[PATCH v4] drm/sun4i: hdmi: Implement I2C adapter for A10s DDC bus
Maxime Ripard
maxime.ripard at free-electrons.com
Mon Jun 26 12:05:15 PDT 2017
On Sat, Jun 24, 2017 at 04:10:54PM +1000, Jonathan Liu wrote:
> The documentation for drm_do_get_edid in drivers/gpu/drm/drm_edid.c states:
> "As in the general case the DDC bus is accessible by the kernel at the I2C
> level, drivers must make all reasonable efforts to expose it as an I2C
> adapter and use drm_get_edid() instead of abusing this function."
>
> Exposing the DDC bus as an I2C adapter is more beneficial as it can be used
> for purposes other than reading the EDID such as modifying the EDID or
> using the HDMI DDC pins as an I2C bus through the I2C dev interface from
> userspace (e.g. i2c-tools).
>
> Implement this for A10s.
>
> Signed-off-by: Jonathan Liu <net147 at gmail.com>
> ---
> Changes for v4:
> - Carry over copyright from initial I2C code into sun4i_hdmi_i2c.c
> - Clean up indentation in sun4i_hdmi.h
> - Rename SUN4I_HDMI_DDC_MAX_TRANSFER_SIZE to SUN4I_HDMI_DDC_BYTE_COUNT_MAX
> and group it under the SUN4I_HDMI_DDC_BYTE_COUNT_REG define, changing the
> value to use the GENMASK macro to make it clear that it is derived from
> the width of the field in the register
> - Fix SUN4I_HDMI_DDC_INT_STATUS_DDC_TX_FIFO_UNDERFLOW typo which should be
> SUN4I_HDMI_DDC_INT_STATUS_DDC_TX_FIFO_OVERFLOW
> - Remove redundant rewriting of SUN4I_HDMI_DDC_INT_STATUS_REG register
> - Change struct i2c_adapter to be const by using devm_kmemdup on creation
> - Return -ETIMEDOUT instead of -EIO if there is timeout while transferring an
> I2C message
> - Instead of waiting for 1-2 bytes to transfer, wait for the time it would
> take for remaining bytes to transfer (limited by FIFO size)
> - Add additional comments
>
> Changes for v3:
> - Explain why drm_do_get_edid should be used and why it's better to expose it
> as an I2C adapter in commit message
> - Reorder bit defines in descending order for consistency
> - Keep old unused macros instead of removing them
> - The v2 algorithm split large transfers into 16 byte transfers but this may
> cause a large single write to be treated as multiple writes causing data
> corruption. The algorithm has been reworked to not split larger transfers
> and make more use of the FIFO to avoid this.
> - Moved the creation of the DDC clock from sun4i_hdmi_enc.c to
> sun4i_hdmi_i2c.c
> - Reformatted code
> - Instead of masking bits that we don't want to check for errors, explicitly
> check the error bits
> - Clear error bits at start of transfer in case of error from previous transfer
> - Poll for completion of FIFO clear after setting FIFO clear bit
>
> Changes for v2:
> - Rebased against Maxime's sunxi-drm/for-next branch
> - Fix up error paths in sun4i_hdmi_bind so that the I2C adapter is deleted if
> any of the calls after the I2C adapter is created fails
> - Remove unnecessary includes in sun4i_hdmi_i2c.c
>
> drivers/gpu/drm/sun4i/Makefile | 1 +
> drivers/gpu/drm/sun4i/sun4i_hdmi.h | 23 ++++
> drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c | 101 ++------------
> drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c | 242 +++++++++++++++++++++++++++++++++
> 4 files changed, 277 insertions(+), 90 deletions(-)
> create mode 100644 drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c
>
> diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
> index e29fd3a2ba9c..43c753cafc88 100644
> --- a/drivers/gpu/drm/sun4i/Makefile
> +++ b/drivers/gpu/drm/sun4i/Makefile
> @@ -2,6 +2,7 @@ sun4i-drm-y += sun4i_drv.o
> sun4i-drm-y += sun4i_framebuffer.o
>
> sun4i-drm-hdmi-y += sun4i_hdmi_enc.o
> +sun4i-drm-hdmi-y += sun4i_hdmi_i2c.o
> sun4i-drm-hdmi-y += sun4i_hdmi_ddc_clk.o
> sun4i-drm-hdmi-y += sun4i_hdmi_tmds_clk.o
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> index 2f2f2ff1ea63..eaff92fe236c 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> @@ -96,6 +96,7 @@
> #define SUN4I_HDMI_DDC_CTRL_ENABLE BIT(31)
> #define SUN4I_HDMI_DDC_CTRL_START_CMD BIT(30)
> #define SUN4I_HDMI_DDC_CTRL_FIFO_DIR_MASK BIT(8)
> +#define SUN4I_HDMI_DDC_CTRL_FIFO_DIR_WRITE (1 << 8)
> #define SUN4I_HDMI_DDC_CTRL_FIFO_DIR_READ (0 << 8)
> #define SUN4I_HDMI_DDC_CTRL_RESET BIT(0)
>
> @@ -105,14 +106,33 @@
> #define SUN4I_HDMI_DDC_ADDR_OFFSET(off) (((off) & 0xff) << 8)
> #define SUN4I_HDMI_DDC_ADDR_SLAVE(addr) ((addr) & 0xff)
>
> +#define SUN4I_HDMI_DDC_INT_STATUS_REG 0x50c
> +#define SUN4I_HDMI_DDC_INT_STATUS_ILLEGAL_FIFO_OPERATION BIT(7)
> +#define SUN4I_HDMI_DDC_INT_STATUS_DDC_RX_FIFO_UNDERFLOW BIT(6)
> +#define SUN4I_HDMI_DDC_INT_STATUS_DDC_TX_FIFO_OVERFLOW BIT(5)
> +#define SUN4I_HDMI_DDC_INT_STATUS_FIFO_REQUEST BIT(4)
> +#define SUN4I_HDMI_DDC_INT_STATUS_ARBITRATION_ERROR BIT(3)
> +#define SUN4I_HDMI_DDC_INT_STATUS_ACK_ERROR BIT(2)
> +#define SUN4I_HDMI_DDC_INT_STATUS_BUS_ERROR BIT(1)
> +#define SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE BIT(0)
> +
> #define SUN4I_HDMI_DDC_FIFO_CTRL_REG 0x510
> #define SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR BIT(31)
>
> +#define SUN4I_HDMI_DDC_FIFO_STATUS_REG 0x514
> +#define SUN4I_HDMI_DDC_FIFO_STATUS_FULL BIT(6)
> +#define SUN4I_HDMI_DDC_FIFO_STATUS_EMPTY BIT(5)
> +#define SUN4I_HDMI_DDC_FIFO_STATUS_LEVEL_MASK GENMASK(4, 0)
> +
> #define SUN4I_HDMI_DDC_FIFO_DATA_REG 0x518
> +
> #define SUN4I_HDMI_DDC_BYTE_COUNT_REG 0x51c
> +#define SUN4I_HDMI_DDC_BYTE_COUNT_MAX GENMASK(9, 0)
>
> #define SUN4I_HDMI_DDC_CMD_REG 0x520
> #define SUN4I_HDMI_DDC_CMD_EXPLICIT_EDDC_READ 6
> +#define SUN4I_HDMI_DDC_CMD_IMPLICIT_READ 5
> +#define SUN4I_HDMI_DDC_CMD_IMPLICIT_WRITE 3
>
> #define SUN4I_HDMI_DDC_CLK_REG 0x528
> #define SUN4I_HDMI_DDC_CLK_M(m) (((m) & 0x7) << 3)
> @@ -146,6 +166,8 @@ struct sun4i_hdmi {
> struct clk *ddc_clk;
> struct clk *tmds_clk;
>
> + struct i2c_adapter *i2c;
> +
> struct sun4i_drv *drv;
>
> bool hdmi_monitor;
> @@ -153,5 +175,6 @@ struct sun4i_hdmi {
>
> int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
> int sun4i_tmds_create(struct sun4i_hdmi *hdmi);
> +int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi);
