Re: [PATCH v3 2/7] drm/tinydrm: Add helper functions

On Tue, Jan 31, 2017 at 05:03:14PM +0100, Noralf Trønnes wrote:

Add common functionality needed by many tinydrm drivers.

Signed-off-by: Noralf Trønnes noralf@tronnes.org Acked-by: Daniel Vetter daniel.vetter@ffwll.ch

---

Documentation/gpu/tinydrm.rst | 9 + drivers/gpu/drm/tinydrm/core/Makefile | 2 +- drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 462 +++++++++++++++++++++++++ include/drm/tinydrm/tinydrm-helpers.h | 100 ++++++ 4 files changed, 572 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c create mode 100644 include/drm/tinydrm/tinydrm-helpers.h

diff --git a/Documentation/gpu/tinydrm.rst b/Documentation/gpu/tinydrm.rst index ec4a20d..fb256d2 100644 --- a/Documentation/gpu/tinydrm.rst +++ b/Documentation/gpu/tinydrm.rst @@ -19,3 +19,12 @@ Core functionality

.. kernel-doc:: drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c :export:

+Additional helpers +==================

+.. kernel-doc:: include/drm/tinydrm/tinydrm-helpers.h

• :internal:

+.. kernel-doc:: drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c

• :export:

diff --git a/drivers/gpu/drm/tinydrm/core/Makefile b/drivers/gpu/drm/tinydrm/core/Makefile index 4f14a0f..fb221e6 100644 --- a/drivers/gpu/drm/tinydrm/core/Makefile +++ b/drivers/gpu/drm/tinydrm/core/Makefile @@ -1,3 +1,3 @@ -tinydrm-y := tinydrm-core.o tinydrm-pipe.o +tinydrm-y := tinydrm-core.o tinydrm-pipe.o tinydrm-helpers.o

obj-$(CONFIG_DRM_TINYDRM) += tinydrm.o diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c new file mode 100644 index 0000000..75e4e54 --- /dev/null +++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c @@ -0,0 +1,462 @@ +/*

• • Copyright (C) 2016 Noralf Trønnes
• • 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 <drm/tinydrm/tinydrm.h> +#include <drm/tinydrm/tinydrm-helpers.h> +#include <linux/backlight.h> +#include <linux/pm.h> +#include <linux/spi/spi.h> +#include <linux/swab.h>

+static unsigned int spi_max; +module_param(spi_max, uint, 0400); +MODULE_PARM_DESC(spi_max, "Set a lower SPI max transfer size");

+/**

• • tinydrm_merge_clips - Merge clip rectangles
• • @dst: Destination clip rectangle
• • @src: Source clip rectangle(s)
• • @num_clips: Number of @src clip rectangles
• • @flags: Dirty fb ioctl flags
• • @max_width: Maximum width of @dst
• • @max_height: Maximum height of @dst
• • This function merges @src clip rectangle(s) into @dst. If @src is NULL,
• • @max_width and @min_width is used to set a full @dst clip rectangle.
• • Returns:
• • true if it's a full clip, false otherwise
• */

+bool tinydrm_merge_clips(struct drm_clip_rect *dst,

• 	 struct drm_clip_rect *src, unsigned int num_clips,
  

• 	 unsigned int flags, u32 max_width, u32 max_height)
  

+{

• unsigned int i;
• if (!src || !num_clips) {

• dst->x1 = 0;
  

• dst->x2 = max_width;
  

• dst->y1 = 0;
  

• dst->y2 = max_height;
  

• return true;
  

• }
• dst->x1 = ~0;
• dst->y1 = ~0;
• dst->x2 = 0;
• dst->y2 = 0;
• for (i = 0; i < num_clips; i++) {

• if (flags & DRM_MODE_FB_DIRTY_ANNOTATE_COPY)
  

• 	i++;
  

• dst->x1 = min(dst->x1, src[i].x1);
  

• dst->x2 = max(dst->x2, src[i].x2);
  

• dst->y1 = min(dst->y1, src[i].y1);
  

• dst->y2 = max(dst->y2, src[i].y2);
  

• }
• if (dst->x2 > max_width || dst->y2 > max_height ||

•    dst->x1 >= dst->x2 || dst->y1 >= dst->y2) {
  

• DRM_DEBUG_KMS("Illegal clip: x1=%u, x2=%u, y1=%u, y2=%u\n",
  

• 	      dst->x1, dst->x2, dst->y1, dst->y2);
  

• dst->x1 = 0;
  

• dst->y1 = 0;
  

• dst->x2 = max_width;
  

• dst->y2 = max_height;
  

• }
• return (dst->x2 - dst->x1) == max_width &&

•       (dst->y2 - dst->y1) == max_height;
  

+} +EXPORT_SYMBOL(tinydrm_merge_clips);

Should this perhaps be part of drm_rect.c?

