64 lines
1.8 KiB
Diff
64 lines
1.8 KiB
Diff
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From 4aded6dfb23129b9bd03f7d37ff655912db5cfb0 Mon Sep 17 00:00:00 2001
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From: kitakar5525 <34676735+kitakar5525@users.noreply.github.com>
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Date: Fri, 6 Dec 2019 23:10:30 +0900
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Subject: [PATCH 10/10] surface3-spi dma
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---
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drivers/input/touchscreen/surface3_spi.c | 26 ++++++++++++++++++++++++
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1 file changed, 26 insertions(+)
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diff --git a/drivers/input/touchscreen/surface3_spi.c b/drivers/input/touchscreen/surface3_spi.c
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index ce4828b1415a..63b0b8ddf090 100644
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--- a/drivers/input/touchscreen/surface3_spi.c
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+++ b/drivers/input/touchscreen/surface3_spi.c
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@@ -25,6 +25,12 @@
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#define SURFACE3_REPORT_TOUCH 0xd2
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#define SURFACE3_REPORT_PEN 0x16
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+bool use_dma = false;
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+module_param(use_dma, bool, 0644);
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+MODULE_PARM_DESC(use_dma,
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+ "Disable DMA mode if you encounter touch input crash. "
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+ "(default: false, disabled to avoid crash)");
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+
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struct surface3_ts_data {
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struct spi_device *spi;
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struct gpio_desc *gpiod_rst[2];
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@@ -326,6 +332,13 @@ static int surface3_spi_create_pen_input(struct surface3_ts_data *data)
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return 0;
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}
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+static bool surface3_spi_can_dma(struct spi_controller *ctlr,
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+ struct spi_device *spi,
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+ struct spi_transfer *tfr)
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+{
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+ return use_dma;
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+}
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+
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static int surface3_spi_probe(struct spi_device *spi)
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{
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struct surface3_ts_data *data;
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@@ -368,6 +381,19 @@ static int surface3_spi_probe(struct spi_device *spi)
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if (error)
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return error;
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+ /*
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+ * Set up DMA
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+ *
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+ * TODO: Currently, touch input with DMA seems to be broken.
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+ * On 4.19 LTS, touch input will crash after suspend.
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+ * On recent stable kernel (at least after 5.1), touch input will crash after
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+ * the first touch. No problem with PIO on those kernels.
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+ * Maybe we need to configure DMA here.
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+ *
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+ * Link to issue: https://github.com/jakeday/linux-surface/issues/596
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+ */
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+ spi->controller->can_dma = surface3_spi_can_dma;
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+
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return 0;
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}
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--
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2.24.1
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