[PATCH v3 1/2] pinctrl: sh-pfc: Improve pinmux macros documentation

[Geert Uytterhoeven <geert+renesas@glider.be>]

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
---
v3:
  - Add Acked-by,
  - Document function names referring to IPSR fields,
  - Replace "configuration register" by more specific terms,
  - Rename "ms" to "msel" or "gsel",
  - EMEV2 PINMUX_IPSR_NOFN() pinmux configurations have a GPIO function,

v2:
  - Clarify same width vs. different widths,
  - Mention GPSR for PINMUX_IPSR_DATA(),
  - Document NOGM (= NOGP + MSEL),
  - Fix s/ispr/ipsr/ typos.
---
 drivers/pinctrl/sh-pfc/sh_pfc.h | 94 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 86 insertions(+), 8 deletions(-)

diff --git a/drivers/pinctrl/sh-pfc/sh_pfc.h b/drivers/pinctrl/sh-pfc/sh_pfc.h
index 6b8180fbdf86a637..d430ee9a652a4a03 100644
--- a/drivers/pinctrl/sh-pfc/sh_pfc.h
+++ b/drivers/pinctrl/sh-pfc/sh_pfc.h
@@ -100,10 +100,31 @@ struct pinmux_cfg_reg {
 	const u8 *var_field_width;
 };
 
+/*
+ * Describe a config register consisting of several fields of the same width
+ *   - name: Register name (unused, for documentation purposes only)
+ *   - r: Physical register address
+ *   - r_width: Width of the register (in bits)
+ *   - f_width: Width of the fixed-width register fields (in bits)
+ * This macro must be followed by initialization data: For each register field
+ * (from left to right, i.e. MSB to LSB), 2^f_width enum IDs must be specified,
+ * one for each possible combination of the register field bit values.
+ */
 #define PINMUX_CFG_REG(name, r, r_width, f_width) \
 	.reg = r, .reg_width = r_width, .field_width = f_width,		\
 	.enum_ids = (const u16 [(r_width / f_width) * (1 << f_width)])
 
+/*
+ * Describe a config register consisting of several fields of different widths
+ *   - name: Register name (unused, for documentation purposes only)
+ *   - r: Physical register address
+ *   - r_width: Width of the register (in bits)
+ *   - var_fw0, var_fwn...: List of widths of the register fields (in bits),
+ *                          From left to right (i.e. MSB to LSB)
+ * This macro must be followed by initialization data: For each register field
+ * (from left to right, i.e. MSB to LSB), 2^var_fwi enum IDs must be specified,
+ * one for each possible combination of the register field bit values.
+ */
 #define PINMUX_CFG_REG_VAR(name, r, r_width, var_fw0, var_fwn...) \
 	.reg = r, .reg_width = r_width,	\
 	.var_field_width = (const u8 [r_width]) \
@@ -116,6 +137,14 @@ struct pinmux_data_reg {
 	const u16 *enum_ids;
 };
 
+/*
+ * Describe a data register
+ *   - name: Register name (unused, for documentation purposes only)
+ *   - r: Physical register address
+ *   - r_width: Width of the register (in bits)
+ * This macro must be followed by initialization data: For each register bit
+ * (from left to right, i.e. MSB to LSB), one enum ID must be specified.
+ */
 #define PINMUX_DATA_REG(name, r, r_width) \
 	.reg = r, .reg_width = r_width,	\
 	.enum_ids = (const u16 [r_width]) \
@@ -124,6 +153,10 @@ struct pinmux_irq {
 	const short *gpios;
 };
 
+/*
+ * Describe the mapping from GPIOs to a single IRQ
+ *   - ids...: List of GPIOs that are mapped to the same IRQ
+ */
 #define PINMUX_IRQ(ids...)			   \
 	{ .gpios = (const short []) { ids, -1 } }
 
@@ -185,18 +218,63 @@ struct sh_pfc_soc_info {
  * sh_pfc_soc_info pinmux_data array macros
  */
 
