ARM: 5628/1: ep93xx: Introduce Pulse Width Modulator (PWM) driver

The EP93xx features two PWMs (one on the EP9307) with the following
features:

  * Configurable dual output
  * Separate input clocks for each PWM output
  * 16-bit resolution
  * Programmable pulse width (duty cycle), interval (frequency), and
    polarity

This adds the necessary core support as well as the driver.  A sysfs
interface is provided to control the PWM outputs.

Signed-off-by: Matthieu Crapet <mcrapet@gmail.com>
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-ep93xx/clock.c

@@ -72,6 +72,9 @@ static struct clk clk_keypad = {
 	.enable_mask	= EP93XX_SYSCON_KEYTCHCLKDIV_KEN,
 	.set_rate	= set_keytchclk_rate,
 };
+static struct clk clk_pwm = {
+	.rate		= EP93XX_EXT_CLK_RATE,
+};
 
 /* DMA Clocks */
 static struct clk clk_m2p0 = {
@@ -137,6 +140,7 @@ static struct clk_lookup clocks[] = {
 	INIT_CK(NULL,			"pll2",		&clk_pll2),
 	INIT_CK("ep93xx-ohci",		NULL,		&clk_usb_host),
 	INIT_CK("ep93xx-keypad",	NULL,		&clk_keypad),
+	INIT_CK(NULL,			"pwm_clk",	&clk_pwm),
 	INIT_CK(NULL,			"m2p0",		&clk_m2p0),
 	INIT_CK(NULL,			"m2p1",		&clk_m2p1),
 	INIT_CK(NULL,			"m2p2",		&clk_m2p2),

arch/arm/mach-ep93xx/core.c

@@ -597,6 +597,91 @@ static struct platform_device ep93xx_leds = {
 };
 
 
+/*************************************************************************
+ * EP93xx pwm peripheral handling
+ *************************************************************************/
+static struct resource ep93xx_pwm0_resource[] = {
+	{
+		.start	= EP93XX_PWM_PHYS_BASE,
+		.end	= EP93XX_PWM_PHYS_BASE + 0x10 - 1,
+		.flags	= IORESOURCE_MEM,
+	},
+};
+
+static struct platform_device ep93xx_pwm0_device = {
+	.name		= "ep93xx-pwm",
+	.id		= 0,
+	.num_resources	= ARRAY_SIZE(ep93xx_pwm0_resource),
+	.resource	= ep93xx_pwm0_resource,
+};
+
+static struct resource ep93xx_pwm1_resource[] = {
+	{
+		.start	= EP93XX_PWM_PHYS_BASE + 0x20,
+		.end	= EP93XX_PWM_PHYS_BASE + 0x30 - 1,
+		.flags	= IORESOURCE_MEM,
+	},
+};
+
+static struct platform_device ep93xx_pwm1_device = {
+	.name		= "ep93xx-pwm",
+	.id		= 1,
+	.num_resources	= ARRAY_SIZE(ep93xx_pwm1_resource),
+	.resource	= ep93xx_pwm1_resource,
+};
+
+void __init ep93xx_register_pwm(int pwm0, int pwm1)
+{
+	if (pwm0)
+		platform_device_register(&ep93xx_pwm0_device);
+
+	/* NOTE: EP9307 does not have PWMOUT1 (pin EGPIO14) */
+	if (pwm1)
+		platform_device_register(&ep93xx_pwm1_device);
+}
+
+int ep93xx_pwm_acquire_gpio(struct platform_device *pdev)
+{
+	int err;
+
+	if (pdev->id == 0) {
+		err = 0;
+	} else if (pdev->id == 1) {
+		err = gpio_request(EP93XX_GPIO_LINE_EGPIO14,
+				   dev_name(&pdev->dev));
+		if (err)
+			return err;
+		err = gpio_direction_output(EP93XX_GPIO_LINE_EGPIO14, 0);
+		if (err)
+			goto fail;
+
+		/* PWM 1 output on EGPIO[14] */
+		ep93xx_devcfg_set_bits(EP93XX_SYSCON_DEVCFG_PONG);
+	} else {
+		err = -ENODEV;
+	}
+
+	return err;
+
+fail:
+	gpio_free(EP93XX_GPIO_LINE_EGPIO14);
+	return err;
+}
+EXPORT_SYMBOL(ep93xx_pwm_acquire_gpio);
+
+void ep93xx_pwm_release_gpio(struct platform_device *pdev)
+{
+	if (pdev->id == 1) {
+		gpio_direction_input(EP93XX_GPIO_LINE_EGPIO14);
+		gpio_free(EP93XX_GPIO_LINE_EGPIO14);
+
+		/* EGPIO[14] used for GPIO */
+		ep93xx_devcfg_clear_bits(EP93XX_SYSCON_DEVCFG_PONG);
+	}
+}
+EXPORT_SYMBOL(ep93xx_pwm_release_gpio);
+
+
 extern void ep93xx_gpio_init(void);
 
 void __init ep93xx_init_devices(void)

arch/arm/mach-ep93xx/include/mach/ep93xx-regs.h

@@ -147,6 +147,7 @@
 #define EP93XX_ADC_BASE			EP93XX_APB_IOMEM(0x00100000)
 #define EP93XX_TOUCHSCREEN_BASE		EP93XX_APB_IOMEM(0x00100000)
 
+#define EP93XX_PWM_PHYS_BASE		(EP93XX_APB_PHYS_BASE + 0x00110000)
 #define EP93XX_PWM_BASE			EP93XX_APB_IOMEM(0x00110000)
 
 #define EP93XX_RTC_PHYS_BASE		(EP93XX_APB_PHYS_BASE + 0x00120000)

arch/arm/mach-ep93xx/include/mach/platform.h

@@ -5,6 +5,7 @@
 #ifndef __ASSEMBLY__
 
 struct i2c_board_info;
+struct platform_device;
 
 struct ep93xx_eth_data
 {
@@ -32,6 +33,9 @@ static inline void ep93xx_devcfg_clear_bits(unsigned int bits)
 
 void ep93xx_register_eth(struct ep93xx_eth_data *data, int copy_addr);
 void ep93xx_register_i2c(struct i2c_board_info *devices, int num);
+void ep93xx_register_pwm(int pwm0, int pwm1);
+int ep93xx_pwm_acquire_gpio(struct platform_device *pdev);
+void ep93xx_pwm_release_gpio(struct platform_device *pdev);
 
 void ep93xx_init_devices(void);
 extern struct sys_timer ep93xx_timer;

drivers/misc/Kconfig

@@ -233,6 +233,19 @@ config ISL29003
 	  This driver can also be built as a module.  If so, the module
 	  will be called isl29003.
 
+config EP93XX_PWM
+	tristate "EP93xx PWM support"
+	depends on ARCH_EP93XX
+	help
+	  This option enables device driver support for the PWM channels
+	  on the Cirrus EP93xx processors.  The EP9307 chip only has one
+	  PWM channel all the others have two, the second channel is an
+	  alternate function of the EGPIO14 pin.  A sysfs interface is
+	  provided to control the PWM channels.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called ep93xx_pwm.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"

drivers/misc/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_SGI_XP)		+= sgi-xp/
 obj-$(CONFIG_SGI_GRU)		+= sgi-gru/
 obj-$(CONFIG_HP_ILO)		+= hpilo.o
 obj-$(CONFIG_ISL29003)		+= isl29003.o
+obj-$(CONFIG_EP93XX_PWM)	+= ep93xx_pwm.o
 obj-$(CONFIG_C2PORT)		+= c2port/
 obj-y				+= eeprom/
 obj-y				+= cb710/