146 lines
4.7 KiB
Diff
146 lines
4.7 KiB
Diff
From 1848bb28f0579582f653ae95355b544fd8a51d1e Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>
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Date: Mon, 18 Sep 2023 18:11:01 +0200
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Subject: [PATCH 3/6] leds: turris-omnia: Do not use SMBUS calls
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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The leds-turris-omnia driver uses three function for I2C access:
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- i2c_smbus_write_byte_data() and i2c_smbus_read_byte_data(), which
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cause an emulated SMBUS transfer,
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- i2c_master_send(), which causes an ordinary I2C transfer.
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The Turris Omnia MCU LED controller is not semantically SMBUS, it
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operates as a simple I2C bus. It does not implement any of the SMBUS
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specific features, like PEC, or procedure calls, or anything. Moreover
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the I2C controller driver also does not implement SMBUS, and so the
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emulated SMBUS procedure from drivers/i2c/i2c-core-smbus.c is used for
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the SMBUS calls, which gives an unnecessary overhead.
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When I first wrote the driver, I was unaware of these facts, and I
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simply used the first function that worked.
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Drop the I2C SMBUS calls and instead use simple I2C transfers.
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Fixes: 089381b27abe ("leds: initial support for Turris Omnia LEDs")
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Signed-off-by: Marek Behún <kabel@kernel.org>
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Link: https://lore.kernel.org/r/20230918161104.20860-2-kabel@kernel.org
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Signed-off-by: Lee Jones <lee@kernel.org>
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---
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drivers/leds/leds-turris-omnia.c | 54 +++++++++++++++++++++++++-------
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1 file changed, 42 insertions(+), 12 deletions(-)
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--- a/drivers/leds/leds-turris-omnia.c
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+++ b/drivers/leds/leds-turris-omnia.c
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@@ -2,7 +2,7 @@
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/*
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* CZ.NIC's Turris Omnia LEDs driver
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*
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- * 2020 by Marek Behún <kabel@kernel.org>
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+ * 2020, 2023 by Marek Behún <kabel@kernel.org>
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*/
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#include <linux/i2c.h>
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@@ -41,6 +41,37 @@ struct omnia_leds {
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struct omnia_led leds[];
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};
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+static int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd, u8 val)
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+{
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+ u8 buf[2] = { cmd, val };
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+
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+ return i2c_master_send(client, buf, sizeof(buf));
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+}
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+
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+static int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
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+{
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+ struct i2c_msg msgs[2];
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+ u8 reply;
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+ int ret;
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+
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+ msgs[0].addr = client->addr;
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+ msgs[0].flags = 0;
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+ msgs[0].len = 1;
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+ msgs[0].buf = &cmd;
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+ msgs[1].addr = client->addr;
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+ msgs[1].flags = I2C_M_RD;
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+ msgs[1].len = 1;
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+ msgs[1].buf = &reply;
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+
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+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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+ if (likely(ret == ARRAY_SIZE(msgs)))
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+ return reply;
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+ else if (ret < 0)
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+ return ret;
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+ else
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+ return -EIO;
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+}
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+
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static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
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enum led_brightness brightness)
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{
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@@ -64,7 +95,7 @@ static int omnia_led_brightness_set_bloc
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if (buf[2] || buf[3] || buf[4])
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state |= CMD_LED_STATE_ON;
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- ret = i2c_smbus_write_byte_data(leds->client, CMD_LED_STATE, state);
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+ ret = omnia_cmd_write_u8(leds->client, CMD_LED_STATE, state);
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if (ret >= 0 && (state & CMD_LED_STATE_ON))
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ret = i2c_master_send(leds->client, buf, 5);
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@@ -114,9 +145,9 @@ static int omnia_led_register(struct i2c
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cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
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/* put the LED into software mode */
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- ret = i2c_smbus_write_byte_data(client, CMD_LED_MODE,
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- CMD_LED_MODE_LED(led->reg) |
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- CMD_LED_MODE_USER);
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+ ret = omnia_cmd_write_u8(client, CMD_LED_MODE,
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+ CMD_LED_MODE_LED(led->reg) |
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+ CMD_LED_MODE_USER);
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if (ret < 0) {
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dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np,
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ret);
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@@ -124,8 +155,8 @@ static int omnia_led_register(struct i2c
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}
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/* disable the LED */
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- ret = i2c_smbus_write_byte_data(client, CMD_LED_STATE,
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- CMD_LED_STATE_LED(led->reg));
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+ ret = omnia_cmd_write_u8(client, CMD_LED_STATE,
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+ CMD_LED_STATE_LED(led->reg));
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if (ret < 0) {
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dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
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return ret;
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@@ -158,7 +189,7 @@ static ssize_t brightness_show(struct de
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struct i2c_client *client = to_i2c_client(dev);
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int ret;
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- ret = i2c_smbus_read_byte_data(client, CMD_LED_GET_BRIGHTNESS);
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+ ret = omnia_cmd_read_u8(client, CMD_LED_GET_BRIGHTNESS);
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if (ret < 0)
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return ret;
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@@ -179,8 +210,7 @@ static ssize_t brightness_store(struct d
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if (brightness > 100)
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return -EINVAL;
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- ret = i2c_smbus_write_byte_data(client, CMD_LED_SET_BRIGHTNESS,
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- (u8)brightness);
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+ ret = omnia_cmd_write_u8(client, CMD_LED_SET_BRIGHTNESS, brightness);
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return ret < 0 ? ret : count;
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}
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@@ -238,8 +268,8 @@ static void omnia_leds_remove(struct i2c
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u8 buf[5];
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/* put all LEDs into default (HW triggered) mode */
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- i2c_smbus_write_byte_data(client, CMD_LED_MODE,
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- CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
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+ omnia_cmd_write_u8(client, CMD_LED_MODE,
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+ CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
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/* set all LEDs color to [255, 255, 255] */
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buf[0] = CMD_LED_COLOR;
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