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Message-ID: <CAGb2v66gdEe4jagsvVe7AeE5FwHfHo-9EvYkmnreK6A9cOc5UA@mail.gmail.com>
Date: Mon, 12 Jun 2017 11:28:46 +0800
From: Chen-Yu Tsai <wens@...e.org>
To: Jonathan Liu <net147@...il.com>
Cc: Maxime Ripard <maxime.ripard@...e-electrons.com>,
David Airlie <airlied@...ux.ie>, Chen-Yu Tsai <wens@...e.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
dri-devel <dri-devel@...ts.freedesktop.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
linux-sunxi <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH] drm/sun4i: hdmi: Implement I2C adapter for A10s DDC bus
On Mon, Jun 12, 2017 at 10:12 AM, Jonathan Liu <net147@...il.com> wrote:
> The drm_get_edid function should be used instead of drm_do_get_edid by
> exposing the DDC bus as an I2C adapter. Implement this for A10s.
Nice!
>
> Signed-off-by: Jonathan Liu <net147@...il.com>
> ---
> drivers/gpu/drm/sun4i/Makefile | 1 +
> drivers/gpu/drm/sun4i/sun4i_hdmi.h | 11 ++-
> drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c | 96 +++----------------
> drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c | 166 +++++++++++++++++++++++++++++++++
> 4 files changed, 190 insertions(+), 84 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 2589bc92be59..8e7a70f67f04 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> @@ -100,6 +100,7 @@
> #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_READ (0 << 8)
> +#define SUN4I_HDMI_DDC_CTRL_FIFO_DIR_WRITE (1 << 8)
> #define SUN4I_HDMI_DDC_CTRL_RESET BIT(0)
>
> #define SUN4I_HDMI_DDC_ADDR_REG 0x504
> @@ -108,6 +109,10 @@
> #define SUN4I_HDMI_DDC_ADDR_OFFSET(off) (((off) & 0xff) << 8)
> #define SUN4I_HDMI_DDC_ADDR_SLAVE(addr) ((addr) & 0xff)
>
> +#define SUN4I_HDMI_DDC_INTERRUPT_STATUS_REG 0x50c
> +#define SUN4I_HDMI_DDC_INTERRUPT_STATUS_FIFO_REQUEST BIT(4)
> +#define SUN4I_HDMI_DDC_INTERRUPT_STATUS_TRANSFER_COMPLETE BIT(0)
> +
> #define SUN4I_HDMI_DDC_FIFO_CTRL_REG 0x510
> #define SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR BIT(31)
>
> @@ -115,7 +120,8 @@
> #define SUN4I_HDMI_DDC_BYTE_COUNT_REG 0x51c
>
> #define SUN4I_HDMI_DDC_CMD_REG 0x520
> -#define SUN4I_HDMI_DDC_CMD_EXPLICIT_EDDC_READ 6
> +#define SUN4I_HDMI_DDC_CMD_IMPLICIT_WRITE 3
> +#define SUN4I_HDMI_DDC_CMD_IMPLICIT_READ 5
>
> #define SUN4I_HDMI_DDC_CLK_REG 0x528
> #define SUN4I_HDMI_DDC_CLK_M(m) (((m) & 0x7) << 3)
> @@ -181,6 +187,8 @@ struct sun4i_hdmi {
> struct clk *ddc_clk;
> struct clk *tmds_clk;
>
> + struct i2c_adapter *i2c;
> +
> struct sun4i_drv *drv;
>
> bool hdmi_monitor;
> @@ -192,5 +200,6 @@ int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
> int sun6i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
> int sun4i_tmds_create(struct sun4i_hdmi *hdmi);
> int sun6i_tmds_create(struct sun4i_hdmi *hdmi);
> +int sun4i_hdmi_i2c_create(struct sun4i_hdmi *hdmi);
However you seem to have based it on the wrong branch/patches.
You based them on my A31 HDMI patches, instead of what Maxime has
in his sunxi-drm/for-next branch.
I could add this to my A31 patches, though it probably won't make
4.13. Alternatively you could rebase them on top of Maxime's branch.
>
> #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 e9abf93eb41c..6c9b11c4cf68 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> @@ -186,93 +186,13 @@ 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;
>
> @@ -284,8 +204,6 @@ 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;
> }
>
> @@ -424,6 +342,7 @@ struct sun4i_hdmi_variant {
> const struct drm_connector_helper_funcs *connector_helpers;
> int (*ddc_create)(struct sun4i_hdmi *hdmi, struct clk *clk);
> int (*tmds_create)(struct sun4i_hdmi *hdmi);
> + int (*hdmi_i2c_create)(struct sun4i_hdmi *hdmi);
> bool has_ddc_parent_clk;
> bool has_reset_control;
>
> @@ -439,6 +358,7 @@ static const struct sun4i_hdmi_variant sun5i_variant = {
> .connector_helpers = &sun4i_hdmi_connector_helper_funcs,
> .ddc_create = sun4i_ddc_create,
> .tmds_create = sun4i_tmds_create,
> + .hdmi_i2c_create = sun4i_hdmi_i2c_create,
> .has_ddc_parent_clk = false,
> .has_reset_control = false,
> .pad_ctrl0_init_val = SUN4I_HDMI_PAD_CTRL0_TXEN |
> @@ -622,6 +542,14 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
> goto err_disable_mod_clk;
> }
>
> + if (hdmi->variant->hdmi_i2c_create) {
I don't think this would be optional.
