Re: [PATCH 3/8] drm/i915: Adding the parsing logic for the i2c element

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Feb 04, 2016 at 12:50:51PM +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
> 
> v5 by Jani:
>  - rebase on the skip i2c element patch
> 
> v6: by Jani:
>  - ignore the gmbus i2c elements (Ville)
> 
> 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 | 64 ++++++++++++++++++++++++++++--
>  1 file changed, 61 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
> index 6f013efba45b..f4d303ee538b 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"
> @@ -235,9 +236,66 @@ out:
>  	return data;
>  }
>  
> -static const u8 *mipi_exec_i2c_skip(struct intel_dsi *intel_dsi, const u8 *data)
> +static const u8 *mipi_exec_i2c(struct intel_dsi *intel_dsi, const u8 *data)
>  {
> -	return data + *(data + 6) + 7;
> +	struct i2c_adapter *adapter;
> +	int ret, i;
> +	u8 reg_offset, payload_size;
> +	struct i2c_msg msg;
> +	u8 *transmit_buffer;
> +	u8 flag, resource_id, bus_number;
> +	u16 slave_add;
> +
> +	flag = *data++;
> +	resource_id = *data++;
> +	bus_number = *data++;
> +	slave_add = *(u16 *)(data);
> +	data += 2;
> +	reg_offset = *data++;
> +	payload_size = *data++;
> +
> +	if (resource_id == 0xff || bus_number == 0xff) {
> +		DRM_DEBUG_KMS("ignoring gmbus (resource id %02x, bus %02x)\n",
> +			      resource_id, bus_number);
> +		goto out;
> +	}
> +

Still missing the check for __i2c_first_dynamic_bus_num which I think
would at least provide some kind of half arsed protection against
something not registering these magic i2c busses.

> +	adapter = i2c_get_adapter(bus_number);
> +	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;
>  }
>  
>  typedef const u8 * (*fn_mipi_elem_exec)(struct intel_dsi *intel_dsi,
> @@ -246,7 +304,7 @@ 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_skip,
> +	[MIPI_SEQ_ELEM_I2C] = mipi_exec_i2c,
>  };
>  
>  /*
> -- 
> 2.1.4
> 
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-- 
Ville Syrjälä
Intel OTC
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