+#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE +/**

• • tinydrm_of_find_backlight - Find backlight device in device-tree
• • @dev: Device
• • This function looks for a DT node pointed to by a property named 'backlight'
• • and uses of_find_backlight_by_node() to get the backlight device.
• • Additionally if the brightness property is zero, it is set to
• • max_brightness.
• • Returns:
• • NULL if there's no backlight property.
• • Error pointer -EPROBE_DEFER if the DT node is found, but no backlight device
• • is found.
• • If the backlight device is found, a pointer to the structure is returned.
• */

+struct backlight_device *tinydrm_of_find_backlight(struct device *dev) +{

• struct backlight_device *backlight;
• struct device_node *np;
• np = of_parse_phandle(dev->of_node, "backlight", 0);
• if (!np)

• return NULL;
  

• backlight = of_find_backlight_by_node(np);
• of_node_put(np);
• if (!backlight)

• return ERR_PTR(-EPROBE_DEFER);
  

• if (!backlight->props.brightness) {

• backlight->props.brightness = backlight->props.max_brightness;
  

• DRM_DEBUG_KMS("Backlight brightness set to %d\n",
  

• 	      backlight->props.brightness);
  

• }
• return backlight;

+} +EXPORT_SYMBOL(tinydrm_of_find_backlight);

+/**

• • tinydrm_enable_backlight - Enable backlight helper
• • @backlight: Backlight device
• • Returns:
• • Zero on success, negative error code on failure.
• */

+int tinydrm_enable_backlight(struct backlight_device *backlight) +{

• unsigned int old_state;
• int ret;
• if (!backlight)

• return 0;
  

• old_state = backlight->props.state;
• backlight->props.state &= ~BL_CORE_FBBLANK;
• DRM_DEBUG_KMS("Backlight state: 0x%x -> 0x%x\n", old_state,

•       backlight->props.state);
  

• ret = backlight_update_status(backlight);
• if (ret)

• DRM_ERROR("Failed to enable backlight %d\n", ret);
  

• return ret;

+} +EXPORT_SYMBOL(tinydrm_enable_backlight);

+/**

• • tinydrm_disable_backlight - Disable backlight helper
• • @backlight: Backlight device
• • Returns:
• • Zero on success, negative error code on failure.
• */

+int tinydrm_disable_backlight(struct backlight_device *backlight) +{

• unsigned int old_state;
• int ret;
• if (!backlight)

• return 0;
  

• old_state = backlight->props.state;
• backlight->props.state |= BL_CORE_FBBLANK;
• DRM_DEBUG_KMS("Backlight state: 0x%x -> 0x%x\n", old_state,

•       backlight->props.state);
  

• ret = backlight_update_status(backlight);
• if (ret)

• DRM_ERROR("Failed to disable backlight %d\n", ret);
  

• return ret;

+} +EXPORT_SYMBOL(tinydrm_disable_backlight); +#endif

These look like they really should be part of the backlight subsystem. I don't see anything DRM specific about them. Well, except for the error messages.

+#ifdef CONFIG_SPI

+/**

• • tinydrm_spi_max_transfer_size - Determine max SPI transfer size
• • @spi: SPI device
• • @max_len: Maximum buffer size needed (optional)
• • This function returns the maximum size to use for SPI transfers. It checks
• • the SPI master, the optional @max_len and the module parameter spi_max and
• • returns the smallest.
• • Returns:
• • Maximum size for SPI transfers
• */

+size_t tinydrm_spi_max_transfer_size(struct spi_device *spi, size_t max_len) +{

• size_t ret;
• ret = min(spi_max_transfer_size(spi), spi->master->max_dma_len);
• if (max_len)

• ret = min(ret, max_len);
  

• if (spi_max)

• ret = min_t(size_t, ret, spi_max);
  

• ret &= ~0x3;
• if (ret < 4)

• ret = 4;
  

• return ret;

+} +EXPORT_SYMBOL(tinydrm_spi_max_transfer_size);

+/**

• • tinydrm_spi_bpw_supported - Check if bits per word is supported
• • @spi: SPI device
• • @bpw: Bits per word
• • This function checks to see if the SPI master driver supports @bpw.
• • Returns:
• • True if @bpw is supported, false otherwise.
• */

+bool tinydrm_spi_bpw_supported(struct spi_device *spi, u8 bpw) +{

• u32 bpw_mask = spi->master->bits_per_word_mask;
• if (bpw == 8)

• return true;
  

• if (!bpw_mask) {

• dev_warn_once(&spi->dev,
  

• 	      "bits_per_word_mask not set, assume 8-bit only\n");
  

• return false;
  

