Merge tag 'intel-pinctrl-v6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pinctrl/intel into devel

intel-pinctrl for v6.15-1

* Introduce devm_kmemdup_array() and convert Intel pin control drivers
* Update PWM handling for the cases when it's provided by Intel pin control
* Miscellaneous fixes, updates, and cleanups

The following is an automated git shortlog grouped by driver:

baytrail:
- copy communities using devm_kmemdup_array()
- Use dedicated helpers for chained IRQ handlers

cherryview:
- use devm_kmemdup_array()

devres:
- Introduce devm_kmemdup_array()

driver core:
- Split devres APIs to device/devres.h

err.h:
- move IOMEM_ERR_PTR() to err.h

iio:
- adc: xilinx-xadc-core: use devm_kmemdup_array()
- imu: st_lsm9ds0: Replace device.h with what is needed

input:
- ipaq-micro-keys: use devm_kmemdup_array()
- sparse-keymap: use devm_kmemdup_array()

intel:
- drop repeated config dependency
- copy communities using devm_kmemdup_array()
- Fix wrong bypass assignment in intel_pinctrl_probe_pwm()
- Import PWM_LPSS namespace for devm_pwm_lpss_probe()

lynxpoint:
- Use dedicated helpers for chained IRQ handlers

MAINTAINERS:
- Add pin control and GPIO to the Intel MID record

pwm:
- lpss: Clarify the bypass member semantics in struct pwm_lpss_boardinfo
- lpss: Actually use a module namespace by defining the namespace earlier

pxa2xx:
- use devm_kmemdup_array()

tangier:
- use devm_kmemdup_array()

Signed-off-by: Linus Walleij <[e-mail]>

MAINTAINERS

···
 F:	arch/x86/include/asm/intel-mid.h
 F:	arch/x86/pci/intel_mid_pci.c
 F:	arch/x86/platform/intel-mid/
+F:	drivers/dma/hsu/
 F:	drivers/extcon/extcon-intel-mrfld.c
+F:	drivers/gpio/gpio-merrifield.c
+F:	drivers/gpio/gpio-tangier.*
 F:	drivers/iio/adc/intel_mrfld_adc.c
 F:	drivers/mfd/intel_soc_pmic_mrfld.c
+F:	drivers/pinctrl/intel/pinctrl-merrifield.c
+F:	drivers/pinctrl/intel/pinctrl-moorefield.c
+F:	drivers/pinctrl/intel/pinctrl-tangier.*
 F:	drivers/platform/x86/intel/mrfld_pwrbtn.c
 F:	drivers/platform/x86/intel_scu_*
 F:	drivers/staging/media/atomisp/
+F:	drivers/tty/serial/8250/8250_mid.c
 F:	drivers/watchdog/intel-mid_wdt.c
 F:	include/linux/mfd/intel_soc_pmic_mrfld.h
 F:	include/linux/platform_data/x86/intel-mid_wdt.h

drivers/iio/adc/xilinx-xadc-core.c

···
 		channel_templates = xadc_us_channels;
 		max_channels = ARRAY_SIZE(xadc_us_channels);
 	}
-	channels = devm_kmemdup(dev, channel_templates,
-				sizeof(channels[0]) * max_channels, GFP_KERNEL);
+	channels = devm_kmemdup_array(dev, channel_templates, max_channels,
+				      sizeof(*channel_templates), GFP_KERNEL);
 	if (!channels)
 		return -ENOMEM;
 

drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_i2c.c

···
  * Author: Andy Shevchenko <[e-mail]>
  */
 
-#include <linux/device.h>
+#include <linux/device/devres.h>
 #include <linux/err.h>
 #include <linux/gfp_types.h>
 #include <linux/i2c.h>

drivers/iio/imu/st_lsm9ds0/st_lsm9ds0_spi.c

···
  * Author: Andy Shevchenko <[e-mail]>
  */
 
-#include <linux/device.h>
+#include <linux/device/devres.h>
 #include <linux/err.h>
 #include <linux/gfp_types.h>
 #include <linux/module.h>

