Re: [PATCH v4 3/3] drm/bridge: anx7625: add MIPI DPI input feature support

From: Robert Foss
Date: Fri Feb 05 2021 - 19:26:39 EST


Hey Xin,

On Thu, 28 Jan 2021 at 04:12, Xin Ji <xji@xxxxxxxxxxxxxxxx> wrote:
>
> Add MIPI rx DPI input support
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Signed-off-by: Xin Ji <xji@xxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/bridge/analogix/anx7625.c | 326 ++++++++++++++++++++++++------
> drivers/gpu/drm/bridge/analogix/anx7625.h | 20 +-
> 2 files changed, 285 insertions(+), 61 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 04536cc..628ae43 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -150,18 +150,18 @@ static int anx7625_write_and(struct anx7625_data *ctx,
> return anx7625_reg_write(ctx, client, offset, (val & (mask)));
> }
>
> -static int anx7625_write_and_or(struct anx7625_data *ctx,
> - struct i2c_client *client,
> - u8 offset, u8 and_mask, u8 or_mask)
> +static int anx7625_config_bit_matrix(struct anx7625_data *ctx)
> {
> - int val;
> + int i, ret;
>
> - val = anx7625_reg_read(ctx, client, offset);
> - if (val < 0)
> - return val;
> + ret = anx7625_write_or(ctx, ctx->i2c.tx_p2_client,
> + AUDIO_CONTROL_REGISTER, 0x80);
> + for (i = 0; i < 13; i++)
> + ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> + VIDEO_BIT_MATRIX_12 + i,
> + 0x18 + i);
>
> - return anx7625_reg_write(ctx, client,
> - offset, (val & and_mask) | (or_mask));
> + return ret;
> }
>
> static int anx7625_read_ctrl_status_p0(struct anx7625_data *ctx)
> @@ -195,6 +195,60 @@ static int wait_aux_op_finish(struct anx7625_data *ctx)
> return 0;
> }
>
> +static int anx7625_aux_dpcd_read(struct anx7625_data *ctx,
> + u8 addrh, u8 addrm, u8 addrl,
> + u8 len, u8 *buf)
> +{
> + struct device *dev = &ctx->client->dev;
> + int ret;
> + u8 cmd;
> +
> + if (len > MAX_DPCD_BUFFER_SIZE) {
> + DRM_DEV_ERROR(dev, "exceed aux buffer len.\n");
> + return -EINVAL;
> + }
> +
> + cmd = ((len - 1) << 4) | 0x09;
> +
> + /* Set command and length */
> + ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> + AP_AUX_COMMAND, cmd);
> +
> + /* Set aux access address */
> + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> + AP_AUX_ADDR_7_0, addrl);
> + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> + AP_AUX_ADDR_15_8, addrm);
> + ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> + AP_AUX_ADDR_19_16, addrh);
> +
> + /* Enable aux access */
> + ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> + AP_AUX_CTRL_STATUS, AP_AUX_CTRL_OP_EN);
> +
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev, "cannot access aux related register.\n");
> + return -EIO;
> + }
> +
> + usleep_range(2000, 2100);
> +
> + ret = wait_aux_op_finish(ctx);
> + if (ret) {
> + DRM_DEV_ERROR(dev, "aux IO error: wait aux op finish.\n");
> + return ret;
> + }
> +
> + ret = anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
> + AP_AUX_BUFF_START, len, buf);
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev, "read dpcd register failed\n");
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> static int anx7625_video_mute_control(struct anx7625_data *ctx,
> u8 status)
> {
> @@ -219,38 +273,6 @@ static int anx7625_video_mute_control(struct anx7625_data *ctx,
> return ret;
> }
>
> -static int anx7625_config_audio_input(struct anx7625_data *ctx)
> -{
> - struct device *dev = &ctx->client->dev;
> - int ret;
> -
> - /* Channel num */
> - ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> - AUDIO_CHANNEL_STATUS_6, I2S_CH_2 << 5);
> -
> - /* FS */
> - ret |= anx7625_write_and_or(ctx, ctx->i2c.tx_p2_client,
> - AUDIO_CHANNEL_STATUS_4,
> - 0xf0, AUDIO_FS_48K);
> - /* Word length */
> - ret |= anx7625_write_and_or(ctx, ctx->i2c.tx_p2_client,
> - AUDIO_CHANNEL_STATUS_5,
> - 0xf0, AUDIO_W_LEN_24_24MAX);
> - /* I2S */
> - ret |= anx7625_write_or(ctx, ctx->i2c.tx_p2_client,
> - AUDIO_CHANNEL_STATUS_6, I2S_SLAVE_MODE);
> - ret |= anx7625_write_and(ctx, ctx->i2c.tx_p2_client,
> - AUDIO_CONTROL_REGISTER, ~TDM_TIMING_MODE);
> - /* Audio change flag */
> - ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> - AP_AV_STATUS, AP_AUDIO_CHG);
> -
> - if (ret < 0)
> - DRM_DEV_ERROR(dev, "fail to config audio.\n");
> -
> - return ret;
> -}
> -
> /* Reduction of fraction a/b */
> static void anx7625_reduction_of_a_fraction(unsigned long *a, unsigned long *b)
> {
> @@ -410,7 +432,7 @@ static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
> ret |= anx7625_write_and(ctx, ctx->i2c.rx_p1_client,
> MIPI_LANE_CTRL_0, 0xfc);
> ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> - MIPI_LANE_CTRL_0, 3);
> + MIPI_LANE_CTRL_0, ctx->pdata.mipi_lanes - 1);

