pwm: Add i.MX TPM PWM driver support

i.MX7ULP has TPM(Low Power Timer/Pulse Width Modulation Module) inside,
it can support multiple PWM channels, all the channels share same
counter and period setting, but each channel can configure its duty and
polarity independently.

There are several TPM modules in i.MX7ULP, the number of channels in TPM
modules are different, it can be read from each TPM module's PARAM
register.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/Kconfig

@@ -210,6 +210,17 @@ config PWM_IMX27
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-imx27.
 
+config PWM_IMX_TPM
+	tristate "i.MX TPM PWM support"
+	depends on ARCH_MXC || COMPILE_TEST
+	depends on HAVE_CLK && HAS_IOMEM
+	help
+	  Generic PWM framework driver for i.MX7ULP TPM module, TPM's full
+	  name is Low Power Timer/Pulse Width Modulation Module.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-imx-tpm.
+
 config PWM_JZ4740
 	tristate "Ingenic JZ47xx PWM support"
 	depends on MACH_INGENIC

drivers/pwm/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_PWM_HIBVT)		+= pwm-hibvt.o
 obj-$(CONFIG_PWM_IMG)		+= pwm-img.o
 obj-$(CONFIG_PWM_IMX1)		+= pwm-imx1.o
 obj-$(CONFIG_PWM_IMX27)		+= pwm-imx27.o
+obj-$(CONFIG_PWM_IMX_TPM)	+= pwm-imx-tpm.o
 obj-$(CONFIG_PWM_JZ4740)	+= pwm-jz4740.o
 obj-$(CONFIG_PWM_LP3943)	+= pwm-lp3943.o
 obj-$(CONFIG_PWM_LPC18XX_SCT)	+= pwm-lpc18xx-sct.o