Linux-libre 4.4-gnupck-4.4-gnu

1 files changed, 243 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
new file mode 100644
index 000000000..0ad338529
--- /dev/null
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -0,0 +1,243 @@
+/*
+ * MediaTek display pulse-width-modulation controller driver.
+ * Copyright (c) 2015 MediaTek Inc.
+ * Author: YH Huang <yh.huang@mediatek.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#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_ENABLE_MASK		BIT(0)
+
+#define DISP_PWM_COMMIT		0x08
+#define PWM_COMMIT_MASK		BIT(0)
+
+#define DISP_PWM_CON_0		0x10
+#define PWM_CLKDIV_SHIFT	16
+#define PWM_CLKDIV_MAX		0x3ff
+#define PWM_CLKDIV_MASK		(PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
+
+#define DISP_PWM_CON_1		0x14
+#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_disp_pwm {
+	struct pwm_chip chip;
+	struct clk *clk_main;
+	struct clk *clk_mm;
+	void __iomem *base;
+};
+
+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_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			       int duty_ns, int period_ns)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	u32 clk_div, period, high_width, value;
+	u64 div, rate;
+	int 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 = div_u64(rate * period_ns, NSEC_PER_SEC) >>
+			  PWM_PERIOD_BIT_WIDTH;
+	if (clk_div > PWM_CLKDIV_MAX)
+		return -EINVAL;
+
+	div = NSEC_PER_SEC * (clk_div + 1);
+	period = div64_u64(rate * period_ns, div);
+	if (period > 0)
+		period--;
+
+	high_width = div64_u64(rate * duty_ns, div);
+	value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
+
+	err = clk_enable(mdp->clk_main);
+	if (err < 0)
+		return err;
+
+	err = clk_enable(mdp->clk_mm);
+	if (err < 0) {
+		clk_disable(mdp->clk_main);
+		return err;
+	}
+
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_0, PWM_CLKDIV_MASK,
+				 clk_div << PWM_CLKDIV_SHIFT);
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_1,
+				 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value);
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 1);
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 0);
+
+	clk_disable(mdp->clk_mm);
+	clk_disable(mdp->clk_main);
+
+	return 0;
+}
+
+static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	int err;
+
+	err = clk_enable(mdp->clk_main);
+	if (err < 0)
+		return err;
+
+	err = clk_enable(mdp->clk_mm);
+	if (err < 0) {
+		clk_disable(mdp->clk_main);
+		return err;
+	}
+
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 1);
+
+	return 0;
+}
+
+static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 0);
+
+	clk_disable(mdp->clk_mm);
+	clk_disable(mdp->clk_main);
+}
+
+static const struct pwm_ops mtk_disp_pwm_ops = {
+	.config = mtk_disp_pwm_config,
+	.enable = mtk_disp_pwm_enable,
+	.disable = mtk_disp_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int mtk_disp_pwm_probe(struct platform_device *pdev)
+{
+	struct mtk_disp_pwm *mdp;
+	struct resource *r;
+	int ret;
+
+	mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
+	if (!mdp)
+		return -ENOMEM;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mdp->base = devm_ioremap_resource(&pdev->dev, r);
+	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);
+
+	ret = clk_prepare(mdp->clk_main);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_prepare(mdp->clk_mm);
+	if (ret < 0)
+		goto disable_clk_main;
+
+	mdp->chip.dev = &pdev->dev;
+	mdp->chip.ops = &mtk_disp_pwm_ops;
+	mdp->chip.base = -1;
+	mdp->chip.npwm = 1;
+
+	ret = pwmchip_add(&mdp->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+		goto disable_clk_mm;
+	}
+
+	platform_set_drvdata(pdev, mdp);
+
+	return 0;
+
+disable_clk_mm:
+	clk_unprepare(mdp->clk_mm);
+disable_clk_main:
+	clk_unprepare(mdp->clk_main);
+	return ret;
+}
+
+static int mtk_disp_pwm_remove(struct platform_device *pdev)
+{
+	struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pwmchip_remove(&mdp->chip);
+	clk_unprepare(mdp->clk_mm);
+	clk_unprepare(mdp->clk_main);
+
+	return ret;
+}
+
+static const struct of_device_id mtk_disp_pwm_of_match[] = {
+	{ .compatible = "mediatek,mt8173-disp-pwm" },
+	{ .compatible = "mediatek,mt6595-disp-pwm" },
+	{ }
+};
+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 = 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");