Re: [PATCH v4 06/13] drm/bridge: Add Synopsys DesignWare MIPI DSI host controller driver

On Fri, Nov 20, 2015 at 04:15:32PM +0800, Chris Zhong wrote:

add Synopsys DesignWare MIPI DSI host controller driver support.

Signed-off-by: Chris Zhong zyw@rock-chips.com

Changes in v4: eliminate some warnning

Changes in v3: None Changes in v2: None

drivers/gpu/drm/bridge/Kconfig | 11 + drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/dw_mipi_dsi.c | 1056 ++++++++++++++++++++++++++++++++++ include/drm/bridge/dw_mipi_dsi.h | 27 + 4 files changed, 1095 insertions(+) create mode 100644 drivers/gpu/drm/bridge/dw_mipi_dsi.c create mode 100644 include/drm/bridge/dw_mipi_dsi.h

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index 6dddd39..c0900e0 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -22,6 +22,17 @@ config DRM_DW_HDMI_AHB_AUDIO Designware HDMI block. This is used in conjunction with the i.MX6 HDMI driver.

+config DRM_DW_MIPI_DSI

• tristate "Synopsys DesignWare MIPI DSI host controller bridge"
• depends on DRM
• select DRM_KMS_HELPER
• select DRM_MIPI_DSI
• select DRM_PANEL
• help

•  Choose this if you want to use the Synopsys DesignWare MIPI DSI host
  

•  controller bridge. If M is selected, the module will be
  

•  called dw_mipi_dsi. DRM_MIPI_DSI support is required for this driver
  

•  to work.
  

Just drop the last sentence, it doesn't add value since that's already expressed in the "select DRM_MIPI_DSI" statement.

Also, please use hyphens instead of underscore to separate parts in module names.

diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index d4e28be..d908c4b 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -2,5 +2,6 @@ ccflags-y := -Iinclude/drm

obj-$(CONFIG_DRM_DW_HDMI) += dw_hdmi.o obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw_hdmi-ahb-audio.o +obj-$(CONFIG_DRM_DW_MIPI_DSI) += dw_mipi_dsi.o

Like I said above, this should be dw-mipi-dsi.o. I know dw_hdmi uses the underscores, but that's something I plan on fixing.

obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o diff --git a/drivers/gpu/drm/bridge/dw_mipi_dsi.c b/drivers/gpu/drm/bridge/dw_mipi_dsi.c new file mode 100644 index 0000000..23b612d --- /dev/null +++ b/drivers/gpu/drm/bridge/dw_mipi_dsi.c @@ -0,0 +1,1056 @@ +/*

• • Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd

Does this need to be updated? We're pretty far into 2015 by now.

+struct dw_mipi_dsi {

• struct mipi_dsi_host dsi_host;
• struct drm_connector connector;
• struct drm_encoder *encoder;

struct drm_bridge already has a pointer to an encoder, can't you reuse that instead?

• struct drm_bridge *bridge;

Typically you'd embed the bridge into the driver structure.

• struct drm_panel *panel;
• struct device *dev;
• void __iomem *base;
• struct clk *pllref_clk;
• struct clk *cfg_clk;
• struct clk *pclk;
• unsigned int lane_mbps; /* per lane */
• u32 channel;
• u32 lanes;
• u32 format;
• u16 input_div;
• u16 feedback_div;
• struct drm_display_mode *mode;
• const struct dw_mipi_dsi_plat_data *pdata;
• bool enabled;

+};

+enum {

• STATUS_TO_CLEAR,
• STATUS_TO_SET,

+};

This seems to be used only as replacement for false/true, so you should just use false/true instead and remove these.

+/* The table is based on 27MHz DPHY pll reference clock. */ +static const struct dphy_pll_testdin_map dptdin_map[] = {

• {90, 0x00}, {100, 0x10}, {110, 0x20}, {130, 0x01},
• {140, 0x11}, {150, 0x21}, {170, 0x02}, {180, 0x12},
• {200, 0x22}, {220, 0x03}, {240, 0x13}, {250, 0x23},
• {270, 0x04}, {300, 0x14}, {330, 0x05}, {360, 0x15},
• {400, 0x25}, {450, 0x06}, {500, 0x16}, {550, 0x07},
• {600, 0x17}, {650, 0x08}, {700, 0x18}, {750, 0x09},
• {800, 0x19}, {850, 0x29}, {900, 0x39}, {950, 0x0a},
• {1000, 0x1a}, {1050, 0x2a}, {1100, 0x3a}, {1150, 0x0b},
• {1200, 0x1b}, {1250, 0x2b}, {1300, 0x3b}, {1350, 0x0c},
• {1400, 0x1c}, {1450, 0x2c}, {1500, 0x3c}

+};

Might be worth reformatting this to be more table-like.