Is this mipi_lanes change independent of the rest of this patch?
If so, extract it to a seperate patch.

>
> /* Htotal */
> htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> @@ -595,6 +617,101 @@ static int anx7625_dsi_config(struct anx7625_data *ctx)
> return ret;
> }
>
> +static int anx7625_api_dpi_config(struct anx7625_data *ctx)
> +{
> + struct device *dev = &ctx->client->dev;
> + u16 freq = ctx->dt.pixelclock.min / 1000;
> + int ret;
> +
> + /* configure pixel clock */
> + ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> + PIXEL_CLOCK_L, freq & 0xFF);
> + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> + PIXEL_CLOCK_H, (freq >> 8));
> +
> + /* set DPI mode */
> + /* set to DPI PLL module sel */
> + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> + MIPI_DIGITAL_PLL_9, 0x20);
> + /* power down MIPI */
> + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> + MIPI_LANE_CTRL_10, 0x08);
> + /* enable DPI mode */
> + ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> + MIPI_DIGITAL_PLL_18, 0x1C);
> + /* set first edge */
> + ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> + VIDEO_CONTROL_0, 0x06);
> + if (ret < 0)
> + DRM_DEV_ERROR(dev, "IO error : dpi phy set failed.\n");
> +
> + return ret;
> +}
> +
> +static int anx7625_dpi_config(struct anx7625_data *ctx)
> +{
> + struct device *dev = &ctx->client->dev;
> + int ret;
> +
> + DRM_DEV_DEBUG_DRIVER(dev, "config dpi\n");
> +
> + /* DSC disable */
> + ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> + R_DSC_CTRL_0, ~DSC_EN);
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev, "IO error : disable dsc failed.\n");
> + return ret;
> + }
> +
> + ret = anx7625_config_bit_matrix(ctx);
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev, "config bit matrix failed.\n");
> + return ret;
> + }
> +
> + ret = anx7625_api_dpi_config(ctx);
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev, "mipi phy(dpi) setup failed.\n");
> + return ret;
> + }
> +
> + /* set MIPI RX EN */
> + ret = anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> + AP_AV_STATUS, AP_MIPI_RX_EN);
> + /* clear mute flag */
> + ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> + AP_AV_STATUS, (u8)~AP_MIPI_MUTE);
> + if (ret < 0)
> + DRM_DEV_ERROR(dev, "IO error : enable mipi rx failed.\n");
> +
> + return ret;
> +}
> +
> +static int anx7625_hdcp_setting(struct anx7625_data *ctx)
> +{
> + u8 bcap;
> + struct device *dev = &ctx->client->dev;
> +
> + if (!ctx->pdata.hdcp_support || !ctx->hdcp_en) {
> + DRM_DEV_DEBUG_DRIVER(dev, "hdcp_support(%d), hdcp_en(%d)\n",
> + ctx->pdata.hdcp_support, ctx->hdcp_en);
> + DRM_DEV_DEBUG_DRIVER(dev, "disable HDCP by config\n");
> + return anx7625_write_and(ctx, ctx->i2c.rx_p1_client,
> + 0xee, 0x9f);
> + }
> +
> + anx7625_aux_dpcd_read(ctx, 0x06, 0x80, 0x28, 1, &bcap);
> + if (!(bcap & 0x01)) {
> + DRM_WARN("downstream not support HDCP 1.4, cap(%x).\n", bcap);
> + return anx7625_write_and(ctx, ctx->i2c.rx_p1_client,
> + 0xee, 0x9f);
> + }
> +
> + DRM_DEV_DEBUG_DRIVER(dev, "enable HDCP 1.4\n");
> +
> + return anx7625_write_or(ctx, ctx->i2c.rx_p1_client, 0xee, 0x20);
> +}

Is the HDCP support change independent of the rest of this patch?
If so, extract it to a seperate patch.

