Re: [PATCH 3/6] drm/bridge: extract some Analogix I2C DP common code

From: Laurent Pinchart
Date: Thu May 23 2019 - 03:57:30 EST

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In reply to: Torsten Duwe: "Re: [PATCH 3/6] drm/bridge: extract some Analogix I2C DP common code"
Next in thread: Torsten Duwe: "[PATCH 4/6] drm/bridge: Add Analogix anx6345 support"
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Hi Torsten,

Thank you for the patch.

On Thu, May 23, 2019 at 08:53:52AM +0200, Torsten Duwe wrote:
> From: Icenowy Zheng <icenowy@xxxxxxx>
>
> Some code can be shared within different DP bridges by Analogix.
>
> Extract them to a new module.
>
> Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
> Signed-off-by: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
> Signed-off-by: Torsten Duwe <duwe@xxxxxxx>
> ---
> drivers/gpu/drm/bridge/analogix/Kconfig | 4 +
> drivers/gpu/drm/bridge/analogix/Makefile | 2 +
> drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c | 146 +-----------------
> .../gpu/drm/bridge/analogix/analogix-i2c-dptx.c | 169 +++++++++++++++++++++
> .../gpu/drm/bridge/analogix/analogix-i2c-dptx.h | 2 +
> 5 files changed, 178 insertions(+), 145 deletions(-)
> create mode 100644 drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c
>
> diff --git a/drivers/gpu/drm/bridge/analogix/Kconfig b/drivers/gpu/drm/bridge/analogix/Kconfig
> index c4d343a2f04d..ed2d05c12546 100644
> --- a/drivers/gpu/drm/bridge/analogix/Kconfig
> +++ b/drivers/gpu/drm/bridge/analogix/Kconfig
> @@ -1,6 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0-only
> config DRM_ANALOGIX_ANX78XX
> tristate "Analogix ANX78XX bridge"
> + select DRM_ANALOGIX_DP_I2C
> select DRM_KMS_HELPER
> select REGMAP_I2C
> help
> @@ -11,3 +12,6 @@ config DRM_ANALOGIX_ANX78XX
> config DRM_ANALOGIX_DP
> tristate
> depends on DRM
> +
> +config DRM_ANALOGIX_DP_I2C
> + tristate
> diff --git a/drivers/gpu/drm/bridge/analogix/Makefile b/drivers/gpu/drm/bridge/analogix/Makefile
> index ce1687e60975..2d523b67487d 100644
> --- a/drivers/gpu/drm/bridge/analogix/Makefile
> +++ b/drivers/gpu/drm/bridge/analogix/Makefile
> @@ -1,4 +1,6 @@
> # SPDX-License-Identifier: GPL-2.0-only
> analogix_dp-objs := analogix_dp_core.o analogix_dp_reg.o
> +analogix_dp_i2c-objs := analogix-i2c-dptx.o
> obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
> obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix_dp.o
> +obj-$(CONFIG_DRM_ANALOGIX_DP_I2C) += analogix_dp_i2c.o

Do we need a separate module for this, or could it be included in
analogix_dp ?

> diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
> index f8433c93f463..bf8291d0ddd0 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
> @@ -45,8 +45,6 @@
> #define I2C_IDX_RX_P1 4
>
> #define XTAL_CLK 270 /* 27M */
> -#define AUX_CH_BUFFER_SIZE 16
> -#define AUX_WAIT_TIMEOUT_MS 15
>
> static const u8 anx78xx_i2c_addresses[] = {
> [I2C_IDX_TX_P0] = TX_P0,
> @@ -109,153 +107,11 @@ static int anx78xx_clear_bits(struct regmap *map, u8 reg, u8 mask)
> return regmap_update_bits(map, reg, mask, 0);
> }
>
> -static bool anx78xx_aux_op_finished(struct anx78xx *anx78xx)
> -{
> - unsigned int value;
> - int err;
> -
> - err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL2_REG,
> - &value);
> - if (err < 0)
> - return false;
> -
> - return (value & SP_AUX_EN) == 0;
> -}
> -
> -static int anx78xx_aux_wait(struct anx78xx *anx78xx)
> -{
> - unsigned long timeout;
> - unsigned int status;
> - int err;
> -
> - timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
> -
> - while (!anx78xx_aux_op_finished(anx78xx)) {
> - if (time_after(jiffies, timeout)) {
> - if (!anx78xx_aux_op_finished(anx78xx)) {
> - DRM_ERROR("Timed out waiting AUX to finish\n");
> - return -ETIMEDOUT;
> - }
> -
> - break;
> - }
> -
> - usleep_range(1000, 2000);
> - }
> -
> - /* Read the AUX channel access status */
> - err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
> - &status);
> - if (err < 0) {
> - DRM_ERROR("Failed to read from AUX channel: %d\n", err);
> - return err;
> - }
> -
> - if (status & SP_AUX_STATUS) {
> - DRM_ERROR("Failed to wait for AUX channel (status: %02x)\n",
> - status);
> - return -ETIMEDOUT;
> - }
> -
> - return 0;
> -}
> -
> -static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
> -{
> - int err;
> -
> - err = regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
> - addr & 0xff);
> - if (err)
> - return err;
> -
> - err = regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
> - (addr & 0xff00) >> 8);
> - if (err)
> - return err;
> -
> - /*
> - * DP AUX CH Address Register #2, only update bits[3:0]
> - * [7:4] RESERVED
> - * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
> - */
> - err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
> - SP_AUX_ADDR_19_16_REG,
> - SP_AUX_ADDR_19_16_MASK,
> - (addr & 0xf0000) >> 16);
> -
> - if (err)
> - return err;
> -
> - return 0;
> -}
> -
> static ssize_t anx78xx_aux_transfer(struct drm_dp_aux *aux,
> struct drm_dp_aux_msg *msg)
> {
> struct anx78xx *anx78xx = container_of(aux, struct anx78xx, aux);
> - u8 ctrl1 = msg->request;
> - u8 ctrl2 = SP_AUX_EN;
> - u8 *buffer = msg->buffer;
> - int err;
> -
> - /* The DP AUX transmit and receive buffer has 16 bytes. */
> - if (WARN_ON(msg->size > AUX_CH_BUFFER_SIZE))
> - return -E2BIG;
> -
> - /* Zero-sized messages specify address-only transactions. */
> - if (msg->size < 1)
> - ctrl2 |= SP_ADDR_ONLY;
> - else /* For non-zero-sized set the length field. */
> - ctrl1 |= (msg->size - 1) << SP_AUX_LENGTH_SHIFT;
> -
> - if ((msg->request & DP_AUX_I2C_READ) == 0) {
> - /* When WRITE | MOT write values to data buffer */
> - err = regmap_bulk_write(anx78xx->map[I2C_IDX_TX_P0],
> - SP_DP_BUF_DATA0_REG, buffer,
> - msg->size);
> - if (err)
> - return err;
> - }
> -
> - /* Write address and request */
> - err = anx78xx_aux_address(anx78xx, msg->address);
> - if (err)
> - return err;
> -
> - err = regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
> - ctrl1);
> - if (err)
> - return err;
> -
> - /* Start transaction */
> - err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
> - SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
> - SP_AUX_EN, ctrl2);
> - if (err)
> - return err;
> -
> - err = anx78xx_aux_wait(anx78xx);
> - if (err)
> - return err;
> -
> - msg->reply = DP_AUX_I2C_REPLY_ACK;
> -
> - if ((msg->size > 0) && (msg->request & DP_AUX_I2C_READ)) {
> - /* Read values from data buffer */
> - err = regmap_bulk_read(anx78xx->map[I2C_IDX_TX_P0],
> - SP_DP_BUF_DATA0_REG, buffer,
> - msg->size);
> - if (err)
> - return err;
> - }
> -
> - err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
> - SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY);
> - if (err)
> - return err;
> -
> - return msg->size;
> + return anx_aux_transfer(anx78xx->map[I2C_IDX_TX_P0], msg);
> }
>
> static int anx78xx_set_hpd(struct anx78xx *anx78xx)
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c b/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c
> new file mode 100644
> index 000000000000..9cb30962032e
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c
> @@ -0,0 +1,169 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright(c) 2017 Icenowy Zheng <icenowy@xxxxxxx>
> + *
> + * Based on analogix-anx78xx.c, which is:
> + * Copyright(c) 2016, Analogix Semiconductor. All rights reserved.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#include <drm/drm.h>
> +#include <drm/drmP.h>
> +#include <drm/drm_dp_helper.h>
> +
> +#include "analogix-i2c-dptx.h"
> +
> +#define AUX_WAIT_TIMEOUT_MS 15
> +#define AUX_CH_BUFFER_SIZE 16
> +
> +static int anx_clear_bits(struct regmap *map, u8 reg, u8 mask)
> +{
> + return regmap_update_bits(map, reg, mask, 0);
> +}
> +
> +static bool anx_aux_op_finished(struct regmap *map_dptx)
> +{
> + unsigned int value;
> + int err;
> +
> + err = regmap_read(map_dptx, SP_DP_AUX_CH_CTRL2_REG, &value);
> + if (err < 0)
> + return false;
> +
> + return (value & SP_AUX_EN) == 0;
> +}
> +
> +static int anx_aux_wait(struct regmap *map_dptx)
> +{
> + unsigned long timeout;
> + unsigned int status;
> + int err;
> +
> + timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
> +
> + while (!anx_aux_op_finished(map_dptx)) {
> + if (time_after(jiffies, timeout)) {
> + if (!anx_aux_op_finished(map_dptx)) {
> + DRM_ERROR("Timed out waiting AUX to finish\n");
> + return -ETIMEDOUT;
> + }
> +
> + break;
> + }
> +
> + usleep_range(1000, 2000);
> + }
> +
> + /* Read the AUX channel access status */
> + err = regmap_read(map_dptx, SP_AUX_CH_STATUS_REG, &status);
> + if (err < 0) {
> + DRM_ERROR("Failed to read from AUX channel: %d\n", err);
> + return err;
> + }
> +
> + if (status & SP_AUX_STATUS) {
> + DRM_ERROR("Failed to wait for AUX channel (status: %02x)\n",
> + status);
> + return -ETIMEDOUT;
> + }
> +
> + return 0;
> +}
> +
> +static int anx_aux_address(struct regmap *map_dptx, unsigned int addr)
> +{
> + int err;
> +
> + err = regmap_write(map_dptx, SP_AUX_ADDR_7_0_REG, addr & 0xff);
> + if (err)
> + return err;
> +
> + err = regmap_write(map_dptx, SP_AUX_ADDR_15_8_REG,
> + (addr & 0xff00) >> 8);
> + if (err)
> + return err;
> +
> + /*
> + * DP AUX CH Address Register #2, only update bits[3:0]
> + * [7:4] RESERVED
> + * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
> + */
> + err = regmap_update_bits(map_dptx, SP_AUX_ADDR_19_16_REG,
> + SP_AUX_ADDR_19_16_MASK,
> + (addr & 0xf0000) >> 16);
> +
> + if (err)
> + return err;
> +
> + return 0;
> +}
> +
> +ssize_t anx_aux_transfer(struct regmap *map_dptx, struct drm_dp_aux_msg *msg)
> +{
> + u8 ctrl1 = msg->request;
> + u8 ctrl2 = SP_AUX_EN;
> + u8 *buffer = msg->buffer;
> + int err;
> +
> + /* The DP AUX transmit and receive buffer has 16 bytes. */
> + if (WARN_ON(msg->size > AUX_CH_BUFFER_SIZE))
> + return -E2BIG;
> +
> + /* Zero-sized messages specify address-only transactions. */
> + if (msg->size < 1)
> + ctrl2 |= SP_ADDR_ONLY;
> + else /* For non-zero-sized set the length field. */
> + ctrl1 |= (msg->size - 1) << SP_AUX_LENGTH_SHIFT;
> +
> + if ((msg->request & DP_AUX_I2C_READ) == 0) {
> + /* When WRITE | MOT write values to data buffer */
> + err = regmap_bulk_write(map_dptx,
> + SP_DP_BUF_DATA0_REG, buffer,
> + msg->size);
> + if (err)
> + return err;
> + }
> +
> + /* Write address and request */
> + err = anx_aux_address(map_dptx, msg->address);
> + if (err)
> + return err;
> +
> + err = regmap_write(map_dptx, SP_DP_AUX_CH_CTRL1_REG, ctrl1);
> + if (err)
> + return err;
> +
> + /* Start transaction */
> + err = regmap_update_bits(map_dptx, SP_DP_AUX_CH_CTRL2_REG,
> + SP_ADDR_ONLY | SP_AUX_EN, ctrl2);
> + if (err)
> + return err;
> +
> + err = anx_aux_wait(map_dptx);
> + if (err)
> + return err;
> +
> + msg->reply = DP_AUX_I2C_REPLY_ACK;
> +
> + if ((msg->size > 0) && (msg->request & DP_AUX_I2C_READ)) {
> + /* Read values from data buffer */
> + err = regmap_bulk_read(map_dptx,
> + SP_DP_BUF_DATA0_REG, buffer,
> + msg->size);
> + if (err)
> + return err;
> + }
> +
> + err = anx_clear_bits(map_dptx, SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY);
> + if (err)
> + return err;
> +
> + return msg->size;
> +}
> +EXPORT_SYMBOL(anx_aux_transfer);

As the code license is GPL and the analogic DP core core is exported
with EXPORT_SYMBOL_GPL, should it be the case here too ?

> +
> +MODULE_DESCRIPTION("Analogix DisplayPort Transmitter common code");
> +MODULE_AUTHOR("Icenowy Zheng <icenowy@xxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.h b/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.h
> index bc0831b127bf..c2ca854613a0 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.h
> @@ -245,4 +245,6 @@
> /* DP AUX Buffer Data Registers */
> #define SP_DP_BUF_DATA0_REG 0xf0
>
> +ssize_t anx_aux_transfer(struct regmap *map_dptx, struct drm_dp_aux_msg *msg);

The name is a bit generic, should it be anx_dp_aux_transfer() ?

> +
> #endif

--
Regards,

Laurent Pinchart

Next message: Shawn Guo: "Re: [PATCHv2] arm64: dts: ls1028a: add flexspi nodes"
Previous message: Lars Persson: "Re: [PATCH 4.14 082/115] cifs: fix memory leak in SMB2_read"
In reply to: Torsten Duwe: "Re: [PATCH 3/6] drm/bridge: extract some Analogix I2C DP common code"
Next in thread: Torsten Duwe: "[PATCH 4/6] drm/bridge: Add Analogix anx6345 support"
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