[RFC PATCH 1/3] spi: spi-mem: add optional prepare/unprepare methods in spi_controller_mem_ops

[Yicong Yang <yangyicong@xxxxxxxxxxxxx>]

Some prepare/unprepare works may be necessary before/after a set of
operations of the spimem device. For example, before/after spi-nor
flash's read/write/erase/lock/unlock.

Add optional prepare/unprepare methods in spi_controller_mem_ops to allow
the controller to do specific works after/before the operations. The upper
user can use spi_mem_{prepare, unprepare}() to call the methods of the
controller.

Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
---
 drivers/spi/spi-mem.c       | 20 ++++++++++++++++++++
 include/linux/spi/spi-mem.h | 11 +++++++++++
 2 files changed, 31 insertions(+)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index adaa0c4..f09cef1 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -220,6 +220,26 @@ bool spi_mem_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
 }
 EXPORT_SYMBOL_GPL(spi_mem_supports_op);
 
+int spi_mem_prepare(struct spi_mem *mem)
+{
+	struct spi_controller *ctlr = mem->spi->controller;
+
+	if (ctlr->mem_ops && ctlr->mem_ops->prepare)
+		return ctlr->mem_ops->prepare(mem);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(spi_mem_prepare);
+
+void spi_mem_unprepare(struct spi_mem *mem)
+{
+	struct spi_controller *ctlr = mem->spi->controller;
+
+	if (ctlr->mem_ops && ctlr->mem_ops->unprepare)
+		ctlr->mem_ops->unprepare(mem);
+}
+EXPORT_SYMBOL_GPL(spi_mem_unprepare);
+
 static int spi_mem_access_start(struct spi_mem *mem)
 {
 	struct spi_controller *ctlr = mem->spi->controller;
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
index af9ff2f..e40b5c3 100644
--- a/include/linux/spi/spi-mem.h
+++ b/include/linux/spi/spi-mem.h
@@ -215,6 +215,12 @@ static inline void *spi_mem_get_drvdata(struct spi_mem *mem)
  *		    limitations)
  * @supports_op: check if an operation is supported by the controller
  * @exec_op: execute a SPI memory operation
+ * @prepare: do some prepare works before a set of operations. for example,
+ *	     read/write/erase/lock/unlock operations of spi-nor flash. This
+ *	     method is optional.
+ * @unprepare: do some post works after a set of operations. for example,
+ *	       read/write/erase/lock/unlock operations of spi-nor flash. This
+ *	       method is optional.
  * @get_name: get a custom name for the SPI mem device from the controller.
  *	      This might be needed if the controller driver has been ported
  *	      to use the SPI mem layer and a custom name is used to keep
@@ -253,6 +259,8 @@ struct spi_controller_mem_ops {
 	int (*adjust_op_size)(struct spi_mem *mem, struct spi_mem_op *op);
 	bool (*supports_op)(struct spi_mem *mem,
 			    const struct spi_mem_op *op);
+	int (*prepare)(struct spi_mem *mem);
+	void (*unprepare)(struct spi_mem *mem);
 	int (*exec_op)(struct spi_mem *mem,
 		       const struct spi_mem_op *op);
 	const char *(*get_name)(struct spi_mem *mem);
@@ -329,6 +337,9 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op);
 bool spi_mem_supports_op(struct spi_mem *mem,
 			 const struct spi_mem_op *op);
 
+int spi_mem_prepare(struct spi_mem *mem);
+void spi_mem_unprepare(struct spi_mem *mem);
+
 int spi_mem_exec_op(struct spi_mem *mem,
 		    const struct spi_mem_op *op);
 
-- 
2.8.1