[v3 5/7] pwm: crc: Add Crystalcove (CRC) PWM driver
Shobhit Kumar
shobhit.kumar at intel.com
Fri Jun 26 02:02:08 PDT 2015
The Crystalcove PMIC provides three PWM signals and this driver exports
one of them on the BYT platform which is used to control backlight for
DSI panel. This is platform device implementation of the drivers/mfd
cell device for CRC PMIC.
CC: Samuel Ortiz <sameo at linux.intel.com>
Cc: Linus Walleij <linus.walleij at linaro.org>
Cc: Alexandre Courbot <gnurou at gmail.com>
Cc: Thierry Reding <thierry.reding at gmail.com>
Cc: Paul Bolle <pebolle at tiscali.nl>
Cc: Paul Gortmaker <paul.gortmaker at windriver.com>
Tested-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar at intel.com>
---
v2: Use the existing config callback with duty_ns and period_ns(Thierry)
v3: Correct the subject line (Lee jones)
v4: Address comment by Thierry & Paul
- Commit message update and fixes for few syntax errors
- Add PWM_CRC in Kconfig and Makefile sorted alphabetically
- Use the PWM_BASE_CLK as 6000000 for better code readability
- Remove the redundant rule of three while calculating pwm level
- Use the platform_device in pwm_chip
- Use builin_platform_driver
v5: Address comments by Varka
- Make the bit definition using BIT macro
- reorder probe and remove code to directly return from pwmchip_add/remove
drivers/pwm/Kconfig | 7 +++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-crc.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 151 insertions(+)
create mode 100644 drivers/pwm/pwm-crc.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index b1541f4..948d9ab 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -111,6 +111,13 @@ config PWM_CLPS711X
To compile this driver as a module, choose M here: the module
will be called pwm-clps711x.
+config PWM_CRC
+ bool "Intel Crystalcove (CRC) PWM support"
+ depends on X86 && INTEL_SOC_PMIC
+ help
+ Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM
+ control.
+
config PWM_EP93XX
tristate "Cirrus Logic EP93xx PWM support"
depends on ARCH_EP93XX
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index ec50eb5..d186f35 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o
obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o
obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o
+obj-$(CONFIG_PWM_CRC) += pwm-crc.o
obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o
obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o
obj-$(CONFIG_PWM_IMG) += pwm-img.o
diff --git a/drivers/pwm/pwm-crc.c b/drivers/pwm/pwm-crc.c
new file mode 100644
index 0000000..7101c70
--- /dev/null
+++ b/drivers/pwm/pwm-crc.c
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2015 Intel Corporation. All rights reserved.
+ *
+ * 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.
+ *
+ * Author: Shobhit Kumar <shobhit.kumar at intel.com>
+ */
+
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/mfd/intel_soc_pmic.h>
+#include <linux/pwm.h>
+
+#define PWM0_CLK_DIV 0x4B
+#define PWM_OUTPUT_ENABLE BIT(7)
+#define PWM_DIV_CLK_0 0x00 /* DIVIDECLK = BASECLK */
+#define PWM_DIV_CLK_100 0x63 /* DIVIDECLK = BASECLK/100 */
+#define PWM_DIV_CLK_128 0x7F /* DIVIDECLK = BASECLK/128 */
+
+#define PWM0_DUTY_CYCLE 0x4E
+#define BACKLIGHT_EN 0x51
+
+#define PWM_MAX_LEVEL 0xFF
+
+#define PWM_BASE_CLK 6000000 /* 6 MHz */
+#define PWM_MAX_PERIOD_NS 21333 /* 46.875KHz */
+
+/**
+ * struct crystalcove_pwm - Crystal Cove PWM controller
+ * @chip: the abstract pwm_chip structure.
+ * @regmap: the regmap from the parent device.
+ */
+struct crystalcove_pwm {
+ struct pwm_chip chip;
+ struct regmap *regmap;
+};
+
+static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *pc)
+{
+ return container_of(pc, struct crystalcove_pwm, chip);
+}
+
+static int crc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
+{
+ struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
+
+ regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
+
+ return 0;
+}
+
+static void crc_pwm_disable(struct pwm_chip *c, struct pwm_device *pwm)
+{
+ struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
+
+ regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
+}
+
+static int crc_pwm_config(struct pwm_chip *c, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
+ struct device *dev = crc_pwm->chip.dev;
+ int level;
+
+ if (period_ns > PWM_MAX_PERIOD_NS) {
+ dev_err(dev, "un-supported period_ns\n");
+ return -EINVAL;
+ }
+
+ if (pwm->period != period_ns) {
+ int clk_div;
+
+ /* changing the clk divisor, need to disable fisrt */
+ crc_pwm_disable(c, pwm);
+ clk_div = PWM_BASE_CLK * period_ns / NSEC_PER_SEC;
+
+ regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
+ clk_div | PWM_OUTPUT_ENABLE);
+
+ /* enable back */
+ crc_pwm_enable(c, pwm);
+ }
+
+ /* change the pwm duty cycle */
+ level = duty_ns * PWM_MAX_LEVEL / period_ns;
+ regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
+
+ return 0;
+}
+
+static const struct pwm_ops crc_pwm_ops = {
+ .config = crc_pwm_config,
+ .enable = crc_pwm_enable,
+ .disable = crc_pwm_disable,
+};
+
+static int crystalcove_pwm_probe(struct platform_device *pdev)
+{
+ struct crystalcove_pwm *pwm;
+ struct device *dev = pdev->dev.parent;
+ struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
+
+ pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+ if (!pwm)
+ return -ENOMEM;
+
+ pwm->chip.dev = &pdev->dev;
+ pwm->chip.ops = &crc_pwm_ops;
+ pwm->chip.base = -1;
+ pwm->chip.npwm = 1;
+
+ /* get the PMIC regmap */
+ pwm->regmap = pmic->regmap;
+
+ platform_set_drvdata(pdev, pwm);
+
+ return pwmchip_add(&pwm->chip);
+}
+
+static int crystalcove_pwm_remove(struct platform_device *pdev)
+{
+ struct crystalcove_pwm *pwm = platform_get_drvdata(pdev);
+
+ return pwmchip_remove(&pwm->chip);
+}
+
+static struct platform_driver crystalcove_pwm_driver = {
+ .probe = crystalcove_pwm_probe,
+ .remove = crystalcove_pwm_remove,
+ .driver = {
+ .name = "crystal_cove_pwm",
+ },
+};
+
+builtin_platform_driver(crystalcove_pwm_driver);
--
1.9.1
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