drivers/input/keyboard/ipaq-micro-keys.c

···
 
 	keys->input->keycodesize = sizeof(micro_keycodes[0]);
 	keys->input->keycodemax = ARRAY_SIZE(micro_keycodes);
-	keys->codes = devm_kmemdup(&pdev->dev, micro_keycodes,
-			   keys->input->keycodesize * keys->input->keycodemax,
-			   GFP_KERNEL);
+	keys->codes = devm_kmemdup_array(&pdev->dev, micro_keycodes, keys->input->keycodemax,
+					 keys->input->keycodesize, GFP_KERNEL);
 	if (!keys->codes)
 		return -ENOMEM;
 

drivers/input/sparse-keymap.c

···
 	for (e = keymap; e->type != KE_END; e++)
 		map_size++;
 
-	map = devm_kmemdup(&dev->dev, keymap, map_size * sizeof(*map),
-			   GFP_KERNEL);
+	map = devm_kmemdup_array(&dev->dev, keymap, map_size, sizeof(*keymap), GFP_KERNEL);
 	if (!map)
 		return -ENOMEM;
 

drivers/pinctrl/intel/Kconfig

···
 
 config PINCTRL_INTEL_PLATFORM
 	tristate "Intel pinctrl and GPIO platform driver"
-	depends on ACPI
 	select PINCTRL_INTEL
 	help
 	  This pinctrl driver provides an interface that allows configuring
···
 
 config PINCTRL_METEORPOINT
 	tristate "Intel Meteor Point pinctrl and GPIO driver"
-	depends on ACPI
 	select PINCTRL_INTEL
 	help
 	  Meteor Point is the PCH of Intel Meteor Lake. This pinctrl driver

drivers/pinctrl/intel/pinctrl-baytrail.c

···
 	void __iomem *reg;
 	unsigned long pending;
 
+	chained_irq_enter(chip, desc);
+
 	/* check from GPIO controller which pin triggered the interrupt */
 	for (base = 0; base < vg->chip.ngpio; base += 32) {
 		reg = byt_gpio_reg(vg, base, BYT_INT_STAT_REG);
···
 		for_each_set_bit(pin, &pending, 32)
 			generic_handle_domain_irq(vg->chip.irq.domain, base + pin);
 	}
-	chip->irq_eoi(data);
+
+	chained_irq_exit(chip, desc);
 }
 
 static bool byt_direct_irq_sanity_check(struct intel_pinctrl *vg, int pin, u32 conf0)
···
 	vg->soc = soc;
 
 	vg->ncommunities = vg->soc->ncommunities;
-	vg->communities = devm_kcalloc(vg->dev, vg->ncommunities,
-				       sizeof(*vg->communities), GFP_KERNEL);
+	vg->communities = devm_kmemdup_array(vg->dev, vg->soc->communities, vg->ncommunities,
+					     sizeof(*vg->soc->communities), GFP_KERNEL);
 	if (!vg->communities)
 		return -ENOMEM;
 
 	for (i = 0; i < vg->soc->ncommunities; i++) {
 		struct intel_community *comm = vg->communities + i;
-
-		*comm = vg->soc->communities[i];
 
 		comm->pad_regs = devm_platform_ioremap_resource(pdev, 0);
 		if (IS_ERR(comm->pad_regs))

drivers/pinctrl/intel/pinctrl-cherryview.c

···
 	pctrl->soc = soc_data;
 
 	pctrl->ncommunities = pctrl->soc->ncommunities;
-	pctrl->communities = devm_kmemdup(dev, pctrl->soc->communities,
-					  pctrl->ncommunities * sizeof(*pctrl->communities),
-					  GFP_KERNEL);
+	pctrl->communities = devm_kmemdup_array(dev, pctrl->soc->communities, pctrl->ncommunities,
+						sizeof(*pctrl->soc->communities), GFP_KERNEL);
 	if (!pctrl->communities)
 		return -ENOMEM;
 

drivers/pinctrl/intel/pinctrl-intel.c

···
 		.clk_rate = 19200000,
 		.npwm = 1,
 		.base_unit_bits = 22,
-		.bypass = true,
 	};
 	struct pwm_chip *chip;
 
