The Pistachio SOC from Imagination Technologies includes a Pulse Width
Modulation DAC which produces 1 to 4 digital bit-outputs which represent
digital waveforms. These PWM outputs are primarily in charge of controlling
backlight LED devices.
Signed-off-by: Naidu Tellapati <Naidu.Tellapati@xxxxxxxxxx>
Signed-off-by: Sai Masarapu <Sai.Masarapu@xxxxxxxxxx>
---
drivers/pwm/Kconfig | 13 +++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-img.c | 250 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 264 insertions(+), 0 deletions(-)
create mode 100644 drivers/pwm/pwm-img.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index ef2dd2e..21b82b9 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -110,6 +110,19 @@ config PWM_FSL_FTM
To compile this driver as a module, choose M here: the module
will be called pwm-fsl-ftm.
+config PWM_IMG
+ tristate "Imagination Technologies PWM driver"
+ depends on HAS_IOMEM
+ depends on MFD_SYSCON
+ depends on COMMON_CLK
+ depends on MIPS || COMPILE_TEST
+ help
+ Generic PWM framework driver for Imagination Technologies
+ PWM block which supports 4 channels.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-img
+
config PWM_IMX
tristate "i.MX PWM support"
depends on ARCH_MXC
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index c458606..29655fd 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o
obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o
obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o
+obj-$(CONFIG_PWM_IMG) += pwm-img.o
obj-$(CONFIG_PWM_IMX) += pwm-imx.o
obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o
obj-$(CONFIG_PWM_LP3943) += pwm-lp3943.o
diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
new file mode 100644
index 0000000..48204cb
--- /dev/null
+++ b/drivers/pwm/pwm-img.c
@@ -0,0 +1,250 @@
+/*
+ * Imagination Technologies Pulse Width Modulator driver
+ *
+ * Copyright (c) 2014, Imagination Technologies
+ *
+ * Based on drivers/pwm/pwm-tegra.c, Copyright (c) 2010, NVIDIA Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+/* PWM registers */
+#define PWM_CTRL_CFG 0x0000
+#define PWM_CTRL_CFG_NO_SUB_DIV 0
+#define PWM_CTRL_CFG_SUB_DIV0 1
+#define PWM_CTRL_CFG_SUB_DIV1 2
+#define PWM_CTRL_CFG_SUB_DIV0_DIV1 3
+#define PWM_CTRL_CFG_DIV_SHIFT(ch) ((ch) * 2 + 4)
+#define PWM_CTRL_CFG_DIV_MASK 0x3
+
+#define PWM_CH_CFG(ch) (0x4 + (ch) * 4)
+#define PWM_CH_CFG_TMBASE_SHIFT 0
+#define PWM_CH_CFG_DUTY_SHIFT 16
+
+#define PERIP_PWM_PDM_CONTROL 0x0140
+#define PERIP_PWM_PDM_CONTROL_CH_MASK 0x1
+#define PERIP_PWM_PDM_CONTROL_CH_SHIFT(ch) ((ch) * 4)
+
+#define MAX_TMBASE_STEPS 65536
+
+struct img_pwm_chip {
+ struct device *dev;
+ struct pwm_chip chip;
+ struct clk *pwm_clk;
+ struct clk *sys_clk;
+ void __iomem *base;
+ struct regmap *periph_regs;
+};
+
+static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct img_pwm_chip, chip);
+}
+
+static inline void img_pwm_writel(struct img_pwm_chip *chip,
+ u32 reg, u32 val)
+{
+ writel(val, chip->base + reg);
+}
+
+static inline u32 img_pwm_readl(struct img_pwm_chip *chip,
+ u32 reg)
+{
+ return readl(chip->base + reg);
+}
+
+static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ u32 val, div, duty, timebase;
+ unsigned long mul, output_clk_hz, input_clk_hz;
+ struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
+
+ input_clk_hz = clk_get_rate(pwm_chip->pwm_clk);
+ output_clk_hz = DIV_ROUND_UP(NSEC_PER_SEC, period_ns);
+
+ mul = DIV_ROUND_UP(input_clk_hz, output_clk_hz);
+ if (mul <= MAX_TMBASE_STEPS) {
+ div = PWM_CTRL_CFG_NO_SUB_DIV;
+ timebase = DIV_ROUND_UP(mul, 1);
+ } else if (mul <= MAX_TMBASE_STEPS * 8) {
+ div = PWM_CTRL_CFG_SUB_DIV0;
+ timebase = DIV_ROUND_UP(mul, 8);
+ } else if (mul <= MAX_TMBASE_STEPS * 64) {
+ div = PWM_CTRL_CFG_SUB_DIV1;
+ timebase = DIV_ROUND_UP(mul, 64);
+ } else if (mul <= MAX_TMBASE_STEPS * 512) {
+ div = PWM_CTRL_CFG_SUB_DIV0_DIV1;
+ timebase = DIV_ROUND_UP(mul, 512);
+ } else if (mul > MAX_TMBASE_STEPS * 512) {
+ dev_err(chip->dev,
+ "failed to configure timebase steps/divider value.\n");
+ return -EINVAL;
