linux-kernel - [PATCH v2 2/2] spi: spi-ti-qspi: Add checking which flash chip has been mmap-ed

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Date:   Fri, 30 Mar 2018 11:41:24 +0200
From:   Arkadiusz Kwiatkowski <arkadiusz.kwiatkowski@...iv.com>
To:     <vigneshr@...com>, <sourav.poddar@...com>, <broonie@...nel.org>
CC:     <linux-spi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Arkadiusz Kwiatkowski" <arkadiusz.kwiatkowski@...iv.com>
Subject: [PATCH v2 2/2] spi: spi-ti-qspi: Add checking which flash chip has been mmap-ed

This patch allows placing more than one flash chip on the qspi bus
by checking which spi device has been memory-mapped and remapping
if necessary.

Signed-off-by: Arkadiusz Kwiatkowski <arkadiusz.kwiatkowski@...iv.com>
---
 drivers/spi/spi-ti-qspi.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
index d0ea62d..5b99a1e 100644
--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -66,7 +66,7 @@ struct ti_qspi {
        u32 cmd;
        u32 dc;

-       bool mmap_enabled;
+       struct spi_device       *mmap_spi_device;
 };

 #define QSPI_PID                       (0x0)
@@ -493,7 +493,7 @@ static void ti_qspi_enable_memory_map(struct spi_device *spi)
                                   MEM_CS_MASK,
                                   MEM_CS_EN(spi->chip_select));
        }
-       qspi->mmap_enabled = true;
+       qspi->mmap_spi_device = spi;
 }

 static void ti_qspi_disable_memory_map(struct spi_device *spi)
@@ -504,7 +504,7 @@ static void ti_qspi_disable_memory_map(struct spi_device *spi)
        if (qspi->ctrl_base)
                regmap_update_bits(qspi->ctrl_base, qspi->ctrl_reg,
                                   MEM_CS_MASK, 0);
-       qspi->mmap_enabled = false;
+       qspi->mmap_spi_device = NULL;
 }

 static void ti_qspi_setup_mmap_read(struct spi_device *spi,
@@ -544,8 +544,12 @@ static int ti_qspi_spi_flash_read(struct spi_device *spi,

        mutex_lock(&qspi->list_lock);

-       if (!qspi->mmap_enabled)
+       if (qspi->mmap_spi_device != spi) {
+               if (qspi->mmap_spi_device)
+                       ti_qspi_disable_memory_map(qspi->mmap_spi_device);
                ti_qspi_enable_memory_map(spi);
+       }
+
        ti_qspi_setup_mmap_read(spi, msg);

        if (qspi->rx_chan) {
@@ -600,7 +604,7 @@ static int ti_qspi_start_transfer_one(struct spi_master *master,

        mutex_lock(&qspi->list_lock);

-       if (qspi->mmap_enabled)
+       if (qspi->mmap_spi_device)
                ti_qspi_disable_memory_map(spi);

        list_for_each_entry(t, &m->transfers, transfer_list) {
@@ -787,7 +791,7 @@ static int ti_qspi_probe(struct platform_device *pdev)
                        master->spi_flash_read = NULL;
                }
        }
-       qspi->mmap_enabled = false;
+       qspi->mmap_spi_device = NULL;

        ret = devm_spi_register_master(&pdev->dev, master);
        if (!ret)
--
2.7.4

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