···
 	 * to the registers.
 	 */
 	pctrl->ncommunities = pctrl->soc->ncommunities;
-	pctrl->communities = devm_kcalloc(dev, pctrl->ncommunities,
-					  sizeof(*pctrl->communities), GFP_KERNEL);
+	pctrl->communities = devm_kmemdup_array(dev, pctrl->soc->communities, pctrl->ncommunities,
+						sizeof(*pctrl->soc->communities), GFP_KERNEL);
 	if (!pctrl->communities)
 		return -ENOMEM;
 
···
 		void __iomem *regs;
 		u32 offset;
 		u32 value;
-
-		*community = pctrl->soc->communities[i];
 
 		regs = devm_platform_ioremap_resource(pdev, community->barno);
 		if (IS_ERR(regs))
···
 MODULE_AUTHOR("Mika Westerberg <[e-mail]>");
 MODULE_DESCRIPTION("Intel pinctrl/GPIO core driver");
 MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS("PWM_LPSS");

drivers/pinctrl/intel/pinctrl-lynxpoint.c

···
 	unsigned long pending;
 	u32 base, pin;
 
+	chained_irq_enter(chip, desc);
+
 	/* check from GPIO controller which pin triggered the interrupt */
 	for (base = 0; base < lg->chip.ngpio; base += 32) {
 		reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
···
 		for_each_set_bit(pin, &pending, 32)
 			generic_handle_domain_irq(lg->chip.irq.domain, base + pin);
 	}
-	chip->irq_eoi(data);
+
+	chained_irq_exit(chip, desc);
 }
 
 static void lp_irq_ack(struct irq_data *d)

drivers/pinctrl/intel/pinctrl-tangier.c

···
 	struct device *dev = &pdev->dev;
 	struct tng_family *families;
 	struct tng_pinctrl *tp;
-	size_t families_len;
 	void __iomem *regs;
 	unsigned int i;
 
···
 	 * Make a copy of the families which we can use to hold pointers
 	 * to the registers.
 	 */
-	families_len = size_mul(sizeof(*families), tp->nfamilies);
-	families = devm_kmemdup(dev, tp->families, families_len, GFP_KERNEL);
+	families = devm_kmemdup_array(dev, tp->families, tp->nfamilies,
+				      sizeof(*tp->families), GFP_KERNEL);
 	if (!families)
 		return -ENOMEM;
 

drivers/pinctrl/pxa/pinctrl-pxa2xx.c

···
 		for (df = pctl->ppins[i].functions; df->name; df++)
 			if (!pxa2xx_find_function(pctl, df->name, functions))
 				(functions + pctl->nfuncs++)->name = df->name;
-	pctl->functions = devm_kmemdup(pctl->dev, functions,
-				       pctl->nfuncs * sizeof(*functions),
-				       GFP_KERNEL);
+	pctl->functions = devm_kmemdup_array(pctl->dev, functions, pctl->nfuncs,
+					     sizeof(*functions), GFP_KERNEL);
 	if (!pctl->functions)
 		return -ENOMEM;
 
···
 						pctl->ppins[j].pin.name;
 		func = pctl->functions + i;
 		func->ngroups = ngroups;
-		func->groups = devm_kmemdup(pctl->dev, gtmp, ngroups * sizeof(*gtmp), GFP_KERNEL);
+		func->groups = devm_kmemdup_array(pctl->dev, gtmp, ngroups,
+						  sizeof(*gtmp), GFP_KERNEL);
 		if (!func->groups)
 			return -ENOMEM;
 	}

drivers/pwm/pwm-lpss.c

···
  * Author: Alan Cox <[e-mail]>
  */
 
+#define DEFAULT_SYMBOL_NAMESPACE "PWM_LPSS"
+
 #include <linux/bits.h>
 #include <linux/delay.h>
 #include <linux/io.h>
···
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
 #include <linux/time.h>
-
-#define DEFAULT_SYMBOL_NAMESPACE "PWM_LPSS"
 
