> @@ -31,6 +31,7 @@
>>>  #include <drm/drm_panel.h>
>>>  #include <linux/slab.h>
>>>  #include <video/mipi_display.h>
>>> +#include <linux/i2c.h>
>>>  #include <asm/intel-mid.h>
>>>  #include <video/mipi_display.h>
>>>  #include "i915_drv.h"
>>> @@ -104,6 +105,62 @@ static struct gpio_table gtable[] = {
>>>  	{ GPIO_NC_11_PCONF0, GPIO_NC_11_PAD, 0}
>>>  };
>>>  
>>> +static const u8 *mipi_exec_i2c(struct intel_dsi *intel_dsi, const u8 *data)
>>> +{
>>> +	struct i2c_adapter *adapter;
>>> +	int ret, i;
>>> +	u8 reg_offset, payload_size;
>>> +	struct i2c_msg msg;
>>> +	u8 *transmit_buffer;
>>> +	u8 flag, bus_number;
>>> +	u16 slave_add;
>>> +
>>> +	flag = *data++;
>>> +	data++; /* index, unused */
>>> +	bus_number = *data++;
>>> +	slave_add = *(u16 *)(data);
>>> +	data += 2;
>>> +	reg_offset = *data++;
>>> +	payload_size = *data++;
>>> +
>>> +	adapter = i2c_get_adapter(bus_number);
>>
>> I'm trying to find who is responsible for registering i2c busses with
>> these magic bus numbers. So far I can't see anything that would be doing
>> it.
>
> *cough* I'm not sure either *cough*
>
> Would you prefer adding a dummy mipi_exec_i2c that just eats and ignores
> the data at this point? It would be a step forward. Now the driver just
> gives up on encountering an unknown element.

I did just that, there's now a new 11/15 just skipping, and this one is
moved at the end. Also sent the rebased version of that.

BR,
Jani.


>
> BR,
> Jani.
>
>
>>
>>> +	if (!adapter) {
>>> +		DRM_ERROR("i2c_get_adapter(%u)\n", bus_number);
>>> +		goto out;
>>> +	}
>>> +
>>> +	transmit_buffer = kmalloc(1 + payload_size, GFP_TEMPORARY);
>>> +	if (!transmit_buffer)
>>> +		goto out_put;
>>> +
>>> +	transmit_buffer[0] = reg_offset;
>>> +	memcpy(&transmit_buffer[1], data, payload_size);
>>> +
>>> +	msg.addr = slave_add;
>>> +	msg.flags = 0;
>>> +	msg.len = payload_size + 1;
>>> +	msg.buf = &transmit_buffer[0];
>>> +
>>> +	for (i = 0; i < 6; i++) {
>>> +		ret = i2c_transfer(adapter, &msg, 1);
>>> +		if (ret == 1) {
>>> +			goto out_free;
>>> +		} else if (ret == -EAGAIN) {
>>> +			usleep_range(1000, 2500);
>>> +		} else {
>>> +			break;
>>> +		}
>>> +	}
>>> +
>>> +	DRM_ERROR("i2c transfer failed: %d\n", ret);
>>> +out_free:
>>> +	kfree(transmit_buffer);
>>> +out_put:
>>> +	i2c_put_adapter(adapter);
>>> +out:
>>> +	return data + payload_size;
>>> +}
>>> +
>>>  static inline enum port intel_dsi_seq_port_to_port(u8 port)
>>>  {
>>>  	return port ? PORT_C : PORT_A;
>>> @@ -235,6 +292,7 @@ static const fn_mipi_elem_exec exec_elem[] = {
>>>  	[MIPI_SEQ_ELEM_SEND_PKT] = mipi_exec_send_packet,
>>>  	[MIPI_SEQ_ELEM_DELAY] = mipi_exec_delay,
>>>  	[MIPI_SEQ_ELEM_GPIO] = mipi_exec_gpio,
>>> +	[MIPI_SEQ_ELEM_I2C] = mipi_exec_i2c,
>>>  };
>>>  
>>>  /*
>>> -- 
>>> 2.1.4
>>> 
>>> _______________________________________________
>>> Intel-gfx mailing list
>>> Intel-gfx at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Technology Center