[PATCH v3 6/6] drm/stm: Add STM32 DSI host driver
Neil Armstrong
narmstrong at baylibre.com
Tue Jun 6 01:11:16 PDT 2017
Hi Philippe,
On 06/02/2017 04:37 PM, Philippe CORNU wrote:
> Add the STM32 DSI host driver that uses the Synopsys DesignWare
> MIPI DSI DRM bridge.
>
> Signed-off-by: Philippe CORNU <philippe.cornu at st.com>
> ---
> drivers/gpu/drm/stm/Kconfig | 8 +
> drivers/gpu/drm/stm/Makefile | 2 +
> drivers/gpu/drm/stm/dw_mipi_dsi-stm.c | 353 ++++++++++++++++++++++++++++++++++
> 3 files changed, 363 insertions(+)
> create mode 100644 drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
>
> diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
> index 4b88223..4c0d670 100644
> --- a/drivers/gpu/drm/stm/Kconfig
> +++ b/drivers/gpu/drm/stm/Kconfig
> @@ -14,3 +14,11 @@ config DRM_STM
> STMicroelectronics STM32 MCUs.
> To compile this driver as a module, choose M here: the module
> will be called stm-drm.
> +
> +config DRM_STM_DSI
> + tristate "STMicroelectronics specific extensions for Synopsys MIPI DSI"
> + depends on DRM_STM
> + select DRM_MIPI_DSI
> + select DRM_DW_MIPI_DSI
> + help
> + Choose this option for MIPI DSI support on STMicroelectronics SoC.
> diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
> index a09ecf4..d883adc 100644
> --- a/drivers/gpu/drm/stm/Makefile
> +++ b/drivers/gpu/drm/stm/Makefile
> @@ -2,4 +2,6 @@ stm-drm-y := \
> drv.o \
> ltdc.o
>
> +obj-$(CONFIG_DRM_STM_DSI) += dw_mipi_dsi-stm.o
> +
> obj-$(CONFIG_DRM_STM) += stm-drm.o
> diff --git a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> new file mode 100644
> index 0000000..8dedc5c
> --- /dev/null
> +++ b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> @@ -0,0 +1,353 @@
> +/*
> + * Copyright (C) STMicroelectronics SA 2017
> + *
> + * Authors: Philippe Cornu <philippe.cornu at st.com>
> + * Yannick Fertre <yannick.fertre at st.com>
> + *
> + * License terms: GNU General Public License (GPL), version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/iopoll.h>
> +#include <linux/math64.h>
> +#include <linux/module.h>
> +#include <drm/drmP.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/bridge/dw_mipi_dsi.h>
> +#include <video/mipi_display.h>
> +
> +/* DSI wrapper register & 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
> +
> +/* Sleep & timeout for regulator on/off, pll lock/unlock & fifo empty */
> +#define SLEEP_US 1000
> +#define TIMEOUT_US 200000
> +
> +struct dw_mipi_dsi_stm {
> + void __iomem *base;
> + struct clk *pllref_clk;
> +};
> +
> +static inline void dsi_write(struct dw_mipi_dsi_stm *dsi, u32 reg, u32 val)
> +{
> + writel_relaxed(val, dsi->base + reg);
> +}
> +
> +static inline u32 dsi_read(struct dw_mipi_dsi_stm *dsi, u32 reg)
> +{
> + return readl_relaxed(dsi->base + reg);
> +}
> +
> +static inline void dsi_set(struct dw_mipi_dsi_stm *dsi, u32 reg, u32 mask)
> +{
> + dsi_write(dsi, reg, dsi_read(dsi, reg) | mask);
> +}
> +
> +static inline void dsi_clear(struct dw_mipi_dsi_stm *dsi, u32 reg, u32 mask)
> +{
> + dsi_write(dsi, reg, dsi_read(dsi, reg) & ~mask);
> +}
> +
> +static inline void dsi_update_bits(struct dw_mipi_dsi_stm *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(enum mipi_dsi_pixel_format 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:
> + DRM_DEBUG_DRIVER("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)
> +{
> + /* prevent from division by 0 */
> + if (idf * odf)
> + return DIV_ROUND_CLOSEST(clkin_khz * ndiv, idf * odf);
> +
> + return 0;
> +}
> +
> +static int dsi_pll_get_params(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 = LANE_MIN_KBPS * 2 * ODF_MAX;
> + fvco_max = 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 dw_mipi_dsi_phy_init(void *priv_data)
> +{
> + struct dw_mipi_dsi_stm *dsi = priv_data;
> + 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,
> + SLEEP_US, TIMEOUT_US);
> + if (ret)
> + DRM_DEBUG_DRIVER("!TIMEOUT! waiting REGU, let's continue\n");
> +
> + /* 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,
> + SLEEP_US, TIMEOUT_US);
> + if (ret)
