* [PATCH 2/3] backlight: tdo24m: add the reset line gpio
2017-10-06 19:58 [PATCH 1/3] backlight: tdo24m: fix the spi cs between transfers Robert Jarzmik
@ 2017-10-06 19:58 ` Robert Jarzmik
2017-10-06 19:58 ` [PATCH 3/3] backlight: tdo24m: add model and status sysfs entries Robert Jarzmik
2017-10-09 11:14 ` [PATCH 1/3] backlight: tdo24m: fix the spi cs between transfers Daniel Thompson
2 siblings, 0 replies; 5+ messages in thread
From: Robert Jarzmik @ 2017-10-06 19:58 UTC (permalink / raw)
To: Lee Jones, Daniel Thompson, Jingoo Han, Bartlomiej Zolnierkiewicz
Cc: linux-fbdev, linux-kernel, Robert Jarzmik
The Toppoly panels have a global reset line. Add an optional gpio
control for this line, for platforms which have the ability to drive it.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
drivers/video/backlight/tdo24m.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/video/backlight/tdo24m.c b/drivers/video/backlight/tdo24m.c
index e4bd63e9db6b..e4b2dfabf192 100644
--- a/drivers/video/backlight/tdo24m.c
+++ b/drivers/video/backlight/tdo24m.c
@@ -10,6 +10,7 @@
*/
#include <linux/module.h>
+#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/device.h>
@@ -32,6 +33,7 @@ struct tdo24m {
struct spi_message msg;
struct spi_transfer xfer;
uint8_t *buf;
+ struct gpio_desc *xres;
int (*adj_mode)(struct tdo24m *lcd, int mode);
int color_invert;
@@ -364,6 +366,7 @@ static int tdo24m_probe(struct spi_device *spi)
if (lcd->buf = NULL)
return -ENOMEM;
+ lcd->xres = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_LOW);
m = &lcd->msg;
x = &lcd->xfer;
--
2.11.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 3/3] backlight: tdo24m: add model and status sysfs entries
2017-10-06 19:58 [PATCH 1/3] backlight: tdo24m: fix the spi cs between transfers Robert Jarzmik
2017-10-06 19:58 ` [PATCH 2/3] backlight: tdo24m: add the reset line gpio Robert Jarzmik
@ 2017-10-06 19:58 ` Robert Jarzmik
2017-10-09 11:14 ` [PATCH 1/3] backlight: tdo24m: fix the spi cs between transfers Daniel Thompson
2 siblings, 0 replies; 5+ messages in thread
From: Robert Jarzmik @ 2017-10-06 19:58 UTC (permalink / raw)
To: Lee Jones, Daniel Thompson, Jingoo Han, Bartlomiej Zolnierkiewicz
Cc: linux-fbdev, linux-kernel, Robert Jarzmik
Add entries to query the panel ASIC to acquire the model number and the
status field. This comes in handy to check that the SPI connection is
functional and that the panel's firmware is alive.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
drivers/video/backlight/tdo24m.c | 73 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 72 insertions(+), 1 deletion(-)
diff --git a/drivers/video/backlight/tdo24m.c b/drivers/video/backlight/tdo24m.c
index e4b2dfabf192..113c28c2145a 100644
--- a/drivers/video/backlight/tdo24m.c
+++ b/drivers/video/backlight/tdo24m.c
@@ -22,7 +22,7 @@
#define POWER_IS_ON(pwr) ((pwr) <= FB_BLANK_NORMAL)
-#define TDO24M_SPI_BUFF_SIZE (4)
+#define TDO24M_SPI_BUFF_SIZE (6)
#define MODE_QVGA 0
#define MODE_VGA 1
@@ -33,6 +33,7 @@ struct tdo24m {
struct spi_message msg;
struct spi_transfer xfer;
uint8_t *buf;
+ uint8_t *rx_buf;
struct gpio_desc *xres;
int (*adj_mode)(struct tdo24m *lcd, int mode);
@@ -219,6 +220,30 @@ static int tdo24m_writes(struct tdo24m *lcd, const uint32_t *array)
return err;
}
+static int tdo24m_read_command(struct tdo24m *lcd, unsigned char cmd,
+ unsigned int *id)
+{
+ struct spi_transfer *x = &lcd->xfer;
+ int err = 0, i;
+
+ lcd->buf[0] = cmd >> 1;
+ lcd->buf[1] = (cmd & 0x01) << 7;
+ lcd->buf[2] = 0;
+ lcd->buf[3] = 0;
+ lcd->buf[4] = 0;
+
+ x->len = 6;
+ err = spi_sync(lcd->spi_dev, &lcd->msg);
+
+ for (i = 0; i < sizeof(lcd->rx_buf) - 2; i++)
+ lcd->rx_buf[i] = (lcd->rx_buf[i + 1] << 2) |
+ (lcd->rx_buf[i + 2] >> 6);
+ *id = (lcd->rx_buf[0] << 24) | (lcd->rx_buf[1] << 16) |
+ (lcd->rx_buf[2] << 8) | lcd->rx_buf[3];
+
+ return err;
+}
+
static int tdo24m_adj_mode(struct tdo24m *lcd, int mode)
{
switch (mode) {
@@ -327,6 +352,43 @@ static int tdo24m_set_mode(struct lcd_device *ld, struct fb_videomode *m)
return lcd->adj_mode(lcd, mode);
}
+static ssize_t tdo24m_model_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct tdo24m *lcd = dev_get_drvdata(dev);
