pwm: Add TI PWM subsystem driver

In some platforms (like am33xx), PWM sub modules (ECAP, EHRPWM, EQEP)
are integrated to PWM subsystem. These PWM submodules has resources
shared and only one register bit-field is provided to control
module/clock enable/disable, makes it difficult to handle common
resources from independent PWMSS submodule drivers.

So the solution here implemented in this patch is, to create driver for
PWMSS and take the role of parent driver for PWM submodules. PWMSS
parent driver enumerates all the child nodes under PWMSS module. Also
symbol "pwmss_submodule_state_change" exported to enable clock gating
for individual PWMSS submodules, and submodule drivers has to enable
clock gating from their drivers.

As this is only supported during DT boot, the parent/child relationship
is created and populated in DT execution flow. The only required change
is inside DTS file, making EHRPWM & ECAP as a child to PWMSS node.

Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-tipwmss.h b/drivers/pwm/pwm-tipwmss.h
new file mode 100644
index 000000000000..11f76a1e266b
--- /dev/null
+++ b/drivers/pwm/pwm-tipwmss.h
@@ -0,0 +1,39 @@
+/*
+ * TI PWM Subsystem driver
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * 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.
+ *
+ * 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.
+ *
+ */
+
+#ifndef __TIPWMSS_H
+#define __TIPWMSS_H
+
+#ifdef CONFIG_PWM_TIPWMSS
+/* PWM substem clock gating */
+#define PWMSS_ECAPCLK_EN	BIT(0)
+#define PWMSS_ECAPCLK_STOP_REQ	BIT(1)
+#define PWMSS_EPWMCLK_EN	BIT(8)
+#define PWMSS_EPWMCLK_STOP_REQ	BIT(9)
+
+#define PWMSS_ECAPCLK_EN_ACK	BIT(0)
+#define PWMSS_EPWMCLK_EN_ACK	BIT(8)
+
+extern u16 pwmss_submodule_state_change(struct device *dev, int set);
+#else
+static inline u16 pwmss_submodule_state_change(struct device *dev, int set)
+{
+	/* return success status value */
+	return 0xFFFF;
+}
+#endif
+#endif	/* __TIPWMSS_H */