> +
> static void anx7625_dp_start(struct anx7625_data *ctx)
> {
> int ret;
> @@ -605,9 +722,13 @@ static void anx7625_dp_start(struct anx7625_data *ctx)
> return;
> }
>
> - anx7625_config_audio_input(ctx);
> + /* HDCP config */
> + anx7625_hdcp_setting(ctx);
>
> - ret = anx7625_dsi_config(ctx);
> + if (ctx->pdata.is_dpi)
> + ret = anx7625_dpi_config(ctx);
> + else
> + ret = anx7625_dsi_config(ctx);
>
> if (ret < 0)
> DRM_DEV_ERROR(dev, "MIPI phy setup error.\n");
> @@ -688,8 +809,7 @@ static int sp_tx_get_edid_block(struct anx7625_data *ctx)
> return c;
> }
>
> -static int edid_read(struct anx7625_data *ctx,
> - u8 offset, u8 *pblock_buf)
> +static int edid_read(struct anx7625_data *ctx, u8 offset, u8 *pblock_buf)

No functional change here, let's try to maintain the 'git blame'
history instead.


> {
> int ret, cnt;
> struct device *dev = &ctx->client->dev;
> @@ -992,8 +1112,9 @@ static void anx7625_chip_control(struct anx7625_data *ctx, int state)
>
> if (state) {
> atomic_inc(&ctx->power_status);
> - if (atomic_read(&ctx->power_status) == 1)
> + if (atomic_read(&ctx->power_status) == 1) {
> anx7625_power_on_init(ctx);
> + }

This too is not a functional change, and the previous format preferred
by the style guide.