>
> #endif /* _SUN4I_HDMI_H_ */
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> index d3398f6250ef..b74607feb35c 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> @@ -29,8 +29,6 @@
> #include "sun4i_hdmi.h"
> #include "sun4i_tcon.h"
>
> -#define DDC_SEGMENT_ADDR 0x30
> -
> static inline struct sun4i_hdmi *
> drm_encoder_to_sun4i_hdmi(struct drm_encoder *encoder)
> {
> @@ -184,93 +182,13 @@ static const struct drm_encoder_funcs sun4i_hdmi_funcs = {
> .destroy = drm_encoder_cleanup,
> };
>
> -static int sun4i_hdmi_read_sub_block(struct sun4i_hdmi *hdmi,
> - unsigned int blk, unsigned int offset,
> - u8 *buf, unsigned int count)
> -{
> - unsigned long reg;
> - int i;
> -
> - reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> - reg &= ~SUN4I_HDMI_DDC_CTRL_FIFO_DIR_MASK;
> - writel(reg | SUN4I_HDMI_DDC_CTRL_FIFO_DIR_READ,
> - hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> -
> - writel(SUN4I_HDMI_DDC_ADDR_SEGMENT(offset >> 8) |
> - SUN4I_HDMI_DDC_ADDR_EDDC(DDC_SEGMENT_ADDR << 1) |
> - SUN4I_HDMI_DDC_ADDR_OFFSET(offset) |
> - SUN4I_HDMI_DDC_ADDR_SLAVE(DDC_ADDR),
> - hdmi->base + SUN4I_HDMI_DDC_ADDR_REG);
> -
> - reg = readl(hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG);
> - writel(reg | SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR,
> - hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG);
> -
> - writel(count, hdmi->base + SUN4I_HDMI_DDC_BYTE_COUNT_REG);
> - writel(SUN4I_HDMI_DDC_CMD_EXPLICIT_EDDC_READ,
> - hdmi->base + SUN4I_HDMI_DDC_CMD_REG);
> -
> - reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> - writel(reg | SUN4I_HDMI_DDC_CTRL_START_CMD,
> - hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> -
> - if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG, reg,
> - !(reg & SUN4I_HDMI_DDC_CTRL_START_CMD),
> - 100, 100000))
> - return -EIO;
> -
> - for (i = 0; i < count; i++)
> - buf[i] = readb(hdmi->base + SUN4I_HDMI_DDC_FIFO_DATA_REG);
> -
> - return 0;
> -}
> -
> -static int sun4i_hdmi_read_edid_block(void *data, u8 *buf, unsigned int blk,
> - size_t length)
> -{
> - struct sun4i_hdmi *hdmi = data;
> - int retry = 2, i;
> -
> - do {
> - for (i = 0; i < length; i += SUN4I_HDMI_DDC_FIFO_SIZE) {
> - unsigned char offset = blk * EDID_LENGTH + i;
> - unsigned int count = min((unsigned int)SUN4I_HDMI_DDC_FIFO_SIZE,
> - length - i);
> - int ret;
> -
> - ret = sun4i_hdmi_read_sub_block(hdmi, blk, offset,
> - buf + i, count);
> - if (ret)
> - return ret;
> - }
> - } while (!drm_edid_block_valid(buf, blk, true, NULL) && (retry--));
> -
> - return 0;
> -}
> -
> static int sun4i_hdmi_get_modes(struct drm_connector *connector)
> {
> struct sun4i_hdmi *hdmi = drm_connector_to_sun4i_hdmi(connector);
> - unsigned long reg;
> struct edid *edid;
> int ret;
>
> - /* Reset i2c controller */
> - writel(SUN4I_HDMI_DDC_CTRL_ENABLE | SUN4I_HDMI_DDC_CTRL_RESET,
> - hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> - if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG, reg,
> - !(reg & SUN4I_HDMI_DDC_CTRL_RESET),
> - 100, 2000))
