diff options
Diffstat (limited to 'drivers/video/tegra20/tegra-pwm-backlight.c')
| -rw-r--r-- | drivers/video/tegra20/tegra-pwm-backlight.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/drivers/video/tegra20/tegra-pwm-backlight.c b/drivers/video/tegra20/tegra-pwm-backlight.c new file mode 100644 index 00000000000..bb677daa8a1 --- /dev/null +++ b/drivers/video/tegra20/tegra-pwm-backlight.c @@ -0,0 +1,156 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2022 Svyatoslav Ryhel <clamor95@gmail.com> + */ + +#define LOG_CATEGORY UCLASS_PANEL_BACKLIGHT + +#include <backlight.h> +#include <common.h> +#include <dm.h> +#include <i2c.h> +#include <log.h> +#include <linux/delay.h> +#include <linux/err.h> + +#include <asm/io.h> +#include <asm/gpio.h> +#include <asm/arch/display.h> + +#define TEGRA_DISPLAY_A_BASE 0x54200000 +#define TEGRA_DISPLAY_B_BASE 0x54240000 + +#define TEGRA_PWM_BL_MIN_BRIGHTNESS 0x10 +#define TEGRA_PWM_BL_MAX_BRIGHTNESS 0xFF + +#define TEGRA_PWM_BL_PERIOD 0xFF +#define TEGRA_PWM_BL_CLK_DIV 0x14 +#define TEGRA_PWM_BL_CLK_SELECT 0x00 + +#define PM_PERIOD_SHIFT 18 +#define PM_CLK_DIVIDER_SHIFT 4 + +#define TEGRA_PWM_PM0 0 +#define TEGRA_PWM_PM1 1 + +struct tegra_pwm_backlight_priv { + struct dc_ctlr *dc; /* Display controller regmap */ + + u32 pwm_source; + u32 period; + u32 clk_div; + u32 clk_select; + u32 dft_brightness; +}; + +static int tegra_pwm_backlight_set_brightness(struct udevice *dev, int percent) +{ + struct tegra_pwm_backlight_priv *priv = dev_get_priv(dev); + struct dc_cmd_reg *cmd = &priv->dc->cmd; + struct dc_com_reg *com = &priv->dc->com; + unsigned int ctrl; + unsigned long out_sel; + unsigned long cmd_state; + + if (percent == BACKLIGHT_DEFAULT) + percent = priv->dft_brightness; + + if (percent < TEGRA_PWM_BL_MIN_BRIGHTNESS) + percent = TEGRA_PWM_BL_MIN_BRIGHTNESS; + + if (percent > TEGRA_PWM_BL_MAX_BRIGHTNESS) + percent = TEGRA_PWM_BL_MAX_BRIGHTNESS; + + ctrl = ((priv->period << PM_PERIOD_SHIFT) | + (priv->clk_div << PM_CLK_DIVIDER_SHIFT) | + priv->clk_select); + + /* The new value should be effected immediately */ + cmd_state = readl(&cmd->state_access); + writel((cmd_state | (1 << 2)), &cmd->state_access); + + switch (priv->pwm_source) { + case TEGRA_PWM_PM0: + /* Select the LM0 on PM0 */ + out_sel = readl(&com->pin_output_sel[5]); + out_sel &= ~(7 << 0); + out_sel |= (3 << 0); + writel(out_sel, &com->pin_output_sel[5]); + writel(ctrl, &com->pm0_ctrl); + writel(percent, &com->pm0_duty_cycle); + break; + case TEGRA_PWM_PM1: + /* Select the LM1 on PM1 */ + out_sel = readl(&com->pin_output_sel[5]); + out_sel &= ~(7 << 4); + out_sel |= (3 << 4); + writel(out_sel, &com->pin_output_sel[5]); + writel(ctrl, &com->pm1_ctrl); + writel(percent, &com->pm1_duty_cycle); + break; + default: + break; + } + + writel(cmd_state, &cmd->state_access); + return 0; +} + +static int tegra_pwm_backlight_enable(struct udevice *dev) +{ + struct tegra_pwm_backlight_priv *priv = dev_get_priv(dev); + + return tegra_pwm_backlight_set_brightness(dev, priv->dft_brightness); +} + +static int tegra_pwm_backlight_probe(struct udevice *dev) +{ + struct tegra_pwm_backlight_priv *priv = dev_get_priv(dev); + + if (dev_read_bool(dev, "nvidia,display-b-base")) + priv->dc = (struct dc_ctlr *)TEGRA_DISPLAY_B_BASE; + else + priv->dc = (struct dc_ctlr *)TEGRA_DISPLAY_A_BASE; + + if (!priv->dc) { + log_err("no display controller address\n"); + return -EINVAL; + } + + priv->pwm_source = + dev_read_u32_default(dev, "nvidia,pwm-source", + TEGRA_PWM_PM0); + priv->period = + dev_read_u32_default(dev, "nvidia,period", + TEGRA_PWM_BL_PERIOD); + priv->clk_div = + dev_read_u32_default(dev, "nvidia,clock-div", + TEGRA_PWM_BL_CLK_DIV); + priv->clk_select = + dev_read_u32_default(dev, "nvidia,clock-select", + TEGRA_PWM_BL_CLK_SELECT); + priv->dft_brightness = + dev_read_u32_default(dev, "nvidia,default-brightness", + TEGRA_PWM_BL_MAX_BRIGHTNESS); + + return 0; +} + +static const struct backlight_ops tegra_pwm_backlight_ops = { + .enable = tegra_pwm_backlight_enable, + .set_brightness = tegra_pwm_backlight_set_brightness, +}; + +static const struct udevice_id tegra_pwm_backlight_ids[] = { + { .compatible = "nvidia,tegra-pwm-backlight" }, + { } +}; + +U_BOOT_DRIVER(tegra_pwm_backlight) = { + .name = "tegra_pwm_backlight", + .id = UCLASS_PANEL_BACKLIGHT, + .of_match = tegra_pwm_backlight_ids, + .probe = tegra_pwm_backlight_probe, + .ops = &tegra_pwm_backlight_ops, + .priv_auto = sizeof(struct tegra_pwm_backlight_priv), +}; |