+ uint32_t data;
+ int err;
+
+ err = tdo24m_read_command(lcd, 0x04, &data);
+ if (!err)
+ return snprintf(buf, PAGE_SIZE, "0x%06x\n", data >> 8);
+
+ return err;
+}
+static DEVICE_ATTR_RO(tdo24m_model);
+
+static ssize_t tdo24m_status_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct tdo24m *lcd = dev_get_drvdata(dev);
+ uint32_t data;
+ int err;
+
+ err = tdo24m_read_command(lcd, 0x09, &data);
+ if (!err)
+ return snprintf(buf, PAGE_SIZE, "0x%08x\n", data);
+
+ return err;
+}
+static DEVICE_ATTR_RO(tdo24m_status);
+
+static struct attribute *tdo24m_attrs[] = {
+ &dev_attr_tdo24m_model.attr,
+ &dev_attr_tdo24m_status.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(tdo24m);
+
static struct lcd_ops tdo24m_ops = {
.get_power = tdo24m_get_power,
.set_power = tdo24m_set_power,
@@ -365,6 +427,9 @@ static int tdo24m_probe(struct spi_device *spi)
lcd->buf = devm_kzalloc(&spi->dev, TDO24M_SPI_BUFF_SIZE, GFP_KERNEL);
if (lcd->buf = NULL)
return -ENOMEM;
+ lcd->rx_buf = devm_kzalloc(&spi->dev, TDO24M_SPI_BUFF_SIZE, GFP_KERNEL);
+ if (lcd->rx_buf = NULL)
+ return -ENOMEM;
lcd->xres = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_LOW);
m = &lcd->msg;
@@ -374,6 +439,7 @@ static int tdo24m_probe(struct spi_device *spi)
x->cs_change = 0;
x->tx_buf = &lcd->buf[0];
+ x->rx_buf = &lcd->rx_buf[0];
spi_message_add_tail(x, m);
switch (model) {
@@ -396,6 +462,11 @@ static int tdo24m_probe(struct spi_device *spi)
return PTR_ERR(lcd->lcd_dev);
spi_set_drvdata(spi, lcd);
+
+ err = devm_device_add_groups(&spi->dev, tdo24m_groups);
+ if (err)
+ return err;
+
err = tdo24m_power(lcd, FB_BLANK_UNBLANK);
if (err)
return err;
--
2.11.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH 1/3] backlight: tdo24m: fix the spi cs between transfers
2017-10-06 19:58 [PATCH 1/3] backlight: tdo24m: fix the spi cs between transfers Robert Jarzmik
2017-10-06 19:58 ` [PATCH 2/3] backlight: tdo24m: add the reset line gpio Robert Jarzmik
2017-10-06 19:58 ` [PATCH 3/3] backlight: tdo24m: add model and status sysfs entries Robert Jarzmik
@ 2017-10-09 11:14 ` Daniel Thompson
2017-10-09 18:30 ` Robert Jarzmik
2 siblings, 1 reply; 5+ messages in thread
From: Daniel Thompson @ 2017-10-09 11:14 UTC (permalink / raw)
To: Robert Jarzmik, Lee Jones, Jingoo Han, Bartlomiej Zolnierkiewicz
Cc: linux-fbdev, linux-kernel
On 06/10/17 20:58, Robert Jarzmik wrote:
> Currently the LCD display (TD035S) on the cm-x300 platform is broken and
> remains blank.
>
> The TD0245S specification requires that the chipselect is toggled
> between commands sent to the panel. This was also the purpose of the
> former patch of commit f64dcac0b124 ("backlight: tdo24m: ensure chip
> select changes between transfers").
>
> Unfortunately, the "cs_change" field of a SPI transfer is
> misleading. Its true meaning is that for a SPI message holding multiple
> transfers, the chip select is toggled between each transfer, but for the
> last transfer it remains asserted.
>
> In this driver, all the SPI messages contain exactly one transfer, which
> means that each transfer is the last of its message, and as a
> consequence the chip select is never toggled.
>
> This fix makes the TD035S work again on a cm-x300 board.
>
> Fixes: f64dcac0b124 ("backlight: tdo24m: ensure chip select changes
> between transfers")
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
I'm a tiny bit worried about see-saw bug fixing here but nevertheless
this change looks correct to me.
Mike's change was eight years ago and it is reasonable to hope that the
patch was really just working around a (hopefully long fixed) bug in the
SPI driver!
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
> drivers/video/backlight/tdo24m.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/video/backlight/tdo24m.c b/drivers/video/backlight/tdo24m.c
> index eab1f842f9c0..e4bd63e9db6b 100644
> --- a/drivers/video/backlight/tdo24m.c
> +++ b/drivers/video/backlight/tdo24m.c
> @@ -369,7 +369,7 @@ static int tdo24m_probe(struct spi_device *spi)
>
> spi_message_init(m);
>
> - x->cs_change = 1;
> + x->cs_change = 0;
> x->tx_buf = &lcd->buf[0];
> spi_message_add_tail(x, m);
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread