Re: [PATCH v2 06/10] video: add support of STM32 MIPI DSI controller driver

[Patrice CHOTARD <patrice.chotard@st.com>]

Hi yannick

On 03/02/2018 04:44 PM, yannick fertre wrote:
> Add the STM32 DSI controller driver that uses the Synopsys DesignWare
> MIPI DSI host controller bridge.
> 
> Signed-off-by: yannick fertre <yannick.fertre@st.com>
> ---
>   drivers/video/stm32/Kconfig     |  10 +
>   drivers/video/stm32/Makefile    |   1 +
>   drivers/video/stm32/stm32_dsi.c | 427 ++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 438 insertions(+)
>   create mode 100644 drivers/video/stm32/stm32_dsi.c
> 
> diff --git a/drivers/video/stm32/Kconfig b/drivers/video/stm32/Kconfig
> index 113a2bb..2ea6f18 100644
> --- a/drivers/video/stm32/Kconfig
> +++ b/drivers/video/stm32/Kconfig
> @@ -15,6 +15,16 @@ menuconfig VIDEO_STM32
>   	  DSI. This option enables these supports which can be used on
>   	  devices which have RGB TFT or DSI display connected.
>   
> +config VIDEO_STM32_DSI
> +	bool "Enable STM32 DSI video support"
> +	depends on VIDEO_STM32
> +	select VIDEO_MIPI_DSI
> +	select VIDEO_BRIDGE
> +	select VIDEO_DW_MIPI_DSI
> +	help
> +	  This option enables support DSI internal bridge which can be used on
> +	  devices which have DSI display connected.
> +
>   config VIDEO_STM32_MAX_XRES
>   	int "Maximum horizontal resolution (for memory allocation purposes)"
>   	depends on VIDEO_STM32
> diff --git a/drivers/video/stm32/Makefile b/drivers/video/stm32/Makefile
> index 372a2e1..f8c3ff7 100644
> --- a/drivers/video/stm32/Makefile
> +++ b/drivers/video/stm32/Makefile
> @@ -8,3 +8,4 @@
>   #
>   
>   obj-${CONFIG_VIDEO_STM32} = stm32_ltdc.o
> +obj-${CONFIG_VIDEO_STM32_DSI} += stm32_dsi.o
> diff --git a/drivers/video/stm32/stm32_dsi.c b/drivers/video/stm32/stm32_dsi.c
> new file mode 100644
> index 0000000..3e26433
> --- /dev/null
> +++ b/drivers/video/stm32/stm32_dsi.c
> @@ -0,0 +1,427 @@
> +/*
> + * Copyright (C) 2018 STMicroelectronics - All Rights Reserved
> + * Author(s): Philippe Cornu <philippe.cornu@st.com> for STMicroelectronics.
> + *	      Yannick Fertre <yannick.fertre@st.com> for STMicroelectronics.
> + *
> + * This driver is based on the mipi dsi driver from
> + * drivers/gpu/drm/stm/dw_mipi_dsi-stm.c (kernel linux).
> + *
> + * SPDX-License-Identifier: GPL-2.0
> + */
> +
> +#include <asm/io.h>
> +#include <asm/arch/gpio.h>
> +#include <common.h>
> +#include <clk.h>
> +#include <dm.h>
> +#include <dm/device-internal.h>
> +#include <mipi_display.h>
> +#include <dw_mipi_dsi.h>
> +#include <linux/iopoll.h>
> +#include <panel.h>
> +#include <reset.h>
> +#include <video.h>
> +#include <video_bridge.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +#define HWVER_130			0x31333000	/* IP version 1.30 */
