[RFC,5/5] Add KSZ8795 SPI driver
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Message ID 93AF473E2DA327428DE3D46B72B1E9FD41121A95@CHN-SV-EXMX02.mchp-main.com
State New, archived
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Series
  • [RFC,1/5] Add KSZ8795 switch driver support in Kconfig
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Commit Message

Tristram.Ha@microchip.com Sept. 7, 2017, 9:17 p.m. UTC
From: Tristram Ha <Tristram.Ha@microchip.com>

Add KSZ8795 switch support with SPI access.

Signed-off-by: Tristram Ha <Tristram.Ha@microchip.com>
---

Comments

Pavel Machek Sept. 8, 2017, 9:26 a.m. UTC | #1
Hi!


> +static int ksz_spi_read(struct ksz_device *dev, u32 reg, u8 *data,
> +			unsigned int len)
> +{
> +	struct spi_device *spi = dev->priv;
> +
> +	return ksz_spi_read_reg(spi, reg, data, len); }
> +
> +static int ksz_spi_read8(struct ksz_device *dev, u32 reg, u8 *val) {
> +	return ksz_spi_read(dev, reg, val, 1); }
> +
> +static int ksz_spi_read16(struct ksz_device *dev, u32 reg, u16 *val) {
> +	int ret = ksz_spi_read(dev, reg, (u8 *)val, 2);
> +
> +	if (!ret)
> +		*val = be16_to_cpu(*val);
> +
> +	return ret;
> +}

> +static int ksz_spi_read32(struct ksz_device *dev, u32 reg, u32 *val) {
> +	int ret = ksz_spi_read(dev, reg, (u8 *)val, 4);
> +
> +	if (!ret)
> +		*val = be32_to_cpu(*val);
> +
> +	return ret;
> +}

Please format according to CodingStyle. (Not only this.)

And this will be common for more drivers. Can it go to a header file
and be included...?


									Pavel
Tristram.Ha@microchip.com Sept. 8, 2017, 5:35 p.m. UTC | #2
> -----Original Message-----
> From: Pavel Machek [mailto:pavel@ucw.cz]
> Sent: Friday, September 08, 2017 2:26 AM
> To: Tristram Ha - C24268
> Cc: andrew@lunn.ch; muvarov@gmail.com; nathan.leigh.conrad@gmail.com;
> vivien.didelot@savoirfairelinux.com; f.fainelli@gmail.com;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Woojung Huh - C21699
> Subject: Re: [PATCH RFC 5/5] Add KSZ8795 SPI driver
> 
> Hi!
> 
> 
> > +static int ksz_spi_read(struct ksz_device *dev, u32 reg, u8 *data,
> > +			unsigned int len)
> > +{
> > +	struct spi_device *spi = dev->priv;
> > +
> > +	return ksz_spi_read_reg(spi, reg, data, len); }
> > +
> > +static int ksz_spi_read8(struct ksz_device *dev, u32 reg, u8 *val) {
> > +	return ksz_spi_read(dev, reg, val, 1); }
> > +
> > +static int ksz_spi_read16(struct ksz_device *dev, u32 reg, u16 *val) {
> > +	int ret = ksz_spi_read(dev, reg, (u8 *)val, 2);
> > +
> > +	if (!ret)
> > +		*val = be16_to_cpu(*val);
> > +
> > +	return ret;
> > +}
> 
> > +static int ksz_spi_read32(struct ksz_device *dev, u32 reg, u32 *val) {
> > +	int ret = ksz_spi_read(dev, reg, (u8 *)val, 4);
> > +
> > +	if (!ret)
> > +		*val = be32_to_cpu(*val);
> > +
> > +	return ret;
> > +}
> 
> Please format according to CodingStyle. (Not only this.)
> 
> And this will be common for more drivers. Can it go to a header file
> and be included...?
> 

Sorry about the formatting.  It seems my e-mail system needs to be checked
to make sure it does not auto-format the contents again.

About the SPI access functions they are the same for each driver except the
low level ksz_spi_read_reg and ksz_spi_write_reg.  The dev_io_ops structure
should contain only those 2 and ksz_spi_get and ksz_spi_set.

But that requires changing ksz_spi.c.  The idea was to keep the code of
KSZ9477 driver with little change as possible while introducing another driver.

The KSZ9477 driver will need to be updated with some of the code in KSZ8795
driver regarding port membership and MIB counter reading.
Andrew Lunn Sept. 8, 2017, 6:37 p.m. UTC | #3
> Sorry about the formatting.  It seems my e-mail system needs to be checked
> to make sure it does not auto-format the contents again.