+ }
+
+ duty = DIV_ROUND_UP(timebase * duty_ns, period_ns);
+
+ val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
+ val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm));
+ val |= (div & PWM_CTRL_CFG_DIV_MASK) <<
+ PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm);
+ img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
+
+ val = (duty << PWM_CH_CFG_DUTY_SHIFT) |
+ (timebase << PWM_CH_CFG_TMBASE_SHIFT);
+ img_pwm_writel(pwm_chip, PWM_CH_CFG(pwm->hwpwm), val);
+
+ return 0;
+}
+
+static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ u32 val;
+ struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
+
+ val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
+ val |= BIT(pwm->hwpwm);
+ img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
+
+ regmap_update_bits(pwm_chip->periph_regs, PERIP_PWM_PDM_CONTROL,
+ PERIP_PWM_PDM_CONTROL_CH_MASK <<
+ PERIP_PWM_PDM_CONTROL_CH_SHIFT(pwm->hwpwm), 0);
+
+ return 0;
+}
+
+static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ u32 val;
+ struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
+
+ val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
+ val &= ~BIT(pwm->hwpwm);
+ img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
+}
+
+static const struct pwm_ops img_pwm_ops = {
+ .config = img_pwm_config,
+ .enable = img_pwm_enable,
+ .disable = img_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static int img_pwm_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct resource *res;
+ struct img_pwm_chip *pwm;
+
+ pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+ if (!pwm)
+ return -ENOMEM;
+
+ pwm->dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pwm->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(pwm->base))
+ return PTR_ERR(pwm->base);
+
+ pwm->periph_regs = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+ "img,cr-periph");
+ if (IS_ERR(pwm->periph_regs))
+ return PTR_ERR(pwm->periph_regs);
+
+ pwm->sys_clk = devm_clk_get(&pdev->dev, "sys");
+ if (IS_ERR(pwm->sys_clk)) {
+ dev_err(&pdev->dev, "failed to get system clock.\n");
+ return PTR_ERR(pwm->sys_clk);
+ }
+
+ pwm->pwm_clk = devm_clk_get(&pdev->dev, "pwm");
+ if (IS_ERR(pwm->pwm_clk)) {
+ dev_err(&pdev->dev, "failed to get pwm clock.\n");
+ return PTR_ERR(pwm->pwm_clk);
+ }
+
+ ret = clk_prepare_enable(pwm->sys_clk);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "could not prepare or enable sys clock.\n");
+ return ret;
+ }
+
+ ret = clk_prepare_enable(pwm->pwm_clk);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "could not prepare or enable pwm clock.\n");
+ goto disable_sysclk;
+ }
+
+ pwm->chip.dev = &pdev->dev;
+ pwm->chip.ops = &img_pwm_ops;
+ pwm->chip.base = -1;
+ pwm->chip.npwm = 4;
+
+ ret = pwmchip_add(&pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);
+ goto disable_pwmclk;
+ }
+
+ platform_set_drvdata(pdev, pwm);
+
+disable_pwmclk:
+ clk_disable_unprepare(pwm->pwm_clk);
+disable_sysclk:
+ clk_disable_unprepare(pwm->sys_clk);
+
+ return 0;
+}
+
+static int img_pwm_remove(struct platform_device *pdev)
+{
+ struct img_pwm_chip *pwm_chip = platform_get_drvdata(pdev);
+ u32 val;
+ unsigned int i;
+
+ for (i = 0; i < pwm_chip->chip.npwm; i++) {
+ val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
+ val &= ~BIT(i);
+ img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
+ }
+
+ clk_disable_unprepare(pwm_chip->pwm_clk);
+ clk_disable_unprepare(pwm_chip->sys_clk);
+
+ return pwmchip_remove(&pwm_chip->chip);
+}
+
+static const struct of_device_id img_pwm_of_match[] = {
+ { .compatible = "img,pistachio-pwm", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, img_pwm_of_match);
+
+static struct platform_driver img_pwm_driver = {
+ .driver = {
+ .name = "img-pwm",
+ .of_match_table = of_match_ptr(img_pwm_of_match),
+ },
+ .probe = img_pwm_probe,
+ .remove = img_pwm_remove,
+};
+module_platform_driver(img_pwm_driver);
+
+MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver");
+MODULE_LICENSE("GPL v2");
--
1.7.0.4
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