> +#define HWVER_131			0x31333100	/* IP version 1.31 */
> +
> +/* DSI digital registers & bit definitions */
> +#define DSI_VERSION			0x00
> +#define VERSION				GENMASK(31, 8)
> +
> +/*
> + * DSI wrapper registers & bit definitions
> + * Note: registers are named as in the Reference Manual
> + */
> +#define DSI_WCFGR	0x0400		/* Wrapper ConFiGuration Reg */
> +#define WCFGR_DSIM	BIT(0)		/* DSI Mode */
> +#define WCFGR_COLMUX	GENMASK(3, 1)	/* COLor MUltipleXing */
> +
> +#define DSI_WCR		0x0404		/* Wrapper Control Reg */
> +#define WCR_DSIEN	BIT(3)		/* DSI ENable */
> +
> +#define DSI_WISR	0x040C		/* Wrapper Interrupt and Status Reg */
> +#define WISR_PLLLS	BIT(8)		/* PLL Lock Status */
> +#define WISR_RRS	BIT(12)		/* Regulator Ready Status */
> +
> +#define DSI_WPCR0	0x0418		/* Wrapper Phy Conf Reg 0 */
> +#define WPCR0_UIX4	GENMASK(5, 0)	/* Unit Interval X 4 */
> +#define WPCR0_TDDL	BIT(16)		/* Turn Disable Data Lanes */
> +
> +#define DSI_WRPCR	0x0430		/* Wrapper Regulator & Pll Ctrl Reg */
> +#define WRPCR_PLLEN	BIT(0)		/* PLL ENable */
> +#define WRPCR_NDIV	GENMASK(8, 2)	/* pll loop DIVision Factor */
> +#define WRPCR_IDF	GENMASK(14, 11)	/* pll Input Division Factor */
> +#define WRPCR_ODF	GENMASK(17, 16)	/* pll Output Division Factor */
> +#define WRPCR_REGEN	BIT(24)		/* REGulator ENable */
> +#define WRPCR_BGREN	BIT(28)		/* BandGap Reference ENable */
> +#define IDF_MIN		1
> +#define IDF_MAX		7
> +#define NDIV_MIN	10
> +#define NDIV_MAX	125
> +#define ODF_MIN		1
> +#define ODF_MAX		8
> +
> +/* dsi color format coding according to the datasheet */
> +enum dsi_color {
> +	DSI_RGB565_CONF1,
> +	DSI_RGB565_CONF2,
> +	DSI_RGB565_CONF3,
> +	DSI_RGB666_CONF1,
> +	DSI_RGB666_CONF2,
> +	DSI_RGB888,
> +};
> +
> +#define LANE_MIN_KBPS	31250
> +#define LANE_MAX_KBPS	500000
> +
> +/* Timeout for regulator on/off, pll lock/unlock & fifo empty */
> +#define TIMEOUT_US	200000
> +
> +struct stm32_dsi_priv {
> +	struct mipi_dsi_device device;
> +	void __iomem *base;
> +	struct udevice *panel;
> +	u32 pllref_clk;
> +	u32 hw_version;
> +	int lane_min_kbps;
> +	int lane_max_kbps;
> +};
> +
> +static inline void dsi_write(struct stm32_dsi_priv *dsi, u32 reg, u32 val)
> +{
> +	writel(val, dsi->base + reg);
> +}
> +
> +static inline u32 dsi_read(struct stm32_dsi_priv *dsi, u32 reg)
> +{
> +	return readl(dsi->base + reg);
> +}
> +
> +static inline void dsi_set(struct stm32_dsi_priv *dsi, u32 reg, u32 mask)
> +{
> +	dsi_write(dsi, reg, dsi_read(dsi, reg) | mask);
> +}
> +
> +static inline void dsi_clear(struct stm32_dsi_priv *dsi, u32 reg, u32 mask)
> +{
> +	dsi_write(dsi, reg, dsi_read(dsi, reg) & ~mask);
> +}
> +
> +static inline void dsi_update_bits(struct stm32_dsi_priv *dsi, u32 reg,
> +				   u32 mask, u32 val)
> +{
