[PATCH 07/10] spi: sh-msiof: Add support for R-Car H2 and M2

[Geert Uytterhoeven <geert@linux-m68k.org>]

From: Geert Uytterhoeven <geert+renesas@linux-m68k.org>

Add support for the MSIOF variant in the R-Car H2 (r8a7790) and M2
(r8a7791) SoCs.

Binding documentation:
  - Add future-proof "renesas,msiof-<soctype>" compatible values,
  - Add example bindings.

Implementation:
  - MSIOF on R-Car H2 and M2 requires the transmission of dummy data if
    data is being received only (cfr. "Set SICTR.TSCKE to 1" and "Write
    dummy transmission data to SITFDR" in paragraph "Transmit and Receive
    Procedures" of the Hardware User's Manual).
  - As RX depends on TX, MSIOF on R-Car H2 and M2 also lacks the RSCR
    register (Receive Clock Select Register), and some bits in the RMDR1
    (Receive Mode Register 1) and TMDR2 (Transmit Mode Register 2)
    registers.
  - Use the recently introduced SPI_MASTER_MUST_TX flag to enable support
    for dummy transmission in the SPI core, and to differentiate from other
    MSIOF implementations in code paths that need this.
  - New DT compatible values ("renesas,msiof-r8a7790" and
    "renesas,msiof-r8a7791") are added, as well as new platform device
    names ("spi_r8a7790_msiof" and "spi_r8a7791_msiof").
  - Hardware features are indicated using a new struct sh_msiof_chipdata,
    which is used for both DT and legacy binding. For now this contains the
    SPI master flags only.

This is loosely based on a set of patches from Takashi Yoshii
<takasi-y@ops.dti.ne.jp>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Cc: Takashi Yoshii <takasi-y@ops.dti.ne.jp>
Cc: devicetree@vger.kernel.org
---
 Documentation/devicetree/bindings/spi/sh-msiof.txt |   21 +++++++-
 drivers/spi/spi-sh-msiof.c                         |   57 ++++++++++++++++----
 2 files changed, 66 insertions(+), 12 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/sh-msiof.txt b/Documentation/devicetree/bindings/spi/sh-msiof.txt
index 52cf5c78705b..1528d30a6f6d 100644
--- a/Documentation/devicetree/bindings/spi/sh-msiof.txt
+++ b/Documentation/devicetree/bindings/spi/sh-msiof.txt
@@ -1,8 +1,13 @@
 Renesas MSIOF spi controller
 
 Required properties:
-- compatible           : "renesas,sh-msiof" for SuperH, or
+- compatible           : "renesas,msiof-<soctype>" for SoCs,
+			 "renesas,sh-msiof" for SuperH, or
 			 "renesas,sh-mobile-msiof" for SH Mobile series.
+			 Examples with soctypes are:
+			 "renesas,msiof-sh7724" (SH)
+			 "renesas,msiof-r8a7790" (R-Car H2)
+			 "renesas,msiof-r8a7791" (R-Car M2)
 - reg                  : Offset and length of the register set for the device
 - interrupt-parent     : The phandle for the interrupt controller that
 			 services interrupts for this device
@@ -20,3 +25,17 @@ Optional properties:
 
 Pinctrl properties might be needed, too.  See
 Documentation/devicetree/bindings/pinctrl/renesas,*.
+
+Example:
+
+	spi1: spi@e6e20000 {
+		compatible = "renesas,msiof-r8a7791";
+		reg = <0 0xe6e20000 0 0x0064>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 156 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&mstp0_clks R8A7791_CLK_MSIOF0>;
+		num-cs = <1>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		status = "disabled";
+	};
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c
index 92515c1ececa..31624fb4997d 100644
--- a/drivers/spi/spi-sh-msiof.c
+++ b/drivers/spi/spi-sh-msiof.c
@@ -20,6 +20,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 
@@ -29,11 +30,17 @@
 
 #include <asm/unaligned.h>
 
+
+struct sh_msiof_chipdata {
+	u16 master_flags;
+};
+
 struct sh_msiof_spi_priv {
 	struct spi_bitbang bitbang; /* must be first for spi_bitbang.c */
 	void __iomem *mapbase;
 	struct clk *clk;
 	struct platform_device *pdev;
+	const struct sh_msiof_chipdata *chipdata;
 	struct sh_msiof_spi_info *info;
 	struct completion done;
 	unsigned long flags;
@@ -210,7 +217,8 @@ static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p,
 	k = min_t(int, k, ARRAY_SIZE(sh_msiof_spi_clk_table) - 1);
 
 	sh_msiof_write(p, TSCR, sh_msiof_spi_clk_table[k].scr);
-	sh_msiof_write(p, RSCR, sh_msiof_spi_clk_table[k].scr);
+	if (!(p->chipdata->master_flags & SPI_MASTER_MUST_TX))
+		sh_msiof_write(p, RSCR, sh_msiof_spi_clk_table[k].scr);
 }
 
