Srinivas, El 26/10/15 a las 11:23, Srinivas Kandagatla escribió: > > > On 19/10/15 18:32, Ariel D'Alessandro wrote: >> This commit adds support for NXP LPC18xx EEPROM memory found in NXP > s/commit/patch OK. > >> LPC185x/3x and LPC435x/3x/2x/1x devices. >> >> EEPROM size is 16384 bytes and it can be entirely read and >> written/erased with 1 word (4 bytes) granularity. The last page >> (128 bytes) contains the EEPROM initialization data and is not writable. >> >> Erase/program time is less than 3ms. The EEPROM device requires a >> ~1500 kHz clock (min 800 kHz, max 1600 kHz) that is generated dividing >> the system bus clock by the division factor, contained in the divider >> register (minus 1 encoded). >> >> Signed-off-by: Ariel D'Alessandro <ariel@xxxxxxxxxxxxxxxxxxxx> >> --- >> drivers/nvmem/Kconfig | 9 ++ >> drivers/nvmem/Makefile | 2 + >> drivers/nvmem/lpc18xx_eeprom.c | 266 >> +++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 277 insertions(+) >> create mode 100644 drivers/nvmem/lpc18xx_eeprom.c >> [snip] >> diff --git a/drivers/nvmem/lpc18xx_eeprom.c >> b/drivers/nvmem/lpc18xx_eeprom.c >> new file mode 100644 >> index 0000000..ccdda66 >> --- /dev/null >> +++ b/drivers/nvmem/lpc18xx_eeprom.c >> @@ -0,0 +1,266 @@ >> +/* >> + * NXP LPC18xx/LPC43xx EEPROM memory NVMEM driver >> + * >> + * Copyright (c) 2015 Ariel D'Alessandro <ariel@xxxxxxxxxxxxxxxxx> >> + * >> + * This program is free software; you can redistribute it and/or >> modify it >> + * under the terms of the GNU General Public License version 2 as >> published by >> + * the Free Software Foundation. >> + */ >> + >> +#include <linux/clk.h> >> +#include <linux/device.h> >> +#include <linux/delay.h> >> +#include <linux/err.h> >> +#include <linux/io.h> >> +#include <linux/module.h> >> +#include <linux/nvmem-provider.h> >> +#include <linux/of_device.h> > Why do you need above? > > Also you should probably include > > #include <linux/platform_device.h> You're right. No need for of_device.h, only platform_device.h. > > >> +#include <linux/regmap.h> >> +#include <linux/reset.h> >> + >> +/* Registers */ >> +#define LPC18XX_EEPROM_AUTOPROG 0x00c >> +#define LPC18XX_EEPROM_AUTOPROG_WORD 0x1 >> + >> +#define LPC18XX_EEPROM_CLKDIV 0x014 >> + >> +#define LPC18XX_EEPROM_PWRDWN 0x018 >> +#define LPC18XX_EEPROM_PWRDWN_NO 0x0 >> +#define LPC18XX_EEPROM_PWRDWN_YES 0x1 >> + >> +/* Fixed page size (bytes) */ >> +#define LPC18XX_EEPROM_PAGE_SIZE 0x80 >> + >> +/* EEPROM device requires a ~1500 kHz clock (min 800 kHz, max 1600 >> kHz) */ >> +#define LPC18XX_EEPROM_CLOCK_HZ 1500000 >> + >> +struct lpc18xx_eeprom_dev { >> + struct clk *clk; >> + void __iomem *reg_base; >> + void __iomem *mem_base; >> + struct nvmem_device *nvmem; >> + unsigned reg_bytes; >> + unsigned val_bytes; >> +}; >> + >> +static inline void lpc18xx_eeprom_writel(struct lpc18xx_eeprom_dev >> *eeprom, >> + u32 reg, u32 val) >> +{ >> + writel(val, eeprom->reg_base + reg); >> +} > I don't have a strong feeling but, I see no point to have a wrapper for > writel which is only used in probe function. Well, to be correct it's also used in remove function. And I might call it in read()/write() functions to allow dynamic power on/off. I'd prefer keeping the wrapper. > >> + >> +static int lpc18xx_eeprom_gather_write(void *context, const void *reg, >> + size_t reg_size, const void *val, >> + size_t val_size) >> +{ >> + struct lpc18xx_eeprom_dev *eeprom = context; >> + unsigned int offset = *(u32 *)reg; >> + >> + /* 3 ms of erase/program time between each writing */ >> + while (val_size) { >> + writel(*(u32 *)val, eeprom->mem_base + offset); >> + usleep_range(3000, 4000); >> + val_size -= eeprom->val_bytes; >> + val += eeprom->val_bytes; >> + offset += eeprom->val_bytes; >> + } >> + >> + return 0; >> +} >> + >> +static int lpc18xx_eeprom_write(void *context, const void *data, >> size_t count) >> +{ >> + struct lpc18xx_eeprom_dev *eeprom = context; >> + unsigned int offset = eeprom->reg_bytes; >> + >> + if (count <= offset) >> + return -EINVAL; >> + >> + > unnecessary new line. ACK. > >> + return