> } else {
> if (atomic_read(&ctx->power_status)) {
> atomic_dec(&ctx->power_status);
> @@ -1051,6 +1172,7 @@ static void anx7625_start_dp_work(struct anx7625_data *ctx)
> return;
> }
>
> + ctx->hpd_status = 1;
> ctx->hpd_high_cnt++;
>
> /* Not support HDCP */
> @@ -1060,8 +1182,10 @@ static void anx7625_start_dp_work(struct anx7625_data *ctx)
> ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, 0xec, 0x10);
> /* Interrupt for DRM */
> ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, 0xff, 0x01);
> - if (ret < 0)
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev, "fail to setting HDCP/auth\n");
> return;
> + }
>
> ret = anx7625_reg_read(ctx, ctx->i2c.rx_p1_client, 0x86);
> if (ret < 0)
> @@ -1080,6 +1204,10 @@ static void anx7625_hpd_polling(struct anx7625_data *ctx)
> int ret, val;
> struct device *dev = &ctx->client->dev;
>
> + /* Interrupt mode, no need poll HPD status, just return */
> + if (ctx->pdata.intp_irq)
> + return;
> +
> if (atomic_read(&ctx->power_status) != 1) {
> DRM_DEV_DEBUG_DRIVER(dev, "No need to poling HPD status.\n");
> return;
> @@ -1130,6 +1258,21 @@ static void anx7625_remove_edid(struct anx7625_data *ctx)
> ctx->slimport_edid_p.edid_block_num = -1;
> }
>
> +static void anx7625_dp_adjust_swing(struct anx7625_data *ctx)
> +{
> + int i;
> +
> + for (i = 0; i < ctx->pdata.dp_lane0_swing_reg_cnt; i++)
> + anx7625_reg_write(ctx, ctx->i2c.tx_p1_client,
> + DP_TX_LANE0_SWING_REG0 + i,
> + ctx->pdata.lane0_reg_data[i] & 0xFF);
> +
> + for (i = 0; i < ctx->pdata.dp_lane1_swing_reg_cnt; i++)
> + anx7625_reg_write(ctx, ctx->i2c.tx_p1_client,
> + DP_TX_LANE1_SWING_REG0 + i,
> + ctx->pdata.lane1_reg_data[i] & 0xFF);
> +}
> +
> static void dp_hpd_change_handler(struct anx7625_data *ctx, bool on)
> {
> struct device *dev = &ctx->client->dev;
> @@ -1145,9 +1288,8 @@ static void dp_hpd_change_handler(struct anx7625_data *ctx, bool on)
> } else {
> DRM_DEV_DEBUG_DRIVER(dev, " HPD high\n");
> anx7625_start_dp_work(ctx);
> + anx7625_dp_adjust_swing(ctx);
> }
> -
> - ctx->hpd_status = 1;
> }
>
> static int anx7625_hpd_change_detect(struct anx7625_data *ctx)
> @@ -1224,20 +1366,69 @@ static irqreturn_t anx7625_intr_hpd_isr(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +static int anx7625_get_swing_setting(struct device *dev,
> + struct anx7625_platform_data *pdata)
> +{
> + int num_regs;
> +
> + if (of_get_property(dev->of_node,
> + "analogix,lane0-swing", &num_regs)) {
> + if (num_regs > DP_TX_SWING_REG_CNT)
> + num_regs = DP_TX_SWING_REG_CNT;
> +
> + pdata->dp_lane0_swing_reg_cnt = num_regs;
> + of_property_read_u32_array(dev->of_node, "analogix,lane0-swing",
> + pdata->lane0_reg_data, num_regs);
> + }
> +
> + if (of_get_property(dev->of_node,
> + "analogix,lane1-swing", &num_regs)) {
> + if (num_regs > DP_TX_SWING_REG_CNT)
> + num_regs = DP_TX_SWING_REG_CNT;
> +
> + pdata->dp_lane1_swing_reg_cnt = num_regs;
> + of_property_read_u32_array(dev->of_node, "analogix,lane1-swing",
> + pdata->lane1_reg_data, num_regs);
> + }
> +
> + return 0;
> +}
> +
> static int anx7625_parse_dt(struct device *dev,
> struct anx7625_platform_data *pdata)
> {
> struct device_node *np = dev->of_node;
> struct drm_panel *panel;
> int ret;
> + int bus_type;
> +
> + anx7625_get_swing_setting(dev, pdata);
>
> + pdata->is_dpi = 1; /* default dpi mode */
> pdata->mipi_host_node = of_graph_get_remote_node(np, 0, 0);
> if (!pdata->mipi_host_node) {
> DRM_DEV_ERROR(dev, "fail to get internal panel.\n");
> return -ENODEV;
> }
>
> - DRM_DEV_DEBUG_DRIVER(dev, "found dsi host node.\n");
> + if (of_property_read_u32(pdata->mipi_host_node, "bus-type", &bus_type))
> + bus_type = 0;
> +
> + if (bus_type == 5) /* bus type is Parallel(DSI) */
> + pdata->is_dpi = 0;
> +
> + pdata->mipi_lanes = of_property_count_u32_elems(pdata->mipi_host_node,
> + "data-lanes");
> + if (pdata->mipi_lanes > MAX_LANES_SUPPORT || pdata->mipi_lanes <= 0)
> + pdata->mipi_lanes = MAX_LANES_SUPPORT;
> +

Is this mipi_lanes change independent of the rest of this patch?
If so, extract it to a seperate patch.

> + if (pdata->is_dpi)
> + DRM_DEV_DEBUG_DRIVER(dev, "found MIPI DPI host node.\n");
> + else
> + DRM_DEV_DEBUG_DRIVER(dev, "found MIPI DSI host node.\n");
> +
> + if (of_property_read_bool(np, "analogix,hdcp-support"))
> + pdata->hdcp_support = 1;

Extract hdcp_support change to separate patch.

>
> ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
> if (ret < 0) {
> @@ -1300,9 +1491,13 @@ static enum drm_connector_status anx7625_sink_detect(struct anx7625_data *ctx)
> {
> struct device *dev = &ctx->client->dev;
>
> - DRM_DEV_DEBUG_DRIVER(dev, "sink detect, return connected\n");
> + DRM_DEV_DEBUG_DRIVER(dev, "sink detect\n");
> +
> + if (ctx->pdata.panel_bridge)
> + return connector_status_connected;
>
> - return connector_status_connected;
> + return ctx->hpd_status ? connector_status_connected :
> + connector_status_disconnected;
> }
>
> static int anx7625_attach_dsi(struct anx7625_data *ctx)
> @@ -1330,7 +1525,7 @@ static int anx7625_attach_dsi(struct anx7625_data *ctx)
> return -EINVAL;
> }
>
> - dsi->lanes = 4;
> + dsi->lanes = ctx->pdata.mipi_lanes;

Extract mipi_lanes change to separate patch.