 static void sh_msiof_spi_set_pin_regs(struct sh_msiof_spi_priv *p,
@@ -233,6 +241,10 @@ static void sh_msiof_spi_set_pin_regs(struct sh_msiof_spi_priv *p,
 	tmp |= !cs_high << MDR1_SYNCAC_SHIFT;
 	tmp |= lsb_first << MDR1_BITLSB_SHIFT;
 	sh_msiof_write(p, TMDR1, tmp | MDR1_TRMD | TMDR1_PCON);
+	if (p->chipdata->master_flags & SPI_MASTER_MUST_TX) {
+		/* These bits are reserved if RX needs TX */
+		tmp &= ~0x0000ffff;
+	}
 	sh_msiof_write(p, RMDR1, tmp);
 
 	tmp = 0;
@@ -253,7 +265,7 @@ static void sh_msiof_spi_set_mode_regs(struct sh_msiof_spi_priv *p,
 {
 	u32 dr2 = MDR2_BITLEN1(bits) | MDR2_WDLEN1(words);
 
-	if (tx_buf)
+	if (tx_buf || (p->chipdata->master_flags & SPI_MASTER_MUST_TX))
 		sh_msiof_write(p, TMDR2, dr2);
 	else
 		sh_msiof_write(p, TMDR2, dr2 | MDR2_GRPMASK1);
@@ -659,6 +671,23 @@ static u32 sh_msiof_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
 }
 
 #ifdef CONFIG_OF
+static const struct sh_msiof_chipdata sh_data = {
+	.master_flags = 0,
+};
+
+static const struct sh_msiof_chipdata r8a779x_data = {
+	.master_flags = SPI_MASTER_MUST_TX,
+};
+
+static const struct of_device_id sh_msiof_match[] = {
+	{ .compatible = "renesas,sh-msiof",        .data = &sh_data },
+	{ .compatible = "renesas,sh-mobile-msiof", .data = &sh_data },
+	{ .compatible = "renesas,msiof-r8a7790",   .data = &r8a779x_data },
+	{ .compatible = "renesas,msiof-r8a7791",   .data = &r8a779x_data },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sh_msiof_match);
+
 static struct sh_msiof_spi_info *sh_msiof_spi_parse_dt(struct device *dev)
 {
 	struct sh_msiof_spi_info *info;
@@ -693,6 +722,7 @@ static int sh_msiof_spi_probe(struct platform_device *pdev)
 {
 	struct resource	*r;
 	struct spi_master *master;
+	const struct of_device_id *of_id;
 	struct sh_msiof_spi_priv *p;
 	int i;
 	int ret;
@@ -706,10 +736,15 @@ static int sh_msiof_spi_probe(struct platform_device *pdev)
 	p = spi_master_get_devdata(master);
 
 	platform_set_drvdata(pdev, p);
-	if (pdev->dev.of_node)
+
+	of_id = of_match_device(sh_msiof_match, &pdev->dev);
+	if (of_id) {
+		p->chipdata = of_id->data;
 		p->info = sh_msiof_spi_parse_dt(&pdev->dev);
-	else
+	} else {
+		p->chipdata = (const void *)pdev->id_entry->driver_data;
 		p->info = dev_get_platdata(&pdev->dev);
+	}
 
 	if (!p->info) {
 		dev_err(&pdev->dev, "failed to obtain device info\n");
@@ -769,7 +804,7 @@ static int sh_msiof_spi_probe(struct platform_device *pdev)
 	/* init master and bitbang code */
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 	master->mode_bits |= SPI_LSB_FIRST | SPI_3WIRE;
-	master->flags = 0;
+	master->flags = p->chipdata->master_flags;
 	master->bus_num = pdev->id;
 	master->dev.of_node = pdev->dev.of_node;
 	master->num_chipselect = p->info->num_chipselect;
@@ -810,18 +845,18 @@ static int sh_msiof_spi_remove(struct platform_device *pdev)
 	return ret;
 }
 
-#ifdef CONFIG_OF
-static const struct of_device_id sh_msiof_match[] = {
-	{ .compatible = "renesas,sh-msiof", },
-	{ .compatible = "renesas,sh-mobile-msiof", },
+static struct platform_device_id spi_driver_ids[] = {
+	{ "spi_sh_msiof",	(kernel_ulong_t)&sh_data },
+	{ "spi_r8a7790_msiof",	(kernel_ulong_t)&r8a779x_data },
+	{ "spi_r8a7791_msiof",	(kernel_ulong_t)&r8a779x_data },
 	{},
 };
-MODULE_DEVICE_TABLE(of, sh_msiof_match);
-#endif
+MODULE_DEVICE_TABLE(platform, spi_driver_ids);
 
 static struct platform_driver sh_msiof_spi_drv = {
 	.probe		= sh_msiof_spi_probe,
 	.remove		= sh_msiof_spi_remove,
+	.id_table	= spi_driver_ids,
 	.driver		= {
 		.name		= "spi_sh_msiof",
 		.owner		= THIS_MODULE,
-- 
1.7.9.5