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Subject[PATCH 2/8] fbdev: ssd1307fb: Unify init code and make controller configurable from device tree
Date
From: Thomas Niederprüm <niederp@physik.uni-kl.de>

This patches unifies the init code for the ssd130X chips and
adds device tree bindings to describe the hardware configuration
of the used controller. This gets rid of the magic bit values
used in the init code so far.

Signed-off-by: Thomas Niederprüm <niederp@physik.uni-kl.de>
---
.../devicetree/bindings/video/ssd1307fb.txt | 11 +
drivers/video/fbdev/ssd1307fb.c | 243 ++++++++++++++-------
2 files changed, 174 insertions(+), 80 deletions(-)

diff --git a/Documentation/devicetree/bindings/video/ssd1307fb.txt b/Documentation/devicetree/bindings/video/ssd1307fb.txt
index 7a12542..1230f68 100644
--- a/Documentation/devicetree/bindings/video/ssd1307fb.txt
+++ b/Documentation/devicetree/bindings/video/ssd1307fb.txt
@@ -15,6 +15,17 @@ Required properties:

Optional properties:
- reset-active-low: Is the reset gpio is active on physical low?
+ - solomon,segment-remap: Invert the order of data column to segment mapping
+ - solomon,offset: Map the display start line to one of COM0 - COM63
+ - solomon,contrast: Set initial contrast of the display
+ - solomon,prechargep1: Set the duration of the precharge period phase1
+ - solomon,prechargep2: Set the duration of the precharge period phase2
+ - solomon,com-alt: Enable/disable alternate COM pin configuration
+ - solomon,com-lrremap: Enable/disable left-right remap of COM pins
+ - solomon,com-invdir: Invert COM scan direction
+ - solomon,vcomh: Set VCOMH regulator voltage
+ - solomon,dclk-div: Set display clock divider
+ - solomon,dclk-frq: Set display clock frequency

[0]: Documentation/devicetree/bindings/pwm/pwm.txt

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 3d6611f..4f435aa 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -16,6 +16,9 @@
#include <linux/pwm.h>
#include <linux/delay.h>

+#define DEVID_SSD1306 6
+#define DEVID_SSD1307 7
+
#define SSD1307FB_DATA 0x40
#define SSD1307FB_COMMAND 0x80

@@ -40,20 +43,33 @@

struct ssd1307fb_par;

-struct ssd1307fb_ops {
- int (*init)(struct ssd1307fb_par *);
- int (*remove)(struct ssd1307fb_par *);
+struct ssd1307fb_deviceinfo {
+ int device_id;
+ u32 default_vcomh;
+ u32 default_dclk_div;
+ u32 default_dclk_frq;
};

struct ssd1307fb_par {
+ u32 com_alt;
+ u32 com_invdir;
+ u32 com_lrremap;
+ u32 contrast;
+ u32 dclk_div;
+ u32 dclk_frq;
+ struct ssd1307fb_deviceinfo *device_info;
struct i2c_client *client;
u32 height;
struct fb_info *info;
- struct ssd1307fb_ops *ops;
+ u32 offset;
u32 page_offset;
+ u32 prechargep1;
+ u32 prechargep2;
struct pwm_device *pwm;
u32 pwm_period;
int reset;
+ u32 seg_remap;
+ u32 vcomh;
u32 width;
};

@@ -254,127 +270,151 @@ static struct fb_deferred_io ssd1307fb_defio = {
.deferred_io = ssd1307fb_deferred_io,
};

-static int ssd1307fb_ssd1307_init(struct ssd1307fb_par *par)
+static int ssd1307fb_init(struct ssd1307fb_par *par)
{
int ret;
+ u32 precharge, dclk, com_invdir, compins;

- par->pwm = pwm_get(&par->client->dev, NULL);
- if (IS_ERR(par->pwm)) {
- dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
- return PTR_ERR(par->pwm);
- }
-
- par->pwm_period = pwm_get_period(par->pwm);
- /* Enable the PWM */
- pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
- pwm_enable(par->pwm);
-
- dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
- par->pwm->pwm, par->pwm_period);
-
- /* Map column 127 of the OLED to segment 0 */
- ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
- if (ret < 0)
- return ret;
-
- /* Turn on the display */
- ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
- if (ret < 0)
- return ret;
-
- return 0;
-}
-
-static int ssd1307fb_ssd1307_remove(struct ssd1307fb_par *par)
-{
- pwm_disable(par->pwm);
- pwm_put(par->pwm);
- return 0;
-}
+ if (par->device_info->device_id == DEVID_SSD1307) {
+ par->pwm = pwm_get(&par->client->dev, NULL);
+ if (IS_ERR(par->pwm)) {
+ dev_err(&par->client->dev, "Could not get PWM from device tree!\n");
+ return PTR_ERR(par->pwm);
+ }