> - return -EIO;
> -
> - writel(SUN4I_HDMI_DDC_LINE_CTRL_SDA_ENABLE |
> - SUN4I_HDMI_DDC_LINE_CTRL_SCL_ENABLE,
> - hdmi->base + SUN4I_HDMI_DDC_LINE_CTRL_REG);
> -
> - clk_prepare_enable(hdmi->ddc_clk);
> - clk_set_rate(hdmi->ddc_clk, 100000);
> -
> - edid = drm_do_get_edid(connector, sun4i_hdmi_read_edid_block, hdmi);
> + edid = drm_get_edid(connector, hdmi->i2c);
> if (!edid)
> return 0;
>
> @@ -282,8 +200,6 @@ static int sun4i_hdmi_get_modes(struct drm_connector *connector)
> ret = drm_add_edid_modes(connector, edid);
> kfree(edid);
>
> - clk_disable_unprepare(hdmi->ddc_clk);
> -
> return ret;
> }
>
> @@ -407,9 +323,9 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
> SUN4I_HDMI_PLL_CTRL_PLL_EN;
> writel(reg, hdmi->base + SUN4I_HDMI_PLL_CTRL_REG);
>
> - ret = sun4i_ddc_create(hdmi, hdmi->tmds_clk);
> + ret = sun4i_hdmi_i2c_create(dev, hdmi);
> if (ret) {
> - dev_err(dev, "Couldn't create the DDC clock\n");
> + dev_err(dev, "Couldn't create the HDMI I2C adapter\n");
> return ret;
> }
>
> @@ -422,13 +338,15 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
> NULL);
> if (ret) {
> dev_err(dev, "Couldn't initialise the HDMI encoder\n");
> - return ret;
> + goto err_del_i2c_adapter;
> }
>
> hdmi->encoder.possible_crtcs = drm_of_find_possible_crtcs(drm,
> dev->of_node);
> - if (!hdmi->encoder.possible_crtcs)
> - return -EPROBE_DEFER;
> + if (!hdmi->encoder.possible_crtcs) {
> + ret = -EPROBE_DEFER;
> + goto err_del_i2c_adapter;
> + }
>
> drm_connector_helper_add(&hdmi->connector,
> &sun4i_hdmi_connector_helper_funcs);
> @@ -451,6 +369,8 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
>
> err_cleanup_connector:
> drm_encoder_cleanup(&hdmi->encoder);
> +err_del_i2c_adapter:
> + i2c_del_adapter(hdmi->i2c);
> return ret;
> }
>
> @@ -461,6 +381,7 @@ static void sun4i_hdmi_unbind(struct device *dev, struct device *master,
>
> drm_connector_cleanup(&hdmi->connector);
> drm_encoder_cleanup(&hdmi->encoder);
> + i2c_del_adapter(hdmi->i2c);
> }
>
> static const struct component_ops sun4i_hdmi_ops = {
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c
> new file mode 100644
> index 000000000000..45cfd6bf483c
> --- /dev/null
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c
> @@ -0,0 +1,242 @@
> +/*
> + * Copyright (C) 2016 Maxime Ripard <maxime.ripard at free-electrons.com>
> + * Copyright (C) 2017 Jonathan Liu <net147 at gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/i2c.h>
> +#include <linux/iopoll.h>
> +#include <linux/ktime.h>
> +
> +#include "sun4i_hdmi.h"
> +
> +#define SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK ( \
> + SUN4I_HDMI_DDC_INT_STATUS_ILLEGAL_FIFO_OPERATION | \
> + SUN4I_HDMI_DDC_INT_STATUS_DDC_RX_FIFO_UNDERFLOW | \
> + SUN4I_HDMI_DDC_INT_STATUS_DDC_TX_FIFO_OVERFLOW | \
> + SUN4I_HDMI_DDC_INT_STATUS_ARBITRATION_ERROR | \
> + SUN4I_HDMI_DDC_INT_STATUS_ACK_ERROR | \
> + SUN4I_HDMI_DDC_INT_STATUS_BUS_ERROR \
> +)
> +
> +static int wait_fifo_flag_unset(struct sun4i_hdmi *hdmi, int len, u32 flag)
> +{
> + /* 1 byte takes 9 clock cycles (8 bits + 1 ack) */