 #include "pwm-lpss.h"
 

include/linux/device.h

···
 #include <linux/atomic.h>
 #include <linux/uidgid.h>
 #include <linux/gfp.h>
-#include <linux/overflow.h>
 #include <linux/device/bus.h>
 #include <linux/device/class.h>
+#include <linux/device/devres.h>
 #include <linux/device/driver.h>
 #include <linux/cleanup.h>
 #include <asm/device.h>
···
 					const struct bin_attribute *attr);
 void device_remove_bin_file(struct device *dev,
 			    const struct bin_attribute *attr);
-
-/* device resource management */
-typedef void (*dr_release_t)(struct device *dev, void *res);
-typedef int (*dr_match_t)(struct device *dev, void *res, void *match_data);
-
-void *__devres_alloc_node(dr_release_t release, size_t size, gfp_t gfp,
-			  int nid, const char *name) __malloc;
-#define devres_alloc(release, size, gfp) \
-	__devres_alloc_node(release, size, gfp, NUMA_NO_NODE, #release)
-#define devres_alloc_node(release, size, gfp, nid) \
-	__devres_alloc_node(release, size, gfp, nid, #release)
-
-void devres_for_each_res(struct device *dev, dr_release_t release,
-			 dr_match_t match, void *match_data,
-			 void (*fn)(struct device *, void *, void *),
-			 void *data);
-void devres_free(void *res);
-void devres_add(struct device *dev, void *res);
-void *devres_find(struct device *dev, dr_release_t release,
-		  dr_match_t match, void *match_data);
-void *devres_get(struct device *dev, void *new_res,
-		 dr_match_t match, void *match_data);
-void *devres_remove(struct device *dev, dr_release_t release,
-		    dr_match_t match, void *match_data);
-int devres_destroy(struct device *dev, dr_release_t release,
-		   dr_match_t match, void *match_data);
-int devres_release(struct device *dev, dr_release_t release,
-		   dr_match_t match, void *match_data);
-
-/* devres group */
-void * __must_check devres_open_group(struct device *dev, void *id, gfp_t gfp);
-void devres_close_group(struct device *dev, void *id);
-void devres_remove_group(struct device *dev, void *id);
-int devres_release_group(struct device *dev, void *id);
-
-/* managed devm_k.alloc/kfree for device drivers */
-void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) __alloc_size(2);
-void *devm_krealloc(struct device *dev, void *ptr, size_t size,
-		    gfp_t gfp) __must_check __realloc_size(3);
-__printf(3, 0) char *devm_kvasprintf(struct device *dev, gfp_t gfp,
-				     const char *fmt, va_list ap) __malloc;
-__printf(3, 4) char *devm_kasprintf(struct device *dev, gfp_t gfp,
-				    const char *fmt, ...) __malloc;
-static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
-{
-	return devm_kmalloc(dev, size, gfp | __GFP_ZERO);
-}
-static inline void *devm_kmalloc_array(struct device *dev,
-				       size_t n, size_t size, gfp_t flags)
-{
-	size_t bytes;
-
-	if (unlikely(check_mul_overflow(n, size, &bytes)))
-		return NULL;
-
-	return devm_kmalloc(dev, bytes, flags);
-}
-static inline void *devm_kcalloc(struct device *dev,
-				 size_t n, size_t size, gfp_t flags)
-{
-	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
-}
-static inline __realloc_size(3, 4) void * __must_check
-devm_krealloc_array(struct device *dev, void *p, size_t new_n, size_t new_size, gfp_t flags)
-{
-	size_t bytes;
-
-	if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
-		return NULL;
-
-	return devm_krealloc(dev, p, bytes, flags);
-}
-
-void devm_kfree(struct device *dev, const void *p);
-char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc;
-const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp);
-void *devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp)
-	__realloc_size(3);
-
-unsigned long devm_get_free_pages(struct device *dev,
-				  gfp_t gfp_mask, unsigned int order);
-void devm_free_pages(struct device *dev, unsigned long addr);
-
-#ifdef CONFIG_HAS_IOMEM
-void __iomem *devm_ioremap_resource(struct device *dev,
-				    const struct resource *res);
-void __iomem *devm_ioremap_resource_wc(struct device *dev,
-				       const struct resource *res);
-
-void __iomem *devm_of_iomap(struct device *dev,
-			    struct device_node *node, int index,
-			    resource_size_t *size);
-#else
-
-static inline
-void __iomem *devm_ioremap_resource(struct device *dev,
-				    const struct resource *res)
-{
-	return ERR_PTR(-EINVAL);
-}
-
-static inline
-void __iomem *devm_ioremap_resource_wc(struct device *dev,
-				       const struct resource *res)
-{
-	return ERR_PTR(-EINVAL);
-}
-
-static inline
-void __iomem *devm_of_iomap(struct device *dev,
-			    struct device_node *node, int index,
-			    resource_size_t *size)
-{
-	return ERR_PTR(-EINVAL);
-}
-
-#endif
 