> +	dsi_write(dsi, reg, (dsi_read(dsi, reg) & ~mask) | val);
> +}
> +
> +static enum dsi_color dsi_color_from_mipi(u32 fmt)
> +{
> +	switch (fmt) {
> +	case MIPI_DSI_FMT_RGB888:
> +		return DSI_RGB888;
> +	case MIPI_DSI_FMT_RGB666:
> +		return DSI_RGB666_CONF2;
> +	case MIPI_DSI_FMT_RGB666_PACKED:
> +		return DSI_RGB666_CONF1;
> +	case MIPI_DSI_FMT_RGB565:
> +		return DSI_RGB565_CONF1;
> +	default:
> +		pr_err("MIPI color invalid, so we use rgb888\n");
> +	}
> +	return DSI_RGB888;
> +}
> +
> +static int dsi_pll_get_clkout_khz(int clkin_khz, int idf, int ndiv, int odf)
> +{
> +	int divisor = idf * odf;
> +
> +	/* prevent from division by 0 */
> +	if (!divisor)
> +		return 0;
> +
> +	return DIV_ROUND_CLOSEST(clkin_khz * ndiv, divisor);
> +}
> +
> +static int dsi_pll_get_params(struct stm32_dsi_priv *dsi,
> +			      int clkin_khz, int clkout_khz,
> +			      int *idf, int *ndiv, int *odf)
> +{
> +	int i, o, n, n_min, n_max;
> +	int fvco_min, fvco_max, delta, best_delta; /* all in khz */
> +
> +	/* Early checks preventing division by 0 & odd results */
> +	if (clkin_khz <= 0 || clkout_khz <= 0)
> +		return -EINVAL;
> +
> +	fvco_min = dsi->lane_min_kbps * 2 * ODF_MAX;
> +	fvco_max = dsi->lane_max_kbps * 2 * ODF_MIN;
> +
> +	best_delta = 1000000; /* big started value (1000000khz) */
> +
> +	for (i = IDF_MIN; i <= IDF_MAX; i++) {
> +		/* Compute ndiv range according to Fvco */
> +		n_min = ((fvco_min * i) / (2 * clkin_khz)) + 1;
> +		n_max = (fvco_max * i) / (2 * clkin_khz);
> +
> +		/* No need to continue idf loop if we reach ndiv max */
> +		if (n_min >= NDIV_MAX)
> +			break;
> +
> +		/* Clamp ndiv to valid values */
> +		if (n_min < NDIV_MIN)
> +			n_min = NDIV_MIN;
> +		if (n_max > NDIV_MAX)
> +			n_max = NDIV_MAX;
> +
> +		for (o = ODF_MIN; o <= ODF_MAX; o *= 2) {
> +			n = DIV_ROUND_CLOSEST(i * o * clkout_khz, clkin_khz);
> +			/* Check ndiv according to vco range */
> +			if (n < n_min || n > n_max)
> +				continue;
> +			/* Check if new delta is better & saves parameters */
> +			delta = dsi_pll_get_clkout_khz(clkin_khz, i, n, o) -
> +				clkout_khz;
> +			if (delta < 0)
> +				delta = -delta;
> +			if (delta < best_delta) {
> +				*idf = i;
> +				*ndiv = n;
> +				*odf = o;
> +				best_delta = delta;
> +			}
> +			/* fast return in case of "perfect result" */
> +			if (!delta)
> +				return 0;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int dsi_phy_init(void *priv_data)
> +{
> +	struct mipi_dsi_device *device = priv_data;
> +	struct stm32_dsi_priv *dsi = dev_get_priv(device->dev);
> +	u32 val;
> +	int ret;
> +
> +	/* Enable the regulator */
> +	dsi_set(dsi, DSI_WRPCR, WRPCR_REGEN | WRPCR_BGREN);
> +	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_RRS,
> +				 TIMEOUT_US);
> +	if (ret) {
> +		pr_err("!TIMEOUT! waiting REGU\n");

