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

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 07 Jan 2016, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> On Mon, Dec 21, 2015 at 03:11:02PM +0200, Jani Nikula wrote:
>> From: vkorjani <vikas.korjani@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@intel.com>
>> Signed-off-by: vkorjani <vikas.korjani@intel.com>
>> Signed-off-by: Deepak M <m.deepak@intel.com>
>> Signed-off-by: Jani Nikula <jani.nikula@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.

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
>> 
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-- 
Jani Nikula, Intel Open Source Technology Center
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