I've never seen issues like this with git send-email. Please use
it. Email problems generally happen with the client, not the
backend. What client did you use to send these patches?

> About the SPI access functions they are the same for each driver except the
> low level ksz_spi_read_reg and ksz_spi_write_reg.  The dev_io_ops structure
> should contain only those 2 and ksz_spi_get and ksz_spi_set.
> 
> But that requires changing ksz_spi.c.  The idea was to keep the code of
> KSZ9477 driver with little change as possible while introducing another driver.

Maintainability is always the primary goal. If you need to change the
KSZ9477 code to make the whole more maintainable, do so. Just make it
lots of small, easy to review, obviously correct changes.

     Andrew
Pavel Machek Sept. 8, 2017, 9:55 p.m. UTC | #4
Hi!

> > Please format according to CodingStyle. (Not only this.)
> > 
> > And this will be common for more drivers. Can it go to a header file
> > and be included...?
> > 
> 
> Sorry about the formatting.  It seems my e-mail system needs to be checked
> to make sure it does not auto-format the contents again.
> 
> About the SPI access functions they are the same for each driver except the
> low level ksz_spi_read_reg and ksz_spi_write_reg.  The dev_io_ops structure
> should contain only those 2 and ksz_spi_get and ksz_spi_set.
> 
> But that requires changing ksz_spi.c.  The idea was to keep the code of
> KSZ9477 driver with little change as possible while introducing another driver.

So we change ksz_spi.c. Goal is to have clean code.