dev_err()

> +		return ret;
> +	}
> +
> +	/* Enable the DSI PLL & wait for its lock */
> +	dsi_set(dsi, DSI_WRPCR, WRPCR_PLLEN);
> +	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_PLLLS,
> +				 TIMEOUT_US);
> +	if (ret) {
> +		pr_err("!TIMEOUT! waiting PLL\n");

dev_err()

> +		return ret;
> +	}
> +
> +	/* Enable the DSI wrapper */
> +	dsi_set(dsi, DSI_WCR, WCR_DSIEN);
> +
> +	return 0;
> +}
> +
> +static int dsi_get_lane_mbps(void *priv_data, struct display_timing *timings,
> +			     u32 lanes, u32 format, unsigned int *lane_mbps)
> +{
> +	struct mipi_dsi_device *device = priv_data;
> +	struct stm32_dsi_priv *dsi = dev_get_priv(device->dev);
> +	int idf, ndiv, odf, pll_in_khz, pll_out_khz;
> +	int ret, bpp;
> +	u32 val;
> +
> +	/* Update lane capabilities according to hw version */
> +	dsi->hw_version = dsi_read(dsi, DSI_VERSION) & VERSION;
> +	dsi->lane_min_kbps = LANE_MIN_KBPS;
> +	dsi->lane_max_kbps = LANE_MAX_KBPS;
> +	if (dsi->hw_version == HWVER_131) {
> +		dsi->lane_min_kbps *= 2;
> +		dsi->lane_max_kbps *= 2;
> +	}
> +
> +	pll_in_khz = dsi->pllref_clk / 1000;
> +
> +	/* Compute requested pll out */
> +	bpp = mipi_dsi_pixel_format_to_bpp(format);
> +	pll_out_khz = (timings->pixelclock.typ / 1000) * bpp / lanes;
> +	/* Add 20% to pll out to be higher than pixel bw (burst mode only) */
> +	pll_out_khz = (pll_out_khz * 12) / 10;
> +	if (pll_out_khz > dsi->lane_max_kbps) {
> +		pll_out_khz = dsi->lane_max_kbps;
> +		pr_warn("Warning max phy mbps is used\n");
> +	}
> +	if (pll_out_khz < dsi->lane_min_kbps) {
> +		pll_out_khz = dsi->lane_min_kbps;
> +		pr_warn("Warning min phy mbps is used\n");
> +	}
> +
> +	/* Compute best pll parameters */
> +	idf = 0;
> +	ndiv = 0;
> +	odf = 0;
> +	ret = dsi_pll_get_params(dsi, pll_in_khz, pll_out_khz,
> +				 &idf, &ndiv, &odf);
> +	if (ret) {
> +		pr_warn("Warning dsi_pll_get_params(): bad params\n");

dev_warn() or dev_err() ?

> +		return ret;
> +	}
> +
> +	/* Get the adjusted pll out value */
> +	pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
> +
> +	/* Set the PLL division factors */
> +	dsi_update_bits(dsi, DSI_WRPCR,	WRPCR_NDIV | WRPCR_IDF | WRPCR_ODF,
> +			(ndiv << 2) | (idf << 11) | ((ffs(odf) - 1) << 16));
> +
> +	/* Compute uix4 & set the bit period in high-speed mode */
> +	val = 4000000 / pll_out_khz;
> +	dsi_update_bits(dsi, DSI_WPCR0, WPCR0_UIX4, val);
> +
> +	/* Select video mode by resetting DSIM bit */
> +	dsi_clear(dsi, DSI_WCFGR, WCFGR_DSIM);
> +
> +	/* Select the color coding */
> +	dsi_update_bits(dsi, DSI_WCFGR, WCFGR_COLMUX,
> +			dsi_color_from_mipi(format) << 1);
> +
> +	*lane_mbps = pll_out_khz / 1000;
> +
> +	pr_info("pll_in %ukHz pll_out %ukHz lane_mbps %uMHz\n",
> +		pll_in_khz, pll_out_khz, *lane_mbps);

is it useful to print this each time ? or is it for debug purpose ? in 
this case use debug()

> +
> +	return 0;
> +}
> +
> +static const struct dw_mipi_dsi_phy_ops dw_mipi_dsi_stm_phy_ops = {
> +	.init = dsi_phy_init,
> +	.get_lane_mbps = dsi_get_lane_mbps,
> +};
> +
> +static int stm32_dsi_attach(struct udevice *dev)
> +{
> +	struct stm32_dsi_priv *priv = dev_get_priv(dev);
> +	struct dw_mipi_dsi_plat_data *platdata = dev_get_platdata(dev);
> +	struct mipi_dsi_device *device = &priv->device;
> +	int ret;
> +
> +	platdata->max_data_lanes = 2;
> +	platdata->phy_ops = &dw_mipi_dsi_stm_phy_ops;
> +
> +	ret = uclass_first_device(UCLASS_PANEL, &platdata->panel);
> +	if (ret) {
> +		pr_err("%s: panel device error %d\n", __func__, ret);

dev_err()