+static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val) +{

• writel(val, dsi->base + reg);

+}

+static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg) +{

• return readl(dsi->base + reg);

+}

+static inline void dsi_modify(struct dw_mipi_dsi *dsi, u32 reg,

• 	      u32 mask, u32 val)
  

+{

• u32 v;
• v = readl(dsi->base + reg);
• v &= ~mask;
• v |= val;
• writel(v, dsi->base + reg);

+}

Perhaps reuse dsi_read() and dsi_write() here?

+static int check_status(struct dw_mipi_dsi *dsi, u32 reg, u32 status,

• 	unsigned int timeout, bool to_set)
  

+{

• unsigned long expire;
• bool out;
• u32 val;
• expire = jiffies + msecs_to_jiffies(timeout);
• for (;;) {

• val = dsi_read(dsi, reg);
  

• out = to_set ? ((val & status) == status) : !(val & status);
  

• if (out)
  

• 	break;
  

• if (time_after(jiffies, expire))
  

• 	return -ETIMEDOUT;
  

• cpu_relax();
  

• }
• return 0;

+}

Perhaps use the helpers in linux/iopoll.h?

+/*

• • The controller should generate 2 frames before
• • preparing the peripheral.
• */

+static void dw_mipi_dsi_wait_for_two_frames(struct dw_mipi_dsi *dsi) +{

• unsigned long expire;
• int refresh, two_frames;
• refresh = drm_mode_vrefresh(dsi->mode);
• two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
• expire = jiffies + msecs_to_jiffies(two_frames);
• while (time_before(jiffies, expire))

• cpu_relax();
  

+}

That's kind of rude. You know already how long it will take for two frames to be sent, why not just sleep for that time? usleep_range() or in this case most likely msleep() would be more civil options.

+static void dw_mipi_dsi_phy_test(struct dw_mipi_dsi *dsi, u8 test_code,

• 		 u8 test_data)
  

+{

• dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLK | PHY_UNTESTCLR);
• dsi_write(dsi, DSI_PHY_TST_CTRL1, PHY_TESTEN | PHY_TESTDOUT(0) |

• 			  PHY_TESTDIN(test_code));
  

• dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLK | PHY_UNTESTCLR);
• dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLK | PHY_UNTESTCLR);
• dsi_write(dsi, DSI_PHY_TST_CTRL1, PHY_UNTESTEN | PHY_TESTDOUT(0) |

• 			  PHY_TESTDIN(test_data));
  

• dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLK | PHY_UNTESTCLR);
• dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLK | PHY_UNTESTCLR);

+}

This looks like it's actually programming something, rather than testing. Can you perhaps add a comment to this explaining what exactly it's doing?

+static int dw_mipi_dsi_phy_init(struct dw_mipi_dsi *dsi) +{

• int ret, testdin, vco;
• vco = (dsi->lane_mbps < 200) ? 0 : (dsi->lane_mbps + 100) / 200;
• testdin = max_mbps_to_testdin(dsi->lane_mbps);
• if (testdin < 0) {

• dev_err(dsi->dev,
  

• 	"failed to get testdin for %dmbps lane clock\n",
  

• 	dsi->lane_mbps);
  

• return testdin;
  

• }
• dsi_write(dsi, DSI_PWR_UP, POWERUP);
• dw_mipi_dsi_phy_test(dsi, 0x10, 0x80 | (vco & 0x7) << 3 | 0x3);
• dw_mipi_dsi_phy_test(dsi, 0x11, 0x8);
• dw_mipi_dsi_phy_test(dsi, 0x12, 0xc0);
• dw_mipi_dsi_phy_test(dsi, 0x44, testdin << 1);
• dw_mipi_dsi_phy_test(dsi, 0x17, dsi->input_div - 1);
• dw_mipi_dsi_phy_test(dsi, 0x18, (dsi->feedback_div - 1) & 0x1f);
• dw_mipi_dsi_phy_test(dsi, 0x18, (dsi->feedback_div - 1) >> 5 | 0x80);
• dw_mipi_dsi_phy_test(dsi, 0x19, 0x30);
• dw_mipi_dsi_phy_test(dsi, 0x20, 0x4d);
• dw_mipi_dsi_phy_test(dsi, 0x21, 0x3d);
• dw_mipi_dsi_phy_test(dsi, 0x21, 0xdf);
• dw_mipi_dsi_phy_test(dsi, 0x22, 0x7);
• dw_mipi_dsi_phy_test(dsi, 0x22, 0x87);
• dw_mipi_dsi_phy_test(dsi, 0x70, 0x80 | 0xf);
• dw_mipi_dsi_phy_test(dsi, 0x71, 0x80 | 0x55);
• dw_mipi_dsi_phy_test(dsi, 0x72, 0x40 | 0xa);

Can we have symbolic names for these values?

• dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK

•   | PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
  

I think it's more conventional to put the | on the first line. I also think it'd be more readable to align PHY_UNRSTZ | PHY_UNSHUTDOWNZ with the other values that form this parameter, like so:

dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK | PHY_UNRSTZ | PHY_UNSHUTDOWNZ);

+static int dw_mipi_dsi_get_lane_bps(struct dw_mipi_dsi *dsi) +{

• int bpp, i;

i should be unsigned int.

• unsigned int max_mbps = 0, target_mbps = 1000;
• unsigned long mpclk, pllref, tmp;
• int m = 1, n = 1, pre;

These can be unsigned int as well.

• for (i = 0; i < ARRAY_SIZE(dptdin_map); i++) {

• if (max_mbps < dptdin_map[i].max_mbps)
  

• 	max_mbps = dptdin_map[i].max_mbps;
  

• }

Looks to me like this will always be 1500. Why go through the trouble of looking up the value if you know that the table is sorted by increasing max_mbps? Hard-coding to 1500 isn't very nice either, but you could do something like:

max_mbps = dptdin_map[ARRAY_SIZE(dptdin_map) - 1].max_mbps;

+static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,

• 		   struct mipi_dsi_device *device)
  

+{

• struct dw_mipi_dsi *dsi = host_to_dsi(host);
• if (device->lanes > dsi->pdata->max_data_lanes) {

• dev_err(dsi->dev, "the number of data lanes(%d) is too many\n",
  

Use %u for unsigned integers.

• 		device->lanes);
  

• return -EINVAL;
  

• }
• if (!(device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) ||

•    !(device->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)) {
  

• dev_err(dsi->dev, "device mode is unsupported\n");
  

• return -EINVAL;
  

• }
• dsi->lanes = device->lanes;
• dsi->channel = device->channel;
• dsi->format = device->format;
• dsi->panel = of_drm_find_panel(device->dev.of_node);

You might want to check this for validity?

• drm_panel_attach(dsi->panel, &dsi->connector);

You should check for errors here.

+static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,

• 		       const struct mipi_dsi_msg *msg)
  

+{

• const u16 *tx_buf = msg->tx_buf;
• u32 val = GEN_HDATA(*tx_buf) | GEN_HTYPE(msg->type);
• if (msg->tx_len > 2) {

• dev_err(dsi->dev, "too long tx buf length %d for short write\n",
  

• 	(int)msg->tx_len);
  

No need to cast here. Simply use %zu as the format specifier.

• return -EINVAL;
  

• }
• return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);

+}

+static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,

• 		      const struct mipi_dsi_msg *msg)
  

+{

• const u32 *tx_buf = msg->tx_buf;
• int len = msg->tx_len, pld_data_bytes = sizeof(*tx_buf), ret;
• u32 val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
• u32 remainder = 0;
• if (msg->tx_len < 3) {

• dev_err(dsi->dev, "wrong tx buf length %d for long write\n",
  

• 	(int)msg->tx_len);
  

Same here.

+static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge) +{

• struct dw_mipi_dsi *dsi = bridge->driver_private;
• if (dsi->enabled)

• return;
  

• if (!IS_ERR(dsi->cfg_clk))

• clk_prepare_enable(dsi->cfg_clk);
  

• clk_prepare_enable(dsi->pclk);

Please always error-check clk_prepare() and clk_enable() (or the combination clk_prepare_enable()). They can fail.

• dw_mipi_dsi_phy_init(dsi);
• dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
• dw_mipi_dsi_wait_for_two_frames(dsi);
• dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
• drm_panel_prepare(dsi->panel);
• dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
• clk_disable_unprepare(dsi->pclk);
• if (!IS_ERR(dsi->cfg_clk))

• clk_disable_unprepare(dsi->cfg_clk);
  

• drm_panel_enable(dsi->panel);
• dsi->enabled = true;

+}

+static void dw_mipi_dsi_bridge_disable(struct drm_bridge *bridge) +{

• struct dw_mipi_dsi *dsi = bridge->driver_private;
• unsigned long expire;
• if (!dsi->enabled)

• return;
  

• drm_panel_disable(dsi->panel);
• if (!IS_ERR(dsi->cfg_clk))

• clk_prepare_enable(dsi->cfg_clk);
  

• clk_prepare_enable(dsi->pclk);
• dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
• drm_panel_unprepare(dsi->panel);
• dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
• /*

• * This is necessary to make sure the peripheral
  

• * will be driven normally when the display is
  

• * enabled again later.
  

• */
  

You can use longer lines for comments. No need to split it across three lines if you can make it fit on two.