• }
• if (bpw_mask & SPI_BPW_MASK(bpw))

• return true;
  

• return false;

+} +EXPORT_SYMBOL(tinydrm_spi_bpw_supported);

+static void +tinydrm_dbg_spi_print(struct spi_device *spi, struct spi_transfer *tr,

•       const void *buf, int idx, bool tx)
  

+{

• u32 speed_hz = tr->speed_hz ? tr->speed_hz : spi->max_speed_hz;
• char linebuf[3 * 32];
• hex_dump_to_buffer(buf, tr->len, 16,

• 	   DIV_ROUND_UP(tr->bits_per_word, 8),
  

• 	   linebuf, sizeof(linebuf), false);
  

• printk(KERN_DEBUG

•       "    tr(%i): speed=%u%s, bpw=%i, len=%u, %s_buf=[%s%s]\n", idx,
  

•       speed_hz > 1000000 ? speed_hz / 1000000 : speed_hz / 1000,
  

•       speed_hz > 1000000 ? "MHz" : "kHz", tr->bits_per_word, tr->len,
  

•       tx ? "tx" : "rx", linebuf, tr->len > 16 ? " ..." : "");
  

+}

+/* called through tinydrm_dbg_spi_message() */ +void _tinydrm_dbg_spi_message(struct spi_device *spi, struct spi_message *m) +{

• struct spi_transfer *tmp;
• struct list_head *pos;
• int i = 0;
• list_for_each(pos, &m->transfers) {

• tmp = list_entry(pos, struct spi_transfer, transfer_list);
  

• if (tmp->tx_buf)
  

• 	tinydrm_dbg_spi_print(spi, tmp, tmp->tx_buf, i, true);
  

• if (tmp->rx_buf)
  

• 	tinydrm_dbg_spi_print(spi, tmp, tmp->rx_buf, i, false);
  

• i++;
  

• }

+} +EXPORT_SYMBOL(_tinydrm_dbg_spi_message);

+/**

• • tinydrm_spi_transfer - SPI transfer helper
• • @spi: SPI device
• • @speed_hz: Override speed (optional)
• • @header: Optional header transfer
• • @bpw: Bits per word
• • @buf: Buffer to transfer
• • @len: Buffer length
• • This SPI transfer helper breaks up the transfer of @buf into chunks which
• • the SPI master driver can handle. If the machine is Little Endian and the
• • SPI master driver doesn't support 16 bits per word, it swaps the bytes and
• • does a 8-bit transfer.
• • If @header is set, it is prepended to each SPI message.
• • Returns:
• • Zero on success, negative error code on failure.
• */

+int tinydrm_spi_transfer(struct spi_device *spi, u32 speed_hz,

• 	 struct spi_transfer *header, u8 bpw, const void *buf,
  

• 	 size_t len)
  

+{

• struct spi_transfer tr = {

• .bits_per_word = bpw,
  

• .speed_hz = speed_hz,
  

• };
• struct spi_message m;
• u16 *swap_buf = NULL;
• size_t max_chunk;
• size_t chunk;
• int ret = 0;
• if (WARN_ON_ONCE(bpw != 8 && bpw != 16))

• return -EINVAL;
  

• max_chunk = tinydrm_spi_max_transfer_size(spi, 0);
• if (drm_debug & DRM_UT_DRIVER)

• pr_debug("[drm:%s] bpw=%u, max_chunk=%zu, transfers:\n",
  

• 	 __func__, bpw, max_chunk);
  

• if (bpw == 16 && !tinydrm_spi_bpw_supported(spi, 16)) {

• tr.bits_per_word = 8;
  

• if (tinydrm_machine_little_endian()) {
  

• 	swap_buf = kmalloc(min(len, max_chunk), GFP_KERNEL);
  

• 	if (!swap_buf)
  

• 		return -ENOMEM;
  

• }
  

• }
• spi_message_init(&m);
• if (header)

• spi_message_add_tail(header, &m);
  

• spi_message_add_tail(&tr, &m);
• while (len) {

• chunk = min(len, max_chunk);
  

• tr.tx_buf = buf;
  

• tr.len = chunk;
  

• if (swap_buf) {
  

• 	const u16 *buf16 = buf;
  

• 	unsigned int i;
  

• 	for (i = 0; i < chunk / 2; i++)
  

• 		swap_buf[i] = swab16(buf16[i]);
  

• 	tr.tx_buf = swap_buf;
  

• }
  

• buf += chunk;
  

• len -= chunk;
  

• tinydrm_dbg_spi_message(spi, &m);
  

• ret = spi_sync(spi, &m);
  

• if (ret)
  

• 	return ret;
  

• };
• return 0;

+} +EXPORT_SYMBOL(tinydrm_spi_transfer);

Similarly for the above.

Thierry