1 files changed, 329 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
new file mode 100644
index 0000000000..a83bd6e18b
--- /dev/null
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -0,0 +1,329 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MediaTek display pulse-width-modulation controller driver.
+ * Copyright (c) 2015 MediaTek Inc.
+ * Author: YH Huang <yh.huang@mediatek.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define DISP_PWM_EN		0x00
+
+#define PWM_CLKDIV_SHIFT	16
+#define PWM_CLKDIV_MAX		0x3ff
+#define PWM_CLKDIV_MASK		(PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
+
+#define PWM_PERIOD_BIT_WIDTH	12
+#define PWM_PERIOD_MASK		((1 << PWM_PERIOD_BIT_WIDTH) - 1)
+
+#define PWM_HIGH_WIDTH_SHIFT	16
+#define PWM_HIGH_WIDTH_MASK	(0x1fff << PWM_HIGH_WIDTH_SHIFT)
+
+struct mtk_pwm_data {
+	u32 enable_mask;
+	unsigned int con0;
+	u32 con0_sel;
+	unsigned int con1;
+
+	bool has_commit;
+	unsigned int commit;
+	unsigned int commit_mask;
+
+	unsigned int bls_debug;
+	u32 bls_debug_mask;
+};
+
+struct mtk_disp_pwm {
+	struct pwm_chip chip;
+	const struct mtk_pwm_data *data;
+	struct clk *clk_main;
+	struct clk *clk_mm;
+	void __iomem *base;
+	bool enabled;
+};
+
+static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
+{
+	return container_of(chip, struct mtk_disp_pwm, chip);
+}
+
+static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
+				     u32 mask, u32 data)
+{
+	void __iomem *address = mdp->base + offset;
+	u32 value;
+
+	value = readl(address);
+	value &= ~mask;
+	value |= data;
+	writel(value, address);
+}
+
+static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			      const struct pwm_state *state)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	u32 clk_div, period, high_width, value;
+	u64 div, rate;
+	int err;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (!state->enabled && mdp->enabled) {
+		mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN,
+					 mdp->data->enable_mask, 0x0);
+		clk_disable_unprepare(mdp->clk_mm);
+		clk_disable_unprepare(mdp->clk_main);
+
+		mdp->enabled = false;
+		return 0;
+	}
+
+	if (!mdp->enabled) {
+		err = clk_prepare_enable(mdp->clk_main);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n",
+				ERR_PTR(err));
+			return err;
+		}
+
+		err = clk_prepare_enable(mdp->clk_mm);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n",
+				ERR_PTR(err));
+			clk_disable_unprepare(mdp->clk_main);
+			return err;
+		}
+	}
+
+	/*
+	 * Find period, high_width and clk_div to suit duty_ns and period_ns.
+	 * Calculate proper div value to keep period value in the bound.
+	 *
+	 * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
+	 * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
+	 *
+	 * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
+	 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
+	 */
+	rate = clk_get_rate(mdp->clk_main);
+	clk_div = mul_u64_u64_div_u64(state->period, rate, NSEC_PER_SEC) >>
+			  PWM_PERIOD_BIT_WIDTH;
+	if (clk_div > PWM_CLKDIV_MAX) {
+		if (!mdp->enabled) {
+			clk_disable_unprepare(mdp->clk_mm);
+			clk_disable_unprepare(mdp->clk_main);
+		}
+		return -EINVAL;
+	}
+
+	div = NSEC_PER_SEC * (clk_div + 1);
+	period = mul_u64_u64_div_u64(state->period, rate, div);
+	if (period > 0)
+		period--;
+
+	high_width = mul_u64_u64_div_u64(state->duty_cycle, rate, div);
+	value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
+
+	if (mdp->data->bls_debug && !mdp->data->has_commit) {
+		/*
+		 * For MT2701, disable double buffer before writing register
+		 * and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
+		 */
+		mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
+					 mdp->data->bls_debug_mask,
+					 mdp->data->bls_debug_mask);
+		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
+					 mdp->data->con0_sel,
+					 mdp->data->con0_sel);
+	}
+
+	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
+				 PWM_CLKDIV_MASK,
+				 clk_div << PWM_CLKDIV_SHIFT);
+	mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
+				 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
+				 value);
+
+	if (mdp->data->has_commit) {
+		mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
+					 mdp->data->commit_mask,
+					 mdp->data->commit_mask);
+		mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
+					 mdp->data->commit_mask,
+					 0x0);
+	}
+
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
+				 mdp->data->enable_mask);
+	mdp->enabled = true;
+
+	return 0;
+}
+
+static int mtk_disp_pwm_get_state(struct pwm_chip *chip,
+				  struct pwm_device *pwm,
+				  struct pwm_state *state)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	u64 rate, period, high_width;
+	u32 clk_div, pwm_en, con0, con1;
+	int err;
+
+	err = clk_prepare_enable(mdp->clk_main);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err));
+		return err;
+	}
+
+	err = clk_prepare_enable(mdp->clk_mm);
+	if (err < 0) {
+		dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err));
+		clk_disable_unprepare(mdp->clk_main);
+		return err;
+	}
+
+	/*
+	 * Apply DISP_PWM_DEBUG settings to choose whether to enable or disable
+	 * registers double buffer and manual commit to working register before
+	 * performing any read/write operation
+	 */
+	if (mdp->data->bls_debug)
+		mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
+					 mdp->data->bls_debug_mask,
+					 mdp->data->bls_debug_mask);
+
+	rate = clk_get_rate(mdp->clk_main);
+	con0 = readl(mdp->base + mdp->data->con0);
+	con1 = readl(mdp->base + mdp->data->con1);
+	pwm_en = readl(mdp->base + DISP_PWM_EN);
+	state->enabled = !!(pwm_en & mdp->data->enable_mask);
+	clk_div = FIELD_GET(PWM_CLKDIV_MASK, con0);
+	period = FIELD_GET(PWM_PERIOD_MASK, con1);
+	/*
+	 * period has 12 bits, clk_div 11 and NSEC_PER_SEC has 30,
+	 * so period * (clk_div + 1) * NSEC_PER_SEC doesn't overflow.