• expire = jiffies + msecs_to_jiffies(120);
• while (time_before(jiffies, expire))

• cpu_relax();
  

Again, cpu_relax() isn't really relaxing the CPU to the extent that it might lead you to think. If you know you want to sleep for 120 ms, just do msleep(120).

• dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
• dw_mipi_dsi_disable(dsi);
• clk_disable_unprepare(dsi->pclk);
• if (!IS_ERR(dsi->cfg_clk))

• clk_disable_unprepare(dsi->cfg_clk);
  

• dsi->enabled = false;

+}

+static void dw_mipi_dsi_bridge_nope(struct drm_bridge *bridge)

Hehe, perhaps dw_mipi_dsi_bridge_nop()? Or simply leave the function pointers NULL, but I guess you had to add this because the DRM bridge infrastructure doesn't allow these to be optional. We might want to change that.

+{

• /* do nothing */

+}

+static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi) +{

• dsi_write(dsi, DSI_PWR_UP, RESET);
• dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK

•   | PHY_RSTZ | PHY_SHUTDOWNZ);
  

• dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |

•   TX_ESC_CLK_DIVIDSION(7));
  

• dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);

+}

+static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,

• 		   struct drm_display_mode *mode)
  

+{

• u32 val = 0, calor = 0;

"color"?

+static void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,

• 			struct drm_display_mode *mode,
  

• 			struct drm_display_mode *adjusted_mode)
  

+{

• struct dw_mipi_dsi *dsi = bridge->driver_private;
• int ret;
• dsi->mode = adjusted_mode;
• ret = dw_mipi_dsi_get_lane_bps(dsi);
• if (ret < 0)

• return;
  

• if (!IS_ERR(dsi->cfg_clk))

• clk_prepare_enable(dsi->cfg_clk);
  

• clk_prepare_enable(dsi->pclk);

Again, check errors from clk_prepare_enable(), ...

• dw_mipi_dsi_init(dsi);
• dw_mipi_dsi_dpi_config(dsi, mode);
• dw_mipi_dsi_packet_handler_config(dsi);
• dw_mipi_dsi_video_mode_config(dsi);
• dw_mipi_dsi_video_packet_config(dsi, mode);
• dw_mipi_dsi_command_mode_config(dsi);
• dw_mipi_dsi_line_timer_config(dsi);
• dw_mipi_dsi_vertical_timing_config(dsi);
• dw_mipi_dsi_dphy_timing_config(dsi);
• dw_mipi_dsi_dphy_interface_config(dsi);
• dw_mipi_dsi_clear_err(dsi);
• dw_mipi_dsi_phy_init(dsi);
• dw_mipi_dsi_wait_for_two_frames(dsi);
• drm_panel_prepare(dsi->panel);

... and drm_panel_prepare().

+static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {

static const, please.

+int dw_mipi_dsi_bind(struct device *dev, struct device *master, void *data,

•      struct drm_encoder *encoder,
  

•      const struct dw_mipi_dsi_plat_data *pdata)
  

+{

[...]

• dsi->cfg_clk = devm_clk_get(dev, "cfg");
• if (IS_ERR(dsi->cfg_clk))

• dev_warn(dev, "Have no configuration clock\n");
  

Is this truly optional?

• dsi->pclk = devm_clk_get(dev, "pclk");
• if (IS_ERR(dsi->pclk)) {

• ret = PTR_ERR(dsi->pclk);
  

• dev_err(dev, "Unable to get configuration clock: %d\n", ret);
  

pclk doesn't seem to be a "configuration clock".

• dev_info(dev, "version number is 0x%08x\n", val);

Do you really need this information? What purpose does it serve to have this in the kernel log?

diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h new file mode 100644 index 0000000..2e351e4 --- /dev/null +++ b/include/drm/bridge/dw_mipi_dsi.h @@ -0,0 +1,27 @@ +/*

• • Copyright (C) 2014-2015 Freescale Semiconductor, Inc.
• • 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.
• */

+#ifndef __DW_MIPI_DSI__ +#define __DW_MIPI_DSI__

+#include <drm/drmP.h>

+struct dw_mipi_dsi_plat_data {

• unsigned int max_data_lanes;
• enum drm_mode_status (*mode_valid)(struct drm_connector *connector,

• 			   struct drm_display_mode *mode);
  

+};

+int dw_mipi_dsi_get_encoder_pixel_format(struct drm_encoder *encoder);

+int dw_mipi_dsi_bind(struct device *dev, struct device *master,

•      void *data, struct drm_encoder *encoder,
  

•      const struct dw_mipi_dsi_plat_data *pdata);
  

+void dw_mipi_dsi_unbind(struct device *dev, struct device *master, void *data); +#endif /* __DW_MIPI_DSI__ */

Should have a blank line between the two above.

Thierry