From: gregkh@linuxfoundation.org
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Aswath Govindraju <a-govindraju@ti.com>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 11/11] misc: eeprom_93xx46: Add quirk to support Microchip 93LC46B eeprom
Date: Wed, 10 Mar 2021 14:25:10 +0100 [thread overview]
Message-ID: <20210310132320.755215994@linuxfoundation.org> (raw)
In-Reply-To: <20210310132320.393957501@linuxfoundation.org>
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
From: Aswath Govindraju <a-govindraju@ti.com>
[ Upstream commit f6f1f8e6e3eea25f539105d48166e91f0ab46dd1 ]
A dummy zero bit is sent preceding the data during a read transfer by the
Microchip 93LC46B eeprom (section 2.7 of[1]). This results in right shift
of data during a read. In order to ignore this bit a quirk can be added to
send an extra zero bit after the read address.
Add a quirk to ignore the zero bit sent before data by adding a zero bit
after the read address.
[1] - https://www.mouser.com/datasheet/2/268/20001749K-277859.pdf
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Link: https://lore.kernel.org/r/20210105105817.17644-3-a-govindraju@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/misc/eeprom/eeprom_93xx46.c | 15 +++++++++++++++
include/linux/eeprom_93xx46.h | 2 ++
2 files changed, 17 insertions(+)
diff --git a/drivers/misc/eeprom/eeprom_93xx46.c b/drivers/misc/eeprom/eeprom_93xx46.c
index d30deee1effd..30b490329f55 100644
--- a/drivers/misc/eeprom/eeprom_93xx46.c
+++ b/drivers/misc/eeprom/eeprom_93xx46.c
@@ -38,6 +38,10 @@ static const struct eeprom_93xx46_devtype_data atmel_at93c46d_data = {
EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH,
};
+static const struct eeprom_93xx46_devtype_data microchip_93lc46b_data = {
+ .quirks = EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE,
+};
+
struct eeprom_93xx46_dev {
struct spi_device *spi;
struct eeprom_93xx46_platform_data *pdata;
@@ -58,6 +62,11 @@ static inline bool has_quirk_instruction_length(struct eeprom_93xx46_dev *edev)
return edev->pdata->quirks & EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH;
}
+static inline bool has_quirk_extra_read_cycle(struct eeprom_93xx46_dev *edev)
+{
+ return edev->pdata->quirks & EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE;
+}
+
static int eeprom_93xx46_read(void *priv, unsigned int off,
void *val, size_t count)
{
@@ -99,6 +108,11 @@ static int eeprom_93xx46_read(void *priv, unsigned int off,
dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
cmd_addr, edev->spi->max_speed_hz);
+ if (has_quirk_extra_read_cycle(edev)) {
+ cmd_addr <<= 1;
+ bits += 1;
+ }
+
spi_message_init(&m);
t[0].tx_buf = (char *)&cmd_addr;
@@ -366,6 +380,7 @@ static void select_deassert(void *context)
static const struct of_device_id eeprom_93xx46_of_table[] = {
{ .compatible = "eeprom-93xx46", },
{ .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, },
+ { .compatible = "microchip,93lc46b", .data = µchip_93lc46b_data, },
{}
};
MODULE_DEVICE_TABLE(of, eeprom_93xx46_of_table);
diff --git a/include/linux/eeprom_93xx46.h b/include/linux/eeprom_93xx46.h
index 885f587a3555..affe4d1d7d4a 100644
--- a/include/linux/eeprom_93xx46.h
+++ b/include/linux/eeprom_93xx46.h
@@ -16,6 +16,8 @@ struct eeprom_93xx46_platform_data {
#define EEPROM_93XX46_QUIRK_SINGLE_WORD_READ (1 << 0)
/* Instructions such as EWEN are (addrlen + 2) in length. */
#define EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH (1 << 1)
+/* Add extra cycle after address during a read */
+#define EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE BIT(2)
/*
* optional hooks to control additional logic
--
2.30.1
next prev parent reply other threads:[~2021-03-10 13:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 13:24 [PATCH 4.9 00/11] 4.9.261-rc1 review gregkh
2021-03-10 13:25 ` [PATCH 4.9 01/11] btrfs: raid56: simplify tracking of Q stripe presence gregkh
2021-03-10 13:25 ` [PATCH 4.9 02/11] btrfs: fix raid6 qstripe kmap gregkh
2021-03-10 13:25 ` [PATCH 4.9 03/11] usbip: tools: fix build error for multiple definition gregkh
2021-03-10 13:25 ` [PATCH 4.9 04/11] ALSA: ctxfi: cthw20k2: fix mask on conf to allow 4 bits gregkh
2021-03-10 13:25 ` [PATCH 4.9 05/11] rsxx: Return -EFAULT if copy_to_user() fails gregkh
2021-03-10 13:25 ` [PATCH 4.9 06/11] dm table: fix iterate_devices based device capability checks gregkh
2021-03-10 13:25 ` [PATCH 4.9 07/11] dm table: fix DAX " gregkh
2021-03-10 13:25 ` [PATCH 4.9 08/11] iommu/amd: Fix sleeping in atomic in increase_address_space() gregkh
2021-03-10 13:25 ` [PATCH 4.9 09/11] platform/x86: acer-wmi: Add new force_caps module parameter gregkh
2021-03-10 13:25 ` [PATCH 4.9 10/11] PCI: Add function 1 DMA alias quirk for Marvell 9215 SATA controller gregkh
2021-03-10 13:25 ` gregkh [this message]
2021-03-10 22:00 ` [PATCH 4.9 00/11] 4.9.261-rc1 review Shuah Khan
2021-03-10 23:50 ` Guenter Roeck
2021-03-11 4:27 ` Florian Fainelli
2021-03-11 8:35 ` Naresh Kamboju
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