+/*
+ * Describe generic pinmux data
+ *   - data_or_mark: *_DATA or *_MARK enum ID
+ *   - ids...: List of enum IDs to associate with data_or_mark
+ */
 #define PINMUX_DATA(data_or_mark, ids...)	data_or_mark, ids, 0
 
-#define PINMUX_IPSR_NOGP(ispr, fn)					\
+/*
+ * Describe a pinmux configuration without GPIO function that needs
+ * configuration in a Peripheral Function Select Register (IPSR)
+ *   - ipsr: IPSR field (unused, for documentation purposes only)
+ *   - fn: Function name, referring to a field in the IPSR
+ */
+#define PINMUX_IPSR_NOGP(ipsr, fn)					\
 	PINMUX_DATA(fn##_MARK, FN_##fn)
+
+/*
+ * Describe a pinmux configuration with GPIO function that needs configuration
+ * in both a Peripheral Function Select Register (IPSR) and in a
+ * GPIO/Peripheral Function Select Register 1 (GPSR)
+ *   - ipsr: IPSR field
+ *   - fn: Function name, also referring to the IPSR field
+ */
 #define PINMUX_IPSR_DATA(ipsr, fn)					\
 	PINMUX_DATA(fn##_MARK, FN_##fn, FN_##ipsr)
-#define PINMUX_IPSR_NOGM(ispr, fn, ms)					\
-	PINMUX_DATA(fn##_MARK, FN_##fn, FN_##ms)
-#define PINMUX_IPSR_NOFN(ipsr, fn, ms)					\
-	PINMUX_DATA(fn##_MARK, FN_##ipsr, FN_##ms)
-#define PINMUX_IPSR_MSEL(ipsr, fn, ms)					\
-	PINMUX_DATA(fn##_MARK, FN_##ms, FN_##ipsr, FN_##fn)
+
+/*
+ * Describe a pinmux configuration without GPIO function that needs
+ * configuration in a Peripheral Function Select Register (IPSR), and where the
+ * pinmux function has a representation in a Module Select Register (MOD_SEL).
+ *   - ipsr: IPSR field
+ *   - fn: Function name, also referring to the IPSR field
+ *   - msel: Module selector
+ */
+#define PINMUX_IPSR_NOGM(ipsr, fn, msel)				\
+	PINMUX_DATA(fn##_MARK, FN_##fn, FN_##msel)
+
+/*
+ * Describe a pinmux configuration with GPIO function where the pinmux function
+ * has no representation in a Peripheral Function Select Register (IPSR), but
+ * instead solely depends on a group selection.
+ *   - gpsr: GPSR field
+ *   - fn: Function name, also referring to the GPSR field
+ *   - gsel: Group selector
+ */
+#define PINMUX_IPSR_NOFN(gpsr, fn, gsel)				\
+	PINMUX_DATA(fn##_MARK, FN_##gpsr, FN_##gsel)
+
+/*
+ * Describe a pinmux configuration where the pinmux function has a
+ * representation in a Module Select Register (MOD_SEL).
+ *   - ipsr: IPSR field
+ *   - fn: Function name, also referring to the IPSR field
+ *   - msel: Module selector
+ */
+#define PINMUX_IPSR_MSEL(ipsr, fn, msel)				\
+	PINMUX_DATA(fn##_MARK, FN_##msel, FN_##ipsr, FN_##fn)
 
 /*
  * Describe a pinmux configuration for a single-function pin.
@@ -334,7 +412,7 @@ struct sh_pfc_soc_info {
 	PINMUX_GPIO_FN(GPIO_FN_##str, PINMUX_FN_BASE, str##_MARK)
 
 /*
- * PORTnCR macro
+ * PORTnCR helper macro for SH-Mobile/R-Mobile
  */
 #define PORTCR(nr, reg)							\
 	{								\
-- 
1.9.1