> dsi->format = MIPI_DSI_FMT_RGB888;
> dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
> MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
> @@ -1376,10 +1571,12 @@ static int anx7625_bridge_attach(struct drm_bridge *bridge,
> return -ENODEV;
> }
>
> - err = anx7625_attach_dsi(ctx);
> - if (err) {
> - DRM_DEV_ERROR(dev, "Fail to attach to dsi : %d\n", err);
> - return err;
> + if (!ctx->pdata.is_dpi) {
> + err = anx7625_attach_dsi(ctx);
> + if (err) {
> + DRM_DEV_ERROR(dev, "Fail to attach to dsi : %d\n", err);
> + return err;
> + }
> }
>
> if (ctx->pdata.panel_bridge) {
> @@ -1478,6 +1675,10 @@ static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
>
> DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
>
> + /* No need fixup for external monitor */
> + if (!ctx->pdata.panel_bridge)
> + return true;
> +
> hsync = mode->hsync_end - mode->hsync_start;
> hfp = mode->hsync_start - mode->hdisplay;
> hbp = mode->htotal - mode->hsync_end;
> @@ -1786,8 +1987,13 @@ static int anx7625_i2c_probe(struct i2c_client *client,
>
> platform->bridge.funcs = &anx7625_bridge_funcs;
> platform->bridge.of_node = client->dev.of_node;
> - platform->bridge.ops = DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_HPD;
> - platform->bridge.type = DRM_MODE_CONNECTOR_eDP;
> + platform->bridge.ops = DRM_BRIDGE_OP_EDID;
> + if (!platform->pdata.panel_bridge)
> + platform->bridge.ops |= DRM_BRIDGE_OP_HPD |
> + DRM_BRIDGE_OP_DETECT;
> + platform->bridge.type = platform->pdata.panel_bridge ?
> + DRM_MODE_CONNECTOR_eDP :
> + DRM_MODE_CONNECTOR_DisplayPort;
> drm_bridge_add(&platform->bridge);
>
> DRM_DEV_DEBUG_DRIVER(dev, "probe done\n");
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
> index 193ad86..127081e 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> @@ -141,12 +141,20 @@
> #define HORIZONTAL_BACK_PORCH_H 0x22 /* Bit[7:4] are reserved */
>
> /******** END of I2C Address 0x72 *********/
> +
> +/***************************************************************/
> +/* Register definition of device address 0x7a */
> +#define DP_TX_SWING_REG_CNT 0x14
> +#define DP_TX_LANE0_SWING_REG0 0x00
> +#define DP_TX_LANE1_SWING_REG0 0x14
> +/******** END of I2C Address 0x7a *********/
> +
> /***************************************************************/
> /* Register definition of device address 0x7e */
>
> #define I2C_ADDR_7E_FLASH_CONTROLLER 0x7E
>
> -#define FLASH_LOAD_STA 0x05
> +#define FLASH_LOAD_STA 0x05
> #define FLASH_LOAD_STA_CHK BIT(7)
>
> #define XTAL_FRQ_SEL 0x3F
> @@ -347,11 +355,20 @@ struct s_edid_data {
>
> /***************** Display End *****************/
>
> +#define MAX_LANES_SUPPORT 4
> +
> struct anx7625_platform_data {
> struct gpio_desc *gpio_p_on;
> struct gpio_desc *gpio_reset;
> struct drm_bridge *panel_bridge;
> int intp_irq;
> + int is_dpi;
> + int mipi_lanes;

Extract mipi_lanes change to separate patch.

> + int hdcp_support;

Extract hdcp_support change to separate patch.

> + int dp_lane0_swing_reg_cnt;
> + int lane0_reg_data[DP_TX_SWING_REG_CNT];
> + int dp_lane1_swing_reg_cnt;
> + int lane1_reg_data[DP_TX_SWING_REG_CNT];
> u32 low_power_mode;
> struct device_node *mipi_host_node;
> };
> @@ -371,6 +388,7 @@ struct anx7625_data {
> atomic_t power_status;
> int hpd_status;
> int hpd_high_cnt;
> + int hdcp_en;

Extract hdcp_support change to separate patch.

> /* Lock for work queue */
> struct mutex lock;
> struct i2c_client *client;
> --
> 2.7.4
>