> + unsigned long byte_time = DIV_ROUND_UP(USEC_PER_SEC,
> + clk_get_rate(hdmi->ddc_clk)) * 9;
> + u32 reg;
> + ktime_t wait_timeout = ktime_add_us(ktime_get(), 100000);
> +
> + for (;;) {
> + /* Check for errors */
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_INT_STATUS_REG);
> + if (reg & SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK)
> + return -EIO;
> +
> + /* Check if requested FIFO flag is unset */
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_FIFO_STATUS_REG);
> + if (!(reg & flag))
> + break;
> +
> + /* Timeout */
> + if (ktime_compare(ktime_get(), wait_timeout) > 0)
> + return -ETIMEDOUT;
> +
> + /* Wait for bytes to transfer (limited by FIFO size) */
> + usleep_range(byte_time,
> + min(len, SUN4I_HDMI_DDC_FIFO_SIZE) * byte_time);
> + }
> +
> + /* Return FIFO level */
> + return (int)(reg & SUN4I_HDMI_DDC_FIFO_STATUS_LEVEL_MASK);
> +}
I still think you should be using readl_poll_timeout here, and then
check for errors. This is both easier to understand and you avoid an
unneeded duplication.
> +
> +static int wait_fifo_read_ready(struct sun4i_hdmi *hdmi, int len)
> +{
> + int level = wait_fifo_flag_unset(hdmi, len,
> + SUN4I_HDMI_DDC_FIFO_STATUS_EMPTY);
> +
> + /* Return number of bytes that can be read from FIFO */
> + return min(len, level);
> +}
The function's name is still inconsistent with what it does, and
returns.
> +
> +static int wait_fifo_write_ready(struct sun4i_hdmi *hdmi, int len)
> +{
> + int level = wait_fifo_flag_unset(hdmi, len,
> + SUN4I_HDMI_DDC_FIFO_STATUS_FULL);
> +
> + /* Return number of bytes that can be written to FIFO */
> + return min(len, SUN4I_HDMI_DDC_FIFO_SIZE - level);
> +}
Same thing here.
> +static int xfer_msg(struct sun4i_hdmi *hdmi, struct i2c_msg *msg)
> +{
> + int i, len;
> + u32 reg;
> +
> + /* Clear errors */
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_INT_STATUS_REG);
> + reg &= ~SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK;
> + writel(reg, hdmi->base + SUN4I_HDMI_DDC_INT_STATUS_REG);
> +
> + /* Set FIFO direction */
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> + reg &= ~SUN4I_HDMI_DDC_CTRL_FIFO_DIR_MASK;
> + reg |= (msg->flags & I2C_M_RD) ?
> + SUN4I_HDMI_DDC_CTRL_FIFO_DIR_READ :
> + SUN4I_HDMI_DDC_CTRL_FIFO_DIR_WRITE;
> + writel(reg, hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> +
> + /* Set I2C address */
> + writel(SUN4I_HDMI_DDC_ADDR_SLAVE(msg->addr),
> + hdmi->base + SUN4I_HDMI_DDC_ADDR_REG);
> +
> + /* Clear FIFO */
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG);
> + writel(reg | SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR,
> + hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG);
> + if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG,
> + reg,
> + !(reg & SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR),
> + 100, 100000))
> + return -EIO;
> +
> + /* Set transfer length */
> + writel(msg->len, hdmi->base + SUN4I_HDMI_DDC_BYTE_COUNT_REG);
> +
> + /* Set command */
> + writel(msg->flags & I2C_M_RD ?