-static struct ssd1307fb_ops ssd1307fb_ssd1307_ops = {
- .init = ssd1307fb_ssd1307_init,
- .remove = ssd1307fb_ssd1307_remove,
-};
+ par->pwm_period = pwm_get_period(par->pwm);
+ /* Enable the PWM */
+ pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
+ pwm_enable(par->pwm);

-static int ssd1307fb_ssd1306_init(struct ssd1307fb_par *par)
-{
- int ret;
+ dev_dbg(&par->client->dev, "Using PWM%d with a %dns period.\n",
+ par->pwm->pwm, par->pwm_period);
+ };

/* Set initial contrast */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
- ret = ret & ssd1307fb_write_cmd(par->client, 0x7f);
if (ret < 0)
return ret;

- /* Set COM direction */
- ret = ssd1307fb_write_cmd(par->client, 0xc8);
+ ret = ssd1307fb_write_cmd(par->client, par->contrast);
if (ret < 0)
return ret;

/* Set segment re-map */
- ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
+ if (par->seg_remap) {
+ ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
+ if (ret < 0)
+ return ret;
+ };
+
+ /* Set COM direction */
+ com_invdir = 0xc0 | (par->com_invdir & 0xf) << 3;
+ ret = ssd1307fb_write_cmd(par->client, com_invdir);
if (ret < 0)
return ret;

/* Set multiplex ratio value */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
- ret = ret & ssd1307fb_write_cmd(par->client, par->height - 1);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, par->height - 1);
if (ret < 0)
return ret;

/* set display offset value */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
- ret = ssd1307fb_write_cmd(par->client, 0x20);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, par->offset);
if (ret < 0)
return ret;

/* Set clock frequency */
+ dclk = (par->dclk_div & 0xf) | (par->dclk_frq & 0xf) << 4;
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
- ret = ret & ssd1307fb_write_cmd(par->client, 0xf0);
if (ret < 0)
return ret;

- /* Set precharge period in number of ticks from the internal clock */
+ ret = ssd1307fb_write_cmd(par->client, dclk);
+ if (ret < 0)
+ return ret;
+
+ /* Set precharge period in number of ticks from the internal clock*/
+ precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
- ret = ret & ssd1307fb_write_cmd(par->client, 0x22);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, precharge);
if (ret < 0)
return ret;

/* Set COM pins configuration */
+ compins = 0x02 | (par->com_alt & 0x1) << 4
+ | (par->com_lrremap & 0x1) << 5;
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
- ret = ret & ssd1307fb_write_cmd(par->client, 0x22);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, compins);
if (ret < 0)
return ret;

/* Set VCOMH */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
- ret = ret & ssd1307fb_write_cmd(par->client, 0x49);
if (ret < 0)
return ret;

- /* Turn on the DC-DC Charge Pump */
- ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
- ret = ret & ssd1307fb_write_cmd(par->client, 0x14);
+ ret = ssd1307fb_write_cmd(par->client, par->vcomh);
if (ret < 0)
return ret;

+ if (par->device_info->device_id == DEVID_SSD1306) {
+ /* Turn on the DC-DC Charge Pump */
+ ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, 0x14);
+ if (ret < 0)
+ return ret;
+ };
+
/* Switch to horizontal addressing mode */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
- ret = ret & ssd1307fb_write_cmd(par->client,
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client,
SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
if (ret < 0)
return ret;

+ /* Set column range */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
- ret = ret & ssd1307fb_write_cmd(par->client, 0x0);
- ret = ret & ssd1307fb_write_cmd(par->client, par->width - 1);
if (ret < 0)
return ret;

+ ret = ssd1307fb_write_cmd(par->client, 0x0);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, par->width - 1);
+ if (ret < 0)
+ return ret;
+
+ /* Set page range */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
- ret = ret & ssd1307fb_write_cmd(par->client, 0x0);
- ret = ret & ssd1307fb_write_cmd(par->client,
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, 0x0);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client,
par->page_offset + (par->height / 8) - 1);
if (ret < 0)
return ret;
@@ -387,18 +427,28 @@ static int ssd1307fb_ssd1306_init(struct ssd1307fb_par *par)
return 0;
}