 /* allows to add/remove a custom action to devres stack */
 int devm_remove_action_nowarn(struct device *dev, void (*action)(void *), void *data);

include/linux/device/devres.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _DEVICE_DEVRES_H_
+#define _DEVICE_DEVRES_H_
+
+#include <linux/err.h>
+#include <linux/gfp_types.h>
+#include <linux/numa.h>
+#include <linux/overflow.h>
+#include <linux/stdarg.h>
+#include <linux/types.h>
+
+struct device;
+struct device_node;
+struct resource;
+
+/* device resource management */
+typedef void (*dr_release_t)(struct device *dev, void *res);
+typedef int (*dr_match_t)(struct device *dev, void *res, void *match_data);
+
+void * __malloc
+__devres_alloc_node(dr_release_t release, size_t size, gfp_t gfp, int nid, const char *name);
+#define devres_alloc(release, size, gfp) \
+	__devres_alloc_node(release, size, gfp, NUMA_NO_NODE, #release)
+#define devres_alloc_node(release, size, gfp, nid) \
+	__devres_alloc_node(release, size, gfp, nid, #release)
+
+void devres_for_each_res(struct device *dev, dr_release_t release,
+			 dr_match_t match, void *match_data,
+			 void (*fn)(struct device *, void *, void *),
+			 void *data);
+void devres_free(void *res);
+void devres_add(struct device *dev, void *res);
+void *devres_find(struct device *dev, dr_release_t release, dr_match_t match, void *match_data);
+void *devres_get(struct device *dev, void *new_res, dr_match_t match, void *match_data);
+void *devres_remove(struct device *dev, dr_release_t release, dr_match_t match, void *match_data);
+int devres_destroy(struct device *dev, dr_release_t release, dr_match_t match, void *match_data);
+int devres_release(struct device *dev, dr_release_t release, dr_match_t match, void *match_data);
+
+/* devres group */
+void * __must_check devres_open_group(struct device *dev, void *id, gfp_t gfp);
+void devres_close_group(struct device *dev, void *id);
+void devres_remove_group(struct device *dev, void *id);
+int devres_release_group(struct device *dev, void *id);
+
+/* managed devm_k.alloc/kfree for device drivers */
+void * __alloc_size(2)
+devm_kmalloc(struct device *dev, size_t size, gfp_t gfp);
+void * __must_check __realloc_size(3)
+devm_krealloc(struct device *dev, void *ptr, size_t size, gfp_t gfp);
+static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
+{
+	return devm_kmalloc(dev, size, gfp | __GFP_ZERO);
+}
+static inline void *devm_kmalloc_array(struct device *dev, size_t n, size_t size, gfp_t flags)
+{
+	size_t bytes;
+
+	if (unlikely(check_mul_overflow(n, size, &bytes)))
+		return NULL;
+
+	return devm_kmalloc(dev, bytes, flags);
+}
+static inline void *devm_kcalloc(struct device *dev, size_t n, size_t size, gfp_t flags)
+{
+	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
+}
+static inline __realloc_size(3, 4) void * __must_check
+devm_krealloc_array(struct device *dev, void *p, size_t new_n, size_t new_size, gfp_t flags)
+{
+	size_t bytes;
+
+	if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
+		return NULL;
+
+	return devm_krealloc(dev, p, bytes, flags);
+}
+
+void devm_kfree(struct device *dev, const void *p);
+
+void * __realloc_size(3)
+devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp);
+static inline void *devm_kmemdup_array(struct device *dev, const void *src,
+				       size_t n, size_t size, gfp_t flags)
+{
+	return devm_kmemdup(dev, src, size_mul(size, n), flags);
+}
+
+char * __malloc
+devm_kstrdup(struct device *dev, const char *s, gfp_t gfp);
+const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp);
+char * __printf(3, 0) __malloc
+devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt, va_list ap);
+char * __printf(3, 4) __malloc
+devm_kasprintf(struct device *dev, gfp_t gfp, const char *fmt, ...);
+
+unsigned long devm_get_free_pages(struct device *dev, gfp_t gfp_mask, unsigned int order);
+void devm_free_pages(struct device *dev, unsigned long addr);
+
+#ifdef CONFIG_HAS_IOMEM
+
+void __iomem *devm_ioremap_resource(struct device *dev, const struct resource *res);
+void __iomem *devm_ioremap_resource_wc(struct device *dev, const struct resource *res);
+
+void __iomem *devm_of_iomap(struct device *dev, struct device_node *node, int index,
+			    resource_size_t *size);
+#else
+
+static inline
+void __iomem *devm_ioremap_resource(struct device *dev, const struct resource *res)
+{
+	return IOMEM_ERR_PTR(-EINVAL);
+}
+
+static inline
+void __iomem *devm_ioremap_resource_wc(struct device *dev, const struct resource *res)
+{
+	return IOMEM_ERR_PTR(-EINVAL);
+}
+
+static inline
+void __iomem *devm_of_iomap(struct device *dev, struct device_node *node, int index,
+			    resource_size_t *size)
+{
+	return IOMEM_ERR_PTR(-EINVAL);
+}
+
+#endif
+
+#endif /* _DEVICE_DEVRES_H_ */