> + DRM_DEBUG_DRIVER("!TIMEOUT! waiting PLL, let's continue\n");
> +
> + /* Enable the DSI wrapper */
> + dsi_set(dsi, DSI_WCR, WCR_DSIEN);
> +
> + return 0;
> +}
> +
> +static int
> +dw_mipi_dsi_get_lane_mbps(void *priv_data, struct drm_display_mode *mode,
> + unsigned long mode_flags, u32 lanes, u32 format,
> + unsigned int *lane_mbps)
> +{
> + struct dw_mipi_dsi_stm *dsi = priv_data;
> + unsigned int idf, ndiv, odf, pll_in_khz, pll_out_khz;
> + int ret, bpp;
> + u32 val;
> +
> + pll_in_khz = (unsigned int)(clk_get_rate(dsi->pllref_clk) / 1000);
> +
> + /* Compute requested pll out */
> + bpp = mipi_dsi_pixel_format_to_bpp(format);
> + pll_out_khz = mode->clock * 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 > LANE_MAX_KBPS) {
> + pll_out_khz = LANE_MAX_KBPS;
> + DRM_DEBUG_DRIVER("Warning max phy mbps is used\n");
> + }
> + if (pll_out_khz < LANE_MIN_KBPS) {
> + pll_out_khz = LANE_MIN_KBPS;
> + DRM_DEBUG_DRIVER("Warning min phy mbps is used\n");
> + }
> +
> + /* Compute best pll parameters */
> + ret = dsi_pll_get_params(pll_in_khz, pll_out_khz, &idf, &ndiv, &odf);
> + if (ret)
> + DRM_DEBUG_DRIVER("Warning dsi_pll_get_params(): bad params\n");
> +
> + /* 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;
> +
> + DRM_DEBUG_DRIVER("pll_in %ukHz pll_out %ukHz lane_mbps %uMHz\n",
> + pll_in_khz, pll_out_khz, *lane_mbps);
> +
> + return 0;
> +}
> +
> +static struct dw_mipi_dsi_phy_ops dw_mipi_dsi_stm_phy_ops = {
> + .init = dw_mipi_dsi_phy_init,
> + .get_lane_mbps = dw_mipi_dsi_get_lane_mbps,
> +};
> +
> +static struct dw_mipi_dsi_plat_data dw_mipi_dsi_stm_plat_data = {
> + .max_data_lanes = 2,
> + .phy_ops = &dw_mipi_dsi_stm_phy_ops,
> +};
> +
> +static const struct of_device_id dw_mipi_dsi_stm_dt_ids[] = {
> + {
> + .compatible = "st,stm32-dsi",
> + .data = &dw_mipi_dsi_stm_plat_data,
Alignement is weird here !
> + },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, dw_mipi_dsi_stm_dt_ids);
> +
> +static int dw_mipi_dsi_stm_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct dw_mipi_dsi_stm *dsi;
> + struct resource *res;
> + int ret;
> +
> + dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> + if (!dsi)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + DRM_ERROR("Unable to get resource\n");
> + return -ENODEV;
> + }
> +
> + dsi->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(dsi->base)) {
> + DRM_ERROR("Unable to get dsi registers\n");
> + return PTR_ERR(dsi->base);
> + }
> +
> + dsi->pllref_clk = devm_clk_get(dev, "ref");
> + if (IS_ERR(dsi->pllref_clk)) {
> + ret = PTR_ERR(dsi->pllref_clk);
> + dev_err(dev, "Unable to get pll reference clock: %d\n", ret);
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(dsi->pllref_clk);
> + if (ret) {
> + dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);
> + return ret;
> + }
> +
> + dw_mipi_dsi_stm_plat_data.base = dsi->base;
> + dw_mipi_dsi_stm_plat_data.priv_data = dsi;
> +
> + ret = dw_mipi_dsi_probe(pdev, &dw_mipi_dsi_stm_plat_data);
> + if (ret) {
> + DRM_ERROR("Failed to initialize mipi dsi host\n");
> + clk_disable_unprepare(dsi->pllref_clk);
> + }
> +
> + return ret;
> +}
> +
> +static int dw_mipi_dsi_stm_remove(struct platform_device *pdev)
> +{
> + struct dw_mipi_dsi_stm *dsi = dw_mipi_dsi_stm_plat_data.priv_data;
> +
> + clk_disable_unprepare(dsi->pllref_clk);
> + dw_mipi_dsi_remove(pdev);
> +
> + return 0;
> +}
> +
> +static struct platform_driver dw_mipi_dsi_stm_driver = {
> + .probe = dw_mipi_dsi_stm_probe,
> + .remove = dw_mipi_dsi_stm_remove,
> + .driver = {
> + .of_match_table = dw_mipi_dsi_stm_dt_ids,
> + .name = "dw_mipi_dsi-stm",
> + },
> +};
> +
> +module_platform_driver(dw_mipi_dsi_stm_driver);
> +
> +MODULE_AUTHOR("Philippe Cornu <philippe.cornu at st.com>");
> +MODULE_AUTHOR("Yannick Fertre <yannick.fertre at st.com>");
> +MODULE_DESCRIPTION("STMicroelectronics DW MIPI DSI host controller driver");
> +MODULE_LICENSE("GPL v2");
>
A part from this small nit,
Reviewed-by: Neil Armstrong <narmstrong at baylibre.com>
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