-static struct ssd1307fb_ops ssd1307fb_ssd1306_ops = {
- .init = ssd1307fb_ssd1306_init,
+static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
+ .device_id = DEVID_SSD1306,
+ .default_vcomh = 0x20,
+ .default_dclk_div = 0,
+ .default_dclk_frq = 8,
+};
+
+static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
+ .device_id = DEVID_SSD1307,
+ .default_vcomh = 0x20,
+ .default_dclk_div = 1,
+ .default_dclk_frq = 12,
};

static const struct of_device_id ssd1307fb_of_match[] = {
{
.compatible = "solomon,ssd1306fb-i2c",
- .data = (void *)&ssd1307fb_ssd1306_ops,
+ .data = (void *)&ssd1307fb_ssd1306_deviceinfo,
},
{
.compatible = "solomon,ssd1307fb-i2c",
- .data = (void *)&ssd1307fb_ssd1307_ops,
+ .data = (void *)&ssd1307fb_ssd1307_deviceinfo,
},
{},
};
@@ -429,8 +479,8 @@ static int ssd1307fb_probe(struct i2c_client *client,
par->info = info;
par->client = client;

- par->ops = (struct ssd1307fb_ops *)of_match_device(ssd1307fb_of_match,
- &client->dev)->data;
+ par->device_info = (struct ssd1307fb_deviceinfo *)of_match_device(
+ ssd1307fb_of_match, &client->dev)->data;

par->reset = of_get_named_gpio(client->dev.of_node,
"reset-gpios", 0);
@@ -449,8 +499,40 @@ static int ssd1307fb_probe(struct i2c_client *client,
par->page_offset = 1;

vmem_size = par->width * par->height / 8;
+ if (of_property_read_u32(node, "solomon,segment-remap", &par->seg_remap))
+ par->seg_remap = 0;
+
+ if (of_property_read_u32(node, "solomon,offset", &par->offset))
+ par->offset = 0;
+
+ if (of_property_read_u32(node, "solomon,contrast", &par->contrast))
+ par->contrast = 128;
+
+ if (of_property_read_u32(node, "solomon,prechargep1", &par->prechargep1))
+ par->prechargep1 = 2;
+
+ if (of_property_read_u32(node, "solomon,prechargep2", &par->prechargep2))
+ par->prechargep2 = 2;
+
+ if (of_property_read_u32(node, "solomon,com-alt", &par->com_alt))
+ par->com_alt = 1;
+
+ if (of_property_read_u32(node, "solomon,com-lrremap", &par->com_lrremap))
+ par->com_lrremap = 0;
+
+ if (of_property_read_u32(node, "solomon,com-invdir", &par->com_invdir))
+ par->com_invdir = 0;
+
+ if (of_property_read_u32(node, "solomon,vcomh", &par->vcomh))
+ par->vcomh = par->device_info->default_vcomh;

vmem = devm_kzalloc(&client->dev, vmem_size, GFP_KERNEL);
+ if (of_property_read_u32(node, "solomon,dclk-div", &par->dclk_div))
+ par->dclk_div = par->device_info->default_dclk_div;
+
+ if (of_property_read_u32(node, "solomon,dclk-frq", &par->dclk_frq))
+ par->dclk_frq = par->device_info->default_dclk_frq;
+
if (!vmem) {
dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
ret = -ENOMEM;
@@ -499,11 +581,9 @@ static int ssd1307fb_probe(struct i2c_client *client,
gpio_set_value(par->reset, 1);
udelay(4);

- if (par->ops->init) {
- ret = par->ops->init(par);
- if (ret)
- goto reset_oled_error;
- }
+ ret = ssd1307fb_init(par);
+ if (ret)
+ goto reset_oled_error;

ret = register_framebuffer(info);
if (ret) {
@@ -516,8 +596,10 @@ static int ssd1307fb_probe(struct i2c_client *client,
return 0;

panel_init_error:
- if (par->ops->remove)
- par->ops->remove(par);
+ if (par->device_info->device_id == DEVID_SSD1307) {
+ pwm_disable(par->pwm);
+ pwm_put(par->pwm);
+ };
reset_oled_error:
fb_deferred_io_cleanup(info);
fb_alloc_error:
@@ -531,11 +613,12 @@ static int ssd1307fb_remove(struct i2c_client *client)
struct ssd1307fb_par *par = info->par;

unregister_framebuffer(info);
- if (par->ops->remove)
- par->ops->remove(par);
+ if (par->device_info->device_id == DEVID_SSD1307) {
+ pwm_disable(par->pwm);
+ pwm_put(par->pwm);
+ };
fb_deferred_io_cleanup(info);
framebuffer_release(info);
-
return 0;
}

--
2.1.1


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