include/linux/err.h

···
 /* Return the pointer in the percpu address space. */
 #define ERR_PTR_PCPU(error) ((void __percpu *)(unsigned long)ERR_PTR(error))
 
+/* Cast an error pointer to __iomem. */
+#define IOMEM_ERR_PTR(error) (__force void __iomem *)ERR_PTR(error)
+
 /**
  * PTR_ERR - Extract the error code from an error pointer.
  * @ptr: An error pointer.

include/linux/io.h

···
 }
 #endif
 
-#define IOMEM_ERR_PTR(err) (__force void __iomem *)ERR_PTR(err)
-
 void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
 			   resource_size_t size);
 void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset,

include/linux/platform_data/x86/pwm-lpss.h

···
 	unsigned int npwm;
 	unsigned long base_unit_bits;
 	/*
-	 * Some versions of the IP may stuck in the state machine if enable
-	 * bit is not set, and hence update bit will show busy status till
-	 * the reset. For the rest it may be otherwise.
+	 * NOTE:
+	 * Intel Broxton, Apollo Lake, and Gemini Lake have different programming flow.
+	 *
+	 * Initial Enable or First Activation
+	 * 1. Program the base unit and on time divisor values.
+	 * 2. Set the software update bit.
+	 * 3. Poll in a loop on the PWMCTRL bit until software update bit is cleared.+
+	 * 4. Enable the PWM output by setting PWM Enable.
+	 * 5. Repeat the above steps for the next PWM Module.
+	 *
+	 * Dynamic update while PWM is Enabled
+	 * 1. Program the base unit and on-time divisor values.
+	 * 2. Set the software update bit.
+	 * 3. Repeat the above steps for the next PWM module.
+	 *
+	 * + After setting PWMCTRL register's SW update bit, hardware automatically
+	 * deasserts the SW update bit after a brief delay. It was observed that
+	 * setting of PWM enable is typically done via read-modify-write of the PWMCTRL
+	 * register. If there is no/little delay between setting software update bit
+	 * and setting enable bit via read-modify-write, it is possible that the read
+	 * could return with software enable as 1. In that case, the last write to set
+	 * enable to 1 could also set sw_update to 1. If this happens, sw_update gets
+	 * stuck and the driver code can hang as it explicitly waits for sw_update bit
+	 * to be 0 after setting the enable bit to 1. To avoid this race condition,
+	 * SW should poll on the software update bit to make sure that it is 0 before
+	 * doing the read-modify-write to set the enable bit to 1.
+	 *
+	 * Also, we noted that if sw_update bit was set in step #1 above then when it
+	 * is set again in step #2, sw_update bit never gets cleared and the flow hangs.
+	 * As such, we need to make sure that sw_update bit is 0 when doing step #1.
 	 */
 	bool bypass;
 	/*