Thanks,
									Pavel

Patch
diff mbox series

diff --git a/drivers/net/dsa/microchip/ksz8795_spi.c b/drivers/net/dsa/microchip/ksz8795_spi.c
new file mode 100644
index 0000000..0f9c731
--- /dev/null
+++ b/drivers/net/dsa/microchip/ksz8795_spi.c
@@ -0,0 +1,229 @@ 
+/*
+ * Microchip KSZ8795 series register access through SPI
+ *
+ * Copyright (C) 2017 Microchip Technology Inc.
+ *	Tristram Ha <Tristram.Ha@microchip.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for 
+any
+ * purpose with or without fee is hereby granted, provided that the 
+above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL 
+WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE 
+FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY 
+DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN 
+AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 
+OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <asm/unaligned.h>
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+#include "ksz_priv.h"
+
+int ksz8795_switch_register(struct ksz_device *dev);
+
+/* SPI frame opcodes */
+#define KS_SPIOP_RD			3
+#define KS_SPIOP_WR			2
+
+#define SPI_ADDR_S			12
+#define SPI_ADDR_M			(BIT(SPI_ADDR_S) - 1)
+#define SPI_TURNAROUND_S		1
+
+/* Enough to read all switch registers. */
+#define SPI_TX_BUF_LEN			0x100
+
+static int ksz_spi_read_reg(struct spi_device *spi, u32 reg, u8 *val,
+			    unsigned int len)
+{
+	u16 txbuf;
+	int ret;
+
+	txbuf = reg & SPI_ADDR_M;
+	txbuf |= KS_SPIOP_RD << SPI_ADDR_S;
+	txbuf <<= SPI_TURNAROUND_S;
+	txbuf = cpu_to_be16(txbuf);
+
+	ret = spi_write_then_read(spi, &txbuf, 2, val, len);
+	return ret;
+}
+
+static int ksz_spi_read(struct ksz_device *dev, u32 reg, u8 *data,
+			unsigned int len)
+{
+	struct spi_device *spi = dev->priv;
+
+	return ksz_spi_read_reg(spi, reg, data, len); }
+
+static int ksz_spi_read8(struct ksz_device *dev, u32 reg, u8 *val) {
+	return ksz_spi_read(dev, reg, val, 1); }
+
+static int ksz_spi_read16(struct ksz_device *dev, u32 reg, u16 *val) {
+	int ret = ksz_spi_read(dev, reg, (u8 *)val, 2);
+
+	if (!ret)
+		*val = be16_to_cpu(*val);
+
+	return ret;
+}
+
+static int ksz_spi_read32(struct ksz_device *dev, u32 reg, u32 *val) {
+	int ret = ksz_spi_read(dev, reg, (u8 *)val, 4);
+
+	if (!ret)
+		*val = be32_to_cpu(*val);
+
+	return ret;
+}
+
+static int ksz_spi_write_reg(struct spi_device *spi, u32 reg, u8 *val,
+			     unsigned int len)
+{
+	u16 *txbuf = (u16 *)val;
+
+	*txbuf = reg & SPI_ADDR_M;
+	*txbuf |= (KS_SPIOP_WR << SPI_ADDR_S);
+	*txbuf <<= SPI_TURNAROUND_S;
+	*txbuf = cpu_to_be16(*txbuf);
+
+	return spi_write(spi, txbuf, 2 + len); }
+
+static int ksz_spi_write(struct ksz_device *dev, u32 reg, void *data,
+			 unsigned int len)
+{
+	struct spi_device *spi = dev->priv;
+
+	if (len > SPI_TX_BUF_LEN)
+		len = SPI_TX_BUF_LEN;
+	memcpy(&dev->txbuf[2], data, len);
+	return ksz_spi_write_reg(spi, reg, dev->txbuf, len); }
+
+static unsigned int ksz_spi_get(struct ksz_device *dev, u32 reg, void *data,
+				unsigned int len)
+{
+	int err;
+
+	err = ksz_spi_read(dev, reg, data, len);
+	if (err)
+		return 0;
+	return len;
+}
+
+static unsigned int ksz_spi_set(struct ksz_device *dev, u32 reg, void *data,
+				unsigned int len)
+{
+	int err;
+
+	err = ksz_spi_write(dev, reg, data, len);
+	if (err)
+		return 0;
+	return len;
+}
+
+static int ksz_spi_write8(struct ksz_device *dev, u32 reg, u8 value) {
+	return ksz_spi_write(dev, reg, &value, 1); }
+
+static int ksz_spi_write16(struct ksz_device *dev, u32 reg, u16 value) 
+{
+	value = cpu_to_be16(value);
+	return ksz_spi_write(dev, reg, &value, 2); }
+
+static int ksz_spi_write32(struct ksz_device *dev, u32 reg, u32 value) 
+{
+	value = cpu_to_be32(value);
+	return ksz_spi_write(dev, reg, &value, 4); }
+
+static const struct ksz_io_ops ksz_spi_ops = {
+	.read8 = ksz_spi_read8,
+	.read16 = ksz_spi_read16,
+	.read32 = ksz_spi_read32,
+	.write8 = ksz_spi_write8,
+	.write16 = ksz_spi_write16,
+	.write32 = ksz_spi_write32,
+	.get = ksz_spi_get,
+	.set = ksz_spi_set,
+};
+
+static int ksz_spi_probe(struct spi_device *spi) {
+	struct ksz_device *dev;
+	int ret;
+
+	dev = ksz_switch_alloc(&spi->dev, &ksz_spi_ops, spi);
+	if (!dev)
+		return -ENOMEM;
+
+	if (spi->dev.platform_data)
+		dev->pdata = spi->dev.platform_data;
+
+	dev->txbuf = devm_kzalloc(dev->dev, 2 + SPI_TX_BUF_LEN, GFP_KERNEL);
+
+	ret = ksz8795_switch_register(dev);
+
+	/* Main DSA driver may not be started yet. */
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, dev);
+
+	return 0;
+}
+
+static int ksz_spi_remove(struct spi_device *spi) {
+	struct ksz_device *dev = spi_get_drvdata(spi);
+
+	if (dev)
+		ksz_switch_remove(dev);
+
+	return 0;
+}
+
+static void ksz_spi_shutdown(struct spi_device *spi) {
+	struct ksz_device *dev = spi_get_drvdata(spi);
+
+	if (dev)
+		dev->dev_ops->reset(dev);
+}
+
+static const struct of_device_id ksz_dt_ids[] = {
+	{ .compatible = "microchip,ksz8795" },
+	{ .compatible = "microchip,ksz8765" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ksz_dt_ids);
+
+static struct spi_driver ksz_spi_driver = {
+	.driver = {
+		.name	= "ksz8795-switch",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(ksz_dt_ids),
+	},
+	.probe	= ksz_spi_probe,
+	.remove	= ksz_spi_remove,
+	.shutdown = ksz_spi_shutdown,
+};
+
+module_spi_driver(ksz_spi_driver);
+
+MODULE_AUTHOR("Tristram Ha <Tristram.Ha@microchip.com>"); 
+MODULE_DESCRIPTION("Microchip KSZ8795 Series Switch SPI Driver"); 
+MODULE_LICENSE("GPL");