> + ret = hdmi->variant->hdmi_i2c_create(hdmi);
> + if (ret) {
> + dev_err(dev, "Couldn't create the HDMI I2C adapter\n");
> + goto err_disable_mod_clk;
> + }
> + }
> +
You should also fix up the error path so that the I2C adapter
gets remove if any of the subsequent calls fail.
> drm_encoder_helper_add(&hdmi->encoder,
> &sun4i_hdmi_helper_funcs);
> ret = drm_encoder_init(drm,
> @@ -676,6 +604,8 @@ static void sun4i_hdmi_unbind(struct device *dev, struct device *master,
>
> drm_connector_cleanup(&hdmi->connector);
> drm_encoder_cleanup(&hdmi->encoder);
> + if (hdmi->i2c)
> + i2c_del_adapter(hdmi->i2c);
So neither should this be optional.
> clk_disable_unprepare(hdmi->mod_clk);
> clk_disable_unprepare(hdmi->bus_clk);
> }
> 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..c33fa13cc668
> --- /dev/null
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c
> @@ -0,0 +1,166 @@
> +/*
> + * Copyright (C) 2017 Jonathan Liu
> + *
> + * Jonathan Liu <net147@...il.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/init.h>
> +#include <linux/module.h>
> +#include <linux/errno.h>
> +#include <linux/clk.h>
> +#include <linux/i2c.h>
> +#include <linux/iopoll.h>
> +
> +#include "sun4i_hdmi.h"
> +
> +static int xfer_msg_chunk(struct sun4i_hdmi *hdmi, struct i2c_msg *msg)
> +{
> + u32 count = min_t(u32, msg->len, SUN4I_HDMI_DDC_FIFO_SIZE);
> + u32 reg;
> + int i;
> +
> + 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(msg->flags & I2C_M_RD
> + ? SUN4I_HDMI_DDC_CMD_IMPLICIT_READ
> + : SUN4I_HDMI_DDC_CMD_IMPLICIT_WRITE,
> + 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 (!(msg->flags & I2C_M_RD)) {
> + for (i = 0; i < count; i++) {
> + writeb(*msg->buf++, hdmi->base
> + + SUN4I_HDMI_DDC_FIFO_DATA_REG);
> + --msg->len;
> + }
> + }
> +
> + if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG,
> + reg,
> + !(reg & SUN4I_HDMI_DDC_CTRL_START_CMD),
> + 100, 100000))
> + return -EIO;
> +
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_INTERRUPT_STATUS_REG);
> + reg &= ~SUN4I_HDMI_DDC_INTERRUPT_STATUS_FIFO_REQUEST;
> +
> + if (reg != SUN4I_HDMI_DDC_INTERRUPT_STATUS_TRANSFER_COMPLETE)
> + return -EIO;
> +
> + if (msg->flags & I2C_M_RD) {
> + for (i = 0; i < count; i++) {
> + *msg->buf++ = readb(hdmi->base
> + + SUN4I_HDMI_DDC_FIFO_DATA_REG);
> + --msg->len;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int xfer_msg(struct sun4i_hdmi *hdmi, struct i2c_msg *msg)
> +{
> + u32 reg;
> + int ret;
> +
> + if (!msg->len)
> + return -EIO;
> +
> + while (msg->len) {
> + reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> + reg &= ~SUN4I_HDMI_DDC_CTRL_FIFO_DIR_MASK;
> +
> + writel(reg | (msg->flags & I2C_M_RD
> + ? SUN4I_HDMI_DDC_CTRL_FIFO_DIR_READ
> + : SUN4I_HDMI_DDC_CTRL_FIFO_DIR_WRITE),
> + hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
> +
> + writel(SUN4I_HDMI_DDC_ADDR_SLAVE(msg->addr),
> + hdmi->base + SUN4I_HDMI_DDC_ADDR_REG);
> +
> + ret = xfer_msg_chunk(hdmi, msg);
> + if (ret)
> + return ret;
> + }
> +
> + 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, ret = num;
> + int i;
> +
> + /* 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 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 sun4i_hdmi *hdmi)
> +{
> + int ret = 0;
> +
> + i2c_set_adapdata(&sun4i_hdmi_i2c_adapter, hdmi);
> +
> + ret = i2c_add_adapter(&sun4i_hdmi_i2c_adapter);
> + if (ret)
> + return ret;
> +
> + hdmi->i2c = &sun4i_hdmi_i2c_adapter;
> +
> + return ret;
> +}
> --
> 2.12.2
>
The rest looks good to me.
Regards
ChenYu
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