[PATCH v4 6/6] drm/stm: Add STM32 DSI host driver
Philippe CORNU
philippe.cornu at st.com
Mon Jun 19 16:28:05 UTC 2017
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>
Reviewed-by: Neil Armstrong <narmstrong at baylibre.com>
---
drivers/gpu/drm/stm/Kconfig | 7 +
drivers/gpu/drm/stm/Makefile | 2 +
drivers/gpu/drm/stm/dw_mipi_dsi-stm.c | 352 ++++++++++++++++++++++++++++++++++
3 files changed, 361 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..f9462bc 100644
--- a/drivers/gpu/drm/stm/Kconfig
+++ b/drivers/gpu/drm/stm/Kconfig
@@ -14,3 +14,10 @@ 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_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..16ae00e
--- /dev/null
+++ b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
@@ -0,0 +1,352 @@
+/*
+ * 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/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(val, dsi->base + reg);
+}
+
+static inline u32 dsi_read(struct dw_mipi_dsi_stm *dsi, u32 reg)
+{
+ return readl(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_WARN("Warning max phy mbps is used\n");
+ }
+ if (pll_out_khz < LANE_MIN_KBPS) {
+ pll_out_khz = LANE_MIN_KBPS;
+ DRM_WARN("Warning min phy mbps is used\n");
+ }
+
+ /* Compute best pll parameters */
+ idf = 0;
+ ndiv = 0;
+ odf = 0;
+ ret = dsi_pll_get_params(pll_in_khz, pll_out_khz, &idf, &ndiv, &odf);
+ if (ret)
+ DRM_WARN("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, },
+ { },
+};
+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");
--
1.9.1
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