+	 */
+	state->period = DIV64_U64_ROUND_UP(period * (clk_div + 1) * NSEC_PER_SEC, rate);
+	high_width = FIELD_GET(PWM_HIGH_WIDTH_MASK, con1);
+	state->duty_cycle = DIV64_U64_ROUND_UP(high_width * (clk_div + 1) * NSEC_PER_SEC,
+					       rate);
+	state->polarity = PWM_POLARITY_NORMAL;
+	clk_disable_unprepare(mdp->clk_mm);
+	clk_disable_unprepare(mdp->clk_main);
+
+	return 0;
+}
+
+static const struct pwm_ops mtk_disp_pwm_ops = {
+	.apply = mtk_disp_pwm_apply,
+	.get_state = mtk_disp_pwm_get_state,
+	.owner = THIS_MODULE,
+};
+
+static int mtk_disp_pwm_probe(struct platform_device *pdev)
+{
+	struct mtk_disp_pwm *mdp;
+	int ret;
+
+	mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
+	if (!mdp)
+		return -ENOMEM;
+
+	mdp->data = of_device_get_match_data(&pdev->dev);
+
+	mdp->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(mdp->base))
+		return PTR_ERR(mdp->base);
+
+	mdp->clk_main = devm_clk_get(&pdev->dev, "main");
+	if (IS_ERR(mdp->clk_main))
+		return PTR_ERR(mdp->clk_main);
+
+	mdp->clk_mm = devm_clk_get(&pdev->dev, "mm");
+	if (IS_ERR(mdp->clk_mm))
+		return PTR_ERR(mdp->clk_mm);
+
+	mdp->chip.dev = &pdev->dev;
+	mdp->chip.ops = &mtk_disp_pwm_ops;
+	mdp->chip.npwm = 1;
+
+	ret = pwmchip_add(&mdp->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pwmchip_add() failed: %pe\n", ERR_PTR(ret));
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, mdp);
+
+	return 0;
+}
+
+static void mtk_disp_pwm_remove(struct platform_device *pdev)
+{
+	struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
+
+	pwmchip_remove(&mdp->chip);
+}
+
+static const struct mtk_pwm_data mt2701_pwm_data = {
+	.enable_mask = BIT(16),
+	.con0 = 0xa8,
+	.con0_sel = 0x2,
+	.con1 = 0xac,
+	.has_commit = false,
+	.bls_debug = 0xb0,
+	.bls_debug_mask = 0x3,
+};
+
+static const struct mtk_pwm_data mt8173_pwm_data = {
+	.enable_mask = BIT(0),
+	.con0 = 0x10,
+	.con0_sel = 0x0,
+	.con1 = 0x14,
+	.has_commit = true,
+	.commit = 0x8,
+	.commit_mask = 0x1,
+};
+
+static const struct mtk_pwm_data mt8183_pwm_data = {
+	.enable_mask = BIT(0),
+	.con0 = 0x18,
+	.con0_sel = 0x0,
+	.con1 = 0x1c,
+	.has_commit = false,
+	.bls_debug = 0x80,
+	.bls_debug_mask = 0x3,
+};
+
+static const struct of_device_id mtk_disp_pwm_of_match[] = {
+	{ .compatible = "mediatek,mt2701-disp-pwm", .data = &mt2701_pwm_data},
+	{ .compatible = "mediatek,mt6595-disp-pwm", .data = &mt8173_pwm_data},
+	{ .compatible = "mediatek,mt8173-disp-pwm", .data = &mt8173_pwm_data},
+	{ .compatible = "mediatek,mt8183-disp-pwm", .data = &mt8183_pwm_data},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
+
+static struct platform_driver mtk_disp_pwm_driver = {
+	.driver = {
+		.name = "mediatek-disp-pwm",
+		.of_match_table = mtk_disp_pwm_of_match,
+	},
+	.probe = mtk_disp_pwm_probe,
+	.remove_new = mtk_disp_pwm_remove,
+};
+module_platform_driver(mtk_disp_pwm_driver);
+
+MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>");
+MODULE_DESCRIPTION("MediaTek SoC display PWM driver");
+MODULE_LICENSE("GPL v2");