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From:   Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
To:     Mark Brown <broonie@kernel.org>
Cc:     Pratyush Yadav <p.yadav@ti.com>,
        Tudor Ambarus <tudor.ambarus@microchip.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Ramuthevar Vadivel Murugan 
        <vadivel.muruganx.ramuthevar@linux.intel.com>,
        linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Subject: [PATCH 1/2] spi: cadence-quadspi: further simplify cqspi_set_protocol()
Date:   Tue, 19 Apr 2022 10:46:39 +0200
Message-Id: <20220419084640.191299-1-matthias.schiffer@ew.tq-group.com>
MIME-Version: 1.0
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- Remove checks for unsupported modes that are already handled by
  supports_op(). This allows to change the function to return void.
- Distinguishing DTR and non-DTR modes is not necessary for the setup of
  the bus widths
- Only cmd DTR flag needs to be checked, supports_op() already checks
  that the DTR flags of all relevant parts of the op match
- Check nbytes instead of buswidth for 0, for consistency with
  supports_op() etc.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---
 drivers/spi/spi-cadence-quadspi.c | 73 +++++--------------------------
 1 file changed, 10 insertions(+), 63 deletions(-)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 19686fb47bb3..96d14f3847b5 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -368,58 +368,13 @@ static unsigned int cqspi_calc_dummy(const struct spi_mem_op *op, bool dtr)
 	return dummy_clk;
 }
 
-static int cqspi_set_protocol(struct cqspi_flash_pdata *f_pdata,
-			      const struct spi_mem_op *op)
+static void cqspi_set_protocol(struct cqspi_flash_pdata *f_pdata,
+			       const struct spi_mem_op *op)
 {
-	/*
-	 * For an op to be DTR, cmd phase along with every other non-empty
-	 * phase should have dtr field set to 1. If an op phase has zero
-	 * nbytes, ignore its dtr field; otherwise, check its dtr field.
-	 */
-	f_pdata->dtr = op->cmd.dtr &&
-		       (!op->addr.nbytes || op->addr.dtr) &&
-		       (!op->data.nbytes || op->data.dtr);
-
-	f_pdata->inst_width = 0;
-	if (op->cmd.buswidth)
-		f_pdata->inst_width = ilog2(op->cmd.buswidth);
-
-	f_pdata->addr_width = 0;
-	if (op->addr.buswidth)
-		f_pdata->addr_width = ilog2(op->addr.buswidth);
-
-	f_pdata->data_width = 0;
-	if (op->data.buswidth)
-		f_pdata->data_width = ilog2(op->data.buswidth);
-
-	/* Right now we only support 8-8-8 DTR mode. */
-	if (f_pdata->dtr) {
-		switch (op->cmd.buswidth) {
-		case 0:
-		case 8:
-			break;
-		default:
-			return -EINVAL;
-		}
-
-		switch (op->addr.buswidth) {
-		case 0:
-		case 8:
-			break;
-		default:
-			return -EINVAL;
-		}
-
-		switch (op->data.buswidth) {
-		case 0:
-		case 8:
-			break;
-		default:
-			return -EINVAL;
-		}
-	}
-
-	return 0;
+	f_pdata->inst_width = op->cmd.nbytes ? ilog2(op->cmd.buswidth) : 0;
+	f_pdata->addr_width = op->addr.nbytes ? ilog2(op->addr.buswidth) : 0;
+	f_pdata->data_width = op->data.nbytes ? ilog2(op->data.buswidth) : 0;
+	f_pdata->dtr = op->cmd.dtr;
 }
 
 static int cqspi_wait_idle(struct cqspi_st *cqspi)
@@ -549,9 +504,7 @@ static int cqspi_command_read(struct cqspi_flash_pdata *f_pdata,
 	size_t read_len;
 	int status;
 
-	status = cqspi_set_protocol(f_pdata, op);
-	if (status)
-		return status;
+	cqspi_set_protocol(f_pdata, op);
 
 	status = cqspi_enable_dtr(f_pdata, op, CQSPI_REG_OP_EXT_STIG_LSB,
 				  f_pdata->dtr);
@@ -622,9 +575,7 @@ static int cqspi_command_write(struct cqspi_flash_pdata *f_pdata,
 	size_t write_len;
 	int ret;
 
-	ret = cqspi_set_protocol(f_pdata, op);
-	if (ret)
-		return ret;
+	cqspi_set_protocol(f_pdata, op);
 
 	ret = cqspi_enable_dtr(f_pdata, op, CQSPI_REG_OP_EXT_STIG_LSB,
 			       f_pdata->dtr);
@@ -1244,9 +1195,7 @@ static ssize_t cqspi_write(struct cqspi_flash_pdata *f_pdata,
 	const u_char *buf = op->data.buf.out;
 	int ret;
 
-	ret = cqspi_set_protocol(f_pdata, op);
-	if (ret)
-		return ret;
+	cqspi_set_protocol(f_pdata, op);
 
 	ret = cqspi_write_setup(f_pdata, op);
 	if (ret)
@@ -1348,9 +1297,7 @@ static ssize_t cqspi_read(struct cqspi_flash_pdata *f_pdata,
 	int ret;
 
 	ddata = of_device_get_match_data(dev);
-	ret = cqspi_set_protocol(f_pdata, op);
-	if (ret)
-		return ret;
+	cqspi_set_protocol(f_pdata, op);
 
 	ret = cqspi_read_setup(f_pdata, op);
 	if (ret)
-- 
2.25.1