> + SUN4I_HDMI_DDC_CMD_IMPLICIT_READ :
> + SUN4I_HDMI_DDC_CMD_IMPLICIT_WRITE,
> + hdmi->base + SUN4I_HDMI_DDC_CMD_REG);
> +
> + /* Start command */
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> + writel(reg | SUN4I_HDMI_DDC_CTRL_START_CMD,
> + hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> +
> + /* Transfer bytes */
> + if (msg->flags & I2C_M_RD) {
> + for (i = 0; i < msg->len; i += len) {
> + len = wait_fifo_read_ready(hdmi, msg->len - i);
> + if (len <= 0)
> + return len;
> +
> + readsb(hdmi->base + SUN4I_HDMI_DDC_FIFO_DATA_REG,
> + msg->buf + i, len);
> + }
> + } else {
> + for (i = 0; i < msg->len; i += len) {
> + len = wait_fifo_write_ready(hdmi, msg->len - i);
> + if (len <= 0)
> + return len;
> +
> + writesb(hdmi->base + SUN4I_HDMI_DDC_FIFO_DATA_REG,
> + msg->buf + i, len);
> + }
> + }
> +
> + /* Wait for command to finish */
> + if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG,
> + reg,
> + !(reg & SUN4I_HDMI_DDC_CTRL_START_CMD),
> + 100, 100000))
> + return -EIO;
> +
> + /* Check for errors */
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_INT_STATUS_REG);
> + if ((reg & SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK) ||
> + !(reg & SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE)) {
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static int sun4i_hdmi_i2c_xfer(struct i2c_adapter *adap,
> + struct i2c_msg *msgs, int num)
> +{
> + struct sun4i_hdmi *hdmi = i2c_get_adapdata(adap);
> + u32 reg;
> + int err, i, ret = num;
> +
> + for (i = 0; i < num; i++) {
> + if (!msgs[i].len)
> + return -EINVAL;
> + if (msgs[i].len > SUN4I_HDMI_DDC_BYTE_COUNT_MAX)
> + return -EINVAL;
> + }
> +
> + /* Reset I2C controller */
> + writel(SUN4I_HDMI_DDC_CTRL_ENABLE | SUN4I_HDMI_DDC_CTRL_RESET,
> + hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> + if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG, reg,
> + !(reg & SUN4I_HDMI_DDC_CTRL_RESET),
> + 100, 2000))
> + return -EIO;
> +
> + writel(SUN4I_HDMI_DDC_LINE_CTRL_SDA_ENABLE |
> + SUN4I_HDMI_DDC_LINE_CTRL_SCL_ENABLE,
> + hdmi->base + SUN4I_HDMI_DDC_LINE_CTRL_REG);
> +
> + clk_prepare_enable(hdmi->ddc_clk);
> + clk_set_rate(hdmi->ddc_clk, 100000);
> +
> + for (i = 0; i < num; i++) {
> + err = xfer_msg(hdmi, &msgs[i]);
> + if (err) {
> + ret = err;
> + break;
> + }
> + }
> +
> + clk_disable_unprepare(hdmi->ddc_clk);
> + return ret;
> +}
> +
> +static u32 sun4i_hdmi_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static const struct i2c_algorithm sun4i_hdmi_i2c_algorithm = {
> + .master_xfer = sun4i_hdmi_i2c_xfer,
> + .functionality = sun4i_hdmi_i2c_func,
> +};
> +
> +static const struct i2c_adapter sun4i_hdmi_i2c_adapter = {
> + .owner = THIS_MODULE,
> + .class = I2C_CLASS_DDC,
> + .algo = &sun4i_hdmi_i2c_algorithm,
> + .name = "sun4i_hdmi_i2c adapter",
> +};
> +
> +int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi)
> +{
> + struct i2c_adapter *adap;
> + int ret = 0;
> +
> + ret = sun4i_ddc_create(hdmi, hdmi->tmds_clk);
> + if (ret)
> + return ret;
> +
> + adap = devm_kmemdup(dev, &sun4i_hdmi_i2c_adapter,
> + sizeof(sun4i_hdmi_i2c_adapter), GFP_KERNEL);
It would be more consistent with what the kernel usually does to just
kmalloc that structure, and fill it.
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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