lpc18xx_eeprom_gather_write(context, data, eeprom->reg_bytes, >> + data + offset, count - offset); >> +} >> + [snip] >> + >> +static int lpc18xx_eeprom_probe(struct platform_device *pdev) >> +{ >> + struct lpc18xx_eeprom_dev *eeprom; >> + struct device *dev = &pdev->dev; >> + struct reset_control *rst; >> + unsigned long clk_rate; >> + struct regmap *regmap; >> + struct resource *res; >> + int ret; >> + >> + eeprom = devm_kzalloc(dev, sizeof(*eeprom), GFP_KERNEL); >> + if (!eeprom) >> + return -ENOMEM; >> + >> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg"); >> + eeprom->reg_base = devm_ioremap_resource(dev, res); >> + if (IS_ERR(eeprom->reg_base)) >> + return PTR_ERR(eeprom->reg_base); >> + >> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem"); >> + eeprom->mem_base = devm_ioremap_resource(dev, res); >> + if (IS_ERR(eeprom->mem_base)) >> + return PTR_ERR(eeprom->mem_base); >> + >> + eeprom->clk = devm_clk_get(&pdev->dev, "eeprom"); >> + if (IS_ERR(eeprom->clk)) { >> + dev_err(&pdev->dev, "failed to get eeprom clock\n"); >> + return PTR_ERR(eeprom->clk); >> + } >> + >> + ret = clk_prepare_enable(eeprom->clk); >> + if (ret < 0) { >> + dev_err(dev, "failed to prepare/enable eeprom clk: %d\n", ret); >> + return ret; >> + } >> + >> + rst = devm_reset_control_get(dev, NULL); >> + if (IS_ERR(rst)) { >> + dev_err(dev, "failed to get reset: %ld\n", PTR_ERR(rst)); >> + ret = PTR_ERR(rst); >> + goto err_clk; >> + } >> + >> + ret = reset_control_deassert(rst); >> + if (ret < 0) { >> + dev_err(dev, "failed to deassert reset: %d\n", ret); >> + goto err_clk; >> + } >> + >> + eeprom->val_bytes = lpc18xx_regmap_config.val_bits / 8; >> + eeprom->reg_bytes = lpc18xx_regmap_config.reg_bits / 8; >> + >> + /* >> + * Clock rate is generated by dividing the system bus clock by the >> + * division factor, contained in the divider register (minus 1 >> encoded). >> + */ >> + clk_rate = clk_get_rate(eeprom->clk); >> + clk_rate = DIV_ROUND_UP(clk_rate, LPC18XX_EEPROM_CLOCK_HZ) - 1; >> + lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_CLKDIV, clk_rate); >> + >> + /* >> + * Writing a single word to the page will start the erase/program >> cycle >> + * automatically >> + */ >> + lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_AUTOPROG, >> + LPC18XX_EEPROM_AUTOPROG_WORD); >> + >> + lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN, >> + LPC18XX_EEPROM_PWRDWN_NO); > > Any reason not power up/dowm dynamically in > lpc18xx_eeprom_write()/lpc18xx_eeprom_read(). > > This can potentially save some power. That sounds good. I'll add this feature and check that it works properly. > >> + >> + lpc18xx_regmap_config.max_register = resource_size(res) - 1; >> + lpc18xx_regmap_config.writeable_reg = lpc18xx_eeprom_writeable_reg; >> + lpc18xx_regmap_config.readable_reg = lpc18xx_eeprom_readable_reg; >> + >> + regmap = devm_regmap_init(dev, &lpc18xx_eeprom_bus, eeprom, >> + &lpc18xx_regmap_config); >> + if (IS_ERR(regmap)) { >> + dev_err(dev, "regmap init failed: %ld\n", PTR_ERR(regmap)); >> + ret = PTR_ERR(regmap); >> + goto err_clk; >> + } >> + >> + lpc18xx_nvmem_config.dev = dev; >> + >> + eeprom->nvmem = nvmem_register(&lpc18xx_nvmem_config); >> + if (IS_ERR(eeprom->nvmem)) { >> + ret = PTR_ERR(eeprom->nvmem); >> + goto err_clk; >> + } >> + >> + platform_set_drvdata(pdev, eeprom); >> + >> + return 0; >> + >> +err_clk: > > Should this error path also include power down/reset assert the eeprom? Yes, I'll add another cleanup routine. > >> + clk_disable_unprepare(eeprom->clk); >> + >> + return ret; >> +} >> + >> +static int lpc18xx_eeprom_remove(struct platform_device *pdev) >> +{ >> + struct lpc18xx_eeprom_dev *eeprom = platform_get_drvdata(pdev); >> + >> + lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN, >> + LPC18XX_EEPROM_PWRDWN_YES); >> + >> + clk_disable_unprepare(eeprom->clk); >> + >> + return nvmem_unregister(eeprom->nvmem); > > Same comment as Joachim, should the reset be asserted too? No. That would cause a reset, disabling EEPROM power down mode. -- Ariel D'Alessandro, VanguardiaSur www.vanguardiasur.com.ar -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html