> +		return ret;
> +	}
> +
> +	ret = dw_mipi_dsi_init_bridge(device);
> +	if (ret) {
> +		pr_err("Failed to initialize mipi dsi host\n");

ditto

> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int stm32_dsi_set_backlight(struct udevice *dev, int percent)
> +{
> +	struct dw_mipi_dsi_plat_data *dplat = dev_get_platdata(dev);
> +	struct stm32_dsi_priv *priv = dev_get_priv(dev);
> +	struct mipi_dsi_device *device = &priv->device;
> +	struct udevice *panel = dplat->panel;
> +	struct mipi_dsi_panel_plat *mplat;
> +	int ret;
> +
> +	mplat = dev_get_platdata(panel);
> +	mplat->device = device;
> +
> +	ret = panel_enable_backlight(panel);
> +	if (ret) {
> +		pr_err("%s: panel %s enable backlight error %d\n",
> +		       __func__, panel->name, ret);

ditto

> +		return ret;
> +	}
> +
> +	dw_mipi_dsi_bridge_enable(device);
> +
> +	return 0;
> +}
> +
> +static int stm32_dsi_probe(struct udevice *dev)
> +{
> +	struct stm32_dsi_priv *priv = dev_get_priv(dev);
> +	struct mipi_dsi_device *device = &priv->device;
> +	struct reset_ctl rst;
> +	struct clk clk;
> +	int ret;
> +
> +	device->dev = dev;
> +
> +	priv->base = (void *)dev_read_addr(dev);
> +	if ((fdt_addr_t)priv->base == FDT_ADDR_T_NONE) {
> +		pr_err("%s: dsi dt register address error\n", __func__);

ditto

> +		return -EINVAL;
> +	}
> +
> +	ret = clk_get_by_name(device->dev, "pclk", &clk);
> +	if (ret) {
> +		pr_err("%s: peripheral clock get error %d\n", __func__, ret);

ditto

> +		return -ENODEV;
> +	}
> +
> +	ret = clk_enable(&clk);
> +	if (ret) {
> +		pr_err("%s: peripheral clock enable error %d\n", __func__, ret);

ditto

> +		return -ENODEV;
> +	}
> +
> +	ret = clk_get_by_name(dev, "ref", &clk);
> +	if (ret) {
> +		pr_err("%s: pll reference clock get error %d\n", __func__, ret);

ditto

> +		return ret;
> +	}
> +
> +	priv->pllref_clk = (unsigned int)clk_get_rate(&clk);
> +
> +	ret = reset_get_by_index(device->dev, 0, &rst);
> +	if (ret) {
> +		pr_err("%s: missing dsi hardware reset\n", __func__);

ditto

> +		return -ENODEV;
> +	}
> +
> +	/* Reset */
> +	reset_deassert(&rst);
> +
> +	return 0;
> +}
> +
> +struct video_bridge_ops stm32_dsi_ops = {
> +	.attach = stm32_dsi_attach,
> +	.set_backlight = stm32_dsi_set_backlight,
> +};
> +
> +static const struct udevice_id stm32_dsi_ids[] = {
> +	{ .compatible = "st,stm32-dsi"},
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(stm32_dsi) = {
> +	.name				= "stm32-display-dsi",
> +	.id				= UCLASS_VIDEO_BRIDGE,
> +	.of_match			= stm32_dsi_ids,
> +	.bind				= dm_scan_fdt_dev,
> +	.probe				= stm32_dsi_probe,
> +	.ops				= &stm32_dsi_ops,
> +	.priv_auto_alloc_size		= sizeof(struct stm32_dsi_priv),
> +	.platdata_auto_alloc_size	= sizeof(struct dw_mipi_dsi_plat_data),
> +};
>